/*
 * 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.lenya.cms.linking;

import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.lenya.cms.cocoon.components.context.ContextUtility;

/**
 * Abstract base class for servlet-oriented link rewriters.
 */
public abstract class ServletLinkRewriter implements LinkRewriter {
    
    protected ServiceManager manager;

    /**
     * @param manager The service manager.
     */
    public ServletLinkRewriter(ServiceManager manager) {
        this.manager = manager;
    }

    private String contextPath;
    
    protected String getContextPath() {
        if (this.contextPath == null) {
            ContextUtility context = null;
            try {
                context = (ContextUtility) this.manager.lookup(ContextUtility.ROLE);
                this.contextPath = context.getRequest().getContextPath();
            } catch (ServiceException e) {
                throw new RuntimeException(e);
            }
            finally {
                if (context != null) {
                    this.manager.release(context);
                }
            }
        }
        return this.contextPath;
    }

}