/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * 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 ThreadLocal<CachedXPathAPI>  local=new ThreadLocal<CachedXPathAPI>();
    static ThreadLocal<Document> localDoc=new ThreadLocal<Document>();

    /**
     * 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=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=local.get();
        if (cx==null) {
            cx=new CachedXPathAPI();
            local.set(cx);
            localDoc.set(null);
        }
        return cx;
    }
}