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 java.util.List; 023import java.util.function.IntSupplier; 024import java.util.stream.Collectors; 025 026import org.apache.turbine.Turbine; 027import org.apache.turbine.TurbineConstants; 028import org.apache.turbine.pipeline.PipelineData; 029import org.apache.turbine.services.TurbineServices; 030import org.apache.turbine.services.assemblerbroker.AssemblerBrokerService; 031 032/** 033 * This is the base class for the loaders. It contains code that is 034 * used across all of the loaders. It also specifies the interface 035 * that is required to be called a Loader. 036 * 037 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 038 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 039 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 040 * @param <T> the specialized assembler type 041 */ 042public abstract class GenericLoader<T extends Assembler> implements Loader<T> 043{ 044 /** The Assembler Broker Service */ 045 protected AssemblerBrokerService ab; 046 047 /** Class of loaded assembler */ 048 private final Class<T> assemblerClass; 049 050 /** Supplier of configured cache for this assembler Class */ 051 private final IntSupplier cacheSizeSupplier; 052 053 /** @serial This can be serialized */ 054 private boolean reload = false; 055 056 /** Base packages path for Turbine */ 057 private static final String TURBINE_PACKAGE = "org.apache.turbine.modules"; 058 059 /** Packages paths for Turbine */ 060 private static List<String> TURBINE_PACKAGES = null; 061 062 /** 063 * Basic constructor for creating a loader. 064 * 065 * @param assemblerClass Class of loaded assembler 066 * @param cacheSizeSupplier Supplier of configured cache size for this assembler Class 067 */ 068 public GenericLoader(Class<T> assemblerClass, IntSupplier cacheSizeSupplier) 069 { 070 super(); 071 this.assemblerClass = assemblerClass; 072 this.cacheSizeSupplier = cacheSizeSupplier; 073 this.ab = (AssemblerBrokerService)TurbineServices.getInstance() 074 .getService(AssemblerBrokerService.SERVICE_NAME); 075 } 076 077 /** 078 * Attempts to load and execute the external action that has been 079 * set. 080 * @param pipelineData the Turbine request 081 * @param name the name of the assembler module 082 * @throws Exception a generic exception. 083 */ 084 public abstract void exec(PipelineData pipelineData, String name) 085 throws Exception; 086 087 /** 088 * Returns whether or not this external action is reload itself. 089 * This is in cases where the Next button would be clicked, but 090 * since we are checking for that, we would go into an endless 091 * loop. 092 * 093 * @return True if the action is reload. 094 */ 095 public boolean reload() 096 { 097 return this.reload; 098 } 099 100 /** 101 * Sets whether or not this external action is reload itself. 102 * This is in cases where the Next button would be clicked, but 103 * since we are checking for that, we would go into an endless 104 * loop. 105 * 106 * @param reload True if the action must be marked as reload. 107 * @return Itself. 108 */ 109 public GenericLoader<T> setReload(boolean reload) 110 { 111 this.reload = reload; 112 return this; 113 } 114 115 /** 116 * Gets the base package where Turbine should find its default 117 * modules. 118 * 119 * @return A String with the base package name. 120 */ 121 public static String getBasePackage() 122 { 123 return TURBINE_PACKAGE; 124 } 125 126 /** 127 * Gets the package list where Turbine should find its 128 * modules. 129 * 130 * @return A List with the package names (including the base package). 131 */ 132 public static List<String> getPackages() 133 { 134 if (TURBINE_PACKAGES == null) 135 { 136 List<String> turbinePackages = Turbine.getConfiguration() 137 .getList(TurbineConstants.MODULE_PACKAGES).stream().map( o -> (String) o ).collect( Collectors.toList() ); 138 139 TURBINE_PACKAGES = turbinePackages; 140 } 141 142 List<String> packages = TURBINE_PACKAGES; 143 144 if (!packages.contains(TURBINE_PACKAGE)) 145 { 146 packages.add(TURBINE_PACKAGE); 147 } 148 149 return packages; 150 } 151 152 /** 153 * Pulls out an instance of the object by name. Name is just the 154 * single name of the object. 155 * 156 * @param name Name of object instance. 157 * @return An Action with the specified name, or null. 158 * @throws Exception a generic exception. 159 */ 160 @Override 161 public T getAssembler(String name) 162 throws Exception 163 { 164 return getAssembler(assemblerClass, name); 165 } 166 167 /** 168 * Pulls out an instance of the object by name. Name is just the 169 * single name of the object. 170 * 171 * @param type Type of the assembler. 172 * @param name Name of object instance. 173 * @return A Screen with the specified name, or null. 174 * @throws Exception a generic exception. 175 */ 176 protected T getAssembler(Class<T> type, String name) 177 throws Exception 178 { 179 T asm = null; 180 181 try 182 { 183 if (ab != null) 184 { 185 // Attempt to load the assembler 186 asm = ab.getAssembler(type, name); 187 } 188 } 189 catch (ClassCastException cce) 190 { 191 // This can alternatively let this exception be thrown 192 // So that the ClassCastException is shown in the 193 // browser window. Like this it shows "Screen not Found" 194 asm = null; 195 } 196 197 if (asm == null) 198 { 199 // If we did not find a screen we should try and give 200 // the user a reason for that... 201 // FIX ME: The AssemblerFactories should each add it's 202 // own string here... 203 List<String> packages = GenericLoader.getPackages(); 204 205 throw new ClassNotFoundException( 206 "\n\n\tRequested " + type + " not found: " + name + 207 "\n\tTurbine looked in the following " + 208 "modules.packages path: \n\t" + packages.toString() + "\n"); 209 } 210 211 return asm; 212 } 213 214 /** 215 * @see org.apache.turbine.modules.Loader#getCacheSize() 216 */ 217 @Override 218 public int getCacheSize() 219 { 220 return cacheSizeSupplier.getAsInt(); 221 } 222}