/*
* 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.
*/
/*
* $Id: ExpressionVisitor.java 468637 2006-10-28 06:51:02Z minchau $
*/
package org.apache.xalan.extensions;
import org.apache.xalan.templates.StylesheetRoot;
import org.apache.xpath.ExpressionOwner;
import org.apache.xpath.XPathVisitor;
import org.apache.xpath.functions.FuncExtFunction;
import org.apache.xpath.functions.FuncExtFunctionAvailable;
import org.apache.xpath.functions.Function;
/**
* When {@link org.apache.xalan.processor.StylesheetHandler} creates
* an {@link org.apache.xpath.XPath}, the ExpressionVisitor
* visits the XPath expression. For any extension functions it
* encounters, it instructs StylesheetRoot to register the
* extension namespace.
*
* This mechanism is required to locate extension functions
* that may be embedded within an expression.
*/
public class ExpressionVisitor extends XPathVisitor
{
private StylesheetRoot m_sroot;
/**
* The constructor sets the StylesheetRoot variable which
* is used to register extension namespaces.
* @param sroot the StylesheetRoot that is being constructed.
*/
public ExpressionVisitor (StylesheetRoot sroot)
{
m_sroot = sroot;
}
/**
* If the function is an extension function, register the namespace.
*
* @param owner The current XPath object that owns the expression.
* @param func The function currently being visited.
*
* @return true to continue the visit in the subtree, if any.
*/
public boolean visitFunction(ExpressionOwner owner, Function func)
{
if (func instanceof FuncExtFunction)
{
String namespace = ((FuncExtFunction)func).getNamespace();
m_sroot.getExtensionNamespacesManager().registerExtension(namespace);
}
else if (func instanceof FuncExtFunctionAvailable)
{
String arg = ((FuncExtFunctionAvailable)func).getArg0().toString();
if (arg.indexOf(":") > 0)
{
String prefix = arg.substring(0,arg.indexOf(":"));
String namespace = this.m_sroot.getNamespaceForPrefix(prefix);
m_sroot.getExtensionNamespacesManager().registerExtension(namespace);
}
}
return true;
}
}