ServletCache.java

/*
 * 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.
 */

package org.apache.sling.scripting.java.impl;

import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * This is a simple in memory cache for compiled servlets.
 */
public final class ServletCache {

    /**
     * Maps servlet source urls to servlet wrappers.
     */
    private ConcurrentHashMap<String, ServletWrapper> servlets = new ConcurrentHashMap<String, ServletWrapper>();

    /**
     * Add a new ServletWrapper.
     *
     * @param servletUri Servlet URI
     * @param sw Servlet wrapper
     */
    public ServletWrapper addWrapper(final String servletUri, final ServletWrapper sw) {
        ServletWrapper previous = servlets.putIfAbsent(servletUri, sw);
        if ( previous != null ) {
            return previous;
        }
        return sw;
    }

    /**
     * Get an already existing ServletWrapper.
     *
     * @param servletUri Servlet URI
     * @return ServletWrapper
     */
    public ServletWrapper getWrapper(final String servletUri) {
        return servlets.get(servletUri);
    }

    /**
     * Remove a  ServletWrapper.
     *
     * @param servletUri Servlet URI
     * @param isRemove Is a remove
     */
    public void removeWrapper(final String servletUri, final boolean isRemove) {
        final ServletWrapper wrapper = servlets.remove(servletUri);
        if ( wrapper != null ) {
            wrapper.destroy();
        } else if ( isRemove ) {
            final Iterator<Map.Entry<String, ServletWrapper>> iter = servlets.entrySet().iterator();
            while ( iter.hasNext() ) {
                final Map.Entry<String, ServletWrapper> entry = iter.next();
                if ( entry.getKey().startsWith(servletUri) ) {
                    iter.remove();
                    entry.getValue().destroy();
                }
            }
        }
    }

    /**
     * Process a "destroy" event for this web application context.
     */
    public void destroy() {
        Iterator<ServletWrapper> i = this.servlets.values().iterator();
        while (i.hasNext()) {
            i.next().destroy();
        }
    }
}