/*
 * Copyright  1999-2004 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.
 *
 */
package com.sun.org.apache.xml.internal.security.utils;

import com.sun.org.apache.xpath.internal.CachedXPathAPI;
import org.w3c.dom.Document;


/**
 * @author Raul Benito
 */
public class CachedXPathAPIHolder {
	 static java.util.logging.Logger log = 
	        java.util.logging.Logger.getLogger(CachedXPathAPIHolder.class.getName());

    static ThreadLocal  local=new ThreadLocal();
    static ThreadLocal localDoc=new ThreadLocal();
  
	/**
	 * Sets the doc for the xpath transformation. Resets the cache if needed
	 * @param doc
	 */
	public static void setDoc(Document doc) {                    
       if (localDoc.get()!=doc) {
            CachedXPathAPI cx=(CachedXPathAPI)local.get();
            if (cx==null) {
               cx=new CachedXPathAPI();
               local.set(cx);
               localDoc.set(doc);
               return;
            }
            //Different docs reset.
            cx.getXPathContext().reset();
            localDoc.set(doc);                     
        }		
	}
    /**
     * @return the cachexpathapi for this thread
     */
    public static CachedXPathAPI getCachedXPathAPI() {        
        CachedXPathAPI cx=(CachedXPathAPI)local.get();        
        if (cx==null) {
            cx=new CachedXPathAPI();
            local.set(cx);
            localDoc.set(null);            
        }
    	return cx;
    }
}