    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 *     https://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 */
    017
    018package org.apache.commons.configuration2;
    019
    020import java.io.IOException;
    021import java.io.InputStream;
    022import java.io.Reader;
    023import java.io.Writer;
    024import java.util.Map;
    025
    026import org.apache.commons.configuration2.ex.ConfigurationException;
    027import org.apache.commons.configuration2.io.InputStreamSupport;
    028import org.apache.commons.configuration2.tree.ImmutableNode;
    029import org.yaml.snakeyaml.DumperOptions;
    030import org.yaml.snakeyaml.LoaderOptions;
    031import org.yaml.snakeyaml.Yaml;
    032import org.yaml.snakeyaml.constructor.SafeConstructor;
    033import org.yaml.snakeyaml.representer.Representer;
    034
    035/**
    036 * <p>
    037 * A specialized hierarchical configuration class that is able to parse YAML documents.
    038 * </p>
    039 *
    040 * @since 2.2
    041 */
    042public class YAMLConfiguration extends AbstractYAMLBasedConfiguration implements FileBasedConfiguration, InputStreamSupport {
    043
    044    /**
    045     * Creates a {@code Yaml} object for reading a Yaml file. The object is configured with some default settings.
    046     *
    047     * @param options options for loading the file
    048     * @return the {@code Yaml} instance for loading a file
    049     */
    050    private static Yaml createYamlForReading(final LoaderOptions options) {
    051        return new Yaml(new SafeConstructor(options), new Representer(new DumperOptions()), new DumperOptions(), options);
    052    }
    053
    054    /**
    055     * Creates a new instance of {@code YAMLConfiguration}.
    056     */
    057    public YAMLConfiguration() {
    058    }
    059
    060    /**
    061     * Creates a new instance of {@code YAMLConfiguration} as a copy of the specified configuration.
    062     *
    063     * @param c the configuration to be copied
    064     */
    065    public YAMLConfiguration(final HierarchicalConfiguration<ImmutableNode> c) {
    066        super(c);
    067    }
    068
    069    public void dump(final Writer out, final DumperOptions options)
    070            throws ConfigurationException, IOException {
    071        final Yaml yaml = new Yaml(options);
    072        yaml.dump(constructMap(getNodeModel().getNodeHandler().getRootNode()), out);
    073    }
    074
    075    /**
    076     * Loads the configuration from the given input stream.
    077     *
    078     * @param in the input stream
    079     * @throws ConfigurationException if an error occurs
    080     */
    081    @Override
    082    public void read(final InputStream in) throws ConfigurationException {
    083        try {
    084            final Yaml yaml = createYamlForReading(new LoaderOptions());
    085            final Map<String, Object> map = yaml.load(in);
    086            load(map);
    087        } catch (final Exception e) {
    088            rethrowException(e);
    089        }
    090    }
    091
    092    public void read(final InputStream in, final LoaderOptions options) throws ConfigurationException {
    093        try {
    094            final Yaml yaml = createYamlForReading(options);
    095            final Map<String, Object> map = yaml.load(in);
    096            load(map);
    097        } catch (final Exception e) {
    098            rethrowException(e);
    099        }
    100    }
    101
    102    @Override
    103    public void read(final Reader in) throws ConfigurationException {
    104        try {
    105            final Yaml yaml = createYamlForReading(new LoaderOptions());
    106            final Map<String, Object> map = yaml.load(in);
    107            load(map);
    108        } catch (final Exception e) {
    109            rethrowException(e);
    110        }
    111    }
    112
    113    public void read(final Reader in, final LoaderOptions options) throws ConfigurationException {
    114        try {
    115            final Yaml yaml = createYamlForReading(options);
    116            final Map<String, Object> map = yaml.load(in);
    117            load(map);
    118        } catch (final Exception e) {
    119            rethrowException(e);
    120        }
    121    }
    122
    123    @Override
    124    public void write(final Writer out) throws ConfigurationException, IOException {
    125        final DumperOptions options = new DumperOptions();
    126        options.setDefaultFlowStyle(DumperOptions.FlowStyle.BLOCK);
    127        dump(out, options);
    128    }
    129
    130}