CombinedBuilderParametersImpl.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.configuration2.builder.combined;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import org.apache.commons.configuration2.ConfigurationUtils;
import org.apache.commons.configuration2.HierarchicalConfiguration;
import org.apache.commons.configuration2.builder.BasicBuilderParameters;
import org.apache.commons.configuration2.builder.BuilderParameters;
import org.apache.commons.configuration2.builder.ConfigurationBuilder;
import org.apache.commons.configuration2.builder.DefaultParametersHandler;
import org.apache.commons.configuration2.builder.DefaultParametersManager;
/**
* <p>
* A specialized parameters object for a {@link CombinedConfigurationBuilder}.
* </p>
* <p>
* This class defines methods for setting properties for customizing a builder for combined configurations. Note that
* some of these properties can also be set in the configuration definition file. If this is the case, the settings in
* the definition file override the content of this object.
* </p>
* <p>
* This class is not thread-safe. It is intended that an instance is constructed and initialized by a single thread
* during configuration of a {@code ConfigurationBuilder}.
* </p>
*
* @since 2.0
*/
public class CombinedBuilderParametersImpl extends BasicBuilderParameters implements CombinedBuilderProperties<CombinedBuilderParametersImpl> {
/** Constant for the key in the parameters map used by this class. */
private static final String PARAM_KEY = RESERVED_PARAMETER_PREFIX + CombinedBuilderParametersImpl.class.getName();
/**
* Looks up an instance of this class in the specified parameters map. This is equivalent to
* {@code fromParameters(params, false);}
*
* @param params the map with parameters (must not be <b>null</b>
* @return the instance obtained from the map or <b>null</b>
* @throws NullPointerException if the map is <b>null</b>
*/
public static CombinedBuilderParametersImpl fromParameters(final Map<String, ?> params) {
return fromParameters(params, false);
}
/**
* Looks up an instance of this class in the specified parameters map and optionally creates a new one if none is found.
* This method can be used to obtain an instance of this class which has been stored in a parameters map. It is
* compatible with the {@code getParameters()} method.
*
* @param params the map with parameters (must not be <b>null</b>
* @param createIfMissing determines the behavior if no instance is found in the map; if <b>true</b>, a new instance
* with default settings is created; if <b>false</b>, <b>null</b> is returned
* @return the instance obtained from the map or <b>null</b>
* @throws NullPointerException if the map is <b>null</b>
*/
public static CombinedBuilderParametersImpl fromParameters(final Map<String, ?> params, final boolean createIfMissing) {
CombinedBuilderParametersImpl result = (CombinedBuilderParametersImpl) params.get(PARAM_KEY);
if (result == null && createIfMissing) {
result = new CombinedBuilderParametersImpl();
}
return result;
}
/** The definition configuration builder. */
private ConfigurationBuilder<? extends HierarchicalConfiguration<?>> definitionBuilder;
/** A parameters object for the definition configuration builder. */
private BuilderParameters definitionBuilderParameters;
/** A map with registered configuration builder providers. */
private final Map<String, ConfigurationBuilderProvider> providers;
/** A list with default parameters for child configuration sources. */
private final Collection<BuilderParameters> childParameters;
/** The manager for default handlers. */
private DefaultParametersManager childDefaultParametersManager;
/** The base path for configuration sources to be loaded. */
private String basePath;
/** A flag whether settings should be inherited by child builders. */
private boolean inheritSettings;
/**
* Creates a new instance of {@code CombinedBuilderParametersImpl}.
*/
public CombinedBuilderParametersImpl() {
providers = new HashMap<>();
childParameters = new LinkedList<>();
inheritSettings = true;
}
/**
* {@inheritDoc} This implementation also clones the parameters object for the definition builder if possible.
*/
@Override
public CombinedBuilderParametersImpl clone() {
final CombinedBuilderParametersImpl copy = (CombinedBuilderParametersImpl) super.clone();
copy.setDefinitionBuilderParameters((BuilderParameters) ConfigurationUtils.cloneIfPossible(getDefinitionBuilderParameters()));
return copy;
}
/**
* Gets the base path for relative names of configuration sources. Result may be <b>null</b> if no base path has been
* set.
*
* @return the base path for resolving relative file names
*/
public String getBasePath() {
return basePath;
}
/**
* Gets the {@code DefaultParametersManager} object for initializing parameter objects for child configuration
* sources. This method never returns <b>null</b>. If no manager was set, a new instance is created right now.
*
* @return the {@code DefaultParametersManager} for child configuration sources
*/
public DefaultParametersManager getChildDefaultParametersManager() {
if (childDefaultParametersManager == null) {
childDefaultParametersManager = new DefaultParametersManager();
}
return childDefaultParametersManager;
}
/**
* Gets a collection with default parameter objects for child configuration sources. This collection contains the
* same objects (in the same order) that were passed to {@code addChildParameters()}. The returned collection is a
* defensive copy; it can be modified, but this has no effect on the parameters stored in this object.
*
* @return a map with default parameters for child sources
*/
public Collection<? extends BuilderParameters> getDefaultChildParameters() {
return new ArrayList<>(childParameters);
}
/**
* Gets the {@code ConfigurationBuilder} object for obtaining the definition configuration.
*
* @return the definition {@code ConfigurationBuilder}
*/
public ConfigurationBuilder<? extends HierarchicalConfiguration<?>> getDefinitionBuilder() {
return definitionBuilder;
}
/**
* Gets the parameters object for the definition configuration builder if present.
*
* @return the parameters object for the definition configuration builder or <b>null</b>
*/
public BuilderParameters getDefinitionBuilderParameters() {
return definitionBuilderParameters;
}
/**
* {@inheritDoc} This implementation returns a map which contains this object itself under a specific key. The static
* {@code fromParameters()} method can be used to extract an instance from a parameters map.
*/
@Override
public Map<String, Object> getParameters() {
final Map<String, Object> params = super.getParameters();
params.put(PARAM_KEY, this);
return params;
}
/**
* Gets an (unmodifiable) map with the currently registered {@code ConfigurationBuilderProvider} objects.
*
* @return the map with {@code ConfigurationBuilderProvider} objects (the keys are the tag names)
*/
public Map<String, ConfigurationBuilderProvider> getProviders() {
return Collections.unmodifiableMap(providers);
}
/**
* {@inheritDoc} This implementation additionally copies some properties defined by this class.
*/
@Override
public void inheritFrom(final Map<String, ?> source) {
super.inheritFrom(source);
final CombinedBuilderParametersImpl srcParams = fromParameters(source);
if (srcParams != null) {
setChildDefaultParametersManager(srcParams.getChildDefaultParametersManager());
setInheritSettings(srcParams.isInheritSettings());
}
}
/**
* Returns the current value of the flag that controls whether the settings of the parent combined configuration builder
* should be inherited by its child configurations.
*
* @return the flag whether settings should be inherited by child configurations
*/
public boolean isInheritSettings() {
return inheritSettings;
}
/**
* Returns the {@code ConfigurationBuilderProvider} which is registered for the specified tag name or <b>null</b> if
* there is no registration for this tag.
*
* @param tagName the tag name
* @return the provider registered for this tag or <b>null</b>
*/
public ConfigurationBuilderProvider providerForTag(final String tagName) {
return providers.get(tagName);
}
/**
* {@inheritDoc} This implementation registers the passed in handler at an internal {@link DefaultParametersManager}
* instance. If none was set, a new instance is created now.
*/
@Override
public <D> CombinedBuilderParametersImpl registerChildDefaultsHandler(final Class<D> paramClass, final DefaultParametersHandler<? super D> handler) {
getChildDefaultParametersManager().registerDefaultsHandler(paramClass, handler);
return this;
}
/**
* {@inheritDoc} This implementation registers the passed in handler at an internal {@link DefaultParametersManager}
* instance. If none was set, a new instance is created now.
*/
@Override
public <D> CombinedBuilderParametersImpl registerChildDefaultsHandler(final Class<D> paramClass, final DefaultParametersHandler<? super D> handler,
final Class<?> startClass) {
getChildDefaultParametersManager().registerDefaultsHandler(paramClass, handler, startClass);
return this;
}
/**
* Registers all {@code ConfigurationBuilderProvider}s in the given parameters object which have not yet been
* registered. This method works like the method with the same name, but the map with providers is obtained from the
* passed in parameters object.
*
* @param params the parameters object from which to copy providers(must not be <b>null</b>)
* @return a reference to this object for method chaining
* @throws IllegalArgumentException if the source parameters object is <b>null</b>
*/
public CombinedBuilderParametersImpl registerMissingProviders(final CombinedBuilderParametersImpl params) {
if (params == null) {
throw new IllegalArgumentException("Source parameters must not be null!");
}
return registerMissingProviders(params.getProviders());
}
/**
* Registers all {@code ConfigurationBuilderProvider}s in the given map to this object which have not yet been
* registered. This method is mainly used for internal purposes: a {@code CombinedConfigurationBuilder} takes the
* providers contained in a parameters object and adds all standard providers. This way it is possible to override a
* standard provider by registering a provider object for the same tag name at the parameters object.
*
* @param providers a map with tag names and corresponding providers (must not be <b>null</b> or contain <b>null</b>
* entries)
* @return a reference to this object for method chaining
* @throws IllegalArgumentException if the map with providers is <b>null</b> or contains <b>null</b> entries
*/
public CombinedBuilderParametersImpl registerMissingProviders(final Map<String, ConfigurationBuilderProvider> providers) {
if (providers == null) {
throw new IllegalArgumentException("Map with providers must not be null!");
}
providers.forEach((k, v) -> {
if (!this.providers.containsKey(k)) {
registerProvider(k, v);
}
});
return this;
}
/**
* Registers the given {@code ConfigurationBuilderProvider} for the specified tag name. This means that whenever this
* tag is encountered in a configuration definition file, the corresponding builder provider is invoked.
*
* @param tagName the name of the tag (must not be <b>null</b>)
* @param provider the {@code ConfigurationBuilderProvider} (must not be <b>null</b>)
* @return a reference to this object for method chaining
* @throws IllegalArgumentException if a required parameter is missing
*/
@Override
public CombinedBuilderParametersImpl registerProvider(final String tagName, final ConfigurationBuilderProvider provider) {
if (tagName == null) {
throw new IllegalArgumentException("Tag name must not be null!");
}
if (provider == null) {
throw new IllegalArgumentException("Provider must not be null!");
}
providers.put(tagName, provider);
return this;
}
/**
* Sets the base path for this combined configuration builder. Normally it it not necessary to set the base path
* explicitly. Per default, relative file names of configuration sources are resolved based on the location of the
* definition file. If this is not desired or if the definition configuration is loaded by a different means, the base
* path for relative file names can be specified using this method.
*
* @param path the base path for resolving relative file names
* @return a reference to this object for method chaining
*/
@Override
public CombinedBuilderParametersImpl setBasePath(final String path) {
basePath = path;
return this;
}
/**
* {@inheritDoc} This implementation stores the passed in manager object. An already existing manager object (either
* explicitly set or created on demand) is overridden. This also removes all default handlers registered before!
*/
@Override
public CombinedBuilderParametersImpl setChildDefaultParametersManager(final DefaultParametersManager manager) {
childDefaultParametersManager = manager;
return this;
}
/**
* Sets the {@code ConfigurationBuilder} for the definition configuration. This is the configuration which contains the
* configuration sources that form the combined configuration.
*
* @param builder the definition {@code ConfigurationBuilder}
* @return a reference to this object for method chaining
*/
@Override
public CombinedBuilderParametersImpl setDefinitionBuilder(final ConfigurationBuilder<? extends HierarchicalConfiguration<?>> builder) {
definitionBuilder = builder;
return this;
}
/**
* Sets the parameters object for the definition configuration builder. This property is evaluated only if the
* definition configuration builder is not set explicitly (using the {@link #setDefinitionBuilder(ConfigurationBuilder)}
* method). In this case, a builder for an XML configuration is created and configured with this parameters object.
*
* @param params the parameters object for the definition configuration builder
* @return a reference to this object for method chaining
*/
@Override
public CombinedBuilderParametersImpl setDefinitionBuilderParameters(final BuilderParameters params) {
definitionBuilderParameters = params;
return this;
}
@Override
public CombinedBuilderParametersImpl setInheritSettings(final boolean inheritSettings) {
this.inheritSettings = inheritSettings;
return this;
}
}