Search Results

Search found 34816 results on 1393 pages for 'copy on write'.

Page 95/1393 | < Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102  | Next Page >

  • Search a string in a file and write the matched lines to another file in Java

    - by Geeta
    For searching a string in a file and writing the lines with matched string to another file it takes 15 - 20 mins for a single zip file of 70MB(compressed state). Is there any ways to minimise it. my source code: getting Zip file entries zipFile = new ZipFile(source_file_name); entries = zipFile.entries(); while (entries.hasMoreElements()) { ZipEntry entry = (ZipEntry)entries.nextElement(); if (entry.isDirectory()) { continue; } searchString(Thread.currentThread(),entry.getName(), new BufferedInputStream (zipFile.getInputStream(entry)), Out_File, search_string, stats); } zipFile.close(); Searching String public void searchString(Thread CThread, String Source_File, BufferedInputStream in, File outfile, String search, String stats) throws IOException { int count = 0; int countw = 0; int countl = 0; String s; String[] str; BufferedReader br2 = new BufferedReader(new InputStreamReader(in)); System.out.println(CThread.currentThread()); while ((s = br2.readLine()) != null) { str = s.split(search); count = str.length - 1; countw += count; //word count if (s.contains(search)) { countl++; //line count WriteFile(CThread,s, outfile.toString(), search); } } br2.close(); in.close(); } -------------------------------------------------------------------------------- public void WriteFile(Thread CThread,String line, String out, String search) throws IOException { BufferedWriter bufferedWriter = null; System.out.println("writre thread"+CThread.currentThread()); bufferedWriter = new BufferedWriter(new FileWriter(out, true)); bufferedWriter.write(line); bufferedWriter.newLine(); bufferedWriter.flush(); } Please help me. Its really taking 40 mins for 10 files using threads and 15 - 20 mins for a single file of 70MB after being compressed. Any ways to minimise the time.

    Read the article

  • Ruby shortest/most efficient way to write rnd hex

    - by Whirlwin
    Hi. What I have is a method used to generate random hex values. E.g 666 or FF7 However, I don't think it is efficient at all.. What I want is to make it more efficient which perhaps will make my code shorter as well, but I don't know how. That is why I need tips or hints Here is my code so far: def random_values random_values = Array.new letters = ['A','B','C','D','E','F'] for i in 1..15 if i <= 9 random_values << i else random_values << letters[i-10] end end return random_values.shuffle[0].to_s + random_values.shuffle[0].to_s + random_values.shuffle[0].to_s end As you probably see, I do not generate random numbers. I just shuffle the array containing the values I want, meaning all the numbers in the array are unique, which is not needed, but was the easiest solution for me when I wrote the code. I am most concerned about the return line.. If only it was possible to write like: return 3.times { random_values.shuffle[0] } or return random_values.shuffle[0].to_s *3 Thanks in advance!

    Read the article

  • Most efficient way to write over file after reading

    - by Ryan McClure
    I'm reading in some data from a file, manipulating it, and then overwriting it to the same file. Until now, I've been doing it like so: open (my $inFile, $file) or die "Could not open $file: $!"; $retString .= join ('', <$inFile>); ... close ($inFile); open (my $outFile, $file) or die "Could not open $file: $!"; print $outFile, $retString; close ($inFile); However I realized I can just use the truncate function and open the file for read/write: open (my $inFile, '+<', $file) or die "Could not open $file: $!"; $retString .= join ('', <$inFile>); ... truncate $inFile, 0; print $inFile $retString; close ($inFile); I don't see any examples of this anywhere. It seems to work well, but am I doing it correctly? Is there a better way to do this?

    Read the article

  • Most readable way to write simple conditional check

    - by JRL
    What would be the most readable/best way to write a multiple conditional check such as shown below? Two possibilities that I could think of (this is Java but the language really doesn't matter here): Option 1: boolean c1 = passwordField.getPassword().length > 0; boolean c2 = !stationIDTextField.getText().trim().isEmpty(); boolean c3 = !userNameTextField.getText().trim().isEmpty(); if (c1 && c2 && c3) { okButton.setEnabled(true); } Option 2: if (passwordField.getPassword().length > 0 && !stationIDTextField.getText().trim().isEmpty() && !userNameTextField.getText().trim().isEmpty() { okButton.setEnabled(true); } What I don't like about option 2 is that the line wraps and then indentation becomes a pain. What I don't like about option 1 is that it creates variables for nothing and requires looking at two places. So what do you think? Any other options?

    Read the article

  • write regex code in java for following data

    - by giri
    <table> <tr> <td style="width:180px"> <a href="/search?q=user:240698+[java]" class="post-tag" title="show all posts by this user in 'java'">java</a><span class="item-multiplier">&times;&nbsp;176</span><br> <a href="/search?q=user:240698+[servlets]" class="post-tag" title="show all posts by this user in 'servlets'">servlets</a><span class="item-multiplier">&times;&nbsp;25</span><br> <a href="/search?q=user:240698+[jsp]" class="post-tag" title="show all posts by this user in 'jsp'">jsp</a><span class="item-multiplier">&times;&nbsp;11</span><br> <a href="/search?q=user:240698+[core]" class="post-tag" title="show all posts by this user in 'core'">core</a><span class="item-multiplier">&times;&nbsp;9</span><br> </tr> </table> from the above code I need to fetch only java, servlets, jsp and core. Can anybody plz help me out to write a regex in java to fetch those? Thanks

    Read the article

  • Trying to write priority queue in Java but getting "Exception in thread "main" java.lang.ClassCastEx

    - by Dan
    For my data structure class, I am trying to write a program that simulates a car wash and I want to give fancy cars a higher priority than regular ones using a priority queue. The problem I am having has something to do with Java not being able to type cast "Object" as an "ArrayQueue" (a simple FIFO implementation). What am I doing wrong and how can I fix it? public class PriorityQueue<E> { private ArrayQueue<E>[] queues; private int highest=0; private int manyItems=0; public PriorityQueue(int h) { highest=h; queues = (ArrayQueue[]) new Object[highest+1]; <----problem is here } public void add(E item, int priority) { queues[priority].add(item); manyItems++; } public boolean isEmpty( ) { return (manyItems == 0); } public E remove() { E answer=null; int counter=0; do { if(!queues[highest-counter].isEmpty()) { answer = queues[highest-counter].remove(); counter=highest+1; } else counter++; }while(highest-counter>=0); return answer; } }

    Read the article

  • Ruby shortest way to write rnd hex

    - by Whirlwin
    Hi. What I have is a method used to generate random hex values. E.g 666 or FF7 However, I don't think it looks simple/elegant at all.. What I want is to make it more simple which perhaps will make my code shorter as well, but I don't know how. That is why I need tips or hints Here is my code so far: def random_values random_values = Array.new letters = ['A','B','C','D','E','F'] for i in 1..15 if i <= 9 random_values << i else random_values << letters[i-10] end end return random_values.shuffle[0].to_s + random_values.shuffle[0].to_s + random_values.shuffle[0].to_s end As you probably see, I do not generate random numbers. I just shuffle the array containing the values I want, meaning all the numbers in the array are unique, which is not needed, but was the easiest solution for me when I wrote the code. I am most concerned about the return line.. If only it was possible to write like: return 3.times { random_values.shuffle[0] } or return random_values.shuffle[0].to_s *3 Thanks in advance!

    Read the article

  • Reading from an write-only(OUT) parameter in pl/sql

    - by sqlgrasshopper5
    When I tried writing to an read-only parameter(IN) of a function, Oracle complains with an error. But that is not the case when reading from an write-only(OUT) parameter of a function. Oracle silently allows this without any error. What is the reason for this behaviour?. The following code executes without any assignment happening to "so" variable: create or replace function foo(a OUT number) return number is so number; begin so := a; --no assignment happens here a := 42; dbms_output.put_line('HiYA there'); dbms_output.put_line('VAlue:' || so); return 5; end; / declare somevar number; a number := 6; begin dbms_output.put_line('Before a:'|| a); somevar := foo(a); dbms_output.put_line('After a:' || a); end; / Here's the output I got: Before a:6 HiYA there VAlue: After a:42

    Read the article

  • Should I write my own forum software?

    - by acidzombie24
    I have already built a site from scratch. It has banning, PM, comments, etc. The PMs and comments are done using markdown (like SO). There are pros and cons for writing my own or using another software. But some cons keeping me from using another forum software is Multiple Logins: One for the site, one for separate forums. Need to Customization code: I'll need to change the toolbar in the forum software so I can access pages on the regular site. Look consistency: It may look drastically different from my site even after applying lots of css changes. Banning and User consistency. Users may be ban on site or on forums but not the other. users may select a different or multiple usernames on the forum instead of being forced to use the same username on both site and forum. Should I write my own forum code or should I use something already written? What are some reasons for or against writing my own and using forum software?

    Read the article

  • Rails : can't write unknown attribute `url'

    - by user2954789
    I am new to ruby on rails,and I am learning by creating a blog. I am not able to save to my blogs table and I get this error "can't write unknown attribute url" Blogs migration :db/migrate/ class CreateBlogs < ActiveRecord::Migration --def change --- create_table :blogs do |t| ---- t.string :title ---- t.text :description ---- t.string :slug ---- t.timestamps --- end --end end Blogs Model :/app/models/blogs.rb class Blogs < ActiveRecord::Base --acts_as_url :title --def to_param ---url --end --validates :title, presence:true end Blogs Controller : /app/controllers/blogs_controller.rb class BlogsController < ApplicationController before_action :require_login --def new --- @blogs = Blogs.new --end --def show ---@blogs = Blogs.find(params[:id]) --end --def create ---@blogs = Blogs.new(blogs_params) --if @blogs.save ---flash[:success] = "Your Blog has been created." ---redirect_to home_path --else ---render 'new' --end -end --def blogs_params ---params.require(:blogs).permit(:title,:description) --end private --def require_login ---unless signed_in? ----flash[:error] = "You must be logged in to create a new Blog" ----redirect_to signin_path ---end --end end Blogs Form:/app/views/blogs/new.html.erb Blockquote <%= form_for @blogs, url: blogs_path do |f| %><br/> <%= render 'shared/error_messages_blogs' %><br/> <%= f.label :title %><br/> <%= f.text_field :title %><br/> <%= f.label :description %><br/> <%= f.text_area :description %><br/> <%= f.submit "Submit Blog", class: "btn btn-large btn-primary" %><br/> <% end %><br/> and I have also added "resources :blogs" to my routes.rb file. I get this error in controller at if @blogs.save

    Read the article

  • Java program will read from database, but not write to it

    - by ck1221
    I have a Java program that successfully connects to a mysql database that is hosted on godaddy's server. I can read from that db with out issue, however, when I try to write to it with INSERT or UPDATE for example, the query does not execute. I am using the 'admin' account that I set up through godaddy, I realize this is not the root account. I have checked and verified that the connection is not read only, and have logged out of phpmyadmin while the query ran. I'm not sure what else I can try or if anyone has experienced this issue. Maybe a setting to the connection I have failed to set? Or maybe its not possible since the db is hosted on godaddy's servers? Any help is great! Thanks. Here is some relevant code: Connection to db: Connection con; public DBconnection(String url, String user, String pass) { try { Class.forName("com.mysql.jdbc.Driver").newInstance(); con = DriverManager.getConnection (url,user,pass); if(!con.isClosed()) System.out.println("connecton open"); } catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();} } Send Query: public ResultSet executeQuery(String query) { ResultSet rs = null; try { Statement stmt = (Statement) con.createStatement(); rs = stmt.executeQuery(query); //while(rs.next()) //System.out.println(rs.getString("ticket_num")); } catch (SQLException e) {} return rs; } Insert Query (works in phpmyadmin): conn.executeQuery("INSERT INTO tickets VALUES(55555,'12/01/2012','me','reports','test','','','0','Nope')");

    Read the article

  • File write not getting updated in Qt 4.5.3

    - by user249490
    Hi, I have an XML file. My application requires manipulation into that XML file. I will be writing the values into the XML value. I also have interface to display the read contents of the file. The user might add values into that XML (through an interface). Without closing the application he may decide to display the File contents also. Now the problem is, after i write the XML contents into the file, when i view the file through the interface , the values are not getting updated. After i close the application and open it the updated values are available.I am using the following code to achieve this. For writing QXmlStreamWriter and for reading QDomDocument, QDomNodeList. After i complete the writing, I flush and close the file too. lFile.flush(); lFile.close(); After reading also i closed the file. Can someone tell me what am doing wrong??

    Read the article

  • Write-Only Reference in C++?

    - by Robert Mason
    Is there a way to code a write-only reference to an object? For example, suppose there was a mutex class: template <class T> class mutex { protected: T _data; public: mutex(); void lock(); //locks the mutex void unlock(); //unlocks the mutex T& data(); //returns a reference to the data, or throws an exception if lock is unowned }; Is there a way to guarantee that one couldn't do this: mutex<type> foo; T& ref; foo.lock(); ref = foo.data(); foo.unlock(); //I have a unguarded reference to foo now On the other hand, is it even worth it? I know that some people assume that programmers won't deliberately clobber the system, but then, why do we have private variables in the first place, eh? It'd be nice to just say it's "Undefined Behavior", but that just seems a little bit too insecure.

    Read the article

  • How can I write simulations in Erlang?

    - by rick
    Hi guys, I want to do some numerical stuff in Erlang like this: You've got an array with the following values: [2,3,4] In each iteration, you calculate 0.1 * [n-1] + 0.7 *[n] + 0.2 * [n+1] This becomes the new [n]. If n == 0 then [n-1] = 0. If [n] == length of array then [n] = 0. So I try an example: [2,3,4] calculations: 0.1 * 0 + 0.7 * 2 + 0.2 * 3 = 2 0.1 * 2 + 0.7 * 3 + 0.2 * 4 = 3.1 0.1 * 3 + 0.7 * 4 + 0.2 * 0 = 3.1 So [2,3,4] becomes to [2, 3.1, 3.1] after one iteration. I know how to write this in a non-functional language like C. But I have difficulties to imagine, how this could be done in Erlang. I found some tutorials on how you read a file to a list. So this is not the problem. How can I spawn different Erlang processes that each process has one element of the list? How can I do calculations by communicating with 'the neighbors', so that the neighbors know where their neigbors are generically, without specifying each? How can I collect the data into a list? Eventually, is it possible to solve that problem in Erlang at all? Thanks for your help.

    Read the article

  • write a program that prompts the user to input five decimal numbers

    - by user312309
    This is the question. write a program that prompts the user to input five decimal numbers. the program should then add the five decimal numbers, convert the sum to the nearest integer,m and print the result. This is what I've gotten so far: // p111n9.cpp : Defines the entry point for the console application. // #include <iostream> using namespace std; double a, b , c , d , e, f; int main(int argc, char* argv[]) { cout << "enter 5 decimals: " << endl; cin >> a >> b >> c >> d >> e; f = a + b + c + d + e; return 0; } Now I just need to convert the sum(f) to the nearest integer, m and print the result. How do I do this?

    Read the article

  • Looking for a book which teaches how to write applications (as opposed to writng code)

    - by rumtscho
    I am not a developer. I have coded for fun and for university projects in several languages, and during an internship, I have written code which is still in use by a department of Fortune Global 500 company. I also have extensive theoretical knowledge of software engineering - process models, architecture, project management, UI construction using Lauesen's virtual windows... you get the picture. But I am not involved with software development in my job. I recently decided to start coding for fun again, and now I have some free days to do it. But this time, I want to do it right. I want to write a real, useful application, install it on my devices and use it myself. Also I want to publish it for others to use, should they want to do so. I am vaguely aware that there is more to writing an application than to writing code. There is stuff like version control software, decision for the right IDE, having a suite of unit tests, producing an installation package - and probably lots of other things I never thought of but which must be taken care of in a proper application, as opposed to a bunch of classes I am running from my IDE. All this is stuff I should know before I start, but I have not learned it. Coding books touch on some of the subjects like IDE choice, but don't go into detail, and are not exhaustive. Theoretical software engineering textbooks are even less helpful. So is there a book which teaches exactly that? I know that I can find information on each of these topics on the Internet, but I'd rather have a systematic book exhaustively listing all the things I should take care of if I want to create a good application, and offering the currently accepted solutions for them. In the best case, it will be language- and platform independent, but if you know of a good book focusing on a specific platform, I would like to know about it too. I know I want a lot, but given how important such knowledge is and how many people need it, surely somebody must have written such a book?

    Read the article

  • Write out to text file using T-SQL

    - by sasfrog
    I am creating a basic data transfer task using TSQL where I am retrieving certain records from one database that are more recent than a given datetime value, and loading them into another database. This will happen periodically throughout the day. It's such a small task that SSIS seems like overkill - I want to just use a scheduled task which runs a .sql file. Where I need guidance is that I need to persist the datetime from the last run of this task, then use this to filter the records next time the task runs. My initial thought is to just store the datetime in a text file, and update (overwrite) it as part of the task each time it runs. I can read the file in without problems using T-SQL, but writing back out has got me stuck. I've seen plenty of examples which make use of a dynamically-built bcp command, which is then executed using xp_cmdshell. Trouble is, security on the server I'm deploying to precludes the use of xp_cmdshell. So, my question is, are there other ways to simply write a datetime value to a file using TSQL, or should I be thinking about a different approach? EDIT: happy to be corrected about SSIS being "overkill"...

    Read the article

  • write a program that prompts the user to input five decimal numbers : C++

    - by user312309
    This is the question. write a program that prompts the user to input five decimal numbers. the program should then add the five decimal numbers, convert the sum to the nearest integer,m and print the result. This is what I've gotten so far: // p111n9.cpp : Defines the entry point for the console application. // #include <iostream> using namespace std; double a, b , c , d , e, f; int main(int argc, char* argv[]) { cout << "enter 5 decimals: " << endl; cin >> a >> b >> c >> d >> e; f = a + b + c + d + e; return 0; } Now I just need to convert the sum(f) to the nearest integer, m and print the result. How do I do this?

    Read the article

  • write a function using generic

    - by user296551
    hi,guy, i want write a function using c#, and it accept any type parameter,i want use generic list to do, but i can't finish, it's wrong, how to do it? perhaps there are other ways?? thinks! public class City { public int Id; public int? ParentId; public string CityName; } public class ProductCategory { public int Id; public int? ParentId; public string Category; public int Price; } public class Test { public void ReSortList<T>(IEnumerable<T> sources, ref IEnumerable<T> returns, int parentId) { //how to do like this: /* var parents = from source in sources where source.ParentId == parentId && source.ParentId.HasValue select source; foreach (T child in parents) { returns.Add(child); ReSortList(sources, ref returns, child.Id); } */ } public void Test() { IList<City> city = new List<City>(); city.Add(new City() { Id = 1, ParentId = 0, CityName = "China" }); city.Add(new City() { Id = 2, ParentId = null, CityName = "America" }); city.Add(new City() { Id = 3, ParentId = 1, CityName = "Guangdong" }); IList<City> results = new List<City>(); ReSortList<City>(city, ref results, 0); //error } }

    Read the article

  • How to write this loop prettier?

    - by Tom
    I've just read this topic http://stackoverflow.com/questions/2930533/highlight-search-keywords-on-hover and actually I use pretty the same structure, but it looks awful. So can you give me an advice, how to write this loop prettier in one php file, I mean php and html at the same time? <table class="result"> <?php while ($row= mysql_fetch_array($result, MYSQL_ASSOC)) { $cQuote = highlightWords(htmlspecialchars($row['cQuotes']), $search_result); ?> <tr> <td style="text-align:right; font-size:15px;"><?php h($row['cArabic']); ?></td> <td style="font-size:16px;"><?php echo $cQuote; ?></td> <td style="font-size:12px;"><?php h($row['vAuthor']); ?></td> <td style="font-size:12px; font-style:italic; text-align:right;"><?php h($row['vReference']); ?></td> </tr> <?php } ?>

    Read the article

  • Synchronization requirements for FileStream.(Begin/End)(Read/Write)

    - by Doug McClean
    Is the following pattern of multi-threaded calls acceptable to a .Net FileStream? Several threads calling a method like this: ulong offset = whatever; // different for each thread byte[] buffer = new byte[8192]; object state = someState; // unique for each call, hence also for each thread lock(theFile) { theFile.Seek(whatever, SeekOrigin.Begin); IAsyncResult result = theFile.BeginRead(buffer, 0, 8192, AcceptResults, state); } if(result.CompletedSynchronously) { // is it required for us to call AcceptResults ourselves in this case? // or did BeginRead already call it for us, on this thread or another? } Where AcceptResults is: void AcceptResults(IAsyncResult result) { lock(theFile) { int bytesRead = theFile.EndRead(result); // if we guarantee that the offset of the original call was at least 8192 bytes from // the end of the file, and thus all 8192 bytes exist, can the FileStream read still // actually read fewer bytes than that? // either: if(bytesRead != 8192) { Panic("Page read borked"); } // or: // issue a new call to begin read, moving the offsets into the FileStream and // the buffer, and decreasing the requested size of the read to whatever remains of the buffer } } I'm confused because the documentation seems unclear to me. For example, the FileStream class says: Any public static members of this type are thread safe. Any instance members are not guaranteed to be thread safe. But the documentation for BeginRead seems to contemplate having multiple read requests in flight: Multiple simultaneous asynchronous requests render the request completion order uncertain. Are multiple reads permitted to be in flight or not? Writes? Is this the appropriate way to secure the location of the Position of the stream between the call to Seek and the call to BeginRead? Or does that lock need to be held all the way to EndRead, hence only one read or write in flight at a time? I understand that the callback will occur on a different thread, and my handling of state, buffer handle that in a way that would permit multiple in flight reads. Further, does anyone know where in the documentation to find the answers to these questions? Or an article written by someone in the know? I've been searching and can't find anything. Relevant documentation: FileStream class Seek method BeginRead method EndRead IAsyncResult interface

    Read the article

  • How to write this JavaScript code without eval?

    - by karlthorwald
    How to write this JavaScript code without eval? var typeOfString = eval("typeof " + that.modules[modName].varName); if (typeOfString !== "undefined") { doSomething(); } The point is that the name of the var that I want to check for is in a string. Maybe it is simple but I don't know how. Edit: Thank you for the very interesting answers so far. I will follow your suggestions and integrate this into my code and do some testing and report. Could take a while. Edit2: I had another look at the could and maybe itis better I show you a bigger picture. I am greatful for the experts to explain so beautiful, it is better with more code: MYNAMESPACE.Loader = ( function() { function C() { this.modules = {}; this.required = {}; this.waitCount = 0; this.appendUrl = ''; this.docHead = document.getElementsByTagName('head')[0]; } function insert() { var that = this; //insert all script tags to the head now! //loop over all modules: for (var modName in this.required) { if(this.required.hasOwnProperty(modName)){ if (this.required[modName] === 'required') { this.required[modName] = 'loading'; this.waitCount = this.waitCount + 1; this.insertModule(modName); } } } //now poll until everything is loaded or //until timout this.intervalId = 0; var checkFunction = function() { if (that.waitCount === 0) { clearInterval(that.intervalId); that.onSuccess(); return; } for (var modName in that.required) { if(that.required.hasOwnProperty(modName)){ if (that.required[modName] === 'loading') { var typeOfString = eval("typeof " + that.modules[modName].varName); if (typeOfString !== "undefined") { //module is loaded! that.required[modName] = 'ok'; that.waitCount = that.waitCount - 1; if (that.waitCount === 0) { clearInterval(that.intervalId); that.onSuccess(); return; } } } } } }; //execute the function twice a second to check if all is loaded: this.intervalId = setInterval(checkFunction, 500); //further execution will be in checkFunction, //so nothing left to do here } C.prototype.insert = insert; //there are more functions here... return C; }()); var myLoader = new MYNAMESPACE.Loader(); //some more lines here... myLoader.insert();

    Read the article

  • Event sourcing: Write event before or after updating the model

    - by Magnus
    I'm reasoning about event sourcing and often I arrive at a chicken and egg problem. Would be grateful for some hints on how to reason around this. If I execute all I/O-bound processing async (ie writing to the event log) then how do I handle, or sometimes even detect, failures? I'm using Akka Actors so processing is sequential for each event/message. I do not have any database at this time, instead I would persist all the events in an event log and then keep an aggregated state of all the events in a model stored in memory. Queries are all against this model, you can consider it to be a cache. Example Creating a new user: Validate that the user does not exist in model Persist event to journal Update model (in memory) If step 3 breaks I still have persisted my event so I can replay it at a later date. If step 2 breaks I can handle that as well gracefully. This is fine, but since step 2 is I/O-bound I figured that I should do I/O in a separate actor to free up the first actor for queries: Updating a user while allowing queries (A0 = Front end/GUI actor, A1 = Processor Actor, A2 = IO-actor, E = event bus). (A0-E-A1) Event is published to update user 'U1'. Validate that the user 'U1' exists in model (A1-A2) Persist event to journal (separate actor) (A0-E-A1-A0) Query for user 'U1' profile (A2-A1) Event is now persisted continue to update model (A0-E-A1-A0) Query for user 'U1' profile (now returns fresh data) This is appealing since queries can be processed while I/O-is churning along at it's own pace. But now I can cause myself all kinds of problems where I could have two incompatible commands (delete and then update) be persisted to the event log and crash on me when replayed up at a later date, since I do the validation before persisting the event and then update the model. My aim is to have a simple reasoning around my model (since Actor processes messages sequentially single threaded) but not be waiting for I/O-bound updates when Querying. I get the feeling I'm modeling a database which in itself is might be a problem. If things are unclear please write a comment.

    Read the article

  • Android , Read in binary data and write it to file

    - by Shpongle
    Hi all , Im trying to read in image file from a server , with the code below . It keeps going into the exception. I know the correct number of bytes are being sent as I print them out when received. Im sending the image file from python like so #open the image file and read it into an object imgfile = open (marked_image, 'rb') obj = imgfile.read() #get the no of bytes in the image and convert it to a string bytes = str(len(obj)) #send the number of bytes self.conn.send( bytes + '\n') if self.conn.sendall(obj) == None: imgfile.flush() imgfile.close() print 'Image Sent' else: print 'Error' Here is the android part , this is where I'm having the problem. Any suggestions on the best way to go about receiving the image and writing it to a file ? //read the number of bytes in the image String noOfBytes = in.readLine(); Toast.makeText(this, noOfBytes, 5).show(); byte bytes [] = new byte [Integer.parseInt(noOfBytes)]; //create a file to store the retrieved image File photo = new File(Environment.getExternalStorageDirectory(), "PostKey.jpg"); DataInputStream dis = new DataInputStream(link.getInputStream()); try{ os =new FileOutputStream(photo); byte buf[]=new byte[1024]; int len; while((len=dis.read(buf))>0) os.write(buf,0,len); Toast.makeText(this, "File recieved", 5).show(); os.close(); dis.close(); }catch(IOException e){ Toast.makeText(this, "An IO Error Occured", 5).show(); } EDIT: I still cant seem to get it working. I have been at it since and the result of all my efforts have either resulted in a file that is not the full size or else the app crashing. I know the file is not corrupt before sending server side. As far as I can tell its definitely sending too as the send all method in python sends all or throws an exception in the event of an error and so far it has never thrown an exception. So the client side is messed up . I have to send the file from the server so I cant use the suggestion suggested by Brian .

    Read the article

  • How to write my own global lock / unlock functions for PostgreSQL

    - by rafalmag
    I have postgresql (in perlu) function getTravelTime(integer, timestamp), which tries to select data for specified ID and timestamp. If there are no data or if data is old, it downloads them from external server (downloading time ~300ms). Multiple process use this database and this function. There is an error when two process do not find data and download them and try to do an insert to travel_time table (id and timestamp pair have to be unique). I thought about locks. Locking whole table would block all processes and allow only one to proceed. I need to lock only on id and timestamp. pg_advisory_lock seems to lock only in "current session". But my processes uses their own sessions. I tried to write my own lock/unlock functions. Am I doing it right? I use active waiting, how can I omit this? Maybe there is a way to use pg_advisory_lock() as global lock? My code: CREATE TABLE travel_time_locks ( id_key integer NOT NULL, time_key timestamp without time zone NOT NULL, UNIQUE (id_key, time_key) ); ------------ -- Function: mylock(integer, timestamp) DROP FUNCTION IF EXISTS mylock(integer, timestamp) CASCADE; -- Usage: SELECT mylock(1, '2010-03-28T19:45'); -- function tries to do a global lock similar to pg_advisory_lock(key, key) CREATE OR REPLACE FUNCTION mylock(id_input integer, time_input timestamp) RETURNS void AS $BODY$ DECLARE rows int; BEGIN LOOP BEGIN -- active waiting here !!!! :( INSERT INTO travel_time_locks (id_key, time_key) VALUES (id_input, time_input); EXCEPTION WHEN unique_violation THEN CONTINUE; END; EXIT; END LOOP; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 1; ------------ -- Function: myunlock(integer, timestamp) DROP FUNCTION IF EXISTS myunlock(integer, timestamp) CASCADE; -- Usage: SELECT myunlock(1, '2010-03-28T19:45'); -- function tries to do a global unlock similar to pg_advisory_unlock(key, key) CREATE OR REPLACE FUNCTION myunlock(id_input integer, time_input timestamp) RETURNS integer AS $BODY$ DECLARE BEGIN DELETE FROM ONLY travel_time_locks WHERE id_key=id_input AND time_key=time_input; RETURN 1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 1;

    Read the article

< Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102  | Next Page >