org.apache.velocity.runtime.directive.contrib.For Maven / Gradle / Ivy
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package org.apache.velocity.runtime.directive.contrib;
/*
* 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.
*/
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.directive.Foreach;
import org.apache.velocity.runtime.directive.MacroParseException;
import org.apache.velocity.runtime.parser.ParseException;
import org.apache.velocity.runtime.parser.Token;
import org.apache.velocity.runtime.parser.node.ASTReference;
import org.apache.velocity.runtime.parser.node.Node;
import org.apache.velocity.runtime.parser.node.ParserTreeConstants;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
/**
* The #for directive provides the behavior of the #foreach directive but also
* provides an 'index' keyword that allows the user to define an optional index variable
* that tracks the loop iterations. e.g.; #for($user in $users index $i).
* As $user iterates through $users the index reference $i will be equal to
* 0, 1, 2, etc..
* @see org.apache.velocity.runtime.directive.Foreach
*/
public class For extends Foreach
{
protected String counterName;
protected int counterInitialValue;
@Override
public String getName()
{
return "for";
}
@Override
public int getType()
{
return BLOCK;
}
@Override
public void init(RuntimeServices rs, InternalContextAdapter context, Node node)
throws TemplateInitException
{
super.init(rs, context, node);
// If we have more then 3 argument then the user has specified an
// index value, i.e.; #foreach($a in $b index $c)
if (node.jjtGetNumChildren() > 4)
{
// The index variable name is at position 4
counterName = ((ASTReference) node.jjtGetChild(4)).getRootString();
// The count value always starts at 0 when using an index.
counterInitialValue = 0;
}
}
@Override
public boolean render(InternalContextAdapter context, Writer writer, Node node)
throws IOException
{
Object c = context.get(counterName);
context.put(counterName, counterInitialValue);
try
{
return super.render(context, writer, node);
}
finally
{
if (c != null)
{
context.put(counterName, c);
}
else
{
context.remove(counterName);
}
}
}
@Override
protected void renderBlock(InternalContextAdapter context, Writer writer, Node node)
throws IOException
{
Object count = context.get(counterName);
if (count instanceof Number)
{
context.put(counterName, ((Number)count).intValue() + 1);
}
super.renderBlock(context, writer, node);
}
/**
* We do not allow a word token in any other arg position except for the 2nd
* since we are looking for the pattern #foreach($foo in $bar).
*/
@Override
public void checkArgs(ArrayList argtypes, Token t,
String templateName) throws ParseException
{
super.checkArgs(argtypes, t, templateName);
// If #foreach is defining an index variable make sure it has the 'index
// $var' combo.
if (argtypes.size() > 3)
{
if (argtypes.get(3) != ParserTreeConstants.JJTWORD)
{
throw new MacroParseException(
"Expected word 'index' at argument position 4 in #foreach",
templateName, t);
}
else if (argtypes.size() == 4
|| argtypes.get(4) != ParserTreeConstants.JJTREFERENCE)
{
throw new MacroParseException(
"Expected a reference after 'index' in #foreach", templateName, t);
}
}
}
}