001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.configuration2.builder.combined; 018 019import java.util.Arrays; 020import java.util.Collection; 021 022import org.apache.commons.configuration2.CombinedConfiguration; 023import org.apache.commons.configuration2.Configuration; 024import org.apache.commons.configuration2.builder.BasicBuilderParameters; 025import org.apache.commons.configuration2.builder.BasicConfigurationBuilder; 026import org.apache.commons.configuration2.builder.BuilderParameters; 027 028/** 029 * <p> 030 * A specialized {@code ConfigurationBuilderProvider} implementation which deals 031 * with combined configuration builders. 032 * </p> 033 * <p> 034 * This class is used to support {@code <configuration>} elements in 035 * configuration definition files. The provider creates another 036 * {@link CombinedConfigurationBuilder} which inherits some of the properties 037 * from its parent builder. 038 * </p> 039 * 040 * @version $Id: CombinedConfigurationBuilderProvider.java 1842194 2018-09-27 22:24:23Z ggregory $ 041 * @since 2.0 042 */ 043public class CombinedConfigurationBuilderProvider extends 044 BaseConfigurationBuilderProvider 045{ 046 /** Constant for the name of the supported builder class. */ 047 private static final String BUILDER_CLASS = 048 "org.apache.commons.configuration2.builder.combined.CombinedConfigurationBuilder"; 049 050 /** Constant for the name of the supported reloading builder class. */ 051 private static final String RELOADING_BUILDER_CLASS = 052 "org.apache.commons.configuration2.builder.combined.ReloadingCombinedConfigurationBuilder"; 053 054 /** Constant for the name of the supported configuration class. */ 055 private static final String CONFIGURATION_CLASS = 056 "org.apache.commons.configuration2.CombinedConfiguration"; 057 058 /** Constant for the combined configuration builder parameters class. */ 059 private static final String COMBINED_PARAMS = 060 "org.apache.commons.configuration2.builder.combined.CombinedBuilderParametersImpl"; 061 062 /** Constant for the name of the file-based builder parameters class. */ 063 private static final String FILE_PARAMS = 064 "org.apache.commons.configuration2.builder.FileBasedBuilderParametersImpl"; 065 066 /** 067 * Creates a new instance of {@code CombinedConfigurationBuilderProvider}. 068 */ 069 public CombinedConfigurationBuilderProvider() 070 { 071 super(BUILDER_CLASS, RELOADING_BUILDER_CLASS, CONFIGURATION_CLASS, 072 Arrays.asList(COMBINED_PARAMS, FILE_PARAMS)); 073 } 074 075 /** 076 * {@inheritDoc} This implementation creates the result builder object 077 * directly, not using reflection. (The reflection-based approach of the 078 * base class does not work here because a combined configuration builder 079 * has constructors with a different signature.) It also performs some 080 * additional initializations. 081 */ 082 @Override 083 protected BasicConfigurationBuilder<? extends Configuration> createBuilder( 084 final ConfigurationDeclaration decl, final Collection<BuilderParameters> params) 085 throws Exception 086 { 087 CombinedConfigurationBuilder builder; 088 if (decl.isReload()) 089 { 090 builder = new ReloadingCombinedConfigurationBuilder(); 091 } 092 else 093 { 094 builder = new CombinedConfigurationBuilder(); 095 } 096 decl.getConfigurationBuilder().initChildEventListeners(builder); 097 return builder; 098 } 099 100 /** 101 * {@inheritDoc} This implementation pre-fills basic parameters from the 102 * basic properties of the parent builder's result configuration. 103 */ 104 @Override 105 protected void initializeParameterObjects(final ConfigurationDeclaration decl, 106 final Collection<BuilderParameters> params) throws Exception 107 { 108 // we know that the first object is the combined builder parameters 109 // object 110 final BasicBuilderParameters basicParams = 111 (BasicBuilderParameters) params.iterator().next(); 112 setUpBasicParameters(decl.getConfigurationBuilder() 113 .getConfigurationUnderConstruction(), basicParams); 114 // now properties set explicitly can be overridden 115 super.initializeParameterObjects(decl, params); 116 } 117 118 /** 119 * Populates the specified parameters object with properties from the given 120 * configuration. This method is used to set default values for basic 121 * properties based on the result configuration of the parent builder. 122 * 123 * @param config the configuration whose properties are to be copied 124 * @param params the target parameters object 125 */ 126 private static void setUpBasicParameters(final CombinedConfiguration config, 127 final BasicBuilderParameters params) 128 { 129 params.setListDelimiterHandler(config.getListDelimiterHandler()) 130 .setLogger(config.getLogger()) 131 .setThrowExceptionOnMissing(config.isThrowExceptionOnMissing()) 132 .setConfigurationDecoder(config.getConfigurationDecoder()); 133 } 134}