1 package org.apache.turbine.modules; 2 3 /* 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 22 import org.apache.turbine.Turbine; 23 import org.apache.turbine.pipeline.PipelineData; 24 25 /** 26 * The purpose of this class is to allow one to load and execute 27 * Navigation modules. 28 * 29 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 30 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 31 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 32 * @version $Id: NavigationLoader.java 1709648 2015-10-20 17:08:10Z tv $ 33 */ 34 public class NavigationLoader 35 extends GenericLoader<Navigation> 36 implements Loader<Navigation> 37 { 38 /** The single instance of this class. */ 39 private static NavigationLoader instance = new NavigationLoader(); 40 41 /** 42 * These ctor's are private to force clients to use getInstance() 43 * to access this class. 44 */ 45 private NavigationLoader() 46 { 47 super(); 48 } 49 50 /** 51 * Attempts to load and execute the external Navigation. This is 52 * used when you want to execute a Navigation which returns its 53 * output via a MultiPartElement instead of out the data.getPage() 54 * value. This allows you to easily chain the execution of 55 * Navigation modules together. 56 * 57 * @param pipelineData Turbine information. 58 * @param name Name of object that will execute the navigation. 59 * @return the navigation module output 60 * @exception Exception a generic exception. 61 */ 62 public String eval(PipelineData pipelineData, String name) 63 throws Exception 64 { 65 // Execute Navigation 66 return getAssembler(name).build(pipelineData); 67 } 68 69 /** 70 * Attempts to load and execute the external Navigation. 71 * 72 * @param pipelineData Turbine information. 73 * @param name Name of object instance. 74 * @exception Exception a generic exception. 75 */ 76 @Override 77 public void exec(PipelineData pipelineData, String name) 78 throws Exception 79 { 80 this.eval(pipelineData, name); 81 } 82 83 /** 84 * Pulls out an instance of the object by name. Name is just the 85 * single name of the object. 86 * 87 * @param name Name of object instance. 88 * @return A Layout with the specified name, or null. 89 * @exception Exception a generic exception. 90 */ 91 @Override 92 public Navigation getAssembler(String name) 93 throws Exception 94 { 95 return getAssembler(Navigation.class, name); 96 } 97 98 /** 99 * @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 }