001package org.apache.turbine.modules;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.apache.turbine.pipeline.PipelineData;
023
024/**
025 * This is the base class that defines what a Navigation module is.
026 *
027 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
028 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
029 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
030 * @version $Id: Navigation.java 1773378 2016-12-09 13:19:59Z tv $
031 */
032public abstract class Navigation
033    extends Assembler
034{
035    /** Prefix for navigation related classes and templates */
036    public static final String PREFIX = "navigations";
037
038    /** Property for the size of the navigation cache if caching is on */
039    public static final String CACHE_SIZE_KEY = "navigation.cache.size";
040
041    /** The default size for the navigation cache */
042    public static final int CACHE_SIZE_DEFAULT = 10;
043
044    /** Represents Navigation Objects */
045    public static final String NAME = "navigation";
046
047    /**
048     * @see org.apache.turbine.modules.Assembler#getPrefix()
049     */
050    @Override
051    public String getPrefix()
052    {
053        return PREFIX;
054    }
055
056    /**
057     * A subclass must override this method to build itself.
058     * Subclasses override this method to store the navigation in
059     * RunData or to write the navigation to the output stream
060     * referenced in RunData.
061     *
062     * @param pipelineData Turbine information.
063     * @return the content of the navigation module
064     * @throws Exception a generic exception.
065     */
066    protected abstract String doBuild(PipelineData pipelineData) throws Exception;
067
068    /**
069     * Subclasses can override this method to add additional
070     * functionality.  This method is protected to force clients to
071     * use NavigationLoader to build a Navigation.
072     *
073     * @param pipelineData Turbine information.
074     * @return the content of the navigation module
075     * @throws Exception a generic exception.
076     */
077    protected String build(PipelineData pipelineData)
078        throws Exception
079    {
080        return doBuild(pipelineData);
081    }
082}