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.ArrayList; 020import java.util.Collection; 021import java.util.Collections; 022import java.util.HashMap; 023import java.util.LinkedList; 024import java.util.Map; 025 026import org.apache.commons.configuration2.ConfigurationUtils; 027import org.apache.commons.configuration2.HierarchicalConfiguration; 028import org.apache.commons.configuration2.builder.BasicBuilderParameters; 029import org.apache.commons.configuration2.builder.BuilderParameters; 030import org.apache.commons.configuration2.builder.ConfigurationBuilder; 031import org.apache.commons.configuration2.builder.DefaultParametersHandler; 032import org.apache.commons.configuration2.builder.DefaultParametersManager; 033 034/** 035 * <p> 036 * A specialized parameters object for a {@link CombinedConfigurationBuilder}. 037 * </p> 038 * <p> 039 * This class defines methods for setting properties for customizing a builder for combined configurations. Note that 040 * some of these properties can also be set in the configuration definition file. If this is the case, the settings in 041 * the definition file override the content of this object. 042 * </p> 043 * <p> 044 * This class is not thread-safe. It is intended that an instance is constructed and initialized by a single thread 045 * during configuration of a {@code ConfigurationBuilder}. 046 * </p> 047 * 048 * @since 2.0 049 */ 050public class CombinedBuilderParametersImpl extends BasicBuilderParameters implements CombinedBuilderProperties<CombinedBuilderParametersImpl> { 051 /** Constant for the key in the parameters map used by this class. */ 052 private static final String PARAM_KEY = RESERVED_PARAMETER_PREFIX + CombinedBuilderParametersImpl.class.getName(); 053 054 /** 055 * Looks up an instance of this class in the specified parameters map. This is equivalent to 056 * {@code fromParameters(params, false);} 057 * 058 * @param params the map with parameters (must not be <b>null</b> 059 * @return the instance obtained from the map or <b>null</b> 060 * @throws NullPointerException if the map is <b>null</b> 061 */ 062 public static CombinedBuilderParametersImpl fromParameters(final Map<String, ?> params) { 063 return fromParameters(params, false); 064 } 065 066 /** 067 * Looks up an instance of this class in the specified parameters map and optionally creates a new one if none is found. 068 * This method can be used to obtain an instance of this class which has been stored in a parameters map. It is 069 * compatible with the {@code getParameters()} method. 070 * 071 * @param params the map with parameters (must not be <b>null</b> 072 * @param createIfMissing determines the behavior if no instance is found in the map; if <b>true</b>, a new instance 073 * with default settings is created; if <b>false</b>, <b>null</b> is returned 074 * @return the instance obtained from the map or <b>null</b> 075 * @throws NullPointerException if the map is <b>null</b> 076 */ 077 public static CombinedBuilderParametersImpl fromParameters(final Map<String, ?> params, final boolean createIfMissing) { 078 CombinedBuilderParametersImpl result = (CombinedBuilderParametersImpl) params.get(PARAM_KEY); 079 if (result == null && createIfMissing) { 080 result = new CombinedBuilderParametersImpl(); 081 } 082 return result; 083 } 084 085 /** The definition configuration builder. */ 086 private ConfigurationBuilder<? extends HierarchicalConfiguration<?>> definitionBuilder; 087 088 /** A parameters object for the definition configuration builder. */ 089 private BuilderParameters definitionBuilderParameters; 090 091 /** A map with registered configuration builder providers. */ 092 private final Map<String, ConfigurationBuilderProvider> providers; 093 094 /** A list with default parameters for child configuration sources. */ 095 private final Collection<BuilderParameters> childParameters; 096 097 /** The manager for default handlers. */ 098 private DefaultParametersManager childDefaultParametersManager; 099 100 /** The base path for configuration sources to be loaded. */ 101 private String basePath; 102 103 /** A flag whether settings should be inherited by child builders. */ 104 private boolean inheritSettings; 105 106 /** 107 * Creates a new instance of {@code CombinedBuilderParametersImpl}. 108 */ 109 public CombinedBuilderParametersImpl() { 110 providers = new HashMap<>(); 111 childParameters = new LinkedList<>(); 112 inheritSettings = true; 113 } 114 115 /** 116 * {@inheritDoc} This implementation also clones the parameters object for the definition builder if possible. 117 */ 118 @Override 119 public CombinedBuilderParametersImpl clone() { 120 final CombinedBuilderParametersImpl copy = (CombinedBuilderParametersImpl) super.clone(); 121 copy.setDefinitionBuilderParameters((BuilderParameters) ConfigurationUtils.cloneIfPossible(getDefinitionBuilderParameters())); 122 return copy; 123 } 124 125 /** 126 * Gets the base path for relative names of configuration sources. Result may be <b>null</b> if no base path has been 127 * set. 128 * 129 * @return the base path for resolving relative file names 130 */ 131 public String getBasePath() { 132 return basePath; 133 } 134 135 /** 136 * Gets the {@code DefaultParametersManager} object for initializing parameter objects for child configuration 137 * sources. This method never returns <b>null</b>. If no manager was set, a new instance is created right now. 138 * 139 * @return the {@code DefaultParametersManager} for child configuration sources 140 */ 141 public DefaultParametersManager getChildDefaultParametersManager() { 142 if (childDefaultParametersManager == null) { 143 childDefaultParametersManager = new DefaultParametersManager(); 144 } 145 return childDefaultParametersManager; 146 } 147 148 /** 149 * Gets a collection with default parameter objects for child configuration sources. This collection contains the 150 * same objects (in the same order) that were passed to {@code addChildParameters()}. The returned collection is a 151 * defensive copy; it can be modified, but this has no effect on the parameters stored in this object. 152 * 153 * @return a map with default parameters for child sources 154 */ 155 public Collection<? extends BuilderParameters> getDefaultChildParameters() { 156 return new ArrayList<>(childParameters); 157 } 158 159 /** 160 * Gets the {@code ConfigurationBuilder} object for obtaining the definition configuration. 161 * 162 * @return the definition {@code ConfigurationBuilder} 163 */ 164 public ConfigurationBuilder<? extends HierarchicalConfiguration<?>> getDefinitionBuilder() { 165 return definitionBuilder; 166 } 167 168 /** 169 * Gets the parameters object for the definition configuration builder if present. 170 * 171 * @return the parameters object for the definition configuration builder or <b>null</b> 172 */ 173 public BuilderParameters getDefinitionBuilderParameters() { 174 return definitionBuilderParameters; 175 } 176 177 /** 178 * {@inheritDoc} This implementation returns a map which contains this object itself under a specific key. The static 179 * {@code fromParameters()} method can be used to extract an instance from a parameters map. 180 */ 181 @Override 182 public Map<String, Object> getParameters() { 183 final Map<String, Object> params = super.getParameters(); 184 params.put(PARAM_KEY, this); 185 return params; 186 } 187 188 /** 189 * Gets an (unmodifiable) map with the currently registered {@code ConfigurationBuilderProvider} objects. 190 * 191 * @return the map with {@code ConfigurationBuilderProvider} objects (the keys are the tag names) 192 */ 193 public Map<String, ConfigurationBuilderProvider> getProviders() { 194 return Collections.unmodifiableMap(providers); 195 } 196 197 /** 198 * {@inheritDoc} This implementation additionally copies some properties defined by this class. 199 */ 200 @Override 201 public void inheritFrom(final Map<String, ?> source) { 202 super.inheritFrom(source); 203 204 final CombinedBuilderParametersImpl srcParams = fromParameters(source); 205 if (srcParams != null) { 206 setChildDefaultParametersManager(srcParams.getChildDefaultParametersManager()); 207 setInheritSettings(srcParams.isInheritSettings()); 208 } 209 } 210 211 /** 212 * Returns the current value of the flag that controls whether the settings of the parent combined configuration builder 213 * should be inherited by its child configurations. 214 * 215 * @return the flag whether settings should be inherited by child configurations 216 */ 217 public boolean isInheritSettings() { 218 return inheritSettings; 219 } 220 221 /** 222 * Returns the {@code ConfigurationBuilderProvider} which is registered for the specified tag name or <b>null</b> if 223 * there is no registration for this tag. 224 * 225 * @param tagName the tag name 226 * @return the provider registered for this tag or <b>null</b> 227 */ 228 public ConfigurationBuilderProvider providerForTag(final String tagName) { 229 return providers.get(tagName); 230 } 231 232 /** 233 * {@inheritDoc} This implementation registers the passed in handler at an internal {@link DefaultParametersManager} 234 * instance. If none was set, a new instance is created now. 235 */ 236 @Override 237 public <D> CombinedBuilderParametersImpl registerChildDefaultsHandler(final Class<D> paramClass, final DefaultParametersHandler<? super D> handler) { 238 getChildDefaultParametersManager().registerDefaultsHandler(paramClass, handler); 239 return this; 240 } 241 242 /** 243 * {@inheritDoc} This implementation registers the passed in handler at an internal {@link DefaultParametersManager} 244 * instance. If none was set, a new instance is created now. 245 */ 246 @Override 247 public <D> CombinedBuilderParametersImpl registerChildDefaultsHandler(final Class<D> paramClass, final DefaultParametersHandler<? super D> handler, 248 final Class<?> startClass) { 249 getChildDefaultParametersManager().registerDefaultsHandler(paramClass, handler, startClass); 250 return this; 251 } 252 253 /** 254 * Registers all {@code ConfigurationBuilderProvider}s in the given parameters object which have not yet been 255 * registered. This method works like the method with the same name, but the map with providers is obtained from the 256 * passed in parameters object. 257 * 258 * @param params the parameters object from which to copy providers(must not be <b>null</b>) 259 * @return a reference to this object for method chaining 260 * @throws IllegalArgumentException if the source parameters object is <b>null</b> 261 */ 262 public CombinedBuilderParametersImpl registerMissingProviders(final CombinedBuilderParametersImpl params) { 263 if (params == null) { 264 throw new IllegalArgumentException("Source parameters must not be null!"); 265 } 266 return registerMissingProviders(params.getProviders()); 267 } 268 269 /** 270 * Registers all {@code ConfigurationBuilderProvider}s in the given map to this object which have not yet been 271 * registered. This method is mainly used for internal purposes: a {@code CombinedConfigurationBuilder} takes the 272 * providers contained in a parameters object and adds all standard providers. This way it is possible to override a 273 * standard provider by registering a provider object for the same tag name at the parameters object. 274 * 275 * @param providers a map with tag names and corresponding providers (must not be <b>null</b> or contain <b>null</b> 276 * entries) 277 * @return a reference to this object for method chaining 278 * @throws IllegalArgumentException if the map with providers is <b>null</b> or contains <b>null</b> entries 279 */ 280 public CombinedBuilderParametersImpl registerMissingProviders(final Map<String, ConfigurationBuilderProvider> providers) { 281 if (providers == null) { 282 throw new IllegalArgumentException("Map with providers must not be null!"); 283 } 284 providers.forEach((k, v) -> { 285 if (!this.providers.containsKey(k)) { 286 registerProvider(k, v); 287 } 288 }); 289 return this; 290 } 291 292 /** 293 * Registers the given {@code ConfigurationBuilderProvider} for the specified tag name. This means that whenever this 294 * tag is encountered in a configuration definition file, the corresponding builder provider is invoked. 295 * 296 * @param tagName the name of the tag (must not be <b>null</b>) 297 * @param provider the {@code ConfigurationBuilderProvider} (must not be <b>null</b>) 298 * @return a reference to this object for method chaining 299 * @throws IllegalArgumentException if a required parameter is missing 300 */ 301 @Override 302 public CombinedBuilderParametersImpl registerProvider(final String tagName, final ConfigurationBuilderProvider provider) { 303 if (tagName == null) { 304 throw new IllegalArgumentException("Tag name must not be null!"); 305 } 306 if (provider == null) { 307 throw new IllegalArgumentException("Provider must not be null!"); 308 } 309 310 providers.put(tagName, provider); 311 return this; 312 } 313 314 /** 315 * Sets the base path for this combined configuration builder. Normally it it not necessary to set the base path 316 * explicitly. Per default, relative file names of configuration sources are resolved based on the location of the 317 * definition file. If this is not desired or if the definition configuration is loaded by a different means, the base 318 * path for relative file names can be specified using this method. 319 * 320 * @param path the base path for resolving relative file names 321 * @return a reference to this object for method chaining 322 */ 323 @Override 324 public CombinedBuilderParametersImpl setBasePath(final String path) { 325 basePath = path; 326 return this; 327 } 328 329 /** 330 * {@inheritDoc} This implementation stores the passed in manager object. An already existing manager object (either 331 * explicitly set or created on demand) is overridden. This also removes all default handlers registered before! 332 */ 333 @Override 334 public CombinedBuilderParametersImpl setChildDefaultParametersManager(final DefaultParametersManager manager) { 335 childDefaultParametersManager = manager; 336 return this; 337 } 338 339 /** 340 * Sets the {@code ConfigurationBuilder} for the definition configuration. This is the configuration which contains the 341 * configuration sources that form the combined configuration. 342 * 343 * @param builder the definition {@code ConfigurationBuilder} 344 * @return a reference to this object for method chaining 345 */ 346 @Override 347 public CombinedBuilderParametersImpl setDefinitionBuilder(final ConfigurationBuilder<? extends HierarchicalConfiguration<?>> builder) { 348 definitionBuilder = builder; 349 return this; 350 } 351 352 /** 353 * Sets the parameters object for the definition configuration builder. This property is evaluated only if the 354 * definition configuration builder is not set explicitly (using the {@link #setDefinitionBuilder(ConfigurationBuilder)} 355 * method). In this case, a builder for an XML configuration is created and configured with this parameters object. 356 * 357 * @param params the parameters object for the definition configuration builder 358 * @return a reference to this object for method chaining 359 */ 360 @Override 361 public CombinedBuilderParametersImpl setDefinitionBuilderParameters(final BuilderParameters params) { 362 definitionBuilderParameters = params; 363 return this; 364 } 365 366 @Override 367 public CombinedBuilderParametersImpl setInheritSettings(final boolean inheritSettings) { 368 this.inheritSettings = inheritSettings; 369 return this; 370 } 371}