return value - Page 334

Are nullable types preferable to magic numbers?

- by Matt H

I have been having a little bit of a debate with a coworker lately. We are specifically using C#, but this could apply to any language with nullable types. Say for example you have a value that represents a maximum. However, this maximum value is optional. I argue that a nullable number would be preferable. My coworker favors the use of zero, citing precedent. Granted, things like network sockets have often used zero to represent an unlimited timeout. If I were to write code dealing with sockets today, I would personally use a nullable value, since I feel it would better represent the fact that there is NO timeout. Which representation is better? Both require a condition checking for the value meaning "none", but I believe that a nullable type conveys the intent a little bit better.

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Setting up a Carousel Component in ADF Mobile

- by Shay Shmeltzer

The Carousel component is one of the slickier ways of showing collections of data, and on a mobile device it works really great with the finger swipe gesture. Using the Carousel component in ADF Mobile is similar to using it in regular web ADF applications, with one major change - right now you can't drag a collection from the data control palette and drop it as a carousel. So here is a quick work around for that, and details about setting up carousels in your application. First thing you'll need is a data control that returns an array of records. In my demo I'm using the Emps collection that you can get from following this tutorial. Then you drag the emps and drop it in your amx page as an ADF mobile iterator. We are doing this as a short cut to getting the right binding needed for a carousel in our page. If you look now in your page's binding you'll see something like this: You can now remark the whole iterator code in your page's source. Next let's add the carousel From the component palette drag the carousel (from the data view category) to the page. Next drag a carousel item and drop it in the nodestamp facet of the carousel. Now we'll hook up the carousel to the binding we got from the iterator - this is quite simple just copy the var and value attributes from the iterator tag to the carousel tag: var="row" value="#{bindings.emps.collectionModel}" Next drop a panelForm, or another layout panel in to the carousel item. Into that panelForm you can now drop items and bind their value property to row.attributeNames - basically copying the way it is in the fields in the iterator for example: value="#{row.hireDate}". By the way you can also copy other attributes like the label. And that's it. Your code should end up looking something like this: <amx:carousel id="c1" var="row" value="#{bindings.emps.collectionModel}"> <amx:facet name="nodeStamp"> <amx:carouselItem id="ci1"> <amx:panelFormLayout id="pfl1"> <amx:inputText label="#{bindings.emps.hints.salary.label}" value="#{row.salary}" id="it1"/> <amx:inputText label="#{bindings.emps.hints.name.label}" value="#{row.name}" id="it2"/> </amx:panelFormLayout> </amx:carouselItem> </amx:facet> </amx:carousel> And when you run your application it will look like this:

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What does this piece of code in C++ mean? [closed]

- by user1838418

const double pi = 3.141592653589793; const angle rightangle = pi/2; inline angle deg2rad(angle degree) { return degree * rightangle / 90.; } angle function1() { return rightangle * ( ((double) rand()) / ((double) RAND_MAX) - .5 ); } bool setmargin(angle theta, angle phi, angle margin) { return (theta > phi-margin && theta < phi+margin); } Please help me. I'm new to C++

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Supply Chain Professionals: Get Connected, Stay Current

- by Stephen Slade

Each day, thousands of supply chain professionals like you face challenges to lower inventory, collaborate better with distant partners and stretch the value from depleting resources. Meeting ever-changing customer demands, with products getting to market faster and lifecycles shortning, the challenges grow even faster. How do we respond? It’s amazing how much material is available on-line for our supply chain community. Many want to stay informed and be connected with better information. One great way to stay current on rapidly changing markets and solutions is to subscribe to the Value Chain Transformation newsletter published quarterly by the content staff at Oracle. In this edition, there’s a few great articles on Cloud, OpenWorld, events and products with solid customer testimony to share with you, our supply chain community. Below is the link to the newsletter and how to subscribe Sept ‘12 Value Chain Newsletter: http://www.oracle.com/us/corporate/newsletter/archive/value-chain-and-procurement-1559127.html Subscription information is located at the bottom of the newsletter.

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XenApp 6.5 – How to create and set a Policy using PowerShell

- by Waclaw Chrabaszcz

Originally posted on: http://geekswithblogs.net/Wchrabaszcz/archive/2013/06/20/xenapp-6.5--how-to-create-and-set-a-policy.aspxHere is my homework Add-PSSnapin -name Citrix.Common.* -ErrorAction SilentlyContinueNew-Item LocalFarmGpo:\User\MyPolicycd LocalFarmGpo:\User\MyPolicy\Settings\ICA\SecuritySet-ItemProperty .\MinimumEncryptionLevel State EnabledSet-ItemProperty .\MinimumEncryptionLevel Value Bits128cd LocalFarmGpo:\User\MyPolicy\Filters\WorkerGroupNew-Item -Name "All Servers" -Value "All Servers"Set-ItemProperty LocalFarmGpo:\User\MyPolicy -Name Priority -Value 2 So cute …

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Is this the right strategy to convert an in-level order binary tree to a doubly linked list?

- by Ankit Soni

So I recently came across this question - Make a function that converts a in-level-order binary tree into a doubly linked list. Apparently, it's a common interview question. This is the strategy I had - Simply do a pre-order traversal of the tree, and instead of returning a node, return a list of nodes, in the order in which you traverse them. i.e return a list, and append the current node to the list at each point. For the base case, return the node itself when you are at a leaf. so you would say left = recursive_function(node.left) right = recursive_function(node.right) return(left.append(node.data)).append(right);` Is this the right approach?

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What does it mean to treat data as an asset?

What does it mean to treat data as an asset? When considering this concept, we must define what data is and how it can be considered an asset. Data can easily be defined as a collection of stored truths that are open to interpretation and manipulation. Expanding on this definition, data can be viewed as a set of captured facts, measurements, and ideas used to make decisions. Furthermore, InvestorsWords.com defines asset as any item of economic value owned by an individual or corporation. Now let’s apply this definition of asset to our definition of data, and ask the following question. Can facts, measurements and ideas be items that are of economic value owned by an individual or corporation? The obvious answer is yes; data can be bought and sold like commodities or analyzed to make smarter business decisions. We can look at the economic value of data in one of two ways. First, data can be sold as a commodity that can take the form of goods like eBooks, Training, Music, Movies, and so on. Customers are willing to pay to gain access to this data for their consumption. This directly implies that there is an economic value for data in the form of a commodity because customers see a value in obtaining it. Secondly data can be used in making smarter business decisions that allow for companies to become more profitable and/or reduce their potential for risk in regards to how they operate. In the past I have worked at companies where we had to analyze previous sales activities in conjunction with current activities to determine how the company was preforming for the quarter. In addition trends can be formulated based on existing data that allow companies to forecast data so that they can make strategic business decisions based sound forecasted data. Companies that truly value their data are constantly trying to grow and upgrade their data and supporting applications because it is the life blood of a company. If we look at an eBook retailer for example, imagine if they lost all of their data. They would be in essence forced out of business because they would have nothing to sell. In turn, if we look at a company that was using data to facilitate better decision making processes and they lost all of their data then they could be losing potential revenue and/ or increasing the company’s losses by making important business decisions virtually in the dark compared to when they were made on solid data.

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Best practice with pyGTK and Builder XML files

- by Phoenix87

I usually design GUI with Glade, thus producing a series of Builder XML files (one such file for each application window). Now my idea is to define a class, e.g. MainWindow, that inherits from gtk.Window and that implements all the signal handlers for the application main window. The problem is that when I retrieve the main window from the containing XML file, it is returned as a gtk.Window instance. The solution I have adopted so far is the following: I have defined a class "Window" in the following way class Window(): def __init__(self, win_name): builder = gtk.Builder() self.builder = builder builder.add_from_file("%s.glade" % win_name) self.window = builder.get_object(win_name) builder.connect_signals(self) def run(self): return self.window.run() def show_all(self): return self.window.show_all() def destroy(self): return self.window.destroy() def child(self, name): return self.builder.get_object(name) In the actual application code I have then defined a new class, say MainWindow, that inherits frow Window, and that looks like class Main(Window): def __init__(self): Window.__init__(self, "main") ### Signal handlers ##################################################### def on_mnu_file_quit_activated(self, widget, data = None): ... The string "main" refers to the main window, called "main", which resides into the XML Builder file "main.glade" (this is a sort of convention I decided to adopt). So the question is: how can I inherit from gtk.Window directly, by defining, say, the class Foo(gtk.Window), and recast the return value of builder.get_object(win_name) to Foo?

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Agile Executives

- by Robert May

Over the years, I have experienced many different styles of software development. In the early days, most of the development was Waterfall development. In the last few years, I’ve become an advocate of Scrum. As I talked about last month, many people have misconceptions about what Scrum really is. The reason why we do Scrum at Veracity is because of the difference it makes in the life of the team doing Scrum. Software is for people, and happy motivated people will build better software. However, not all executives understand Scrum and how to get the information from development teams that use Scrum. I think that these executives need a support system for managing Agile teams. Historical Software Management When Henry Ford pioneered the assembly line, I doubt he realized the impact he’d have on Management through the ages. Historically, management was about managing the process of building things. The people were just cogs in that process. Like all cogs, they were replaceable. Unfortunately, most of the software industry followed this same style of management. Many of today’s senior managers learned how to manage companies before software was a significant influence on how the company did business. Software development is a very creative process, but too many managers have treated it like an assembly line. Idea’s go in, working software comes out, and we just have to figure out how to make sure that the ideas going in are perfect, then the software will be perfect. Lean Manufacturing In the manufacturing industry, Lean manufacturing has revolutionized Henry Ford’s assembly line. Derived from the Toyota process, Lean places emphasis on always providing value for the customer. Anything the customer wouldn’t be willing to pay for is wasteful. Agile is based on similar principles. We’re building software for people, and anything that isn’t useful to them doesn’t add value. Waterfall development would have teams build reams and reams of documentation about how the software should work. Agile development dispenses with this work because excessive documentation doesn’t add value. Instead, teams focus on building documentation only when it truly adds value to the customer. Many other Agile principals are similar. Playing Catch-up Just like in the manufacturing industry, many managers in the software industry have yet to understand the value of the principles of Lean and Agile. They think they can wrap the uncertainties of software development up in a nice little package and then just execute, usually followed by failure. They spend a great deal of time and money trying to exactly predict the future. That expenditure of time and money doesn’t add value to the customer. Managers that understand that Agile know that there is a better way. They will instead focus on the priorities of the near term in detail, and leave the future to take care of itself. They have very detailed two week plans with less detailed quarterly plans. These plans are guided by a general corporate strategy that doesn’t focus on the exact implementation details. These managers also think in smaller features rather than large functionality. This adds a great deal of value to customers, since the features that matter most are the ones that the team focuses on in the near term and then are able to deliver to the customers that are paying for them. Agile managers also realize that stale software is very costly. They know that keeping the technology in their software current is much less expensive and risky than large rewrites that occur infrequently and schedule time in each release for refactoring of the existing software. Agile Executives Even though Agile is a better way, I’ve still seen failures using the Agile process. While some of these failures can be attributed to the team, most of them are caused by managers, not the team. Managers fail to understand what Agile is, how it works, and how to get the information that they need to make good business decisions. I think this is a shame. I’m very pleased that Veracity understands this problem and is trying to do something about it. Veracity is a key sponsor of Agile Executives. In fact, Galen is this year’s acting president for Agile Executives. The purpose of Agile Executives is to help managers better manage Agile teams and see better success. Agile Executives is trying to build a community of executives that range from managers interested in Agile to managers that have successfully adopted Agile. Together, these managers can form a community of support and ideas that will help make Agile teams more successful. Helping Your Team You can help too! Talk with your manager and get them involved in Agile Executives. Help Veracity build the community. If your manager understands Agile better, he’ll understand how to help his teams, which will result in software that adds more value for customers. If you have any questions about how you can be involved, please let me know. Technorati Tags: Agile,Agile Executives

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What can procs and lambdas do that functions can't in ruby

- by SecurityGate

I've been working in Ruby for the last couple weeks, and I've come to the subject of procs, lambdas and blocks. After reading a fair share of examples from a variety of sources, I don't how they're much different from small, specialized functions. It's entirely possible that the examples I've read aren't showing the power behind procs and lambdas. def zero_function(x) x = x.to_s if x.length == 1 return x = "0" + x else return x end end zero_lambda = lambda {|x| x = x.to_s if x.length == 1 return x = "0" + x else return x end } zero_proc = Proc.new {|x| x = x.to_s if x.length == 1 puts x = "0" + x else puts x end } puts zero_function(4) puts zero_lambda.call(3) zero_proc.call(2) This function, proc, and lambda do the exact same thing, just slightly different. Is there any reason to choose one over another?

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Code contracts and inheritance

- by DigiMortal

In my last posting about code contracts I introduced you how to force code contracts to classes through interfaces. In this posting I will go step further and I will show you how code contracts work in the case of inherited classes. As a first thing let’s take a look at my interface and code contracts. [ContractClass(typeof(ProductContracts))] public interface IProduct { int Id { get; set; } string Name { get; set; } decimal Weight { get; set; } decimal Price { get; set; } } [ContractClassFor(typeof(IProduct))] internal sealed class ProductContracts : IProduct { private ProductContracts() { } int IProduct.Id { get { return default(int); } set { Contract.Requires(value > 0); } } string IProduct.Name { get { return default(string); } set { Contract.Requires(!string.IsNullOrWhiteSpace(value)); Contract.Requires(value.Length <= 25); } } decimal IProduct.Weight { get { return default(decimal); } set { Contract.Requires(value > 3); Contract.Requires(value < 100); } } decimal IProduct.Price { get { return default(decimal); } set { Contract.Requires(value > 0); Contract.Requires(value < 100); } } } And here is the product class that inherits IProduct interface. public class Product : IProduct { public int Id { get; set; } public string Name { get; set; } public virtual decimal Weight { get; set; } public decimal Price { get; set; } } if we run this code and violate the code contract set to Id we will get ContractException. public class Program { static void Main(string[] args) { var product = new Product(); product.Id = -100; } } Now let’s make Product to be abstract class and let’s define new class called Food that adds one more contract to Weight property. public class Food : Product { public override decimal Weight { get { return base.Weight; } set { Contract.Requires(value > 1); Contract.Requires(value < 10); base.Weight = value; } } } Now we should have the following rules at place for Food: weight must be greater than 1, weight must be greater than 3, weight must be less than 100, weight must be less than 10. Interesting part is what happens when we try to violate the lower and upper limits of Food weight. To see what happens let’s try to violate rules #2 and #4. Just comment one of the last lines out in the following method to test another assignment. public class Program { static void Main(string[] args) { var food = new Food(); food.Weight = 12; food.Weight = 2; } } And here are the results as pictures to see where exceptions are thrown. Click on images to see them at original size. Violation of lower limit. Violation of upper limit. As you can see for both violations we get ContractException like expected. Code contracts inheritance is powerful and at same time dangerous feature. Although you can always narrow down the conditions that come from more general classes it is possible to define impossible or conflicting contracts at different points in inheritance hierarchy.

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What is the simplest human readable configuration file format?

- by Juha

Current configuration file is as follows: mainwindow.title = 'test' mainwindow.position.x = 100 mainwindow.position.y = 200 mainwindow.button.label = 'apply' mainwindow.button.size.x = 100 mainwindow.button.size.y = 30 logger.datarate = 100 logger.enable = True logger.filename = './test.log' This is read with python to a nested dictionary: { 'mainwindow':{ 'button':{ 'label': {'value':'apply'}, ... }, 'logger':{ datarate: {'value': 100}, enable: {'value': True}, filename: {'value': './test.log'} }, ... } Is there a better way of doing this? The idea is to get XML type of behavior and avoid XML as long as possible. The end user is assumed almost totally computer illiterate and basically uses notepad and copy-paste. Thus the python standard "header + variables" type is considered too difficult. The dummy user edits the config file, able programmers handle the dictionaries. Nested dictionary is chosen for easy splitting (logger does not need or even cannot have/edit mainwindow parameters).

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Clear list of recent repositories in Git Extensions

- by Marko Apfel

Orphaned and wrong specified repositories in the recent list are annoying. Straightaway I does not found an option to clean this entries. And also not the persistence place for that. So it was time for Process Explorer. The storage happens under: HKEY_CURRENT_USER\Software\GitExtensions\GitExtensions\1.0.0.0 in the string value “history” You could edit the content of the string value or delete it – than during restarting Git Extensions the string value will be created with a default skeleton.

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IsNullOrEmpty generic method for Array to avoid Re-Sharper warning

- by Michael Freidgeim

I’ve used the following extension method in many places. public static bool IsNullOrEmpty(this Object[] myArr) { return (myArr == null || myArr.Length == 0); }Recently I’ve noticed that Resharper shows warning covariant array conversion to object[] may cause an exception for the following codeObjectsOfMyClass.IsNullOrEmpty()I’ve resolved the issue by creating generic extension method public static bool IsNullOrEmpty<T>(this T[] myArr) { return (myArr == null || myArr.Length == 0); }Related linkshttp://connect.microsoft.com/VisualStudio/feedback/details/94089/add-isnullorempty-to-array-class public static bool IsNullOrEmpty(this System.Collections.IEnumerable source) { if (source == null) return true; else { return !source.GetEnumerator().MoveNext(); } }http://stackoverflow.com/questions/8560106/isnullorempty-equivalent-for-array-c-sharp

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Database Rebuild

- by Robert May

I promised I’d have a simpler mechanism for rebuilding the database. Below is a complete MSBuild targets file for rebuilding the database from scratch. I don’t know if I’ve explained the rational for this. The reason why you’d WANT to do this is so that each developer has a clean version of the database on their local machine. This also includes the continuous integration environment. Basically, you can do whatever you want to the database without fear, and in a minute or two, have a completely rebuilt database structure. DBDeploy (including the KTSC build task for dbdeploy) is used in this script to do change tracking on the database itself. The MSBuild ExtensionPack is used in this target file. You can get an MSBuild DBDeploy task here. There are two database scripts that you’ll see below. First is the task for creating an admin (dbo) user in the system. This script looks like the following: USE [master] GO If not Exists (select Name from sys.sql_logins where name = '$(User)') BEGIN CREATE LOGIN [$(User)] WITH PASSWORD=N'$(Password)', DEFAULT_DATABASE=[$(DatabaseName)], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF END GO EXEC master..sp_addsrvrolemember @loginame = N'$(User)', @rolename = N'sysadmin' GO USE [$(DatabaseName)] GO CREATE USER [$(User)] FOR LOGIN [$(User)] GO ALTER USER [$(User)] WITH DEFAULT_SCHEMA=[dbo] GO EXEC sp_addrolemember N'db_owner', N'$(User)' GO The second creates the changelog table. This script can also be found in the dbdeploy.net install\scripts directory. CREATE TABLE changelog ( change_number INTEGER NOT NULL, delta_set VARCHAR(10) NOT NULL, start_dt DATETIME NOT NULL, complete_dt DATETIME NULL, applied_by VARCHAR(100) NOT NULL, description VARCHAR(500) NOT NULL ) GO ALTER TABLE changelog ADD CONSTRAINT Pkchangelog PRIMARY KEY (change_number, delta_set) GO Finally, Here’s the targets file. <Projectxmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0" DefaultTargets="Update"> <PropertyGroup> <DatabaseName>TestDatabase</DatabaseName> <Server>localhost</Server> <ScriptDirectory>.\Scripts</ScriptDirectory> <RebuildDirectory>.\Rebuild</RebuildDirectory> <TestDataDirectory>.\TestData</TestDataDirectory> <DbDeploy>.\DBDeploy</DbDeploy> <User>TestUser</User> <Password>TestPassword</Password> <BCP>bcp</BCP> <BCPOptions>-S$(Server) -U$(User) -P$(Password) -N -E -k</BCPOptions> <OutputFileName>dbDeploy-output.sql</OutputFileName> <UndoFileName>dbDeploy-output-undo.sql</UndoFileName> <LastChangeToApply>99999</LastChangeToApply> </PropertyGroup> <ImportProject="$(MSBuildExtensionsPath)\ExtensionPack\4.0\MSBuild.ExtensionPack.tasks"/> <UsingTask TaskName="Ktsc.Build.DBDeploy" AssemblyFile="$(DbDeploy)\Ktsc.Build.dll"/> <ItemGroup> <VariableInclude="DatabaseName"> <Value>$(DatabaseName)</Value> </Variable> <VariableInclude="Server"> <Value>$(Server)</Value> </Variable> <VariableInclude="User"> <Value>$(User)</Value> </Variable> <VariableInclude="Password"> <Value>$(Password)</Value> </Variable> </ItemGroup> <TargetName="Rebuild">  <MSBuild.ExtensionPack.SqlServer.SqlCmd Variables="@(Variable)" Database="$(DatabaseName)" TaskAction="Execute" CommandLineQuery ="ALTER DATABASE $(DatabaseName) SET OFFLINE WITH ROLLBACK IMMEDIATE"/>  <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="SetOnline" DatabaseItem="$(DatabaseName)"/>  <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Delete" DatabaseItem="$(DatabaseName)"/>  <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Create" DatabaseItem="$(DatabaseName)" Force="True"/>  <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" InputFiles="$(RebuildDirectory)\0002 Create Admin User.sql" Variables="@(Variable)" />  <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(RebuildDirectory)\0003 Create Changelog.sql" Variables="@(Variable)" /> <CallTarget Targets="Update;ImportData"/> </Target> <TargetName="Update" DependsOnTargets="CreateUpdateScript"> <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(OutputFileName)" Variables="@(Variable)" /> </Target> <TargetName="CreateUpdateScript"> <ktsc.Build.DBDeploy DbType="mssql" DbConnection="User=$(User);Password=$(Password);Data Source=$(Server);Initial Catalog=$(DatabaseName);" Dir="$(ScriptDirectory)" OutputFile="..\$(OutputFileName)" UndoOutputFile="..\$(UndoFileName)" LastChangeToApply="$(LastChangeToApply)"/> </Target> <TargetName="ImportData"> <ItemGroup> <TestData Include="$(TestDataDirectory)\*.dat"/> </ItemGroup> <ExecCommand="$(BCP) $(DatabaseName).dbo.%(TestData.Filename) in"%(TestData.Identity)"$(BCPOptions)"/> </Target> </Project> Technorati Tags: MSBuild

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IsNullOrDefault generic helper function for nullable types

- by Michael Freidgeim

I've wrote IsNullOrDefault generic helper function public static bool IsNullOrDefault<T>(this Nullable<T> param) where T : struct { T deflt = default(T); if (!param.HasValue) return true; else if (param.Value.Equals(deflt)) return true; return false; } , but then realized that there is more short implementation on stackoverflow submitted by Josh

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EM12c: Using the LIST verb in emcli

- by SubinDaniVarughese

Many of us who use EM CLI to write scripts and automate our daily tasks should not miss out on the new list verb released with Oracle Enterprise Manager 12.1.0.3.0. The combination of list and Jython based scripting support in EM CLI makes it easier to achieve automation for complex tasks with just a few lines of code. Before I jump into a script, let me highlight the key attributes of the list verb and why it’s simply excellent! 1. Multiple resources under a single verb:A resource can be set of users or targets, etc. Using the list verb, you can retrieve information about a resource from the repository database.Here is an example which retrieves the list of administrators within EM.Standard mode$ emcli list -resource="Administrators" Interactive modeemcli>list(resource="Administrators")The output will be the same as standard mode.Standard mode$ emcli @myAdmin.pyEnter password : ******The output will be the same as standard mode.Contents of myAdmin.py scriptlogin()print list(resource="Administrators",jsonout=False).out()To get a list of all available resources use$ emcli list -helpWith every release of EM, more resources are being added to the list verb. If you have a resource which you feel would be valuable then go ahead and contact Oracle Support to log an enhancement request with product development. Be sure to say how the resource is going to help improve your daily tasks. 2. Consistent Formatting:It is possible to format the output of any resource consistently using these options: –column This option is used to specify which columns should be shown in the output. Here is an example which shows the list of administrators and their account status$ emcli list -resource="Administrators" -columns="USER_NAME,REPOS_ACCOUNT_STATUS" To get a list of columns in a resource use:$ emcli list -resource="Administrators" -help You can also specify the width of the each column. For example, here the column width of user_type is set to 20 and department to 30. $ emcli list -resource=Administrators -columns="USER_NAME,USER_TYPE:20,COST_CENTER,CONTACT,DEPARTMENT:30"This is useful if your terminal is too small or you need to fine tune a list of specific columns for your quick use or improved readability. –colsize This option is used to resize column widths.Here is the same example as above, but using -colsize to define the width of user_type to 20 and department to 30.$ emcli list -resource=Administrators -columns="USER_NAME,USER_TYPE,COST_CENTER,CONTACT,DEPARTMENT" -colsize="USER_TYPE:20,DEPARTMENT:30" The existing standard EMCLI formatting options are also available in list verb. They are: -format="name:pretty" | -format="name:script” | -format="name:csv" | -noheader | -scriptThere are so many uses depending on your needs. Have a look at the resources and columns in each resource. Refer to the EMCLI book in EM documentation for more information.3. Search:Using the -search option in the list verb makes it is possible to search for a specific row in a specific column within a resource. This is similar to the sqlplus where clause. The following operators are supported: = != > < >= <= like is (Must be followed by null or not null)Here is an example which searches for all EM administrators in the marketing department located in the USA.$emcli list -resource="Administrators" -search="DEPARTMENT ='Marketing'" -search="LOCATION='USA'" Here is another example which shows all the named credentials created since a specific date. $emcli list -resource=NamedCredentials -search="CredCreatedDate > '11-Nov-2013 12:37:20 PM'"Note that the timestamp has to be in the format DD-MON-YYYY HH:MI:SS AM/PM Some resources need a bind variable to be passed to get output. A bind variable is created in the resource and then referenced in the command. For example, this command will list all the default preferred credentials for target type oracle_database.Here is an example$ emcli list -resource="PreferredCredentialsDefault" -bind="TargetType='oracle_database'" -colsize="SetName:15,TargetType:15" You can provide multiple bind variables. To verify if a column is searchable or requires a bind variable, use the –help option. Here is an example:$ emcli list -resource="PreferredCredentialsDefault" -help 4. Secure accessWhen list verb collects the data, it only displays content for which the administrator currently logged into emcli, has access. For example consider this usecase:AdminA has access only to TargetA. AdminA logs into EM CLIExecuting the list verb to get the list of all targets will only show TargetA.5. User defined SQLUsing the –sql option, user defined sql can be executed. The SQL provided in the -sql option is executed as the EM user MGMT_VIEW, which has read-only access to the EM published MGMT$ database views in the SYSMAN schema. To get the list of EM published MGMT$ database views, go to the Extensibility Programmer's Reference book in EM documentation. There is a chapter about Using Management Repository Views. It’s always recommended to reference the documentation for the supported MGMT$ database views. Consider you are using the MGMT$ABC view which is not in the chapter. During upgrade, it is possible, since the view was not in the book and not supported, it is likely the view might undergo a change in its structure or the data in it. Using a supported view ensures that your scripts using -sql will continue working after upgrade.Here’s an example $ emcli list -sql='select * from mgmt$target' 6. JSON output support JSON (JavaScript Object Notation) enables data to be displayed in a collection of name/value pairs. There is lot of reading material about JSON on line for more information.As an example, we had a requirement where an EM administrator had many 11.2 databases in their test environment and the developers had requested an Administrator to change the lifecycle status from Test to Production which meant the admin had to go to the EM “All targets” page and identify the set of 11.2 databases and then to go into each target database page and manually changes the property to Production. Sounds easy to say, but this Administrator had numerous targets and this task is repeated for every release cycle.We told him there is an easier way to do this with a script and he can reuse the script whenever anyone wanted to change a set of targets to a different Lifecycle status. Here is a jython script which uses list and JSON to change all 11.2 database target’s LifeCycle Property value.If you are new to scripting and Jython, I would suggest visiting the basic chapters in any Jython tutorials. Understanding Jython is important to write the logic depending on your usecase.If you are already writing scripts like perl or shell or know a programming language like java, then you can easily understand the logic.Disclaimer: The scripts in this post are subject to the Oracle Terms of Use located here. 1 from emcli import * 2 search_list = ['PROPERTY_NAME=\'DBVersion\'','TARGET_TYPE= \'oracle_database\'','PROPERTY_VALUE LIKE \'11.2%\''] 3 if len(sys.argv) == 2: 4 print login(username=sys.argv[0]) 5 l_prop_val_to_set = sys.argv[1] 6 l_targets = list(resource="TargetProperties", search=search_list, columns="TARGET_NAME,TARGET_TYPE,PROPERTY_NAME") 7 for target in l_targets.out()['data']: 8 t_pn = 'LifeCycle Status' 9 print "INFO: Setting Property name " + t_pn + " to value " + l_prop_val_to_set + " for " + target['TARGET_NAME'] 10 print set_target_property_value(property_records= target['TARGET_NAME']+":"+target['TARGET_TYPE']+":"+ t_pn+":"+l_prop_val_to_set) 11 else: 12 print "\n ERROR: Property value argument is missing" 13 print "\n INFO: Format to run this file is filename.py <username> <Database Target LifeCycle Status Property Value>" You can download the script from here. I could not upload the file with .py extension so you need to rename the file to myScript.py before executing it using emcli.A line by line explanation for beginners: Line 1 Imports the emcli verbs as functions 2 search_list is a variable to pass to the search option in list verb. I am using escape character for the single quotes. In list verb to pass more than one value for the same option, you should define as above comma separated values, surrounded by square brackets. 3 This is an “if” condition to ensure the user does provide two arguments with the script, else in line #15, it prints an error message. 4 Logging into EM. You can remove this if you have setup emcli with autologin. For more details about setup and autologin, please go the EM CLI book in EM documentation. 5 l_prop_val_to_set is another variable. This is the property value to be set. Remember we are changing the value from Test to Production. The benefit of this variable is you can reuse the script to change the property value from and to any other values. 6 Here the output of the list verb is stored in l_targets. In the list verb I am passing the resource as TargetProperties, search as the search_list variable and I only need these three columns – target_name, target_type and property_name. I don’t need the other columns for my task. 7 This is a for loop. The data in l_targets is available in JSON format. Using the for loop, each pair will now be available in the ‘target’ variable. 8 t_pn is the “LifeCycle Status” variable. If required, I can have this also as an input and then use my script to change any target property. In this example, I just wanted to change the “LifeCycle Status”. 9 This a message informing the user the script is setting the property value for dbxyz. 10 This line shows the set_target_property_value verb which sets the value using the property_records option. Once it is set for a target pair, it moves to the next one. In my example, I am just showing three dbs, but the real use is when you have 20 or 50 targets. The script is executed as:$ emcli @myScript.py subin Production The recommendation is to first test the scripts before running it on a production system. We tested on a small set of targets and optimizing the script for fewer lines of code and better messaging.For your quick reference, the resources available in Enterprise Manager 12.1.0.4.0 with list verb are:$ emcli list -helpWatch this space for more blog posts using the list verb and EM CLI Scripting use cases. I hope you enjoyed reading this blog post and it has helped you gain more information about the list verb. Happy Scripting!!Disclaimer: The scripts in this post are subject to the Oracle Terms of Use located here. Stay Connected: Twitter | Facebook | YouTube | Linkedin | Newsletter mt=8">Download the Oracle Enterprise Manager 12c Mobile app

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Alternative of SortedDictionary in Silverlight

- by Rajneesh Verma

Hi, As we know SortedDictionary is not not present in Silverlightso to find alternative of this i am using Dictionary as System.Collections.Generic . Dictionary (Of TKey, TValue ) . KeyCollection and for sorting i am using LINQ query. see the full code below. Dim sortedLists As New Dictionary(Of String, Object) Dim query = From sortedList In sortedLists Order By sortedList.Key Ascending Select sortedList.Key, sortedList.Value For Each que In query 'get the key value using que.Key 'get the value using...(read more)

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Collision Error

- by Manji

I am having trouble with collision detection part of the game. I am using touch events to fire the gun as you will see in the video. Note, the android icon is a temporary graphic for the bullets When ever the user touches (represented by clicks in the video)the bullet appears and kills random sprites. As you can see it never touches the sprites it kills or kill the sprites it does touch. My Question is How do I fix it, so that the sprite dies when the bullet hits it? Collision Code snippet: //Handles Collision private void CheckCollisions(){ synchronized(mSurfaceHolder){ for (int i = sprites.size() - 1; i >= 0; i--){ Sprite sprite = sprites.get(i); if(sprite.isCollision(bullet)){ sprites.remove(sprite); mScore++; if(sprites.size() == 0){ mLevel = mLevel +1; currentLevel++; initLevel(); } break; } } } } Sprite Class Code Snippet: //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public boolean isCollision(Beam other) { // TODO Auto-generated method stub if(this.left>other.right || other.left<other.right)return false; if(this.bottom>other.top || other.bottom<other.top)return false; return true; } EDIT 1: Sprite Class: public class Sprite { // direction = 0 up, 1 left, 2 down, 3 right, // animation = 3 back, 1 left, 0 front, 2 right int[] DIRECTION_TO_ANIMATION_MAP = { 3, 1, 0, 2 }; private static final int BMP_ROWS = 4; private static final int BMP_COLUMNS = 3; private static final int MAX_SPEED = 5; private HitmanView gameView; private Bitmap bmp; private int x; private int y; private int xSpeed; private int ySpeed; private int currentFrame = 0; private int width; private int height; //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public Sprite(HitmanView gameView, Bitmap bmp) { this.width = bmp.getWidth() / BMP_COLUMNS; this.height = bmp.getHeight() / BMP_ROWS; this.gameView = gameView; this.bmp = bmp; Random rnd = new Random(); x = rnd.nextInt(gameView.getWidth() - width); y = rnd.nextInt(gameView.getHeight() - height); xSpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; ySpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; } private void update() { if (x >= gameView.getWidth() - width - xSpeed || x + xSpeed <= 0) { xSpeed = -xSpeed; } x = x + xSpeed; if (y >= gameView.getHeight() - height - ySpeed || y + ySpeed <= 0) { ySpeed = -ySpeed; } y = y + ySpeed; currentFrame = ++currentFrame % BMP_COLUMNS; } public void onDraw(Canvas canvas) { update(); int srcX = currentFrame * width; int srcY = getAnimationRow() * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bmp, src, dst, null); } private int getAnimationRow() { double dirDouble = (Math.atan2(xSpeed, ySpeed) / (Math.PI / 2) + 2); int direction = (int) Math.round(dirDouble) % BMP_ROWS; return DIRECTION_TO_ANIMATION_MAP[direction]; } public boolean isCollision(float x2, float y2){ return x2 > x && x2 < x + width && y2 > y && y2 < y + height; } public boolean isCollision(Beam other) { // TODO Auto-generated method stub if(this.left>other.right || other.left<other.right)return false; if(this.bottom>other.top || other.bottom<other.top)return false; return true; } } Bullet Class: public class Bullet { int mX; int mY; private Bitmap mBitmap; //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public Bullet (Bitmap mBitmap){ this.mBitmap = mBitmap; } public void draw(Canvas canvas, int mX, int mY) { this.mX = mX; this.mY = mY; canvas.drawBitmap(mBitmap, mX, mY, null); } }

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Adaptive Layout for ADF Faces on Tablets

- by Shay Shmeltzer

In the 11.1.16 version of Oracle ADF we started adding specific features to the ADF Faces components so they'll work better on iPad tablets. In this entry I'm going to highlight some new capabilities that we have added to the 11.1.2.3 release. (note if you are still on the 11.1.1.* branch - you'll need to wait for 11.1.1.7 to get the features discussed here). The two key additions in the 11.1.2.3 version compared to the 11.1.1.6 features for iPad support include: pagination for tables and adaptive flow layout. The pagination for table is self explanatory, basically since iPad don't support scroll bars, we automatically switch the table component to render with a pagination toolbar that allow you to scroll set of records or directly jump to a specific set. See the image below. The adaptive flow layout takes a bit more explanation. On regular desktops the UI that you usually build for ADF Faces screens is going to use stretch layout - meaning that it stretches to fill the whole area of the browser window. If you resize the browser windoe, the ADF Faces page resizes with it. If your browser window is too small, scroll bars will appear to allow you to scroll to areas that are "hidden". However on an iPad, this is probably not the type of layout you want - you would rather have a flow layout that eliminates scroll bars and instead allows you to scroll down the page. Basically your want the page to be sized based on its content, rather then based on the browser window size. In ADF Faces terminology this can be done with the dimensionsFrom property set to "children". And here comes the tricky part, since in the past(and also today) when you create an ADF Faces page and add a stretchable component to it, the dimensionsFrom property is set to parent by default. This will be true to other layout components you'll add as well. At this point you might be wondering "Does this mean I'll need to go to each of the layout components in my page and modify the dimensionsFrom property value to be children?" ADF Faces to the rescue... To eliminate the need to do this tedious manual changes, we introduced a new web.xml parameter "oracle.adf.view.rich.geometry.DEFAULT_DIMENSIONS" You'll basically add the following to your web.xml <context-param> <description> This parameter controls the default value for component geometry on the page. Supported values are: legacy - component attributes use the default values as specified for the attributes in the tag documentation (default value) auto - component attributes use the correct default value given the value of their parent component. For example, with this setting, the panelStretchLayout will use "auto" as the default value for its "dimensionsFrom" attribute instead of "parent". </description> <param-name>oracle.adf.view.rich.geometry.DEFAULT_DIMENSIONS</param-name> <param-value>auto</param-value> </context-param> Once you set this parameter, you only need to set the dimensionsFrom attribute for the top level layout component on your page, and the rest of the components will adjust accordingly. One trick that you can use, and that is used in the demo below, is to have the dimensionsFrom property depend on the type of client that access your application. This way you can switch between stretch or flow layout based on the device accessing your application. For example I use the following in my page: <af:panelStretchLayout topHeight="70px" startWidth="0px" endWidth="0px" dimensionsFrom="#{adfFacesContext.agent.capabilities['touchScreen'] eq 'none' ? 'parent' : 'children' }"> Which results in a flow layout for iPads and a stretch layout for regular browsers. Check out the result in the below demo: &lt;span id=&quot;XinhaEditingPostion&quot;&gt;&lt;/span&gt;

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Generate texture for a heightmap

- by James

I've recently been trying to blend multiple textures based on the height at different points in a heightmap. However i've been getting poor results. I decided to backtrack and just attempt to recreate one single texture from an SDL_Surface (i'm using SDL) and just send that into opengl. I'll put my code for creating the texture and reading the colour values. It is a 24bit TGA i'm loading, and i've confirmed that the rest of my code works because i was able to send the surfaces pixels directly to my createTextureFromData function and it drew fine. struct RGBColour { RGBColour() : r(0), g(0), b(0) {} RGBColour(unsigned char red, unsigned char green, unsigned char blue) : r(red), g(green), b(blue) {} unsigned char r; unsigned char g; unsigned char b; }; // main loading code SDLSurfaceReader* reader = new SDLSurfaceReader(m_renderer); reader->readSurface("images/grass.tga"); // new texture unsigned char* newTexture = new unsigned char[reader->m_surface->w * reader->m_surface->h * 3 * reader->m_surface->w]; for (int y = 0; y < reader->m_surface->h; y++) { for (int x = 0; x < reader->m_surface->w; x += 3) { int index = (y * reader->m_surface->w) + x; RGBColour colour = reader->getColourAt(x, y); newTexture[index] = colour.r; newTexture[index + 1] = colour.g; newTexture[index + 2] = colour.b; } } unsigned int id = m_renderer->createTextureFromData(newTexture, reader->m_surface->w, reader->m_surface->h, RGB); // functions for reading pixels RGBColour SDLSurfaceReader::getColourAt(int x, int y) { Uint32 pixel; Uint8 red, green, blue; RGBColour rgb; pixel = getPixel(m_surface, x, y); SDL_LockSurface(m_surface); SDL_GetRGB(pixel, m_surface->format, &red, &green, &blue); SDL_UnlockSurface(m_surface); rgb.r = red; rgb.b = blue; rgb.g = green; return rgb; } // this function taken from SDL documentation // http://www.libsdl.org/cgi/docwiki.cgi/Introduction_to_SDL_Video#getpixel Uint32 SDLSurfaceReader::getPixel(SDL_Surface* surface, int x, int y) { int bpp = m_surface->format->BytesPerPixel; Uint8 *p = (Uint8*)m_surface->pixels + y * m_surface->pitch + x * bpp; switch (bpp) { case 1: return *p; case 2: return *(Uint16*)p; case 3: if (SDL_BYTEORDER == SDL_BIG_ENDIAN) return p[0] << 16 | p[1] << 8 | p[2]; else return p[0] | p[1] << 8 | p[2] << 16; case 4: return *(Uint32*)p; default: return 0; } } I've been stumped at this, and I need help badly! Thanks so much for any advice.

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Android Bitmap : collision Detecting [on hold]

- by user2505374

I am writing an Android game right now and I would need some help in the collision of the wall on screen. When I drag the ball in the top and right it able to collide in wall but when I drag it faster it was able to overlap in the wall. public boolean onTouchEvent(MotionEvent event) { int x = (int) event.getX(); int y = (int) event.getY(); switch (event.getAction()) { // if the player moves case MotionEvent.ACTION_MOVE: { if (playerTouchRect.contains(x, y)) { boolean left = false; boolean right = false; boolean up = false; boolean down = false; boolean canMove = false; boolean foundFinish = false; if (x != pLastXPos) { if (x < pLastXPos) { left = true; } else { right = true; } pLastXPos = x; } if (y != pLastYPos) { if (y < pLastYPos) { up = true; } else { down = true; } pLastYPos = y; } plCellRect = getRectFromPos(x, y); newplRect.set(playerRect); newplRect.left = x - (int) (playerRect.width() / 2); newplRect.right = x + (int) (playerRect.width() / 2); newplRect.top = y - (int) (playerRect.height() / 2); newplRect.bottom = y + (int) (playerRect.height() / 2); int currentRow = 0; int currentCol = 0; currentRow = getRowFromYPos(newplRect.top); currentCol = getColFromXPos(newplRect.right); if(!canMove){ canMove = mapManager.getCurrentTile().pMaze[currentRow][currentCol] == Cell.wall; canMove =true; } finishTest = mapManager.getCurrentTile().pMaze[currentRow][currentCol]; foundA = finishTest == Cell.valueOf(letterNotGet + ""); canMove = mapManager.getCurrentTile().pMaze[currentRow][currentCol] != Cell.wall; canMove = (finishTest == Cell.floor || finishTest == Cell.pl) && canMove; if (canMove) { invalidate(); setTitle(); } if (foundA) { mapManager.getCurrentTile().pMaze[currentRow][currentCol] = Cell.floor; // finishTest letterGotten.add(letterNotGet); playCurrentLetter(); /*sounds.play(sExplosion, 1.0f, 1.0f, 0, 0, 1.5f);*/ foundS = letterNotGet == 's'; letterNotGet++; }if(foundS){ AlertDialog.Builder builder = new AlertDialog.Builder(mainActivity); builder.setTitle(mainActivity.getText(R.string.finished_title)); LayoutInflater inflater = mainActivity.getLayoutInflater(); View view = inflater.inflate(R.layout.finish, null); builder.setView(view); View closeButton =view.findViewById(R.id.closeGame); closeButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View clicked) { if(clicked.getId() == R.id.closeGame) { mainActivity.finish(); } } }); AlertDialog finishDialog = builder.create(); finishDialog.show(); } else { Log.d(TAG, "INFO: updated player position"); playerRect.set(newplRect); setTouchZone(); updatePlayerCell(); } } // end of (CASE) if playerTouch break; } // end of (SWITCH) Case motion }//end of Switch return true; }//end of TouchEvent private void finish() { // TODO Auto-generated method stub } public int getColFromXPos(int xPos) { val = xPos / (pvWidth / mapManager.getCurrentTile().pCols); if (val == mapManager.getCurrentTile().pCols) { val = mapManager.getCurrentTile().pCols - 1; } return val; } /** * Given a y pixel position, return the row of the cell it is in This is * used when determining the type of adjacent Cells. * * @param yPos * y position in pixels * @return The cell this position is in */ public int getRowFromYPos(int yPos) { val = yPos / (pvHeight / mapManager.getCurrentTile().pRows); if (val == mapManager.getCurrentTile().pRows) { val = mapManager.getCurrentTile().pRows - 1; } return val; } /** * When preserving the position we need to know which cell the player is in, * so calculate it from the centre on its Rect */ public void updatePlayerCell() { plCell.x = (playerRect.left + (playerRect.width() / 2)) / (pvWidth / mapManager.getCurrentTile().pCols); plCell.y = (playerRect.top + (playerRect.height() / 2)) / (pvHeight / mapManager.getCurrentTile().pRows); if (mapManager.getCurrentTile().pMaze[plCell.y][plCell.x] == Cell.floor) { for (int row = 0; row < mapManager.getCurrentTile().pRows; row++) { for (int col = 0; col < mapManager.getCurrentTile().pCols; col++) { if (mapManager.getCurrentTile().pMaze[row][col] == Cell.pl) { mapManager.getCurrentTile().pMaze[row][col] = Cell.floor; break; } } } mapManager.getCurrentTile().pMaze[plCell.y][plCell.x] = Cell.pl; } } public Rect getRectFromPos(int x, int y) { calcCell.left = ((x / cellWidth) + 0) * cellWidth; calcCell.right = calcCell.left + cellWidth; calcCell.top = ((y / cellHeight) + 0) * cellHeight; calcCell.bottom = calcCell.top + cellHeight; Log.d(TAG, "Rect: " + calcCell + " Player: " + playerRect); return calcCell; } public void setPlayerRect(Rect newplRect) { playerRect.set(newplRect); } private void setTouchZone() { playerTouchRect.set( playerRect.left - playerRect.width() / TOUCH_ZONE, playerRect.top - playerRect.height() / TOUCH_ZONE, playerRect.right + playerRect.width() / TOUCH_ZONE, playerRect.bottom + playerRect.height() / TOUCH_ZONE); } public Rect getPlayerRect() { return playerRect; } public Point getPlayerCell() { return plCell; } public void setPlayerCell(Point cell) { plCell = cell; }

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Sortable & Filterable PrimeFaces DataTable

- by Geertjan

<h:form> <p:dataTable value="#{resultManagedBean.customers}" var="customer"> <p:column id="nameHeader" filterBy="#{customer.name}" sortBy="#{customer.name}"> <f:facet name="header"> <h:outputText value="Name" /> </f:facet> <h:outputText value="#{customer.name}" /> </p:column> <p:column id="cityHeader" filterBy="#{customer.city}" sortBy="#{customer.city}"> <f:facet name="header"> <h:outputText value="City" /> </f:facet> <h:outputText value="#{customer.city}" /> </p:column> </p:dataTable> </h:form> That gives me this: And here's the filter in action: Behind this, I have: import com.mycompany.mavenproject3.entities.Customer; import java.io.Serializable; import java.util.List; import javax.annotation.PostConstruct; import javax.ejb.EJB; import javax.faces.bean.RequestScoped; import javax.inject.Named; @Named(value = "resultManagedBean") @RequestScoped public class ResultManagedBean implements Serializable { @EJB private CustomerSessionBean customerSessionBean; public ResultManagedBean() { } private List<Customer> customers; @PostConstruct public void init(){ customers = customerSessionBean.getCustomers(); } public List<Customer> getCustomers() { return customers; } public void setCustomers(List<Customer> customers) { this.customers = customers; } } And the above refers to the EJB below, which is a standard EJB that I create in all my Java EE 6 demos: import com.mycompany.mavenproject3.entities.Customer; import java.io.Serializable; import java.util.List; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; @Stateless public class CustomerSessionBean implements Serializable{ @PersistenceContext EntityManager em; public List getCustomers() { return em.createNamedQuery("Customer.findAll").getResultList(); } } Only problem is that the columns are only sortable after the first time I use the filter.

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Optimizing a thread safe Java NIO / Serialization / FIFO Queue [migrated]

- by trialcodr

I've written a thread safe, persistent FIFO for Serializable items. The reason for reinventing the wheel is that we simply can't afford any third party dependencies in this project and want to keep this really simple. The problem is it isn't fast enough. Most of it is undoubtedly due to reading and writing directly to disk but I think we should be able to squeeze a bit more out of it anyway. Any ideas on how to improve the performance of the 'take'- and 'add'-methods? /** * <code>DiskQueue</code> Persistent, thread safe FIFO queue for * <code>Serializable</code> items. */ public class DiskQueue<ItemT extends Serializable> { public static final int EMPTY_OFFS = -1; public static final int LONG_SIZE = 8; public static final int HEADER_SIZE = LONG_SIZE * 2; private InputStream inputStream; private OutputStream outputStream; private RandomAccessFile file; private FileChannel channel; private long offs = EMPTY_OFFS; private long size = 0; public DiskQueue(String filename) { try { boolean fileExists = new File(filename).exists(); file = new RandomAccessFile(filename, "rwd"); if (fileExists) { size = file.readLong(); offs = file.readLong(); } else { file.writeLong(size); file.writeLong(offs); } } catch (FileNotFoundException e) { throw new RuntimeException(e); } catch (IOException e) { throw new RuntimeException(e); } channel = file.getChannel(); inputStream = Channels.newInputStream(channel); outputStream = Channels.newOutputStream(channel); } /** * Add item to end of queue. */ public void add(ItemT item) { try { synchronized (this) { channel.position(channel.size()); ObjectOutputStream s = new ObjectOutputStream(outputStream); s.writeObject(item); s.flush(); size++; file.seek(0); file.writeLong(size); if (offs == EMPTY_OFFS) { offs = HEADER_SIZE; file.writeLong(offs); } notify(); } } catch (IOException e) { throw new RuntimeException(e); } } /** * Clears overhead by moving the remaining items up and shortening the file. */ public synchronized void defrag() { if (offs > HEADER_SIZE && size > 0) { try { long totalBytes = channel.size() - offs; ByteBuffer buffer = ByteBuffer.allocateDirect((int) totalBytes); channel.position(offs); for (int bytes = 0; bytes < totalBytes;) { int res = channel.read(buffer); if (res == -1) { throw new IOException("Failed to read data into buffer"); } bytes += res; } channel.position(HEADER_SIZE); buffer.flip(); for (int bytes = 0; bytes < totalBytes;) { int res = channel.write(buffer); if (res == -1) { throw new IOException("Failed to write buffer to file"); } bytes += res; } offs = HEADER_SIZE; file.seek(LONG_SIZE); file.writeLong(offs); file.setLength(HEADER_SIZE + totalBytes); } catch (IOException e) { throw new RuntimeException(e); } } } /** * Returns the queue overhead in bytes. */ public synchronized long overhead() { return (offs == EMPTY_OFFS) ? 0 : offs - HEADER_SIZE; } /** * Returns the first item in the queue, blocks if queue is empty. */ public ItemT peek() throws InterruptedException { block(); synchronized (this) { if (offs != EMPTY_OFFS) { return readItem(); } } return peek(); } /** * Returns the number of remaining items in queue. */ public synchronized long size() { return size; } /** * Removes and returns the first item in the queue, blocks if queue is empty. */ public ItemT take() throws InterruptedException { block(); try { synchronized (this) { if (offs != EMPTY_OFFS) { ItemT result = readItem(); size--; offs = channel.position(); file.seek(0); if (offs == channel.size()) { truncate(); } file.writeLong(size); file.writeLong(offs); return result; } } return take(); } catch (IOException e) { throw new RuntimeException(e); } } /** * Throw away all items and reset the file. */ public synchronized void truncate() { try { offs = EMPTY_OFFS; file.setLength(HEADER_SIZE); size = 0; } catch (IOException e) { throw new RuntimeException(e); } } /** * Block until an item is available. */ protected void block() throws InterruptedException { while (offs == EMPTY_OFFS) { try { synchronized (this) { wait(); file.seek(LONG_SIZE); offs = file.readLong(); } } catch (IOException e) { throw new RuntimeException(e); } } } /** * Read and return item. */ @SuppressWarnings("unchecked") protected ItemT readItem() { try { channel.position(offs); return (ItemT) new ObjectInputStream(inputStream).readObject(); } catch (ClassNotFoundException e) { throw new RuntimeException(e); } catch (IOException e) { throw new RuntimeException(e); } } }

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Information about how much time in spent in a function, based on the input of this function

- by olchauvin

Is there a (quantitative) tool to measure performance of functions based on its input? So far, the tools I used to measure performance of my code, tells me how much time I spent in functions (like Jetbrain Dottrace for .Net), but I'd like to have more information about the parameters passed to the function in order to know which parameters impact the most the performance. Let's say that I have function like that: int myFunction(int myParam1, int myParam 2) { // Do and return something based on the value of myParam1 and myParam2. // The code is likely to use if, for, while, switch, etc.... } If would like a tool that would allow me to tell me how much time is spent in myFunction based on the value of myParam1 and myParam2. For example, the tool would give me a result looking like this: For "myFunction" : value | value | Number of | Average myParam1 | myParam2 | call | time ---------|----------|-----------|-------- 1 | 5 | 500 | 301 ms 2 | 5 | 250 | 1253 ms 3 | 7 | 1268 | 538 ms ... That would mean that myFunction has been call 500 times with myParam1=1 and myParam2=5, and that with those parameters, it took on average 301ms to return a value. The idea behind that is to do some statistical optimization by organizing my code such that, the blocs of codes that are the most likely to be executed are tested before the one that are less likely to be executed. To put it bluntly, if I know which values are used the most, I can reorganize the if/while/for etc.. structure of the function (and the whole program) to optimize it. I'd like to find such tools for C++, Java or.Net. Note: I am not looking for technical tips to optimize the code (like passing parameters as const, inlining functions, initializing the capacity of vectors and the like).

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