astifstatement.java

velocity 的脚本语言的全部代码集合

package org.apache.velocity.runtime.parser.node;

/*
 * Copyright 2000-2001,2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 */


/**
 * Please look at the Parser.jjt file which is
 * what controls the generation of this class.
 *
 * @author <a href="mailto:[e-mail]">Jason van Zyl</a>
 * @author <a href="mailto:[e-mail]">Geir Magnusson Jr.</a>
 * @version $Id: ASTIfStatement.java,v 1.9.8.1 2004/03/03 23:22:58 geirm Exp $ 
*/


import java.io.Writer;
import java.io.IOException;

import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.runtime.parser.*;

import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;


public class ASTIfStatement extends SimpleNode
{    
    public ASTIfStatement(int id)
    {
        super(id);
    }
    
    public ASTIfStatement(Parser p, int id)
    {
        super(p, id);
    }
    
    /** Accept the visitor. **/
    public Object jjtAccept(ParserVisitor visitor, Object data)
    {
        return visitor.visit(this, data);
    }
    
    public boolean render( InternalContextAdapter context, Writer writer)
        throws IOException,MethodInvocationException,
        	ResourceNotFoundException, ParseErrorException
    {
        /*
         * Check if the #if(expression) construct evaluates to true:
         * if so render and leave immediately because there
         * is nothing left to do!
         */
        if (jjtGetChild(0).evaluate(context))
        {
            jjtGetChild(1).render(context, writer);
            return true;
        }
    
        int totalNodes = jjtGetNumChildren();
        
        /*
         * Now check the remaining nodes left in the
         * if construct. The nodes are either elseif
         *  nodes or else nodes. Each of these node
         * types knows how to evaluate themselves. If
         * a node evaluates to true then the node will
         * render itself and this method will return
         * as there is nothing left to do.
         */
        for (int i = 2; i < totalNodes; i++)
        {
            if (jjtGetChild(i).evaluate(context))
            {
                jjtGetChild(i).render(context, writer);
                return true;
            }
        }
    
        /*
         * This is reached when an ASTIfStatement
         * consists of an if/elseif sequence where
         * none of the nodes evaluate to true.
         */
        return true;
    }

    public void process( InternalContextAdapter context, ParserVisitor visitor)
    {
    }
}