Struts example source code file (If.java)

This example Struts source code file (If.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

answer, answer, boolean, boolean, component, expression, if, if, io, string, string, strutstag, strutstagattribute

The Struts If.java source code

/*
 * $Id: If.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * 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.util.ValueStack;

/**
 * <!-- START SNIPPET: javadoc -->
 *
 * <p>Perform basic condition flow. 'If' tag could be used by itself or
 * with 'Else If' Tag and/or single/multiple 'Else' Tag.</p>
 *
 * <!-- END SNIPPET: javadoc -->
 *
 *
 * <!-- START SNIPPET: params -->
 *
 * <ul>
 *
 *  <li>test* (Boolean) - Logic to determined if body of tag is to be displayed
 *
 * </ul>
 *
 * <!-- END SNIPPET: params -->
 *
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 *  <s:if test="%{false}">
 *      <div>Will Not Be Executed</div>
 *  </s:if>
 *  <s:elseif test="%{true}">
 *      <div>Will Be Executed</div>
 *  </s:elseif>
 *  <s:else>
 *      <div>Will Not Be Executed</div>
 *  </s:else>
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * @see Else
 * @see ElseIf
 *
 */
@StrutsTag(name="if", tldTagClass="org.apache.struts2.views.jsp.IfTag", description="If tag")
public class If extends Component {
    public static final String ANSWER = "struts.if.answer";

    Boolean answer;
    String test;

    @StrutsTagAttribute(description="Expression to determine if body of tag is to be displayed", type="Boolean", required=true)
    public void setTest(String test) {
        this.test = test;
    }

    public If(ValueStack stack) {
        super(stack);
    }

    public boolean start(Writer writer) {
        answer = (Boolean) findValue(test, Boolean.class);

        if (answer == null) {
            answer = Boolean.FALSE;
        }
        stack.getContext().put(ANSWER, answer);
        return answer.booleanValue();
    }

    public boolean end(Writer writer, String body) {
        stack.getContext().put(ANSWER, answer);
        return super.end(writer, body);
    }
}