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Posted to commits@tapestry.apache.org by bu...@apache.org on 2017/09/16 02:22:41 UTC
svn commit: r1018228 [20/41] - in /websites/production/tapestry/content: ./
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Modified: websites/production/tapestry/content/injection-in-detail.html
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--- websites/production/tapestry/content/injection-in-detail.html (original)
+++ websites/production/tapestry/content/injection-in-detail.html Sat Sep 16 02:22:40 2017
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- <div id="ConfluenceContent"><p><strong>Injection</strong> in Tapestry IoC can be a complicated subject for a number of reasons:</p><ul><li>Injection can occur in many places: on fields, and on parameters to methods and constructors of certain objects.</li><li>Parts of Injection are themselves defined in terms of Tapestry IoC services, many of which are extensible.</li></ul><div class="aui-label" style="float:right" title="Related Articles">
-
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-<h3>Related Articles</h3>
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- <div>
- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
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- <div class="details">
- <a href="injection-in-detail.html">Injection in Detail</a>
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- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
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- <div class="details">
- <a href="injection-faq.html">Injection FAQ</a>
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- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
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-<p>Despite this, injection generally <em>Just Works</em>: most of the time, you want Tapestry to inject a service, and only a single service implements the service interface.</p><p>This document discusses what to do when you hit a case that doesn't Just Work, or when you want to extend the injection logic in some way.</p><p>Some aspects of this discussion reflect Tapestry IoC used within a Tapestry web application: the tapestry-core module makes some extensions to injection.</p><h1 id="InjectioninDetail-InjectionTriggers">Injection Triggers</h1><p>Injection is triggered in a number of ways:</p><ul><li>A field in a component class, autobuilt object, or service implementation class is annotated with @Inject.</li><li>A method parameter to a service builder method, a decorator method, or a contribute method (in a Tapestry IoC module class).</li><li>A constructor parameter to an autobuilt object, or a service implementation class.</li><li>Any of the above with an @InjectService annotatio
n.</li></ul><p>These define the <em>point of injection</em>.</p><p>Injection also covers a related matter: providing special resources to a service or component (remember that pages are specialized components). For a service, the service's id (as a string) or extensible configuration (as a Collection, List or Map) may be provided. For a component, the component's id, locale, message catalog, or component resources may be provided.</p><h1 id="InjectioninDetail-StandardInjectionProcessing">Standard Injection Processing</h1><p>This section describes standard injection, which applies at the IoC layer: autobuilt objects and service implementations. The steps for injection into Tapestry components are slightly different and are covered later.</p><p>So a the point of injection, Tapestry has identified a field or parameter that should be injected. At this point, Tapestry knows the following:</p><ul><li>The field name (if field injection). The parameter name is not available.</li><li>Th
e field or parameter type, as a Java class. In many cases, this will be enough to identify what object shall be injected.</li><li>Any additional annotations on the field or parameter.</li></ul><p>Tapestry proceeds with this information.</p><h2 id="InjectioninDetail-Checkfor@InjectService">Check for @InjectService</h2><p>Tapestry checks first for the @InjectService annotation. The value of this annotation is the service id to inject. When @InjectService is present at the point of injection, the search is complete, though the injection can fail (throwing an exception) if the service id indicated does not exist, or if the service's interface is not compatible with the field's type.</p><h2 id="InjectioninDetail-Checkforserviceresources">Check for service resources</h2><p>This step applies only to IoC layer injection (not to injection into components).</p><p>When the @Inject annotation is <em>not present</em> at the point of injection, Tapestry checks to see if a resource can be injected
. Services are global values, but resources are specific to the service under construction.</p><p>When the Inject annotation is present, this step is skipped (this is necessary when the object to be injected has a type that conflicts with a resource type, such as List or Class).</p><ul><li>org.slf4j.Logger – The Logger of the service being constructed (or the logger of the Module class being instantiated).</li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ObjectLocator.html">ObjectLocator</a> – For contribute methods, used to locate additional objects.</li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ServiceResources.html">ServiceResources</a> – For service builder methods, an extended version of ObjectLocator. </li><li>Class – The service interface type.</li><li><a class="external-link" href="http://tapestry.apache.org/current/apido
cs/org/apache/tapestry5/ioc/OperationTracker.html">OperationTracker</a> – Used to track deeply nested operations so that errors can be reported sensibly.</li><li>Object, or service interface type – Passed to decorator methods.</li><li>Collection, List, Map – Assembled service configurations passed to service builder methods (or service class constructors).</li><li><p>Configuration, OrderedConfiguration, MappedConfiguration – Configuration passed to contribute methods, to build service configurations. <br clear="none" class="atl-forced-newline"> <br clear="none" class="atl-forced-newline"> If field type does not match any of the available resource types, or the Inject annotation is present, logic continues to the next step.</p><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>Injection
of resources into fields is triggered by the presence of the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/InjectResource.html">InjectResource</a> annotation, whereas injection of resources into parameters occurs when the Inject or InjectService annotation is <em>not</em> present. These rules are slightly tricky, which reflects a desire to avoid any annotations except when needed, and the fact that field injection came much later than parameter injection.</p></div></div></li></ul><h2 id="InjectioninDetail-ServiceLookupbyTypeandAnnotations">Service Lookup by Type and Annotations</h2><p>Tapestry attempts to find a matching <em>service</em>.</p><p>First, it generates a set of services whose service interface is compatible with the injection type. This is based on assignability.</p><p>If the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Local.html">Local<
/a> annotation is present, then services not from the module containing the service being constructed will be eliminated.</p><p>Tapestry then works through the known marker annotations. For each marker annotation that is present at the point of injection, Tapestry eliminates services which <em>do not</em> have the marker. Thus, if multiple marker annotations are present, the final service must have <em>all of them</em>.</p><p>At the end, of this, Tapestry determines how many services match.</p><ul><li>If there is a single matching service, then the service to inject as been identified.</li><li>If there are no matches, and there were no marker annotations at the point of injection, then the Tapestry continues to the next step.</li><li>Otherwise there were either no matches, or too many matches: Tapestry will throw a RuntimeException.</li></ul><h2 id="InjectioninDetail-MasterObjectProviderLookup">MasterObjectProvider Lookup</h2><p>This is the point at which Tapestry's extensibility co
mes into play. MasterObjectProvider is a service, with a configuration of <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ObjectProvider.html">ObjectProviders</a>.</p><p>The MasterObjectProvider is also the point at which Tapestry's IoC layer injection, and Tapestry's component injection, unite.</p><p>As a chain-of-command, each of the following ObjectProviders will be considered and will attempt to identify the object to be injected.</p><div class="confluence-information-macro confluence-information-macro-note"><span class="aui-icon aui-icon-small aui-iconfont-warning confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>A common problem when extending injection is that contributions into the MasterObjectProvider configuration have to be handled carefully. Any dependencies of the contributed objects should be resolvable using only the early stages of the injection process, otherwise MasterObje
ctProvider will have to be instantiated in order to handle its own injection: Tapestry will detect this impossibility and throw an exception. In addition, the <a href="typecoercer-service.html">TypeCoercer</a> service is used by several ObjectProvider implementations, so the same restrictions apply to TypeCoercer service contributions.</p></div></div><h3 id="InjectioninDetail-ValueObjectProvider">Value ObjectProvider</h3><p>Checks for the presence of the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Value.html">Value</a> annotation. If present, then the annotation's value is evaluated (to expand any symbol references), and the TypeCoercer service is used to convert the resulting String to the injection type (the field or parameter type).</p><h3 id="InjectioninDetail-SymbolObjectProvider">Symbol ObjectProvider</h3><p>Similar to the Value ObjectProvider: the @<a class="external-link" href="http://tapestry.apache.org/
current/apidocs/org/apache/tapestry5/ioc/annotations/Symbol.html">Symbol</a> annotation's value (if present) is looked up using the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/SymbolSource.html">SymbolSource</a> service, and converted to the injection type via the TypeCoercer service.</p><h3 id="InjectioninDetail-AutobuildObjectProvider">Autobuild ObjectProvider</h3><p>Checks to see if the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Autobuild.html">Autobuild</a> annotation is present and, if so, autobuilds the value for the parameter. Of course, the object being built will itself be configured via injection.</p><h3 id="InjectioninDetail-ServiceOverrideObjectProvider">ServiceOverride ObjectProvider</h3><p>Checks any contributions to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/Ser
viceOverride.html">ServiceOverride</a> service. Contributions map a type to an object of that type. Thus, ServiceOverrides will override injections of services that are not qualified with a marker annotation.</p><h3 id="InjectioninDetail-AliasObjectProvider(tapestry-core)">Alias ObjectProvider (tapestry-core)</h3><p>Uses the Alias service (<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/Alias.html">API</a>) to look for an object that can be injected.</p><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>Deprecated in Tapestry 5.2 and removed in 5.4.</p></div></div><p>This is commonly used to override a built-in service by contributing an object with the exact same interface. This is an older and more complex version of the ServiceOverride provider.</p><h
3 id="InjectioninDetail-AssetObjectProvider(tapestry-core)">Asset ObjectProvider (tapestry-core)</h3><p>Checks for the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Path.html">Path</a> annotation.</p><p>If present, the annotation's value has embedded symbols expanded, and is converted into an Asset (which must exist).</p><p>The TypeCoercer can then convert the Asset to the injection type, for example, as Resource.</p><h3 id="InjectioninDetail-ServiceObjectProvider(tapestry-core)">Service ObjectProvider (tapestry-core)</h3><p>Looks for the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Service.html">Service</a> annotation; if present, the annotation's value is the exact service id to inject. This is necessary because injections into <em>component</em> fields are always triggered by the Inject annotation.</p><div class="confluence-information-macro confluence-in
formation-macro-note"><span class="aui-icon aui-icon-small aui-iconfont-warning confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>This is supported but no longer necessary, as the @InjectService annotation is now also supported for component fields.</p></div></div><h3 id="InjectioninDetail-SpringBeanObjectProvider(tapestry-spring)">SpringBean ObjectProvider (tapestry-spring)</h3><p>Attempts to resolve a Spring bean purely by object type (Spring qualifiers are not supported). If no beans are assignable to the type, then processing continues. If exactly one is assignable, it is used as the injection value. If more than one bean is assignable, it is an error (and a list of matching beans names will be part of the thrown exception).</p><h2 id="InjectioninDetail-ServiceLookup">Service Lookup</h2><p>If none of the ObjectProviders can identify the value to inject, a last step occurs: lookup by service type. If exactly <em>one</em> service matches t
he injection type, then that service is injected.</p><p>Otherwise, the lookup fails because either no services match, or more than one matches. An exception will be thrown with the details, including a list of matching services (if there is more than one match).</p><h1 id="InjectioninDetail-Post-InjectionMethods">Post-Injection Methods</h1><p>Autobuilt objects (services and the like, but <em>not</em> components) may have post-injection methods.</p><p>Any public method may have the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/PostInjection.html">PostInjection</a> annotation.</p><p>Such methods are invoked after constructor and/or field injection. Only <strong>public methods</strong> will be invoked. Any return value is ignored.</p><p>The method often takes no parameters; however if the method has parameters, these parameters are new points of injection.</p><p>Often this is used to perform additional setup, such as regist
erring a service as a listener of events produced by another service:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">public class MyServiceImpl implements MyService, UpdateListener
+ <div id="ConfluenceContent"><p><strong>Injection</strong> in Tapestry IoC can be a complicated subject for a number of reasons:</p><ul><li>Injection can occur in many places: on fields, and on parameters to methods and constructors of certain objects.</li><li>Parts of Injection are themselves defined in terms of Tapestry IoC services, many of which are extensible.</li></ul><parameter ac:name="style">float:right</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="class">aui-label</parameter><rich-text-body><parameter ac:name="showLabels">false</parameter><parameter ac:name="showSpace">false</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="cql">label = "injection" and space = currentSpace()</parameter></rich-text-body><p>Despite this, injection generally <em>Just Works</em>: most of the time, you want Tapestry to inject a service, and only a single service implements the service interface.</p><p>Thi
s document discusses what to do when you hit a case that doesn't Just Work, or when you want to extend the injection logic in some way.</p><p>Some aspects of this discussion reflect Tapestry IoC used within a Tapestry web application: the tapestry-core module makes some extensions to injection.</p><h1 id="InjectioninDetail-InjectionTriggers">Injection Triggers</h1><p>Injection is triggered in a number of ways:</p><ul><li>A field in a component class, autobuilt object, or service implementation class is annotated with @Inject.</li><li>A method parameter to a service builder method, a decorator method, or a contribute method (in a Tapestry IoC module class).</li><li>A constructor parameter to an autobuilt object, or a service implementation class.</li><li>Any of the above with an @InjectService annotation.</li></ul><p>These define the <em>point of injection</em>.</p><p>Injection also covers a related matter: providing special resources to a service or component (remember that pag
es are specialized components). For a service, the service's id (as a string) or extensible configuration (as a Collection, List or Map) may be provided. For a component, the component's id, locale, message catalog, or component resources may be provided.</p><h1 id="InjectioninDetail-StandardInjectionProcessing">Standard Injection Processing</h1><p>This section describes standard injection, which applies at the IoC layer: autobuilt objects and service implementations. The steps for injection into Tapestry components are slightly different and are covered later.</p><p>So a the point of injection, Tapestry has identified a field or parameter that should be injected. At this point, Tapestry knows the following:</p><ul><li>The field name (if field injection). The parameter name is not available.</li><li>The field or parameter type, as a Java class. In many cases, this will be enough to identify what object shall be injected.</li><li>Any additional annotations on the field or parameter.<
/li></ul><p>Tapestry proceeds with this information.</p><h2 id="InjectioninDetail-Checkfor@InjectService">Check for @InjectService</h2><p>Tapestry checks first for the @InjectService annotation. The value of this annotation is the service id to inject. When @InjectService is present at the point of injection, the search is complete, though the injection can fail (throwing an exception) if the service id indicated does not exist, or if the service's interface is not compatible with the field's type.</p><h2 id="InjectioninDetail-Checkforserviceresources">Check for service resources</h2><p>This step applies only to IoC layer injection (not to injection into components).</p><p>When the @Inject annotation is <em>not present</em> at the point of injection, Tapestry checks to see if a resource can be injected. Services are global values, but resources are specific to the service under construction.</p><p>When the Inject annotation is present, this step is skipped (this is necessary when th
e object to be injected has a type that conflicts with a resource type, such as List or Class).</p><ul><li>org.slf4j.Logger – The Logger of the service being constructed (or the logger of the Module class being instantiated).</li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ObjectLocator.html">ObjectLocator</a> – For contribute methods, used to locate additional objects.</li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ServiceResources.html">ServiceResources</a> – For service builder methods, an extended version of ObjectLocator. </li><li>Class – The service interface type.</li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/OperationTracker.html">OperationTracker</a> – Used to track deeply nested operations so that errors can be reported sensibly.</li><li>Object, or servi
ce interface type – Passed to decorator methods.</li><li>Collection, List, Map – Assembled service configurations passed to service builder methods (or service class constructors).</li><li><p>Configuration, OrderedConfiguration, MappedConfiguration – Configuration passed to contribute methods, to build service configurations. <br clear="none" class="atl-forced-newline"> <br clear="none" class="atl-forced-newline"> If field type does not match any of the available resource types, or the Inject annotation is present, logic continues to the next step.</p><rich-text-body><p>Injection of resources into fields is triggered by the presence of the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/InjectResource.html">InjectResource</a> annotation, whereas injection of resources into parameters occurs when the Inject or InjectService annotation is <em>not</em> present. These rules are slightly tricky, which refl
ects a desire to avoid any annotations except when needed, and the fact that field injection came much later than parameter injection.</p></rich-text-body></li></ul><h2 id="InjectioninDetail-ServiceLookupbyTypeandAnnotations">Service Lookup by Type and Annotations</h2><p>Tapestry attempts to find a matching <em>service</em>.</p><p>First, it generates a set of services whose service interface is compatible with the injection type. This is based on assignability.</p><p>If the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Local.html">Local</a> annotation is present, then services not from the module containing the service being constructed will be eliminated.</p><p>Tapestry then works through the known marker annotations. For each marker annotation that is present at the point of injection, Tapestry eliminates services which <em>do not</em> have the marker. Thus, if multiple marker annotations are present, the final ser
vice must have <em>all of them</em>.</p><p>At the end, of this, Tapestry determines how many services match.</p><ul><li>If there is a single matching service, then the service to inject as been identified.</li><li>If there are no matches, and there were no marker annotations at the point of injection, then the Tapestry continues to the next step.</li><li>Otherwise there were either no matches, or too many matches: Tapestry will throw a RuntimeException.</li></ul><h2 id="InjectioninDetail-MasterObjectProviderLookup">MasterObjectProvider Lookup</h2><p>This is the point at which Tapestry's extensibility comes into play. MasterObjectProvider is a service, with a configuration of <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/ObjectProvider.html">ObjectProviders</a>.</p><p>The MasterObjectProvider is also the point at which Tapestry's IoC layer injection, and Tapestry's component injection, unite.</p><p>As a chain-of-command, each of t
he following ObjectProviders will be considered and will attempt to identify the object to be injected.</p><rich-text-body><p>A common problem when extending injection is that contributions into the MasterObjectProvider configuration have to be handled carefully. Any dependencies of the contributed objects should be resolvable using only the early stages of the injection process, otherwise MasterObjectProvider will have to be instantiated in order to handle its own injection: Tapestry will detect this impossibility and throw an exception. In addition, the <a href="typecoercer-service.html">TypeCoercer</a> service is used by several ObjectProvider implementations, so the same restrictions apply to TypeCoercer service contributions.</p></rich-text-body><h3 id="InjectioninDetail-ValueObjectProvider">Value ObjectProvider</h3><p>Checks for the presence of the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Value.html">Valu
e</a> annotation. If present, then the annotation's value is evaluated (to expand any symbol references), and the TypeCoercer service is used to convert the resulting String to the injection type (the field or parameter type).</p><h3 id="InjectioninDetail-SymbolObjectProvider">Symbol ObjectProvider</h3><p>Similar to the Value ObjectProvider: the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Symbol.html">Symbol</a> annotation's value (if present) is looked up using the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/SymbolSource.html">SymbolSource</a> service, and converted to the injection type via the TypeCoercer service.</p><h3 id="InjectioninDetail-AutobuildObjectProvider">Autobuild ObjectProvider</h3><p>Checks to see if the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Autobuild.htm
l">Autobuild</a> annotation is present and, if so, autobuilds the value for the parameter. Of course, the object being built will itself be configured via injection.</p><h3 id="InjectioninDetail-ServiceOverrideObjectProvider">ServiceOverride ObjectProvider</h3><p>Checks any contributions to the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/ServiceOverride.html">ServiceOverride</a> service. Contributions map a type to an object of that type. Thus, ServiceOverrides will override injections of services that are not qualified with a marker annotation.</p><h3 id="InjectioninDetail-AliasObjectProvider(tapestry-core)">Alias ObjectProvider (tapestry-core)</h3><p>Uses the Alias service (<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/Alias.html">API</a>) to look for an object that can be injected.</p><rich-text-body><p>Deprecated in Tapestry 5.2 and removed in 5.4.</p></ric
h-text-body><p>This is commonly used to override a built-in service by contributing an object with the exact same interface. This is an older and more complex version of the ServiceOverride provider.</p><h3 id="InjectioninDetail-AssetObjectProvider(tapestry-core)">Asset ObjectProvider (tapestry-core)</h3><p>Checks for the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Path.html">Path</a> annotation.</p><p>If present, the annotation's value has embedded symbols expanded, and is converted into an Asset (which must exist).</p><p>The TypeCoercer can then convert the Asset to the injection type, for example, as Resource.</p><h3 id="InjectioninDetail-ServiceObjectProvider(tapestry-core)">Service ObjectProvider (tapestry-core)</h3><p>Looks for the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Service.html">Service</a> annotation; if present, the annotation's value is
the exact service id to inject. This is necessary because injections into <em>component</em> fields are always triggered by the Inject annotation.</p><rich-text-body><p>This is supported but no longer necessary, as the @InjectService annotation is now also supported for component fields.</p></rich-text-body><h3 id="InjectioninDetail-SpringBeanObjectProvider(tapestry-spring)">SpringBean ObjectProvider (tapestry-spring)</h3><p>Attempts to resolve a Spring bean purely by object type (Spring qualifiers are not supported). If no beans are assignable to the type, then processing continues. If exactly one is assignable, it is used as the injection value. If more than one bean is assignable, it is an error (and a list of matching beans names will be part of the thrown exception).</p><h2 id="InjectioninDetail-ServiceLookup">Service Lookup</h2><p>If none of the ObjectProviders can identify the value to inject, a last step occurs: lookup by service type. If exactly <em>one</em> service matche
s the injection type, then that service is injected.</p><p>Otherwise, the lookup fails because either no services match, or more than one matches. An exception will be thrown with the details, including a list of matching services (if there is more than one match).</p><h1 id="InjectioninDetail-Post-InjectionMethods">Post-Injection Methods</h1><p>Autobuilt objects (services and the like, but <em>not</em> components) may have post-injection methods.</p><p>Any public method may have the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/PostInjection.html">PostInjection</a> annotation.</p><p>Such methods are invoked after constructor and/or field injection. Only <strong>public methods</strong> will be invoked. Any return value is ignored.</p><p>The method often takes no parameters; however if the method has parameters, these parameters are new points of injection.</p><p>Often this is used to perform additional setup, such as reg
isterring a service as a listener of events produced by another service:</p><plain-text-body>public class MyServiceImpl implements MyService, UpdateListener
{
@PostInjection
public void registerAsListener(UpdateListenerHub hub)
@@ -126,8 +75,7 @@
hub.addUpdateListener(this);
}
}
-</pre>
-</div></div><h1 id="InjectioninDetail-ComponentInjection">Component Injection</h1><p>Inside Tapestry components, injection occurs exclusively on <em>fields</em> and is always triggered by the @Inject (or @InjectService) annotation.</p><p>Component field injection is very similar to IoC layer, but with a different set of injectable resources.</p><p>Injection is the responsibility of the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/InjectionProvider.html">InjectionProvider</a> service, which is a chain-of-command across a number of implementations.</p><h2 id="InjectioninDetail-BlockInjectionProvider">Block InjectionProvider</h2><p>Checks if the field type is Block. If so, determines the block id to inject (either from the field name, or from an @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Id.html">Id</a> annotation, if present).</p><h2 id="InjectioninDetail-Defau
ltInjectionProvider">Default InjectionProvider</h2><p>Uses the MasterObjectProvider service to provide the injectable value. The Service Lookup stage is skipped.</p><h2 id="InjectioninDetail-ComponentResourcesInjectionProvider">ComponentResources InjectionProvider</h2><p>Injects fields of type ComponentResources.</p><h2 id="InjectioninDetail-CommonResourcesInjectionProvider">CommonResources InjectionProvider</h2><p>Injects fields with common resources:</p><ul><li>String: the components' complete id</li><li>org.slf4j.Logger: Logger for the component (based on component class name)</li><li>Locale: locale for the containing page (page locale is immutable)</li><li>Messages: Component's message catalog</li><li>ComponentResourceSelector: selector for the containing page (selector is immutable)</li></ul>
+</plain-text-body><h1 id="InjectioninDetail-ComponentInjection">Component Injection</h1><p>Inside Tapestry components, injection occurs exclusively on <em>fields</em> and is always triggered by the @Inject (or @InjectService) annotation.</p><p>Component field injection is very similar to IoC layer, but with a different set of injectable resources.</p><p>Injection is the responsibility of the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/InjectionProvider.html">InjectionProvider</a> service, which is a chain-of-command across a number of implementations.</p><h2 id="InjectioninDetail-BlockInjectionProvider">Block InjectionProvider</h2><p>Checks if the field type is Block. If so, determines the block id to inject (either from the field name, or from an @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Id.html">Id</a> annotation, if present).</p><h2 id="InjectioninDetail
-DefaultInjectionProvider">Default InjectionProvider</h2><p>Uses the MasterObjectProvider service to provide the injectable value. The Service Lookup stage is skipped.</p><h2 id="InjectioninDetail-ComponentResourcesInjectionProvider">ComponentResources InjectionProvider</h2><p>Injects fields of type ComponentResources.</p><h2 id="InjectioninDetail-CommonResourcesInjectionProvider">CommonResources InjectionProvider</h2><p>Injects fields with common resources:</p><ul><li>String: the components' complete id</li><li>org.slf4j.Logger: Logger for the component (based on component class name)</li><li>Locale: locale for the containing page (page locale is immutable)</li><li>Messages: Component's message catalog</li><li>ComponentResourceSelector: selector for the containing page (selector is immutable)</li></ul>
<div class="confluence-information-macro confluence-information-macro-information"><p class="title">Added in 5.3</p><span class="aui-icon aui-icon-small aui-iconfont-info confluence-information-macro-icon"></span><div class="confluence-information-macro-body">
</div></div>
Modified: websites/production/tapestry/content/injection.html
==============================================================================
--- websites/production/tapestry/content/injection.html (original)
+++ websites/production/tapestry/content/injection.html Sat Sep 16 02:22:40 2017
@@ -27,16 +27,6 @@
</title>
<link type="text/css" rel="stylesheet" href="/resources/space.css" />
- <link href='/resources/highlighter/styles/shCoreCXF.css' rel='stylesheet' type='text/css' />
- <link href='/resources/highlighter/styles/shThemeCXF.css' rel='stylesheet' type='text/css' />
- <script src='/resources/highlighter/scripts/shCore.js' type='text/javascript'></script>
- <script src='/resources/highlighter/scripts/shBrushJava.js' type='text/javascript'></script>
- <script src='/resources/highlighter/scripts/shBrushXml.js' type='text/javascript'></script>
- <script src='/resources/highlighter/scripts/shBrushPlain.js' type='text/javascript'></script>
- <script>
- SyntaxHighlighter.defaults['toolbar'] = false;
- SyntaxHighlighter.all();
- </script>
<link href="/styles/style.css" rel="stylesheet" type="text/css"/>
@@ -77,84 +67,42 @@
</div>
<div id="content">
- <div id="ConfluenceContent"><p><strong>Injection</strong> is Tapestry's way of making a dependency – such as a resource, asset, component, block or service – available in a page, component, mixin or service class.</p><div class="aui-label" style="float:right" title="Related Articles">
-
-
-
-
-
-
-
-
-<h3>Related Articles</h3>
-
-<ul class="content-by-label"><li>
- <div>
- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
-
- <div class="details">
- <a href="injection-in-detail.html">Injection in Detail</a>
-
-
- </div>
- </li><li>
- <div>
- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
-
- <div class="details">
- <a href="injection-faq.html">Injection FAQ</a>
-
-
- </div>
- </li><li>
- <div>
- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
-
- <div class="details">
- <a href="injection.html">Injection</a>
-
-
- </div>
- </li></ul>
-</div>
-
-
-<p>Injection is a key concept in Tapestry, and it is used in several different but related ways.</p><h2 id="Injection-InjectioninTapestryIOCServices">Injection in Tapestry IOC Services</h2><p>Main Article: <a href="tapestry-ioc-overview.html">Tapestry IoC Overview</a></p><p>The Tapestry IoC container makes use of injection primarily through constructors and via parameters to service builder methods.</p><h2 id="Injection-InjectioninComponentClasses">Injection in Component Classes</h2><p>For components, however, Tapestry takes a completely different tack: injection directly into component fields.</p><p>The @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation is used to identify fields that will contain injected services and other resources.</p><p>Tapestry allows for two kinds of injection:</p><ul><li><strong>Default injection</strong>, where Tapestry determines the object to inject into the
field based on its type.</li><li><strong>Explicit injection</strong>, where the particular service to be injected is specified.</li></ul><p>In both cases, the field is transformed into a read only value. As elsewhere in Tapestry, this transformation occurs at runtime (which is very important in terms of being able to test your components). Attempting to update an injected field will result in a runtime exception.</p><p>In addition, there are a few special cases that are triggered by specific field types, or additional annotations, in addition, to @Inject, on a field.</p><h3 id="Injection-BlockInjection">Block Injection</h3><p>For field type <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Block.html">Block</a>, the value of the Inject annotation is the id of the <a href="component-templates.html"><t:block></a> element within the component's template. Normally, the id of the block is determined from the field name (after strippin
g out any leading "_" and "$" characters):</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+ <div id="ConfluenceContent"><p><strong>Injection</strong> is Tapestry's way of making a dependency – such as a resource, asset, component, block or service – available in a page, component, mixin or service class.</p><parameter ac:name="style">float:right</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="class">aui-label</parameter><rich-text-body><parameter ac:name="showLabels">false</parameter><parameter ac:name="showSpace">false</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="cql">label = "injection" and space = currentSpace()</parameter></rich-text-body><p>Injection is a key concept in Tapestry, and it is used in several different but related ways.</p><h2 id="Injection-InjectioninTapestryIOCServices">Injection in Tapestry IOC Services</h2><p>Main Article: <a href="tapestry-ioc-overview.html">Tapestry IoC Overview</a></p><p>The Tapestry IoC container makes use of injection prima
rily through constructors and via parameters to service builder methods.</p><h2 id="Injection-InjectioninComponentClasses">Injection in Component Classes</h2><p>For components, however, Tapestry takes a completely different tack: injection directly into component fields.</p><p>The @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation is used to identify fields that will contain injected services and other resources.</p><p>Tapestry allows for two kinds of injection:</p><ul><li><strong>Default injection</strong>, where Tapestry determines the object to inject into the field based on its type.</li><li><strong>Explicit injection</strong>, where the particular service to be injected is specified.</li></ul><p>In both cases, the field is transformed into a read only value. As elsewhere in Tapestry, this transformation occurs at runtime (which is very important in terms of being able to test your c
omponents). Attempting to update an injected field will result in a runtime exception.</p><p>In addition, there are a few special cases that are triggered by specific field types, or additional annotations, in addition, to @Inject, on a field.</p><h3 id="Injection-BlockInjection">Block Injection</h3><p>For field type <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Block.html">Block</a>, the value of the Inject annotation is the id of the <a href="component-templates.html"><t:block></a> element within the component's template. Normally, the id of the block is determined from the field name (after stripping out any leading "_" and "$" characters):</p><parameter ac:name="">java</parameter><plain-text-body>@Inject
private Block foo;
-</pre>
-</div></div><p>Where that is not appropriate, an @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Id.html">Id</a> annotation can be supplied:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+</plain-text-body><p>Where that is not appropriate, an @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Id.html">Id</a> annotation can be supplied:</p><plain-text-body>@Inject
@Id("bar")
private Block barBlock;
-</pre>
-</div></div><p>The first injection will inject the Block with id "foo" (as always, case is ignored). The second injection will inject the Block with id "bar".</p><h3 id="Injection-ResourceInjection">Resource Injection</h3><p>For a particular set of field types, Tapestry will inject a <em>resource</em> related to the component, such as its Locale.</p><p>A very common example occurs when a component needs access to its <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ComponentResources.html">resources</a>. The component can define a field of the appropriate type and use the <code>@Inject</code> annotation without a value:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+</plain-text-body><p>The first injection will inject the Block with id "foo" (as always, case is ignored). The second injection will inject the Block with id "bar".</p><h3 id="Injection-ResourceInjection">Resource Injection</h3><p>For a particular set of field types, Tapestry will inject a <em>resource</em> related to the component, such as its Locale.</p><p>A very common example occurs when a component needs access to its <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ComponentResources.html">resources</a>. The component can define a field of the appropriate type and use the <code>@Inject</code> annotation without a value:</p><parameter ac:name="">java</parameter><plain-text-body>@Inject
private ComponentResources resources;
-</pre>
-</div></div><p>Tapestry uses the type of the field, ComponentResources, to determine what to inject into this field.</p><p>The following types are supported for resources injection:</p><ul><li><strong>java.lang.String</strong> – The complete id of the component, which incorporates the complete class name of the containing page and the nested id of the component within the page.</li></ul><ul><li><strong>java.util.Locale</strong> – The locale for the component (all components within a page use the same locale).</li></ul><ul><li><strong>org.slf4j.Logger</strong> – A Logger instance configured for the component, based on the component's class name. <a class="external-link" href="http://www.slf4j.org/" rel="nofollow">SLF4J</a> is a wrapper around Log4J or other logging toolkits.</li></ul><ul><li><strong>org.apache.tapestry5.ComponentResources</strong> – The resources for the component, often used to generate links related to the component.</li></ul><ul><li><stron
g>org.apache.tapestry5.ioc.Messages</strong> – The component message catalog for the component, from which <a href="injection.html">localized</a> messages can be generated.</li></ul><h3 id="Injection-AssetInjection">Asset Injection</h3><p>Main Article: <a href="assets.html">Assets</a></p><p>When the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Path.html">Path</a> annotation is also present, then the injected value (relative to the component) will be a localized asset.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+</plain-text-body><p>Tapestry uses the type of the field, ComponentResources, to determine what to inject into this field.</p><p>The following types are supported for resources injection:</p><ul><li><strong>java.lang.String</strong> – The complete id of the component, which incorporates the complete class name of the containing page and the nested id of the component within the page.</li></ul><ul><li><strong>java.util.Locale</strong> – The locale for the component (all components within a page use the same locale).</li></ul><ul><li><strong>org.slf4j.Logger</strong> – A Logger instance configured for the component, based on the component's class name. <a class="external-link" href="http://www.slf4j.org/" rel="nofollow">SLF4J</a> is a wrapper around Log4J or other logging toolkits.</li></ul><ul><li><strong>org.apache.tapestry5.ComponentResources</strong> – The resources for the component, often used to generate links related to the component.</li></ul><ul><li>
<strong>org.apache.tapestry5.ioc.Messages</strong> – The component message catalog for the component, from which <a href="injection.html">localized</a> messages can be generated.</li></ul><h3 id="Injection-AssetInjection">Asset Injection</h3><p>Main Article: <a href="assets.html">Assets</a></p><p>When the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Path.html">Path</a> annotation is also present, then the injected value (relative to the component) will be a localized asset.</p><parameter ac:name="">java</parameter><plain-text-body>@Inject
@Path("context:images/top_banner.png")
private Asset banner;
-</pre>
-</div></div><p>Symbols in the annotation value are expanded.</p><h3 id="Injection-ServiceInjection">Service Injection</h3><p>Here, a custom EmployeeService service is injected, but any custom or built-in service may be injected in the same way.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+</plain-text-body><p>Symbols in the annotation value are expanded.</p><h3 id="Injection-ServiceInjection">Service Injection</h3><p>Here, a custom EmployeeService service is injected, but any custom or built-in service may be injected in the same way.</p><parameter ac:name="">java</parameter><plain-text-body>@Inject
private EmployeeService employeeService;
-</pre>
-</div></div><p>A large number of services are provided by Tapestry. See the following packages:</p><div class="navmenu" style="float:left; width:15em; background:white; margin:3px; padding:3px">
-<ul><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/package-summary.html">Core Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ajax/package-summary.html">AJAX Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/assets/package-summary.html">Assets Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/dynamic/package-summary.html">Dynamic Component Services</a></li></ul>
-</div><div class="navmenu" style="float:left; width:15em; background:white; margin:3px; padding:3px">
-<ul><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/javascript/package-summary.html">JavaScript Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/linktransform/package-summary.html">Link Transformation Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/messages/package-summary.html">Message Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/meta/package-summary.html">Component Metadata Services</a></li></ul>
-</div><div class="navmenu" style="float:left; width:15em; background:white; margin:3px; padding:3px">
-<ul><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/pageload/package-summary.html">Page Loading Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/security/package-summary.html">Security Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/templates/package-summary.html">Template Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/transform/package-summary.html">Class Transformation Services</a></li></ul>
-</div><div class="navmenu" style="float:left; width:15em; background:white; margin:3px; padding:3px">
-<ul><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/package-summary.html">Tapestry IOC Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/cron/package-summary.html">Tapestry IOC Cron Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/kaptcha/services/package-summary.html">Kaptcha Services</a></li><li><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/upload/services/package-summary.html">File Upload Services</a></li></ul>
-</div><div style="clear:both"></div> <h3 id="Injection-ExplicitServiceInjection">Explicit Service Injection</h3><p>Here, a specific object is requested. A @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Service.html">Service</a> annotation is used to identify the service name.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Inject
+</plain-text-body><p>A large number of services are provided by Tapestry. See the following packages:<plain-text-body>{float:left|width=15em}
+* [Core Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/package-summary.html]
+* [AJAX Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ajax/package-summary.html]
+* [Assets Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/assets/package-summary.html]
+* [Dynamic Component Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/dynamic/package-summary.html]
+{float}</plain-text-body><plain-text-body>{float:left|width=15em}
+* [JavaScript Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/javascript/package-summary.html]
+* [Link Transformation Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/linktransform/package-summary.html]
+* [Message Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/messages/package-summary.html]
+* [Component Metadata Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/meta/package-summary.html]
+{float}</plain-text-body><plain-text-body>{float:left|width=15em}
+* [Page Loading Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/pageload/package-summary.html]
+* [Security Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/security/package-summary.html]
+* [Template Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/templates/package-summary.html]
+* [Class Transformation Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/transform/package-summary.html]
+{float}</plain-text-body><plain-text-body>{float:left|width=15em}
+* [Tapestry IOC Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/package-summary.html]
+* [Tapestry IOC Cron Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/services/cron/package-summary.html]
+* [Kaptcha Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/kaptcha/services/package-summary.html]
+* [File Upload Services|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/upload/services/package-summary.html]
+{float}</plain-text-body><parameter ac:name="atlassian-macro-output-type">INLINE</parameter><plain-text-body><div style="clear:both"></div></plain-text-body> </p><h3 id="Injection-ExplicitServiceInjection">Explicit Service Injection</h3><p>Here, a specific object is requested. A @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Service.html">Service</a> annotation is used to identify the service name.</p><parameter ac:name="">java</parameter><plain-text-body>@Inject
@Service("Request")
private Request request;
-</pre>
-</div></div><p>This is generally not necessary; you should always be able to identify the service to be injected just by type, not by explicit id. Explicit ids have the disadvantage of not being refactoring-safe: this won't happen with the Request service, but perhaps in your own code ... if you rename the service interface and rename the service id to match, your existing injections using the explicit service id will break.</p><h2 id="Injection-DefaultInjection">Default Injection</h2><p>When the type and/or other annotations are not sufficient to identify the object or service to inject, Tapestry falls back on two remaining steps. It assumes that the field type will be used to identify a service, by the service interface.</p><p>First, the object provider created by the Alias service is consulted. This object provider is used to disambiguate injections when there is more than one service that implements the same service interface.</p><p>Second, a search for a unique service that imp
lements the interface occurs. This will fail if either there are no services that implement the interface, or there is more than one. In the latter case, you must disambiguate, either with a contribution to the Alias service, or by explicitly identifying the service with the @Service annotation.</p><h2 id="Injection-DefiningNewInjectionLogic">Defining New Injection Logic</h2><p>Anonymous injection is controlled by the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/InjectionProvider.html">InjectionProvider</a> service. The configuration for this service is a <a href="chainbuilder-service.html">chain of command</a> for handling component injections.</p></div>
+</plain-text-body><p>This is generally not necessary; you should always be able to identify the service to be injected just by type, not by explicit id. Explicit ids have the disadvantage of not being refactoring-safe: this won't happen with the Request service, but perhaps in your own code ... if you rename the service interface and rename the service id to match, your existing injections using the explicit service id will break.</p><h2 id="Injection-DefaultInjection">Default Injection</h2><p>When the type and/or other annotations are not sufficient to identify the object or service to inject, Tapestry falls back on two remaining steps. It assumes that the field type will be used to identify a service, by the service interface.</p><p>First, the object provider created by the Alias service is consulted. This object provider is used to disambiguate injections when there is more than one service that implements the same service interface.</p><p>Second, a search for a unique service th
at implements the interface occurs. This will fail if either there are no services that implement the interface, or there is more than one. In the latter case, you must disambiguate, either with a contribution to the Alias service, or by explicitly identifying the service with the @Service annotation.</p><h2 id="Injection-DefiningNewInjectionLogic">Defining New Injection Logic</h2><p>Anonymous injection is controlled by the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/InjectionProvider.html">InjectionProvider</a> service. The configuration for this service is a <a href="chainbuilder-service.html">chain of command</a> for handling component injections.</p></div>
</div>
<div class="clearer"></div>
Modified: websites/production/tapestry/content/integrating-with-spring-framework.html
==============================================================================
--- websites/production/tapestry/content/integrating-with-spring-framework.html (original)
+++ websites/production/tapestry/content/integrating-with-spring-framework.html Sat Sep 16 02:22:40 2017
@@ -27,15 +27,6 @@
</title>
<link type="text/css" rel="stylesheet" href="/resources/space.css" />
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- <div id="ConfluenceContent"><p>Tapestry easily integrates with Spring Framework, allowing beans defined by Spring to be injected into Tapestry IoC services, and into Tapestry components. In addition, with Tapestry 5.2 and later, you can also go the other way, injecting Tapestry services in Spring beans.</p><div class="aui-label" style="float:right" title="Related Articles">
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- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
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- <a href="integrating-with-spring-framework.html">Integrating with Spring Framework</a>
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- <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
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-<p>For integrating Spring Security into your application, see <a href="security.html">Security</a>.</p><p><strong>Contents</strong></p><p><style type="text/css">/*<![CDATA[*/
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-<ul class="toc-indentation"><li>Related Articles</li></ul>
-<ul><li><a href="#IntegratingwithSpringFramework-SpringVersion">Spring Version</a></li><li><a href="#IntegratingwithSpringFramework-Usage">Usage</a>
-<ul class="toc-indentation"><li><a href="#IntegratingwithSpringFramework-Requireddependency">Required dependency</a></li><li><a href="#IntegratingwithSpringFramework-Updateyourweb.xmlfile">Update your web.xml file</a></li><li><a href="#IntegratingwithSpringFramework-AccessingtheSpringApplicationContext">Accessing the Spring Application Context</a></li><li><a href="#IntegratingwithSpringFramework-Injectingbeans">Injecting beans</a></li><li><a href="#IntegratingwithSpringFramework-InjectingTapestryservicesinSpringbeans">Injecting Tapestry services in Spring beans</a></li></ul>
-</li><li><a href="#IntegratingwithSpringFramework-ApplicationContextCustomizer">ApplicationContextCustomizer</a></li><li><a href="#IntegratingwithSpringFramework-5.0CompatibilityMode">5.0 Compatibility Mode</a></li><li><a href="#IntegratingwithSpringFramework-ChangesFrom5.0">Changes From 5.0</a></li><li><a href="#IntegratingwithSpringFramework-Limitations">Limitations</a></li></ul>
-</div><h2 id="IntegratingwithSpringFramework-SpringVersion">Spring Version</h2><p>This module is compiled and tested against Spring Framework 2.5.6. It should be reasonable to override the dependency to earlier versions of Spring, though the code makes use of some APIs that were added to Spring to support JDK 1.5 annotations.</p><h2 id="IntegratingwithSpringFramework-Usage">Usage</h2><p>The integration is designed to be a very thin layer on top of Spring's normal configuration for a web application.</p><p>Detailed instructions are available in the <a class="external-link" href="http://static.springframework.org/spring/docs/2.5.x/reference/beans.html#context-create" rel="nofollow">Spring documentation</a>. Please omit the part about creating a ContextLoaderListener: this is now done automatically by Tapestry.</p><h3 id="IntegratingwithSpringFramework-Requireddependency">Required dependency</h3><p>To integrate Spring with Tapestry, you should add the below dependency in your classpat
h. The following exemple is for Maven users.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"> <dependency>
+ <div id="ConfluenceContent"><p>Tapestry easily integrates with Spring Framework, allowing beans defined by Spring to be injected into Tapestry IoC services, and into Tapestry components. In addition, with Tapestry 5.2 and later, you can also go the other way, injecting Tapestry services in Spring beans.</p><parameter ac:name="style">float:right</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="class">aui-label</parameter><rich-text-body><parameter ac:name="showLabels">false</parameter><parameter ac:name="showSpace">false</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="cql">label = "spring" and space = currentSpace()</parameter></rich-text-body><p>For integrating Spring Security into your application, see <a href="security.html">Security</a>.</p><p><strong>Contents</strong></p><p><parameter ac:name="maxLevel">3</parameter><parameter ac:name="type">list</parameter></p><h2 id="IntegratingwithSpri
ngFramework-SpringVersion">Spring Version</h2><p>This module is compiled and tested against Spring Framework 2.5.6. It should be reasonable to override the dependency to earlier versions of Spring, though the code makes use of some APIs that were added to Spring to support JDK 1.5 annotations.</p><h2 id="IntegratingwithSpringFramework-Usage">Usage</h2><p>The integration is designed to be a very thin layer on top of Spring's normal configuration for a web application.</p><p>Detailed instructions are available in the <a class="external-link" href="http://static.springframework.org/spring/docs/2.5.x/reference/beans.html#context-create" rel="nofollow">Spring documentation</a>. Please omit the part about creating a ContextLoaderListener: this is now done automatically by Tapestry.</p><h3 id="IntegratingwithSpringFramework-Requireddependency">Required dependency</h3><p>To integrate Spring with Tapestry, you should add the below dependency in your classpath. The following exemple is for M
aven users.</p><parameter ac:name="language">xml</parameter><plain-text-body> <dependency>
<groupId>org.apache.tapestry</groupId>
<artifactId>tapestry-spring</artifactId>
<version>[your-tapestry-version]</version>
</dependency>
-</pre>
-</div></div><h3 id="IntegratingwithSpringFramework-Updateyourweb.xmlfile">Update your web.xml file</h3><p>The short form is that you must make two small changes to your application's web.xml.</p><p>First, a special filter is used in replace of the standard TapestryFilter:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"> <filter>
+</plain-text-body><h3 id="IntegratingwithSpringFramework-Updateyourweb.xmlfile">Update your web.xml file</h3><p>The short form is that you must make two small changes to your application's web.xml.</p><p>First, a special filter is used in replace of the standard TapestryFilter:</p><parameter ac:name="language">java</parameter><plain-text-body> <filter>
<filter-name>app</filter-name>
<!-- Special filter that adds in a T5 IoC module derived from the Spring WebApplicationContext. -->
<filter-class>org.apache.tapestry5.spring.TapestrySpringFilter</filter-class>
- </filter></pre>
-</div></div><p>Secondly, you may add the normal Spring configuration, consisting of an optional <context-param> identifying which Spring bean configuration file(s) to load:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"><context-param>
+ </filter></plain-text-body><p>Secondly, you may add the normal Spring configuration, consisting of an optional <context-param> identifying which Spring bean configuration file(s) to load:</p><parameter ac:name="language">java</parameter><plain-text-body><context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/daoContext.xml /WEB-INF/applicationContext.xml</param-value>
</context-param>
-</pre>
-</div></div><p>The <context-param> lists the Spring bean configuration file. It is optional and defaults to just /WEB-INF/applicationContext.xml if omitted.</p><h3 id="IntegratingwithSpringFramework-AccessingtheSpringApplicationContext">Accessing the Spring Application Context</h3><p>By integrating Spring in Tapestry, you get full access on Spring ApplicationContext as if you were accessing to any Tapestry service. Simply @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> into your pages and components.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"> @Inject
+</plain-text-body><p>The <context-param> lists the Spring bean configuration file. It is optional and defaults to just /WEB-INF/applicationContext.xml if omitted.</p><h3 id="IntegratingwithSpringFramework-AccessingtheSpringApplicationContext">Accessing the Spring Application Context</h3><p>By integrating Spring in Tapestry, you get full access on Spring ApplicationContext as if you were accessing to any Tapestry service. Simply @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> into your pages and components.</p><parameter ac:name="language">java</parameter><plain-text-body> @Inject
private ApplicationContext springContext;
-</pre>
-</div></div><h3 id="IntegratingwithSpringFramework-Injectingbeans">Injecting beans</h3><p>Inside your component classes, you may use the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation. Typically, just adding @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> to the field type is sufficient to identify the Spring bean to inject:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"> @Inject
- private UserDAO userDAO;</pre>
-</div></div><p>Searching for Spring beans is threaded into the <a href="injection.html">MasterObjectProvider service</a>. The Spring context becomes one more place that Tapestry searches when determining the injection for a injected field or method parameter.</p><h3 id="IntegratingwithSpringFramework-InjectingTapestryservicesinSpringbeans">Injecting Tapestry services in Spring beans</h3>
+</plain-text-body><h3 id="IntegratingwithSpringFramework-Injectingbeans">Injecting beans</h3><p>Inside your component classes, you may use the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation. Typically, just adding @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> to the field type is sufficient to identify the Spring bean to inject:</p><parameter ac:name="language">java</parameter><plain-text-body> @Inject
+ private UserDAO userDAO;</plain-text-body><p>Searching for Spring beans is threaded into the <a href="injection.html">MasterObjectProvider service</a>. The Spring context becomes one more place that Tapestry searches when determining the injection for a injected field or method parameter.</p><h3 id="IntegratingwithSpringFramework-InjectingTapestryservicesinSpringbeans">Injecting Tapestry services in Spring beans</h3>
<div class="confluence-information-macro confluence-information-macro-information"><p class="title">Added in 5.2</p><span class="aui-icon aui-icon-small aui-iconfont-info confluence-information-macro-icon"></span><div class="confluence-information-macro-body">
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