    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 <strong>null</strong>
    059     * @return the instance obtained from the map or <strong>null</strong>
    060     * @throws NullPointerException if the map is <strong>null</strong>
    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 <strong>null</strong>
    072     * @param createIfMissing determines the behavior if no instance is found in the map; if <strong>true</strong>, a new instance
    073     *        with default settings is created; if <strong>false</strong>, <strong>null</strong> is returned
    074     * @return the instance obtained from the map or <strong>null</strong>
    075     * @throws NullPointerException if the map is <strong>null</strong>
    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 <strong>null</strong> 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 <strong>null</strong>. 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 <strong>null</strong>
    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 <strong>null</strong> 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 <strong>null</strong>
    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 <strong>null</strong>)
    259     * @return a reference to this object for method chaining
    260     * @throws IllegalArgumentException if the source parameters object is <strong>null</strong>
    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 <strong>null</strong> or contain <strong>null</strong>
    276     *        entries)
    277     * @return a reference to this object for method chaining
    278     * @throws IllegalArgumentException if the map with providers is <strong>null</strong> or contains <strong>null</strong> 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 <strong>null</strong>)
    297     * @param provider the {@code ConfigurationBuilderProvider} (must not be <strong>null</strong>)
    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}