    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.Turbine;
    023import org.apache.turbine.pipeline.PipelineData;
    024
    025/**
    026 * The purpose of this class is to allow one to load and execute Page
    027 * modules.
    028 *
    029 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    030 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    031 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    032 * @version $Id: PageLoader.java 1773378 2016-12-09 13:19:59Z tv $
    033 */
    034public class PageLoader
    035    extends GenericLoader<Page>
    036    implements Loader<Page>
    037{
    038    /** The single instance of this class. */
    039    private static PageLoader instance = new PageLoader();
    040
    041    /**
    042     * These ctor's are private to force clients to use getInstance()
    043     * to access this class.
    044     */
    045    private PageLoader()
    046    {
    047        super();
    048    }
    049
    050    /**
    051     * Attempts to load and execute the external page.
    052     *
    053     * @param pipelineData Turbine information.
    054     * @param name Name of object that will execute the page.
    055     * @throws Exception a generic exception.
    056     */
    057    @Override
    058    public void exec(PipelineData pipelineData, String name)
    059            throws Exception
    060    {
    061        // Execute page
    062        getAssembler(name).build(pipelineData);
    063    }
    064
    065    /**
    066     * Pulls out an instance of the object by name.  Name is just the
    067     * single name of the object.
    068     *
    069     * @param name Name of object instance.
    070     * @return A Screen with the specified name, or null.
    071     * @throws Exception a generic exception.
    072     */
    073    @Override
    074    public Page getAssembler(String name)
    075        throws Exception
    076    {
    077        return getAssembler(Page.class, name);
    078    }
    079
    080    /**
    081     * @see org.apache.turbine.modules.Loader#getCacheSize()
    082     */
    083    @Override
    084    public int getCacheSize()
    085    {
    086        return PageLoader.getConfiguredCacheSize();
    087    }
    088
    089    /**
    090     * The method through which this class is accessed.
    091     *
    092     * @return The single instance of this class.
    093     */
    094    public static PageLoader getInstance()
    095    {
    096        return instance;
    097    }
    098
    099    /**
    100     * Helper method to get the configured cache size for this module
    101     *
    102     * @return the configure cache size
    103     */
    104    private static int getConfiguredCacheSize()
    105    {
    106        return Turbine.getConfiguration().getInt(Page.CACHE_SIZE_KEY,
    107                Page.CACHE_SIZE_DEFAULT);
    108    }
    109}