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