001package org.apache.commons.jcs.utils.props; 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.commons.jcs.access.exception.ConfigurationException; 023 024import java.util.Properties; 025 026/** 027 * Provides a mechanism to load properties into objects. 028 * <p> 029 * Functions that depend on properties should call ensureProperties() before it uses any properties. 030 */ 031public abstract class AbstractPropertyContainer 032{ 033 /** File, db, etc */ 034 private static final PropertiesFactory DEFAULT_PROPERTIES_FACTORY = new PropertiesFactoryFileImpl(); 035 036 /** 037 * A property group is a subsection of properties. It's sent to the properties factory to 038 * specify which group of properties to pull back. This will probably mean different things to 039 * different property factories. For PropertiesFactoryFileImpl, the propertiesGroup maps to a 040 * filename. 041 */ 042 private String propertiesGroup; 043 044 /** 045 * The property heading is used to specify a starting point in the properties object. This is 046 * used so that settings can be relative to this propertiesHeading, as opposed to being 047 * statically coded. There's no enforcement of this, but users are encouraged to call 048 * getProperties().get( getPropertiesHeading() + ".foo" ); 049 */ 050 private String propertiesHeading; 051 052 /** The factory to use. */ 053 private PropertiesFactory propertiesFactory; 054 055 /** The loaded properties. */ 056 private Properties properties; 057 058 /** 059 * Makes sure an AbstractPropertyClass has all the properties it needs. 060 * <p> 061 * Synchronized mutators so multiple threads cannot cause problems. We wouldn't want the 062 * properties heading to get changed as we were processing the properties. 063 * <p> 064 * @throws ConfigurationException on configuration failure 065 */ 066 public synchronized void ensureProperties() 067 throws ConfigurationException 068 { 069 if ( getProperties() == null ) 070 { 071 initializeProperties(); 072 } 073 } 074 075 /** 076 * Loads the properties and then calls handleProperties. Typically, you don't need to call this. 077 * This is primarily intended for reinitialization. 078 * <p> 079 * If the properties object is null, when you call ensureProperties initialize will be called. 080 * <p> 081 * @throws ConfigurationException on configuration failure 082 */ 083 public synchronized void initializeProperties() 084 throws ConfigurationException 085 { 086 loadProperties(); 087 088 handleProperties(); 089 } 090 091 /** 092 * This loads the properties regardless of whether or not they have already been loaded. 093 * <p> 094 * @throws ConfigurationException on configuration failure 095 */ 096 private void loadProperties() 097 throws ConfigurationException 098 { 099 if ( getPropertiesGroup() == null ) 100 { 101 throw new ConfigurationException( "Properties group is null and it shouldn't be" ); 102 } 103 104 if ( getPropertiesHeading() == null ) 105 { 106 throw new ConfigurationException( "Properties heading is null and it shouldn't be" ); 107 } 108 109 if ( getPropertiesFactory() == null ) 110 { 111 setProperties( DEFAULT_PROPERTIES_FACTORY.getProperties( getPropertiesGroup() ) ); 112 } 113 else 114 { 115 setProperties( getPropertiesFactory().getProperties( getPropertiesGroup() ) ); 116 } 117 } 118 119 /** 120 * Sets fields for properties, and verifies that all necessary properties are there. 121 * <p> 122 * @throws ConfigurationException on configuration failure 123 */ 124 protected abstract void handleProperties() 125 throws ConfigurationException; 126 127 /** 128 * @return Returns the properties. 129 */ 130 public synchronized Properties getProperties() 131 { 132 return properties; 133 } 134 135 /** 136 * @param properties The properties to set. 137 */ 138 public synchronized void setProperties( Properties properties ) 139 { 140 this.properties = properties; 141 } 142 143 /** 144 * @return Returns the propertiesHeading. 145 */ 146 public synchronized String getPropertiesHeading() 147 { 148 return propertiesHeading; 149 } 150 151 /** 152 * @param propertiesHeading The propertiesHeading to set. 153 */ 154 public synchronized void setPropertiesHeading( String propertiesHeading ) 155 { 156 this.propertiesHeading = propertiesHeading; 157 } 158 159 /** 160 * @return Returns the propertiesFactory. 161 */ 162 public PropertiesFactory getPropertiesFactory() 163 { 164 return propertiesFactory; 165 } 166 167 /** 168 * @param propertiesFactory The propertiesFactory to set. 169 */ 170 public void setPropertiesFactory( PropertiesFactory propertiesFactory ) 171 { 172 this.propertiesFactory = propertiesFactory; 173 } 174 175 /** 176 * @return Returns the propertiesGroup. 177 */ 178 public String getPropertiesGroup() 179 { 180 return propertiesGroup; 181 } 182 183 /** 184 * @param propertiesGroup The propertiesGroup to set. 185 */ 186 public void setPropertiesGroup( String propertiesGroup ) 187 { 188 this.propertiesGroup = propertiesGroup; 189 } 190}