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 027 * Navigation 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: NavigationLoader.java 1709648 2015-10-20 17:08:10Z tv $ 033 */ 034public class NavigationLoader 035 extends GenericLoader<Navigation> 036 implements Loader<Navigation> 037{ 038 /** The single instance of this class. */ 039 private static NavigationLoader instance = new NavigationLoader(); 040 041 /** 042 * These ctor's are private to force clients to use getInstance() 043 * to access this class. 044 */ 045 private NavigationLoader() 046 { 047 super(); 048 } 049 050 /** 051 * Attempts to load and execute the external Navigation. This is 052 * used when you want to execute a Navigation which returns its 053 * output via a MultiPartElement instead of out the data.getPage() 054 * value. This allows you to easily chain the execution of 055 * Navigation modules together. 056 * 057 * @param pipelineData Turbine information. 058 * @param name Name of object that will execute the navigation. 059 * @return the navigation module output 060 * @exception Exception a generic exception. 061 */ 062 public String eval(PipelineData pipelineData, String name) 063 throws Exception 064 { 065 // Execute Navigation 066 return getAssembler(name).build(pipelineData); 067 } 068 069 /** 070 * Attempts to load and execute the external Navigation. 071 * 072 * @param pipelineData Turbine information. 073 * @param name Name of object instance. 074 * @exception Exception a generic exception. 075 */ 076 @Override 077 public void exec(PipelineData pipelineData, String name) 078 throws Exception 079 { 080 this.eval(pipelineData, name); 081 } 082 083 /** 084 * Pulls out an instance of the object by name. Name is just the 085 * single name of the object. 086 * 087 * @param name Name of object instance. 088 * @return A Layout with the specified name, or null. 089 * @exception Exception a generic exception. 090 */ 091 @Override 092 public Navigation getAssembler(String name) 093 throws Exception 094 { 095 return getAssembler(Navigation.class, name); 096 } 097 098 /** 099 * @see org.apache.turbine.modules.Loader#getCacheSize() 100 */ 101 @Override 102 public int getCacheSize() 103 { 104 return NavigationLoader.getConfiguredCacheSize(); 105 } 106 107 /** 108 * The method through which this class is accessed. 109 * 110 * @return The single instance of this class. 111 */ 112 public static NavigationLoader getInstance() 113 { 114 return instance; 115 } 116 117 /** 118 * Helper method to get the configured cache size for this module 119 * 120 * @return the configure cache size 121 */ 122 private static int getConfiguredCacheSize() 123 { 124 return Turbine.getConfiguration().getInt(Navigation.CACHE_SIZE_KEY, 125 Navigation.CACHE_SIZE_DEFAULT); 126 } 127}