    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.Map;
    020
    021import org.apache.commons.configuration2.ConfigurationUtils;
    022import org.apache.commons.configuration2.builder.BasicBuilderParameters;
    023import org.apache.commons.configuration2.builder.BuilderParameters;
    024
    025/**
    026 * <p>
    027 * A specialized parameters object for {@link MultiFileConfigurationBuilder}.
    028 * </p>
    029 * <p>
    030 * A parameters object of this type is used by a configuration builder with
    031 * manages multiple file-based configurations. Such a builder is a bit special
    032 * because it does not create a configuration on its own, but delegates to a
    033 * file-based builder for this purpose. Therefore, parameters inherited from the
    034 * super class are treated differently:
    035 * </p>
    036 * <ul>
    037 * <li>The {@link org.apache.commons.configuration2.interpol.ConfigurationInterpolator
    038 * ConfigurationInterpolator} is needed by a
    039 * {@code MultiFileConfigurationBuilder} to resolve the file pattern. It is
    040 * expected to be set and will not be passed to sub configurations created by
    041 * the builder.</li>
    042 * <li>All other parameters are evaluated when creating sub configurations.
    043 * However, it is preferred to use the
    044 * {@link #setManagedBuilderParameters(BuilderParameters)} method to define all
    045 * properties of sub configurations in a single place. If such a parameters
    046 * object is set, its properties take precedence.</li>
    047 * </ul>
    048 * <p>
    049 * This class is not thread-safe. It is intended that an instance is constructed
    050 * and initialized by a single thread during configuration of a
    051 * {@code ConfigurationBuilder}.
    052 * </p>
    053 *
    054 * @since 2.0
    055 */
    056public class MultiFileBuilderParametersImpl extends BasicBuilderParameters
    057        implements MultiFileBuilderProperties<MultiFileBuilderParametersImpl>
    058{
    059    /** Constant for the key in the parameters map used by this class. */
    060    private static final String PARAM_KEY = RESERVED_PARAMETER_PREFIX
    061            + MultiFileBuilderParametersImpl.class.getName();
    062
    063    /** The parameters object for managed builders. */
    064    private BuilderParameters managedBuilderParameters;
    065
    066    /** The file pattern. */
    067    private String filePattern;
    068
    069    /**
    070     * Obtains an instance of this class from the given map with parameters. If
    071     * this map does not contain an instance, result is <b>null</b>. This is
    072     * equivalent to {@code fromParameters(params, false)}.
    073     *
    074     * @param params the map with parameters (must not be <b>null</b>)
    075     * @return an instance of this class fetched from the map or <b>null</b>
    076     * @throws NullPointerException if the map with parameters is <b>null</b>
    077     */
    078    public static MultiFileBuilderParametersImpl fromParameters(
    079            final Map<String, Object> params)
    080    {
    081        return fromParameters(params, false);
    082    }
    083
    084    /**
    085     * Obtains an instance of this class from the given map with parameters and
    086     * creates a new object if such an instance cannot be found. This method can
    087     * be used to obtain an instance from a map which has been created using the
    088     * {@code getParameters()} method. If the map does not contain an instance
    089     * under the expected key and the {@code createIfMissing} parameter is
    090     * <b>true</b>, a new instance is created. Otherwise, result is <b>null</b>.
    091     *
    092     * @param params the map with parameters (must not be <b>null</b>)
    093     * @param createIfMissing a flag whether a new instance should be created if
    094     *        necessary
    095     * @return an instance of this class fetched from the map or <b>null</b>
    096     * @throws NullPointerException if the map with parameters is <b>null</b>
    097     */
    098    public static MultiFileBuilderParametersImpl fromParameters(
    099            final Map<String, Object> params, final boolean createIfMissing)
    100    {
    101        MultiFileBuilderParametersImpl instance =
    102                (MultiFileBuilderParametersImpl) params.get(PARAM_KEY);
    103        if (instance == null && createIfMissing)
    104        {
    105            instance = new MultiFileBuilderParametersImpl();
    106        }
    107        return instance;
    108    }
    109
    110    /**
    111     * Returns the pattern for determining file names for managed
    112     * configurations.
    113     *
    114     * @return the file pattern
    115     */
    116    public String getFilePattern()
    117    {
    118        return filePattern;
    119    }
    120
    121    @Override
    122    public MultiFileBuilderParametersImpl setFilePattern(final String p)
    123    {
    124        filePattern = p;
    125        return this;
    126    }
    127
    128    /**
    129     * Returns the parameters object for managed configuration builders.
    130     *
    131     * @return the parameters for sub configurations
    132     */
    133    public BuilderParameters getManagedBuilderParameters()
    134    {
    135        return managedBuilderParameters;
    136    }
    137
    138    @Override
    139    public MultiFileBuilderParametersImpl setManagedBuilderParameters(
    140            final BuilderParameters p)
    141    {
    142        managedBuilderParameters = p;
    143        return this;
    144    }
    145
    146    /**
    147     * {@inheritDoc} This implementation puts a reference to this object under a
    148     * reserved key in the resulting parameters map.
    149     */
    150    @Override
    151    public Map<String, Object> getParameters()
    152    {
    153        final Map<String, Object> params = super.getParameters();
    154        params.put(PARAM_KEY, this);
    155        return params;
    156    }
    157
    158    /**
    159     * {@inheritDoc} This implementation also tries to clone the parameters
    160     * object for managed builders if possible.
    161     */
    162    @Override
    163    public MultiFileBuilderParametersImpl clone()
    164    {
    165        final MultiFileBuilderParametersImpl copy =
    166                (MultiFileBuilderParametersImpl) super.clone();
    167        copy.setManagedBuilderParameters((BuilderParameters) ConfigurationUtils
    168                .cloneIfPossible(getManagedBuilderParameters()));
    169        return copy;
    170    }
    171}