/*
* Copyright (c) 1998-2010 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.xpath;
import com.caucho.xpath.pattern.AbstractPattern;
import com.caucho.xpath.pattern.NodeIterator;
import org.w3c.dom.Node;
import java.util.Iterator;
import java.util.logging.Logger;
/**
* A node selection pattern. Patterns represent compiled XPath node selectors.
* They can be used to find nodes, select nodes, and test if a node matches
* a pattern.
*
* <p>There are two types of patterns: select patterns and match patterns.
* <p>Select patterns match a node relative to another node.
* <code>find</code> and <code>select</code> use select patterns.
* <p>Match patterns match a node in isolation. <code>isMatch</code> uses
* match patterns.
*/
public class Pattern {
protected final static Logger log
= Logger.getLogger(Pattern.class.getName());
private AbstractPattern pattern;
Pattern(AbstractPattern pattern)
{
this.pattern = pattern;
}
/**
* Returns the first node matching the pattern. The pattern should
* be a select pattern.
*
* @param node node represented by '.' and start of match.
*
* @return first matching node
*/
public Node find(Node node)
throws XPathException
{
if (node == null)
throw new NullPointerException();
Env env = XPath.createEnv();
// XXX: doesn't make sense for a match to have a context?
//env.setCurrentNode(node);
//env.setContextNode(node);
Iterator iter = pattern.select(node, env);
Node value = null;
if (iter.hasNext())
value = (Node) iter.next();
XPath.freeEnv(env);
return value;
}
/**
* Returns the first node matching the pattern. The pattern should
* be a select pattern.
*
* @param node node represented by '.' and start of match.
* @param env variable environment.
*
* @return first matching node
*/
public Node find(Node node, ExprEnvironment env)
throws XPathException
{
if (node == null)
throw new NullPointerException();
if (env instanceof Env) {
Env globalEnv = (Env) env;
// XXX: doesn't make sense for a match to have a context?
//globalEnv.setCurrentNode(node);
//globalEnv.setContextNode(node);
}
Iterator iter = pattern.select(node, env);
Node value = null;
if (iter.hasNext())
value = (Node) iter.next();
return value;
}
/**
* Selects all nodes matching the pattern. The pattern should be a
* select pattern.
*
* @param node node represented by '.' and start of match.
*
* @return iterator of matching nodes
*/
public NodeIterator select(Node node)
throws XPathException
{
if (node == null)
throw new NullPointerException();
Env env = XPath.createEnv();
env.setCurrentNode(node);
NodeIterator iter = pattern.select(node, env);
XPath.freeEnv(env);
return iter;
}
/**
* Selects all nodes matching the pattern. The pattern should be a
* select pattern.
*
* @param context node represented by '.' and start of match.
* @param env variable environment.
*
* @return iterator of matching nodes
*/
public NodeIterator select(Node node, ExprEnvironment env)
throws XPathException
{
if (node == null)
throw new NullPointerException();
if (env instanceof Env) {
Env globalEnv = (Env) env;
globalEnv.setCurrentNode(node);
globalEnv.setContextNode(node);
}
return pattern.select(node, env);
}
/**
* Test if the node matches the pattern. The pattern should be a
* match pattern.
*
* @param node node to test
*
* @return true if the pattern matches.
*/
public boolean isMatch(Node node)
throws XPathException
{
Env env = XPath.createEnv();
// XXX: doesn't make sense for a match to have a context?
//env.setCurrentNode(node);
//env.setContextNode(node);
boolean value = pattern.match(node, env);
XPath.freeEnv(env);
return value;
}
/**
* Test if the node matches the pattern. The pattern should be a
* match pattern.
*
* @param node node to test
* @param env variable environment.
*
* @return true if the pattern matches.
*/
public boolean isMatch(Node node, ExprEnvironment env)
throws XPathException
{
return pattern.match(node, env);
}
/**
* Returns the underlying pattern implementation.
*/
public AbstractPattern getPattern()
{
return pattern;
}
public String toString()
{
return pattern.toString();
}
}