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  • How do I get spring to inject my EntityManager?

    - by Trampas Kirk
    I'm following the guide here, but when the DAO executes, the EntityManager is null. I've tried a number of fixes I found in the comments on the guide, on various forums, and here (including this), to no avail. No matter what I seem to do the EntityManager remains null. Here are the relevant files, with packages etc changed to protect the innocent. spring-context.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd" xmlns:p="http://www.springframework.org/schema/p"> <context:component-scan base-package="com.group.server"/> <context:annotation-config/> <tx:annotation-driven/> <bean id="propertyPlaceholderConfigurer" class="com.group.DecryptingPropertyPlaceholderConfigurer" p:systemPropertiesModeName="SYSTEM_PROPERTIES_MODE_OVERRIDE"> <property name="locations"> <list> <value>classpath*:spring-*.properties</value> <value>classpath*:${application.environment}.properties</value> </list> </property> </bean> <bean id="orderDao" class="com.package.service.OrderDaoImpl"/> <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="MyServer"/> <property name="loadTimeWeaver"> <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/> </property> <property name="dataSource" ref="dataSource"/> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="showSql" value="${com.group.server.vendoradapter.showsql}"/> <property name="generateDdl" value="${com.group.server.vendoradapter.generateDdl}"/> <property name="database" value="${com.group.server.vendoradapter.database}"/> </bean> </property> </bean> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory"/> <property name="dataSource" ref="dataSource"/> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="${com.group.server.datasource.driverClassName}"/> <property name="url" value="${com.group.server.datasource.url}"/> <property name="username" value="${com.group.server.datasource.username}"/> <property name="password" value="${com.group.server.datasource.password}"/> </bean> <bean id="executorService" class="java.util.concurrent.Executors" factory-method="newCachedThreadPool"/> </beans> persistence.xml <persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0"> <persistence-unit name="MyServer" transaction-type="RESOURCE_LOCAL"/> </persistence> OrderDaoImpl package com.group.service; import com.group.model.Order; import org.springframework.stereotype.Repository; import org.springframework.transaction.annotation.Transactional; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import java.util.List; @Repository @Transactional public class OrderDaoImpl implements OrderDao { private EntityManager entityManager; @PersistenceContext public void setEntityManager(EntityManager entityManager) { this.entityManager = entityManager; } @Override public Order find(Integer id) { Order order = entityManager.find(Order.class, id); return order; } @Override public List<Order> findAll() { Query query = entityManager.createQuery("select o from Order o"); return query.getResultList(); } @Override public List<Order> findBySymbol(String symbol) { Query query = entityManager.createQuery("select o from Order o where o.symbol = :symbol"); return query.setParameter("symbol", symbol).getResultList(); } }

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  • How can I inject multiple repositories in a NServicebus message handler?

    - by Paco
    I use the following: public interface IRepository<T> { void Add(T entity); } public class Repository<T> { private readonly ISession session; public Repository(ISession session) { this.session = session; } public void Add(T entity) { session.Save(entity); } } public class SomeHandler : IHandleMessages<SomeMessage> { private readonly IRepository<EntityA> aRepository; private readonly IRepository<EntityB> bRepository; public SomeHandler(IRepository<EntityA> aRepository, IRepository<EntityB> bRepository) { this.aRepository = aRepository; this.bRepository = bRepository; } public void Handle(SomeMessage message) { aRepository.Add(new A(message.Property); bRepository.Add(new B(message.Property); } } public class MessageEndPoint : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization { public void Init() { ObjectFactory.Configure(config => { config.For<ISession>() .CacheBy(InstanceScope.ThreadLocal) .TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<ISessionFactory>().OpenSession()); config.ForRequestedType(typeof(IRepository<>)) .TheDefaultIsConcreteType(typeof(Repository<>)); } } My problem with the threadlocal storage is, is that the same session is used during the whole application thread. I discovered this when I saw the first level cache wasn't cleared. What I want is using a new session instance, before each call to IHandleMessages<.Handle. How can I do this with structuremap? Do I have to create a message module?

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  • How does one inject variables into page templates from a custom Drupal module?

    - by Michael T. Smith
    We've created a custom module for organizing and publishing our newsletter content. The issue I'm running into now -- and I'm new to theming and Drupal module development, so it could just be a knowledge issue as opposed to a Drupal issue -- is how to get each newsletter themed. At this point the URL structure of our newsletter will be: /newsletters/{newsletter-name}/{edition-name}/{issue-date} which means that we can create template files in our theme using filenames like page-newsletters-{newsletter-name}-{edition-name}.tpl.php, which is great. The one issue I'm running into is that all of the content comes through in the $content variable of the theme. I'd like to have it come through as different variables (so that I can, inside the theme, place certain content in certain areas.) Is there a proper way for doing this?

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  • Dependency Injection with @Inject in Weld (JSR-299 RI). How is the corresponding @Produces found?

    - by Thorbjørn Ravn Andersen
    I have played with the JSR-299 Reference Implementation "Weld" with the purpose of using it in a stand-alone application, and I have had a look at the documentation, and marveled at the magic. My question is how the producer of a given object to be @Inject'ed is found? Either the java compiler produces hints for annotations which is easily found by the classloader, or the complete classpath must be traversed loading all classes to see what they do which sounds highly inefficient to me, or it is a completely different approach. What is the trick?

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  • Need help writing jQuery to loop through table and inject markers into google map?

    - by abemonkey
    I am new to jQuery. I've done some simple things with it but what I am attempting now is a over my head and I need some help. I am building a locator for all the firearms dealers in the US for a client. I am working within Drupal. I have a proximity search by zip code that works great. If you search by zip a list of paginated results shows up in an html table that can by paged through via ajax. I would like a map to be above this list with markers corresponding to the names and addresses being listed. I already have all the lat and long values in the table results. I want the script to update the markers and automatically zoom to fit the markers in the view when a user changes the sort order of the table or pages through the results. Also, I'd like to have a hover highlight effect over the rows of the table that simultaneously highlight the corresponding marker, and have a click on the table row equal a click on a marker that pops up a marker info window to be populated using jQuery to read the name and address fields of the table. Hope this all makes sense. I know I'm putting a lot out there, I'm not asking for someone to write the whole script, just wanted to give as many details as possible. Thanks for any help. I'm just lost when it comes to looping and moving data around. If you want to check out what I have so far on the project please visit: www.axtsweapons.com and login with the username: "test" and the password: "1234" and then visit this direct link: www.axtsweapons.com/ffllocator. For just a simple page that would be easy to manipulate and play with goto: http://www.axtsweapons.com/maptest.html Thanks!

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  • How can I dynamically inject code to event handlers in Delphi?

    - by mjustin
    For debugging / performance tests I would like to dynamically add logging code to all event handlers of components of a given type. For example, for all Dataset components located ona TDatamodule, I would like to add some code for the BeforeOpen and the AfterOpen event to store the start and end time and send a line to a logger with the elapsed time in the AfterOpen event. I would prefer to do this dynamically (no component subclassing), so that I can add this to all existing datamodules and forms with minimal effort only when needed. Iterating all components and filtering by their type is easy, but for the components which already have event handlers assigned, I need a way to store the existing event handlers, and assign a new modified event handler which first does the logging and then will invoke the original code which was already present. Is there a design pattern which can be applied, or even some example code which shows how to implement this in Delphi?

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  • Isthere an equivalent in CDI(WELD) to Guice modules and Inject ?

    - by mP
    I like the way Guice makes it fairly straight forward to manually create your own modules each with their own bindings done in code. CDI on the other hand seems to rely more on magic rather than programmatic access to sest bindings. Am i wrong or how can one achieve the same effect with WELD. Any code sample would be appreciated...

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  • How can I dynamically inject code into event handlers in Delphi?

    - by mjustin
    For debugging / performance tests I would like to dynamically add logging code to all event handlers of components of a given type. For example, for all Dataset components located ona TDatamodule, I would like to add some code for the BeforeOpen and the AfterOpen event to store the start and end time and send a line to a logger with the elapsed time in the AfterOpen event. I would prefer to do this dynamically (no component subclassing), so that I can add this to all existing datamodules and forms with minimal effort only when needed. Iterating all components and filtering by their type is easy, but for the components which already have event handlers assigned, I need a way to store the existing event handlers, and assign a new modified event handler which first does the logging and then will invoke the original code which was already present. Is there a design pattern which can be applied, or even some example code which shows how to implement this in Delphi?

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  • How to inject a key string to andoid device through ADB?

    - by Nandi
    Hi, Can somebody help me for the following. I want to select a perticular string in the list displayed in android phone. If i take example of phone book. i want to pass a person name to the device using adb interface and that name should get highlighted in the list. I tried all adb commands for this but could pass string and key events to the screen but not able to select the respective string. please help. Thanks in advance.

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  • How to inject php code from database into php script ?

    - by luxquarta
    I want to store php code inside my database and then use it into my script. class A { public function getName() { return "lux"; } } // instantiates a new A $a = new A(); Inside my database there is data like "hello {$a->getName()}, how are you ?" In my php code I load the data into a variable $string $string = load_data_from_db(); echo $string; // echoes hello {$a->getName()}, how are you ? So now $string contains "hello {$a-getName()}, how are you ?" {$a-getName()} still being un-interpretated Question: I can't find how to write the rest of the code so that {$a-getName()} gets interpretated "into hello lux, how are you". Can someone help ? $new_string = ?????? echo $new_string; //echoes hello lux, how are you ? Is there a solution with eval() ? (please no debate about evil eval ;)) Or any other solution ?

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  • What is the best way to inject a javascript script from another domain into a page? (without using a

    - by lowellk
    Here is a snippet of javascript for loading a script onto a given page asynchronously. I was wondering if there was anything wrong with it? Can it be improved? I haven't played with this yet, but some things I'm worried about are: - cross browser support - when script.readyState is true, will the old version of that function get clobbered? - can i always count on there being a head or body element? Here it is: function injectScript(url, callback){ var script = document.createElement('script'); script.type = "text/javascript"; script.setAttribute('async', 'true'); script.src = url; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(script); if (callback) { if (script.readyState){ script.onreadystatechange = function(){ if(script.readyState === "loaded" || script.readyState === "complete"){ script.onreadystatechange = null; callback(); } }; }else{ script.onload = function() { callback(); } } } }

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  • Java EE 7 Survey Results!

    - by reza_rahman
    On November 8th, the Java EE EG posted a survey to gather broad community feedback on a number of critical open issues. For reference, you can find the original survey here. We kept the survey open for about three weeks until November 30th. To our delight, over 1100 developers took time out of their busy lives to let their voices be heard! The results of the survey were sent to the EG on December 12th. The subsequent EG discussion is available here. The exact summary sent to the EG is available here. We would like to take this opportunity to thank each and every one the individuals who took the survey. It is very appreciated, encouraging and worth it's weight in gold. In particular, I tried to capture just some of the high-quality, intelligent, thoughtful and professional comments in the summary to the EG. I highly encourage you to continue to stay involved, perhaps through the Adopt-a-JSR program. We would also like to sincerely thank java.net, JavaLobby, TSS and InfoQ for helping spread the word about the survey. Below is a brief summary of the results... APIs to Add to Java EE 7 Full/Web Profile The first question asked which of the four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. As the following graph shows, there was significant support for adding all the new APIs to the full profile: Support is relatively the weakest for Batch 1.0, but still good. A lot of folks saw WebSocket 1.0 as a critical technology with comments such as this one: "A modern web application needs Web Sockets as first class citizens" While it is clearly seen as being important, a number of commenters expressed dissatisfaction with the lack of a higher-level JSON data binding API as illustrated by this comment: "How come we don't have a Data Binding API for JSON" JCache was also seen as being very important as expressed with comments like: "JCache should really be that foundational technology on which other specs have no fear to depend on" The results for the Web Profile is not surprising. While there is strong support for adding WebSocket 1.0 and JSON-P 1.0 to the Web Profile, support for adding JCache 1.0 and Batch 1.0 is relatively weak. There was actually significant opposition to adding Batch 1. 0 (with 51.8% casting a 'No' vote). Enabling CDI by Default The second question asked was whether CDI should be enabled in Java EE environments by default. A significant majority of 73.3% developers supported enabling CDI, only 13.8% opposed. Comments such as these two reflect a strong general support for CDI as well as a desire for better Java EE alignment with CDI: "CDI makes Java EE quite valuable!" "Would prefer to unify EJB, CDI and JSF lifecycles" There is, however, a palpable concern around the performance impact of enabling CDI by default as exemplified by this comment: "Java EE projects in most cases use CDI, hence it is sensible to enable CDI by default when creating a Java EE application. However, there are several issues if CDI is enabled by default: scanning can be slow - not all libs use CDI (hence, scanning is not needed)" Another significant concern appears to be around backwards compatibility and conflict with other JSR 330 implementations like Spring: "I am leaning towards yes, however can easily imagine situations where errors would be caused by automatically activating CDI, especially in cases of backward compatibility where another DI engine (such as Spring and the like) happens to use the same mechanics to inject dependencies and in that case there would be an overlap in injections and probably an uncertain outcome" Some commenters such as this one attempt to suggest solutions to these potential issues: "If you have Spring in use and use javax.inject.Inject then you might get some unexpected behavior that could be equally confusing. I guess there will be a way to switch CDI off. I'm tempted to say yes but am cautious for this reason" Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations. A slight majority of 53.3% developers supported using @Inject consistently across JSRs. 28.8% said using custom injection annotations is OK, while 18.0% were not sure. The vast majority of commenters were strongly supportive of CDI and general Java EE alignment with CDI as illistrated by these comments: "Dependency Injection should be standard from now on in EE. It should use CDI as that is the DI mechanism in EE and is quite powerful. Having a new JSR specific DI mechanism to deal with just means more reflection, more proxies. JSRs should also be constructed to allow some of their objects Injectable. @Inject @TransactionalCache or @Inject @JMXBean etc...they should define the annotations and stereotypes to make their code less procedural. Dog food it. If there is a shortcoming in CDI for a JSR fix it and we will all be grateful" "We're trying to make this a comprehensive platform, right? Injection should be a fundamental part of the platform; everything else should build on the same common infrastructure. Each-having-their-own is just a recipe for chaos and having to learn the same thing 10 different ways" Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A significant majority of 62.3% developers supported expanding the use of @Stereotype, only 13.3% opposed. A majority of commenters supported the idea as well as the theme of general CDI/Java EE alignment as expressed in these examples: "Just like defining new types for (compositions of) existing classes, stereotypes can help make software development easier" "This is especially important if many EJB services are decoupled from the EJB component model and can be applied via individual annotations to Java EE components. @Stateless is a nicely compact annotation. Code will not improve if that will have to be applied in the future as @Transactional, @Pooled, @Secured, @Singlethreaded, @...." Some, however, expressed concerns around increased complexity such as this commenter: "Could be very convenient, but I'm afraid if it wouldn't make some important class annotations less visible" Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE... A very solid 96.3% of developers wanted to expand interceptor use to all Java EE components. 35.7% even wanted to expand interceptors to other Java EE managed classes. Most developers (54.9%) were not sure if there is any place that injection is supported that should not support interceptors. 32.8% thought any place that supports injection should also support interceptors. Only 12.2% were certain that there are places where injection should be supported but not interceptors. The comments reflected the diversity of opinions, generally supportive of interceptors: "I think interceptors are as fundamental as injection and should be available anywhere in the platform" "The whole usage of interceptors still needs to take hold in Java programming, but it is a powerful technology that needs some time in the Sun. Basically it should become part of Java SE, maybe the next step after lambas?" A distinct chain of thought separated interceptors from filters and listeners: "I think that the Servlet API already provides a rich set of possibilities to hook yourself into different Servlet container events. I don't find a need to 'pollute' the Servlet model with the Interceptors API"

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  • Should an object be fully complete before injected as a dependency?

    - by Hans
    This is an extension of this question: http://stackoverflow.com/questions/3027082/understanding-how-to-inject-object-dependencies. Since it is a bit different, I wanted to separate them, to make it, hopefully, easier to answer. Also, this is not a real system, just a simplified example that I thought we'd all be familiar with. TIA. : DB threads: thread_id, thread_name, etc posts: post_id, thread_id, post_name, post_contents, post_date, post_user_id, etc Overview Basically I'm looking at the most maintainable way to load $post_id and have it cascade and load the other things I want to know about and I'm trying to keep the controller skinny. BUT: I'm ending up with too many dependencies to inject I'm passing in initialized but empty objects I want to limit how many parameters I am passing around I could inject $post(-many) into $thread(one<-), but on that page I'm not looking at a thread, I'm looking at a post I could combine/inject them into a new object Detail If I am injecting an object into another, is it best to have it fully created first? I'm trying to limit how many parameters I have to pass in to a page, but I end up with a circle. // 1, empty object injected via constructor $thread = new Thread; $post = new Post($thread); // $thread is just an empty object $post->load($post_id); // I could now do something like $post->get('thread_id') to get everything I want in $post // 2, complete object injected via constructor $thread = new Thread; $thread->load($thread_id); // this page would have to have passed in a $thread_id, too $post = new Post($thread); // thread is a complete object, with the data I need, like thread name $post->load($post_id); // 3, inject $post into $thread, but this makes less sense to me, since I'm looking at a post page, not a thread page $post = new Post(); $post->load($post_id); $thread = new Thread($post); $thread->load(); // would load based on the $post->get('post_id') and combine. Now I have all the data I want, but it's non-intuitive to be heirarchially Thread->Post instead of Post-with-thread-info // Or, I could inject $post into $thread, but if I'm on a post page, // having an object with a top level of Thread instead of // Post-which-contains-thread-info, makes less sense to me. // to go with example 1 class post { public function __construct(&$thread) { $this->thread=$thread; } public function load($id) { // ... here I would load all the post data based on $id // now include the thread data $this->thread->load($this->get('thread_id')); return $this; } } // I don't want to do $thread = new Thread; $post = new Post; $post->load($post_id); $thread->load($post->get('post_id')); Or, I could create a new object and inject both $post and $thread into it, but then I have object with an increasing number of dependencies.

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  • How to use DI and DI containers

    - by Pinetree
    I am building a small PHP mvc framework (yes, yet another one), mostly for learning purposes, and I am trying to do it the right way, so I'd like to use a DI container, but I am not asking which one to use but rather how to use one. Without going into too much detail, the mvc is divided into modules which have controllers which render views for actions. This is how a request is processed: a Main object instantiates a Request object, and a Router, and injects the Request into the Router to figure out which module was called. then it instantiates the Module object and sends the Request to that the Module creates a ModuleRouter and sends the Request to figure out the controller and action it then creates the Controller and the ViewRenderer, and injects the ViewRenderer into the Controller (so that the controller can send data to the view) the ViewRenderer needs to know which module, controller and action were called to figure out the path to the view scripts, so the Module has to figure out this and inject it to the ViewRenderer the Module then calls the action method on the controller and calls the render method on the ViewRenderer For now, I do not have any DI container set up, but what I do have are a bunch of initX() methods that create the required component if it is not already there. For instance, the Module has the initViewRenderer() method. These init methods get called right before that component is needed, not before, and if the component was already set it will not initialize it. This allows for the components to be switched, but it does not require manually setting them if they are not there. Now, I'd like to do this by implementing a DI container, but still keep the manual configuration to a bare minimum, so if the directory structure and naming convention is followed, everything should work, without even touching the config. If I use the DI container, do I then inject it into everything (the container would inject itself when creating a component), so that other components can use it? When do I register components with the DI? Can a component register other components with the DI during run-time? Do I create a 'common' config and use that? How do I then figure out on the fly which components I need and how they need to be set up? If Main uses Router which uses Request, Main then needs to use the container to get Module (or does the module need to be found and set beforehand? How?) Module uses Router but needs to figure out the settings for the ViewRenderer and the Controller on the fly, not in advance, so my DI container can't be setting those on the Module before the module figures out the controller and action... What if the controller needs some other service? Do I inject the container into every controller? If I start doing that, I might just inject it into everything... Basically I am looking for the best practices when dealing with stuff like this. I know what DI is and what DI containers do, but I am looking for guidance to using them in real life, and not some isolated examples on the net. Sorry for the lengthy post and many thanks in advance.

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  • close camera application in blackberry

    - by user324884
    I need to close camera when a file is taken from camera. I invoke camera by Invoke method and added FileJournalListener and then use Inject.post. But it si working fine in simulator and but not working in actual device. any Idea. ....... case FileSystemJournalEntry.FILE_ADDED: filepath=path; EventInjector.KeyEvent inject = new EventInjector.KeyEvent(EventInjector.KeyEvent.KEY_DOWN,Characters.ESCAPE, 50); inject.post(); inject.post(); ............

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  • Is there any injection vunerability in the body of an email?

    - by Brett
    Hey guys..... AFAIK there is only a vulnerability within the HEADERS of an email when using user data correct? I am using the below function to sanitize my data, however I have some textarea fields on the page & hence these may contain linebreaks.. so was wondering if that user data is only going to be put in the body of the email, can it not bother with being sanitized - apart from stripping html of course? Here is the function: function is_injected($str) { $injections = array('(\n+)', '(\r+)', '(\t+)', '(%0A+)', '(%0D+)', '(%08+)', '(%09+)' ); $inject = join('|', $injections); $inject = "/$inject/i"; if (preg_match($inject,$str)) { return true; } else { return false; } } As a side note, surprised there wasn't currently a tag for mail-injection / email-injection. Thanks!

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  • How to use a variable in a function expression which is injected in a page?

    - by anonymous
    I'm trying to inject a function into a webpage via Chrome extension content script by: function inject(code) { var actualCode = '(' + code + ')();'; var script = document.createElement('script'); script.textContent = actualCode; (document.head||document.documentElement).appendChild(script); script.parentNode.removeChild(script); } var myObj = person; // myObj/person is passed in from elsewhere var fn = function() { alert(myObj.name); }; inject(fn); // myObj undefined My issue is, since fn is a function expression, I can't pass in myObj.personName. So my question is, how can I construct a function expression that includes a variable? Do I do some sort of string concatenation instead? I also tried to pass the object to the function, as follows: function inject(code, myObj) { var actualCode = '(' + code + ')(' + myObj +');'; ... But this did not work, and caused a "Uncaught SyntaxError: Unexpected identifier" error. Related: Building a Chrome Extension - Inject code in a page using a Content script

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  • Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

    - by dotneteer
    Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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  • How You Helped Shape Java EE 7...

    - by reza_rahman
    I have been working with the JCP in various roles since EJB 3/Java EE 5 (much of it on my own time), eventually culminating in my decision to accept my current role at Oracle (despite it's inevitable set of unique challenges, a role I find by and large positive and fulfilling). During these years, it has always been clear to me that pretty much everyone in the JCP genuinely cares about openness, feedback and developer participation. Perhaps the most visible sign to date of this high regard for grassroots level input is a survey on Java EE 7 gathered a few months ago. The survey was designed to get open feedback on a number of critical issues central to the Java EE 7 umbrella specification including what APIs to include in the standard. When we started the survey, I don't think anyone was certain what the level of participation from developers would really be. I also think everyone was pleasantly surprised that a large number of developers (around 1100) took the time out to vote on these very important issues that could impact their own professional life. And it wasn't just a matter of the quantity of responses. I was particularly impressed with the quality of the comments made through the survey (some of which I'll try to do justice to below). With Java EE 7 under our belt and the horizons for Java EE 8 emerging, this is a good time to thank everyone that took the survey once again for their thoughts and let you know what the impact of your voice actually was. As an aside, you may be happy to know that we are working hard behind the scenes to try to put together a similar survey to help kick off the agenda for Java EE 8 (although this is by no means certain). I'll break things down by the questions asked in the survey, the responses and the resulting change in the specification. APIs to Add to Java EE 7 Full/Web Profile The first question in the survey asked which of four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. Developers by and large wanted all the new APIs added to the full platform. The comments expressed particularly strong support for WebSocket and JCache. Others expressed dissatisfaction over the lack of a JSON binding (as opposed to JSON processing) API. WebSocket, JSON-P and JBatch are now part of Java EE 7. In addition, the long-awaited Java EE Concurrency Utilities API was also included in the Full Profile. Unfortunately, JCache was not finalized in time for Java EE 7 and the decision was made not to hold up the Java EE release any longer. JCache continues to move forward strongly and will very likely be included in Java EE 8 (it will be available much sooner than Java EE 8 to boot). An emergent standard for JSON-B is also a strong possibility for Java EE 8. When it came to the Web Profile, developers were supportive of adding WebSocket and JSON-P, but not JBatch and JCache. Both WebSocket and JSON-P are now part of the Web Profile, now also including the already popular JAX-RS API. Enabling CDI by Default The second question asked whether CDI should be enabled in Java EE by default. The overwhelming majority of developers supported the default enablement of CDI. In addition, developers expressed a desire for better CDI/Java EE alignment (with regards to EJB and JSF in particular). Some developers expressed legitimate concerns over the performance implications of enabling CDI globally as well as the potential conflict with other JSR 330 implementations like Spring and Guice. CDI is enabled by default in Java EE 7. Respecting the legitimate concerns, CDI 1.1 was very careful to add additional controls around component scanning. While a lot of work was done in Java EE 6 and Java EE 7 around CDI alignment, further alignment is under serious consideration for Java EE 8. Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations (e.g. @BatchContext). A majority of developers wanted consistent usage of @Inject. The comments again reflected a strong desire for CDI/Java EE alignment. A lot of emphasis in Java EE 7 was put into using @Inject consistently. For example, the JBatch specification is focused on using @Inject wherever possible. JAX-RS remains an exception with it's existing custom injection annotations. However, the JAX-RS specification leads understand the importance of eventual convergence, hopefully in Java EE 8. Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A solid majority of developers supported the idea of making @Stereotype more universal in Java EE. The comments maintained the general theme of strong support for CDI/Java EE alignment Unfortunately, there was not enough time and resources in Java EE 7 to implement this fairly pervasive feature. However, it remains a serious consideration for Java EE 8. Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE. Developers strongly supported the concept. Along with injection, interceptors are now supported across all Java EE 7 components including Servlets, Filters, Listeners, JAX-WS endpoints, JAX-RS resources, WebSocket endpoints and so on. I hope you are encouraged by how your input to the survey helped shape Java EE 7 and continues to shape Java EE 8. Participating in these sorts of surveys is of course just one way of contributing to Java EE. Another great way to stay involved is the Adopt-A-JSR Program. A large number of developers are already participating through their local JUGs. You could of course become a Java EE JSR expert group member or observer. You should stay tuned to The Aquarium for the progress of Java EE 8 JSRs if that's something you want to look into...

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  • Desktop application, dependency injection

    - by liori
    I am thinking of applying a real dependency injection library to my toy C#/GTK# desktop application. I chose NInject, but I think this is irrelevant to my question. There is a database object, a main window and several utility window classes. It's clear that I can inject the database into every window object, so here DI is useful. But does it make sense to inject utility window classes into other window classes? Example: I have classes such as: class MainWindow {…} class AddItemWindow {…} class AddAttachmentWindow {…} class BrowseItemsWindow {…} class QueryBuilderWindow {…} class QueryBrowserWindow {…} class PreferencesWindow {…} … Each of the utility classes can be opened from MainWindow. Some utility windows can also be opened from other utility windows. Generally, there might be a really complex graph of who can open whom. So each of those classes might need quite a lot of other window classes injected. I'm worried that such usage will go against the suggestion not to inject too many classes at once and become a code smell. Should I use some kind of a service locator object here?

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  • Ninject/DI: How to correctly pass initialisation data to injected type at runtime

    - by MrLane
    I have the following two classes: public class StoreService : IStoreService { private IEmailService _emailService; public StoreService(IEmailService emailService) { _emailService = emailService; } } public class EmailService : IEmailService { } Using Ninject I can set up bindings no problem to get it to inject a concrete implementation of IEmailService into the StoreService constructor. StoreService is actually injected into the code behind of an ASP.NET WebForm as so: [Ninject.Inject] public IStoreService StoreService { get; set; } But now I need to change EmailService to accept an object that contains SMTP related settings (that are pulled from the ApplicationSettings of the Web.config). So I changed EmailService to now look like this: public class EmailService : IEmailService { private SMTPSettings _smtpSettings; public void SetSMTPSettings(SMTPSettings smtpSettings) { _smtpSettings = smtpSettings; } } Setting SMTPSettings in this way also requires it to be passed into StoreService (via another public method). This has to be done in the Page_Load method in the WebForms code behind (I only have access to the Settings class in the UI layer). With manual/poor mans DI I could pass SMTPSettings directly into the constructor of EmailService and then inject EmailService into the StoreService constructor. With Ninject I don't have access to the instances of injected types outside of the objects they are injected to, so I have to set their data AFTER Ninject has already injected them via a separate public setter method. This to me seems wrong. How should I really be solving this scenario?

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  • Correct way of using/testing event service in Eclipse E4 RCP

    - by Thorsten Beck
    Allow me to pose two coupled questions that might boil down to one about good application design ;-) What is the best practice for using event based communication in an e4 RCP application? How can I write simple unit tests (using JUnit) for classes that send/receive events using dependency injection and IEventBroker ? Let’s be more concrete: say I am developing an Eclipse e4 RCP application consisting of several plugins that need to communicate. For communication I want to use the event service provided by org.eclipse.e4.core.services.events.IEventBroker so my plugins stay loosely coupled. I use dependency injection to inject the event broker to a class that dispatches events: @Inject static IEventBroker broker; private void sendEvent() { broker.post(MyEventConstants.SOME_EVENT, payload) } On the receiver side, I have a method like: @Inject @Optional private void receiveEvent(@UIEventTopic(MyEventConstants.SOME_EVENT) Object payload) Now the questions: In order for IEventBroker to be successfully injected, my class needs access to the current IEclipseContext. Most of my classes using the event service are not referenced by the e4 application model, so I have to manually inject the context on instantiation using e.g. ContextInjectionFactory.inject(myEventSendingObject, context); This approach works but I find myself passing around a lot of context to wherever I use the event service. Is this really the correct approach to event based communication across an E4 application? how can I easily write JUnit tests for a class that uses the event service (either as a sender or receiver)? Obviously, none of the above annotations work in isolation since there is no context available. I understand everyone’s convinced that dependency injection simplifies testability. But does this also apply to injecting services like the IEventBroker? This article describes creation of your own IEclipseContext to include the process of DI in tests. Not sure if this could resolve my 2nd issue but I also hesitate running all my tests as JUnit Plug-in tests as it appears impractible to fire up the PDE for each unit test. Maybe I just misunderstand the approach. This article speaks about “simply mocking IEventBroker”. Yes, that would be great! Unfortunately, I couldn’t find any information on how this can be achieved. All this makes me wonder whether I am still on a "good path" or if this is already a case of bad design? And if so, how would you go about redesigning? Move all event related actions to dedicated event sender/receiver classes or a dedicated plugin?

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  • Build path issues learning Guice

    - by Preston
    I can't figure out why I'm getting this error below I have included all the appropriate jars as far as I can tell(I have included eclipses .classpath file below.) All of the classpath entries resolve just fine. What am I missing? The type javax.servlet.ServletContextListener cannot be resolved. It is indirectly referenced from required .class files on the "extends GuiceServletContextListener" line - import com.google.inject.Guice; import com.google.inject.Injector; import com.google.inject.servlet.GuiceServletContextListener; import com.google.inject.servlet.ServletModule; public class ServletConfig extends GuiceServletContextListener { @Override protected Injector getInjector() { return Guice.createInjector(new ServletModule(){ @Override protected void configureServlets() { // TODO: add necessary code to bind } }); } } .Classpath <?xml version="1.0" encoding="UTF-8"?> <classpath> <classpathentry kind="src" path="src"/> <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/jdk1.7.0_21"> <attributes> <attribute name="owner.project.facets" value="java"/> </attributes> </classpathentry> <classpathentry kind="con" path="oracle.eclipse.tools.glassfish.lib.system"> <attributes> <attribute name="owner.project.facets" value="jst.web"/> </attributes> </classpathentry> <classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.web.container"/> <classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.module.container"/> <classpathentry kind="lib" path="guice-3.0/aopalliance.jar"/> <classpathentry kind="lib" path="guice-3.0/guice-3.0.jar"/> <classpathentry kind="lib" path="guice-3.0/guice-servlet-3.0.jar"/> <classpathentry kind="lib" path="guice-3.0/javax.inject.jar"/> <classpathentry kind="output" path="build/classes"/> </classpath>

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  • Injecting correct object graph using StructureMap in Queue of different Objects

    - by davy
    I have a queuing service that has to inject a different dependency graph depending on the type of object in the queue. I'm using Structure Map. So, if the object in the queue is TypeA the concrete classes for TypeA are used and if it's TypeB, the concrete classes for TypeB are used. I'd like to avoid code in the queue like: if (typeA) { // setup TypeA graph } else if (typeB) { // setup TypeB graph } Within the graph, I also have a generic classes such as an IReader(ISomething, ISpomethingElse) where IReader is generic but needs to inject the correct ISomething and ISomethingElse for the type. ISomething will also have dependencies and so on. Currently I create a TypeA or TypeB object and inject a generic Processor class using StructureMap into it and then pass a factory manually inject a TypeA or TypeB factory into a method like: Processor.Process(new TypeAFactory) // perhaps I should have an abstract factory... However, because the factory then creates the generic IReader mentioned above, I end up manually injecting all the TypeA or TypeB classes fro there on. I hope enough of this makes sense. I am new to StructureMap and was hoping somebody could point me in the right direction here for a flexible and elegant solution. Thanks

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