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Struts example source code file (Bean.java)
The Struts Bean.java source code/* * $Id: Bean.java 768855 2009-04-27 02:09:35Z wesw $ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.struts2.components; import java.io.Writer; import org.apache.struts2.views.annotations.StrutsTag; import org.apache.struts2.views.annotations.StrutsTagAttribute; import com.opensymphony.xwork2.ObjectFactory; import com.opensymphony.xwork2.inject.Inject; import com.opensymphony.xwork2.util.ClassLoaderUtil; import com.opensymphony.xwork2.util.ValueStack; import com.opensymphony.xwork2.util.logging.Logger; import com.opensymphony.xwork2.util.logging.LoggerFactory; import com.opensymphony.xwork2.util.reflection.ReflectionProvider; /** * <!-- START SNIPPET: javadoc --> * <p>Instantiates a class that conforms to the JavaBeans specification. This tag has a body which can contain * a number of {@link Param} elements to set any mutator methods on that class.</p> * <p/> * <p>If the var attribute is set on the BeanTag, it will place the instantiated bean into the * stack's Context.</p> * <p/> * <!-- END SNIPPET: javadoc --> * * * <!-- START SNIPPET: params --> * <ul> * <li>var - the stack's context name (if supplied) that the created bean will be store under * <li>name* - the class name of the bean to be instantiated (must respect JavaBean specification) * </ul> * <!-- END SNIPPET: params --> * * * <p>Examples: * <p/> * <pre> * <!-- START SNIPPET: examples --> * <-- in freemarker form --> * [@s.bean name="org.apache.struts2.example.counter.SimpleCounter" var="counter"] * [s:param name="foo" value="BAR"/] * The value of foo is : [s:property value="foo"/], when inside the bean tag.<br /> * [/s:bean] * * <-- in jsp form --> * <s:bean name="org.apache.struts2.example.counter.SimpleCounter" var="counter"> * <s:param name="foo" value="BAR" /> * The value of foot is : <s:property value="foo"/>, when inside the bean tag <br /> * </s:bean> * <!-- END SNIPPET: examples --> * </pre> * <p/> * * <!-- START SNIPPET: examplesdescription --> * <p>This example instantiates a bean called SimpleCounter and sets the foo property (setFoo('BAR')). The * SimpleCounter object is then pushed onto the Valuestack, which means that we can call its accessor methods (getFoo()) * with the Property tag and get their values.</p> * <p/> * <p>In the above example, the id has been set to a value of counter. This means that the SimpleCounter class * will be placed into the stack's context. You can access the SimpleCounter class using a Struts tag:</p> * <p/> * <pre> * <-- jsp form --> * <s:property value="#counter" /> * * <-- freemarker form --> * [s:property value="#counter.foo"/] * </pre> * <p/> * <p>In the property tag example, the # tells Ognl to search the context for the SimpleCounter class which has * an id(key) of <i>counter * <!-- END SNIPPET: examplesdescription --> * * @see Param */ @StrutsTag(name="bean", tldTagClass="org.apache.struts2.views.jsp.BeanTag", description="Instantiate a JavaBean and place it in the context") public class Bean extends ContextBean { protected static final Logger LOG = LoggerFactory.getLogger(Bean.class); protected Object bean; protected String name; protected ObjectFactory objectFactory; protected ReflectionProvider reflectionProvider; public Bean(ValueStack stack) { super(stack); } @Inject public void setObjectFactory(ObjectFactory objectFactory) { this.objectFactory = objectFactory; } @Inject public void setReflectionProvider(ReflectionProvider prov) { this.reflectionProvider = prov; } public boolean start(Writer writer) { boolean result = super.start(writer); ValueStack stack = getStack(); try { String beanName = findString(name, "name", "Bean name is required. Example: com.acme.FooBean"); bean = objectFactory.buildBean(ClassLoaderUtil.loadClass(beanName, getClass()), stack.getContext()); } catch (Exception e) { LOG.error("Could not instantiate bean", e); return false; } // push bean on stack stack.push(bean); // store for reference later putInContext(bean); return result; } public boolean end(Writer writer, String body) { ValueStack stack = getStack(); stack.pop(); return super.end(writer, body); } public void addParameter(String key, Object value) { reflectionProvider.setProperty(key, value, bean, getStack().getContext()); } @StrutsTagAttribute(description="The class name of the bean to be instantiated (must respect JavaBean specification)", required=true) public void setName(String name) { this.name = name; } } Other Struts examples (source code examples)Here is a short list of links related to this Struts Bean.java source code file: |
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