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  • How to avoid injecting dependencies into an object so that it can pass them on?

    - by Pheter
    I am interested in applying dependency injection to my current project, which makes use of the MVC pattern. My controllers will call the models and therefore will need to inject the dependencies into the models. To do this, the controller must have the dependencies (such as a database object) in the first place. The controller doesn't need to make use of some of these dependencies (such as the database object), so I feel that it shouldn't be given this dependency. However, it has to have these dependencies if it is to inject them into the model objects. How can I avoid having dependencies injected into an object just so that it can pass them on? Doing so feels wrong and can result in many dependencies being injected into an object. Edit: I am using PHP.

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  • Sample source code for processing messages of a window created by an external program?

    - by David
    I know I have to use SetWindowLongPtr with GWLP_WNDPROC and create my own WndProc that handles the message I want (such as WM_GETMINMAXINFO and modify the MINMAXINFO structure). However, because I want to do this for a window created by another program (like notepad.exe), I can't do this from my C#/WinForms program, I have to create a native C/C++ DLL that I have to inject in the the process that created the window. Can you provide a link or the sample code to do this (the native C++ DLL and the way to call it from C# and inject it into the external process)? Thank you

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  • How to combine designable components with dependency injection

    - by Wim Coenen
    When creating a designable .NET component, you are required to provide a default constructor. From the IComponent documentation: To be a component, a class must implement the IComponent interface and provide a basic constructor that requires no parameters or a single parameter of type IContainer. This makes it impossible to do dependency injection via constructor arguments. (Extra constructors could be provided, but the designer would ignore them.) Some alternatives we're considering: Service Locator Don't use dependency injection, instead use the service locator pattern to acquire dependencies. This seems to be what IComponent.Site.GetService is for. I guess we could create a reusable ISite implementation (ConfigurableServiceLocator?) which can be configured with the necessary dependencies. But how does this work in a designer context? Dependency Injection via properties Inject dependencies via properties. Provide default instances if they are necessary to show the component in a designer. Document which properties need to be injected. Inject dependencies with an Initialize method This is much like injection via properties but it keeps the list of dependencies that need to be injected in one place. This way the list of required dependencies is documented implicitly, and the compiler will assists you with errors when the list changes. Any idea what the best practice is here? How do you do it? edit: I have removed "(e.g. a WinForms UserControl)" since I intended the question to be about components in general. Components are all about inversion of control (see section 8.3.1 of the UMLv2 specification) so I don't think that "you shouldn't inject any services" is a good answer. edit 2: It took some playing with WPF and the MVVM pattern to finally "get" Mark's answer. I see now that visual controls are indeed a special case. As for using non-visual components on designer surfaces, I think the .NET component model is fundamentally incompatible with dependency injection. It appears to be designed around the service locator pattern instead. Maybe this will start to change with the infrastructure that was added in .NET 4.0 in the System.ComponentModel.Composition namespace.

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  • JSR-303 dependency injection and Hibernate

    - by Jam
    Spring 3.0.2, Hibernate 3.5.0, Hibernate-Validator 4.0.2.GA I am trying to inject Spring dependencies into a ConstraintValidator using: @PersistenceContext private EntityManager entityManager; I have configured the application context with: <bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/> Which, according to the Spring documentation, should allow “custom ConstraintValidators to benefit from dependency injection like any other Spring bean” Within the debugger I can see Spring calling getBean to create the ConstraintValidator. Later when flush triggers the preInsert, a different ConstraintValidator is created and called. The problem is the EntityManager is null within this new ConstraintValidator. I’ve tried injecting other dependencies within the ConstraintValidator and these are always null. Does anyone know if it is possible to inject dependencies into a ConstraintValidator?

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  • deep injection - spring

    - by Bob
    What is the best way (or options) for accessing spring components at layers deep within the application that aren't managed by spring? For example, I have a low level utility POJO class into which I need to autowire/inject a spring component. I'll call it LowLevelHelper. There are multiple classes that use LowLevelHelper - most are layers away from anything that is hooked up with spring. One option would be to make all the layers in to spring components, but that seems like I'm hacking my design to force spring to help me. I have some complex things going on that won't be nearly as clean if I have to @Autowire all the pieces and don't new anything. Another option might be to manually inject the component in the low level class, but I'm not really sure if this is possible or the right solution.

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  • google maps everytime fails to place some markers on the map

    - by Luca
    hello! im trying to place like 130/140 markers on a custom google map. i inject the map with jquery and gmaps (http://gmap.nurtext.de/) everytime, at random (not related to specific markers) a lots of markers are not shown. firebug report this error: a is null and this error comes from this file: http://maps.gstatic.com/intl/it_ALL/mapfiles/285c/maps2.api/main.js if i refresh the page...some other markers are "hidden" and other ones are shown. anyone had this problem/can help me or suggest another safe way to show all markers? thanks a lot! EDIT: this is how i inject the map and the markers (with a lots of address, but in this example only few) $(document).ready(function() { $("#container").gMap( { scrollwheel: false, maptype: G_PHYSICAL_MAP, icon: { image: "files/images/gmap_pin.png", iconsize: [32, 37], iconanchor: [32, 37], infowindowanchor: [12, 0] }, address: "Milano", zoom: 4, markers: [ { address: "Viale Certosa, Milano" }, { address: "Viale Ceccarini, Milano" }, { address: "Viale Italia, Milano" }, { address: "Via Rodi, Milano" }, ] }); });

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  • Solr Facet Search spring-data-solr

    - by sv1
    I am new to Solr and we are using Spring-data for Solr I have a question may be its too simple but I am unable to comprehend. Basically I need to search on any field but I have a "zip" field as one of the facet fields. I have a Solr repository . (Am not sure if the annotations on the Repository are correct.) public interface MyRepository extends SolrCrudRepository<MyPOJO, String> { @Query(value = "*:*") @Facet(fields={"zip"}) public FacetPage<MyPOJO> findByQueryandAnno(String searchTerm,Pageable page); } In my Service class I am trying to call this methods by Injecting MyRepository like below public class MyService { @Inject MyRepository solrRepo; @Inject SolrTemplate solrTemplate; public FacetPage<MyPOJO> tryFacets(String searchString){ //Here is where I am struggling SimpleFacetQuery query = new SimpleQuery(new SimpleStringCriteria(searchString)); query.setFacetOptions(new FacetOptions("zip")); //Not sure how to get the Pageable object. //But the repository doesnt accept without it. return solrTemplate.queryForPage(query,{Pageable Instance to be passed here}) } From my jUnit I am loading context files needed for Solr and Spring //In jUnit the test method looks like this service.tryFacets("some value"); and it fails with - method not found in the service class at the call to the repository method. *********EDIT**************** As per ChristophStrobl's advice created a copyfield called multivaluedCopyField and the searchString argument works good. But the facet still isnt working...Now my code looks like this. I get the MyPOJO object as response but the facetcount and the faceted values are missing. public interface MyRepository extends SolrCrudRepository<MyPOJO, String> { @Query(value = "*:*") @Facet(fields={"zip"}) public FacetPage<MyPOJO> findByQueryandAnno(String searchTerm,Pageable page); } My service class looks like public class MyService { @Inject MyRepository solrRepo; public FacetPage<MyPOJO> tryFacets(String searchString){ //Here is where I am struggling SimpleFacetQuery query = new SimpleQuery(new SimpleStringCriteria(searchString)).setPageRequest new PageRequest(0,5)); query.setFacetOptions(new FacetOptions("zip")); FacetPage<MyPOJO> facetedPOJO= solrRepo.findByQueryandAnno(searchString,query.getPageRequest()); return facetedPOJO; } My jUnit method call is like service.tryFacets("some value");

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  • Flex 4 app with mate design question

    - by chchrist
    Hi all, I have a view with a DropDownList component and a DataGroup component. The dropdownlist has to be updated from a remote php object and on change to call another remote object service in order to update the datagroup's provider. So I am thinks to dispatch an event from my view and the in my EventMap to call the service and inject the result to the drop down. When the dropdown changes I'll dispatch another event and in the EventMap I'll call another service and I'll inject the result to the datagroup. Is there another more sophisticated way? Thanks in advance

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  • CDI @Conversation not propagated with handleNavigation()

    - by Thomas Kernstock
    I have a problem with the propagation of a long runnig conversation when I redirect the view by the handleNavigation() method. Here is my test code: I have a conversationscoped bean and two views: conversationStart.xhtml is called in Browser with URL http://localhost/tests/conversationStart.jsf?paramTestId=ParameterInUrl <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core"> <f:metadata> <f:viewParam name="paramTestId" value="#{conversationTest.fieldTestId}" /> <f:event type="preRenderView" listener="#{conversationTest.preRenderView}" /> </f:metadata> <h:head> <title>Conversation Test</title> </h:head> <h:body> <h:form> <h2>Startpage Test Conversation with Redirect</h2> <h:messages /> <h:outputText value="Testparameter: #{conversationTest.fieldTestId}"/><br /> <h:outputText value="Logged In: #{conversationTest.loggedIn}"/><br /> <h:outputText value="Conversation ID: #{conversationTest.convID}"/><br /> <h:outputText value="Conversation Transient: #{conversationTest.convTransient}"/><br /> <h:commandButton action="#{conversationTest.startLogin}" value="Login ->" rendered="#{conversationTest.loggedIn==false}" /><br /> <h:commandLink action="/tests/conversationLogin.xhtml?faces-redirect=true" value="Login ->" rendered="#{conversationTest.loggedIn==false}" /><br /> </h:form> <h:link outcome="/tests/conversationLogin.xhtml" value="Login Link" rendered="#{conversationTest.loggedIn==false}"> <f:param name="cid" value="#{conversationTest.convID}"></f:param> </h:link> </h:body> </html> The Parameter is written to the beanfield and displayed in the view correctly. There are 3 different possibilites to navigate to the next View. All 3 work fine. The beanfield shows up the next view (conversationLogin.xhtml) too: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core"> <h:head> <title>Conversation Test</title> </h:head> <h:body> <h:form> <h2>Loginpage Test Conversation with Redirect</h2> <h:messages /> <h:outputText value="Testparameter: #{conversationTest.fieldTestId}"/><br /> <h:outputText value="Logged In: #{conversationTest.loggedIn}"/><br /> <h:outputText value="Conversation ID: #{conversationTest.convID}"/><br /> <h:outputText value="Conversation Transient: #{conversationTest.convTransient}"/><br /> <h:commandButton action="#{conversationTest.login}" value="Login And Return" /><br /> </h:form> </h:body> </html> When I return to the Startpage by clicking the button the conversation bean still contains all values. So everything is fine. Here is the bean: package test; import java.io.Serializable; import javax.annotation.PostConstruct; import javax.enterprise.context.Conversation; import javax.enterprise.context.ConversationScoped; import javax.faces.event.ComponentSystemEvent; import javax.inject.Inject; import javax.inject.Named; @Named @ConversationScoped public class ConversationTest implements Serializable{ private static final long serialVersionUID = 1L; final String CONVERSATION_NAME="longRun"; @Inject Conversation conversation; private boolean loggedIn; private String fieldTestId; @PostConstruct public void init(){ if(conversation.isTransient()){ conversation.begin(CONVERSATION_NAME); System.out.println("New Conversation started"); } loggedIn=false; } public String getConvID(){ return conversation.getId(); } public boolean isConvTransient(){ return conversation.isTransient(); } public boolean getLoggedIn(){ return loggedIn; } public String startLogin(){ return "/tests/conversationLogin.xhtml?faces-redirect=true"; } public String login(){ loggedIn=true; return "/tests/conversationStart.xhtml?faces-redirect=true"; } public void preRenderView(ComponentSystemEvent ev) { // if(!loggedIn){ // System.out.println("Will redirect to Login"); // FacesContext ctx = FacesContext.getCurrentInstance(); // ctx.getApplication().getNavigationHandler().handleNavigation(ctx, null, "/tests/conversationLogin.xhtml?faces-redirect=true"); // ctx.renderResponse(); // } } public void setFieldTestId(String fieldTestId) { System.out.println("fieldTestID was set to: "+fieldTestId); this.fieldTestId = fieldTestId; } public String getFieldTestId() { return fieldTestId; } } Now comes the problem !! As soon as I try to redirect the page in the preRenderView method of the bean (just uncomment the code in the method), using handleNavigation() the bean is created again in the next view instead of using the allready created instance. Although the cid parameter is propagated to the next view ! Has anybody an idea what's wrong ? best regards Thomas

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  • How do I get property injection working in Ninject for a ValidationAttribute in MVC?

    - by jaltiere
    I have a validation attribute set up where I need to hit the database to accomplish the validation. I tried setting up property injection the same way I do elsewhere in the project but it's not working. What step am I missing? public class ApplicationIDValidAttribute : ValidationAttribute { [Inject] protected IRepository<MyType> MyRepo; public override bool IsValid(object value) { if (value == null) return true; int id; if (!Int32.TryParse(value.ToString(), out id)) return false; // MyRepo is null here and is never injected var obj= MyRepo.LoadById(id); return (obj!= null); } One other thing to point out, I have the Ninject kernel set up to inject non-public properties, so I don't think that is the problem. I'm using Ninject 2, MVC 2, and the MVC 2 version of Ninject.Web.MVC. Thanks!

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  • NHibernate on WCF Dependency Injection

    - by Diego Dias
    Hi, I would like of inject a wrapper of my sessionfactory in my wcf service, but my service is in other server and I want set nhibernate in my site asp.net. I have a interface as: public interface ISessionBuilder { ISession Current{get;}; void Close(); } public class SessionBuilder : ISessionBuilder { static SessionBuilder() { Initialize(); } public ISession Current{ get; private set; } public void Close() { //aqui eu fecho a session } private static void Initialize() { //aqui eu configuro o NHibernate } } I want to be able of set SessionBuilder in the site asp.net and inject this implementation in my wcf Service where I have my repositories which will consume SessionBuilder to query my database. Anyone have some sugestion?

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  • Adding CSS styles to injected DOM elements

    - by Nyxynyx
    I am using javascript to inject a few DOM elements into the page. I am able to inject a single DOM element and apply CSS style to it: var $e = $('<div id="header"></div>'); $('body').append($e); $e.css({ background: '#fbf7f7', }); Problem: If I have nested elements within $e, how can I apply CSS styles to the parents and its children seperately? var $e = $('<div id="header"><div class="header-content"><span class="title"></span></div></div>');

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  • How to create list of numbers and append its reverse to it efficiently in Ruby

    - by Kiwi
    Given a minimum integer and maximum integer, I want to create an array which counts from the minimum to the maximum by two, then back down (again by two, repeating the maximum number). For example, if the minimum number is 1 and the maximum is 9, I want [1, 3, 5, 7, 9, 9, 7, 5, 3, 1]. I'm trying to be as concise as possible, which is why I'm using one-liners. In Python, I would do this: range(1, 10, 2) + range(9, 0, -2) In Ruby, which I'm just beginning to learn, all I've come up with so far is: (1..9).inject([]) { |r, num| num%2 == 1 ? r << num : r }.reverse.inject([]) { |r, num| r.unshift(num).push(num) } Which works, but I know there must be a better way. What is it?

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  • jms unresolved message-destination-ref

    - by portoalet
    hi, I am using netbeans 6.8, and glassfish v3, and making a simple jms application to work. I got this: com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Unresolved Message-Destination-Ref jms/[email protected]@null into class enterpriseapplication4.Main Code: public class Main { @Resource(name = "jms/myQueue") private static Topic myQueue; @Resource(name = "jms/myFactory") private static ConnectionFactory myFactory; ... // the rest is just boiler plate created by netbeans } In my Glassfish v3 admin console, I have jms/myFactory as my ConnectionFactory and jms/myQueue as my Destination Resources. What am I missing? Full stack: WARNING: enterprise.deployment.backend.invalidDescriptorMappingFailure com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Unresolved Message-Destination-Ref jms/[email protected]@null into class enterpriseapplication4.Main at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:614) at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.inject(InjectionManagerImpl.java:384) at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.injectClass(InjectionManagerImpl.java:210) at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.injectClass(InjectionManagerImpl.java:202) at org.glassfish.appclient.client.acc.AppClientContainer$ClientMainClassSetting.getClientMainClass(AppClientContainer.java:599) at org.glassfish.appclient.client.acc.AppClientContainer.getMainMethod(AppClientContainer.java:498) at org.glassfish.appclient.client.acc.AppClientContainer.completePreparation(AppClientContainer.java:397) at org.glassfish.appclient.client.acc.AppClientContainer.prepare(AppClientContainer.java:311) at org.glassfish.appclient.client.AppClientFacade.prepareACC(AppClientFacade.java:264) at org.glassfish.appclient.client.acc.agent.AppClientContainerAgent.premain(AppClientContainerAgent.java:75) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:323) at sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:338) Caused by: javax.naming.NamingException: Lookup failed for 'java:comp/env/jms/myQueue' in SerialContext targetHost=localhost,targetPort=3700 [Root exception is javax.naming.NameNotFoundException: No object bound for java:comp/env/jms/myQueue [Root exception is java.lang.NullPointerException]] at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:442) at javax.naming.InitialContext.lookup(InitialContext.java:392) at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:513) ... 15 more Caused by: javax.naming.NameNotFoundException: No object bound for java:comp/env/jms/myQueue [Root exception is java.lang.NullPointerException] at com.sun.enterprise.naming.impl.JavaURLContext.lookup(JavaURLContext.java:218) at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:428) ... 17 more Caused by: java.lang.NullPointerException at javax.naming.InitialContext.getURLScheme(InitialContext.java:269) at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:318) at javax.naming.InitialContext.lookup(InitialContext.java:392) at com.sun.enterprise.naming.util.JndiNamingObjectFactory.create(JndiNamingObjectFactory.java:75) at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.lookup(GlassfishNamingManagerImpl.java:688) at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.lookup(GlassfishNamingManagerImpl.java:657) at com.sun.enterprise.naming.impl.JavaURLContext.lookup(JavaURLContext.java:148) ... 18 more Regards

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  • Injecting relationships in DBIx::Class

    - by Carl
    I have a handful of DBIx::Class::Core objects that model various database tables. For some of those models (those that have a 'queue' column), I have another class inject subs (basically, to 'move' the model object along it's queue states). I'd like to also have that class inject has_many relationships ala class($name)->has_many('queue_history','MySchema::Result::QueueHistory', { 'foreign.record_id'=>'self.id' }, { where => { type => $name }} ); but I can't seem to get the relationships to register properly (keep getting "No Such Relationship" errors - however, when calling the relationship method on the sources provides back the relationship). Any clues as to what's wrong?

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  • Parameter attributes in c#

    - by ng
    How can I do the following with c# attributes. Below is a snippet of Java that annotates parameters in a constructor. public class Factory { private final String name; private final String value; public Factory(@Inject("name") String name, @Inject("value") String value) { this.name = name; this.value = value; } } From looking at c# annotations it does not look like I can annotate parameters. Is this possible?

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  • Auto injecting logger with guice

    - by koss
    With reference to Guice's custom injections article, its TypeListener performs a check for InjectLogger.class annotation - which can be optional. Removing that check will inject to all Logger.class types. class Log4JTypeListener implements TypeListener { public <T> void hear(TypeLiteral<T> typeLiteral, TypeEncounter<T> typeEncounter) { for (Field field : typeLiteral.getRawType().getDeclaredFields()) { if (field.getType() == Logger.class && field.isAnnotationPresent(InjectLogger.class)) { typeEncounter.register(new Log4JMembersInjector<T>(field)); } } } } I'm tempted to remove "&& field.isAnnotationPresent(InjectLogger.class)" from the listener. If we're using Guice to inject all instances of our Logger, is there any reason not to do it automatically (without need to annotate)?

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  • Injecting a dependancy into a base class

    - by Jamie Dixon
    Hey everyone, I'm on a roll today with questions. I'm starting out with Dependency Injection and am having some trouble injecting a dependency into a base class. I have a BaseController controller which my other controllers inherit from. Inside of this base controller I do a number of checks such as determining if the user has the right privileges to view the current page, checking for the existence of some session variables etc. I have a dependency inside of this base controller that I'd like to inject using Ninject however when I set this up as I would for my other dependencies I'm told by the compiler that: Error 1 'MyProject.Controllers.BaseController' does not contain a constructor that takes 0 argument This makes sense but I'm just not sure how to inject this dependency. Should I be using this pattern of using a base controller at all or should I be doing this in a more efficient/correct way?

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  • Multiple calculations on the same set of data: ruby or database?

    - by Pierre
    Hi, I have a model Transaction for which I need to display the results of many calculations on many fields for a subset of transactions. I've seen 2 ways to do it, but am not sure which is the best. I'm after the one that will have the least impact in terms of performance when data set grows and number of concurrent users increases. data[:total_before] = Transaction.where(xxx).sum(:amount_before) data[:total_after] = Transaction.where(xxx).sum(:amount_after) ... or transactions = Transaction.where(xxx) data[:total_before]= transactions.inject(0) {|s, e| s + e.amount_before } data[:total_after]= transactions.inject(0) {|s, e| s + e.amount_after } ... Which one should I choose? (or is there a 3rd, better way?) Thanks, P.

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  • Accommodating null values in a list?

    - by h259bws
    Hi, I'm new to Java and Groovy and am running into trouble with the following Groovy script. I created this whittled down version of a larger script to facilitate debugging. The script is iterating through a list trying to calc a running total of the values of all objects in the list. Some or all of these objects' values may be null. Script import org.apache.commons.lang.math.NumberUtils class Field { def name def value } def fields = [ new Field(name:'Annuities %', value:75), new Field(name:'Other %', value:null), ] //def totalFunding = fields.inject(0) {int total, Field myField - // total + NumberUtils.toInt(myField.value,0) as Integer def totalFunding = fields.inject(0) {int total, Field myField - total + myField?.value as Integer } It gets this error: Exception thrown: java.lang.NullPointerException java.lang.NullPointerException at Script3$_run_closure1.doCall(Script3:15) at Script3.run(Script3:14) What is the correct way to accomodate null values? Thanks, Betsy

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  • Is it a good or bad practice to call instance methods from a java constructor?

    - by Steve
    There are several different ways I can initialize complex objects (with injected dependencies and required set-up of injected members), are all seem reasonable, but have various advantages and disadvantages. I'll give a concrete example: final class MyClass { private final Dependency dependency; @Inject public MyClass(Dependency dependency) { this.dependency = dependency; dependency.addHandler(new Handler() { @Override void handle(int foo) { MyClass.this.doSomething(foo); } }); doSomething(0); } private void doSomething(int foo) { dependency.doSomethingElse(foo+1); } } As you can see, the constructor does 3 things, including calling an instance method. I've been told that calling instance methods from a constructor is unsafe because it circumvents the compiler's checks for uninitialized members. I.e. I could have called doSomething(0) before setting this.dependency, which would have compiled but not worked. What is the best way to refactor this? Make doSomething static and pass in the dependency explicitly? In my actual case I have three instance methods and three member fields that all depend on one another, so this seems like a lot of extra boilerplate to make all three of these static. Move the addHandler and doSomething into an @Inject public void init() method. While use with Guice will be transparent, it requires any manual construction to be sure to call init() or else the object won't be fully-functional if someone forgets. Also, this exposes more of the API, both of which seem like bad ideas. Wrap a nested class to keep the dependency to make sure it behaves properly without exposing additional API:class DependencyManager { private final Dependency dependency; public DependecyManager(Dependency dependency) { ... } public doSomething(int foo) { ... } } @Inject public MyClass(Dependency dependency) { DependencyManager manager = new DependencyManager(dependency); manager.doSomething(0); } This pulls instance methods out of all constructors, but generates an extra layer of classes, and when I already had inner and anonymous classes (e.g. that handler) it can become confusing - when I tried this I was told to move the DependencyManager to a separate file, which is also distasteful because it's now multiple files to do a single thing. So what is the preferred way to deal with this sort of situation?

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  • Castle Windsor Weak Typed Factory

    - by JeffN825
    In a very very limited number of scenarios, I need to go from an unknown Type (at compile time) to an instance of the object registered for that type. For the most part, I use typed factories and I know the type I want to resolve at compile time...so I inject a Func<IMyType> into a constructor ...but in these limited number of scenarios, in order to avoid a direct call to the container (and thus having to reference Windsor from the library, which is an anti-pattern I'd like to avoid), I need to inject a Func<Type,object>...which I want to internally container.Resolve(type) for the Type parameter of the Func. Does anyone have some suggestions on the easiest/most straightforward way of setting this up? I tried the following, but with this setup, I end up bypassing the regular TypedFactoryFacility altogether which is definitely not what I want: Kernel.Register(Component.For(typeof (Func<Type, object>)).LifeStyle.Singleton.UsingFactoryMethod( (kernel, componentModel, creationContext) => kernel.Resolve(/* not sure what to put here... */))); Thanks in advance for any assistance.

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  • Instantiating custom PropertySourcesPlaceholderConfigurer from spring context

    - by mmona
    I want to define a custom PropertySourcesPlaceholderConfigurer in spring context xml. I want to use there multiple PropertySources, so that I can load part of the configuration from several property files and provide other part dynamically by my custom PropertySource implementation. The advantage is that it should be then easy to adjust the order of loading these property sources just by making modifications to the xml spring configuration. And here I run into a problem: how to define an arbitrary list of PropertySources and inject it into PropertySourcesPlaceholderConfigurer, so that it uses the sources defined by me? Seems to be a basic thing that should be provided by spring, but since yesterday I cannot find a way to do it. Using namespace would enable me to load several property files, but I also need to define the id of the PropertySourcesPlaceholderConfigurer (as other projects refer to it), and also I want to use my custom implementation. That is why I am defining the bean explicitly and not using the namespace. The most intuitive way would be to inject a list of PropertySources into PropertySourcesPlaceholderConfigurer like this: <bean id="applicationPropertyPlaceholderConfigurer" class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer"> <property name="ignoreUnresolvablePlaceholders" value="true" /> <property name="ignoreResourceNotFound" value="true" /> <property name="order" value="0"/> <property name="propertySources"> <list> <!-- my PropertySource objects --> </list> </property> </bean> but unfortunately propertySources is of type PropertySources and does not accept a list. The PropertySources interface has one and only implementor which is MutablePropertySources, which indeed stores list of PropertySource objects, but has no constructor nor setter through which I can inject this list. It only has add*(PropertySource) methods. The only workaround I see now is to implement my own PropertySources class, extending MutablePropertySources, which would accept list of PropertySource objects on creation and manually add it via using add*(PropertySource) method. But why so much workaround would be needed to provide something that I thought was supposed to be the main reason of introducing the PropertySources (having flexible configuration manageable from spring configuration level). Please clarify what am I getting wrong :)

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  • Using LINQ Lambda Expressions to Design Customizable Generic Components

    LINQ makes code easier to write and maintain by abstracting the data source. It provides a uniform way to handle widely diverse data structures within an application. LINQ’s Lambda syntax is clever enough to even allow you to create generic building blocks with hooks, into which you can inject arbitrary functions. Michael Sorens explains, and demonstrates with examples. span.fullpost {display:none;}

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