001 package 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 */ 021 022 import org.apache.ecs.ConcreteElement; 023 import org.apache.turbine.Turbine; 024 import org.apache.turbine.pipeline.PipelineData; 025 import org.apache.turbine.util.RunData; 026 027 /** 028 * The purpose of this class is to allow one to load and execute 029 * Navigation modules. 030 * 031 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 032 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 033 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 034 * @version $Id: NavigationLoader.java 1078552 2011-03-06 19:58:46Z tv $ 035 */ 036 public class NavigationLoader 037 extends GenericLoader<Navigation> 038 implements Loader<Navigation> 039 { 040 /** The single instance of this class. */ 041 private static NavigationLoader instance = new NavigationLoader(); 042 043 /** 044 * These ctor's are private to force clients to use getInstance() 045 * to access this class. 046 */ 047 private NavigationLoader() 048 { 049 super(); 050 } 051 052 /** 053 * Attempts to load and execute the external Navigation. This is 054 * used when you want to execute a Navigation which returns its 055 * output via a MultiPartElement instead of out the data.getPage() 056 * value. This allows you to easily chain the execution of 057 * Navigation modules together. 058 * 059 * @deprecated Use PipelineData version instead. 060 * @param data Turbine information. 061 * @param name Name of object that will execute the navigation. 062 * @exception Exception a generic exception. 063 */ 064 @Deprecated 065 public ConcreteElement eval(RunData data, String name) 066 throws Exception 067 { 068 // Execute Navigation 069 return getAssembler(name).build(data); 070 } 071 072 /** 073 * Attempts to load and execute the external Navigation. This is 074 * used when you want to execute a Navigation which returns its 075 * output via a MultiPartElement instead of out the data.getPage() 076 * value. This allows you to easily chain the execution of 077 * Navigation modules together. 078 * 079 * @param data Turbine information. 080 * @param name Name of object that will execute the navigation. 081 * @exception Exception a generic exception. 082 */ 083 public ConcreteElement eval(PipelineData pipelineData, String name) 084 throws Exception 085 { 086 // Execute Navigation 087 return getAssembler(name).build(pipelineData); 088 } 089 090 091 /** 092 * Attempts to load and execute the external Navigation. 093 * @deprecated Use PipelineData version instead. 094 * @param data Turbine information. 095 * @param name Name of object instance. 096 * @exception Exception a generic exception. 097 */ 098 @Deprecated 099 @Override 100 public void exec(RunData data, String name) 101 throws Exception 102 { 103 this.eval(data, name); 104 } 105 106 /** 107 * Attempts to load and execute the external Navigation. 108 * 109 * @param pipelineData Turbine information. 110 * @param name Name of object instance. 111 * @exception Exception a generic exception. 112 */ 113 @Override 114 public void exec(PipelineData pipelineData, String name) 115 throws Exception 116 { 117 this.eval(pipelineData, name); 118 } 119 120 121 /** 122 * Pulls out an instance of the object by name. Name is just the 123 * single name of the object. This is equal to getInstance but 124 * returns an Assembler object and is needed to fulfil the Loader 125 * interface. 126 * 127 * @param name Name of object instance. 128 * @return A Layout with the specified name, or null. 129 * @exception Exception a generic exception. 130 */ 131 public Navigation getAssembler(String name) 132 throws Exception 133 { 134 return getAssembler(Navigation.NAME, name); 135 } 136 137 /** 138 * @see org.apache.turbine.modules.Loader#getCacheSize() 139 */ 140 public int getCacheSize() 141 { 142 return NavigationLoader.getConfiguredCacheSize(); 143 } 144 145 /** 146 * The method through which this class is accessed. 147 * 148 * @return The single instance of this class. 149 */ 150 public static NavigationLoader getInstance() 151 { 152 return instance; 153 } 154 155 /** 156 * Helper method to get the configured cache size for this module 157 * 158 * @return the configure cache size 159 */ 160 private static int getConfiguredCacheSize() 161 { 162 return Turbine.getConfiguration().getInt(Navigation.CACHE_SIZE_KEY, 163 Navigation.CACHE_SIZE_DEFAULT); 164 } 165 }