001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.eclipse.aether.metadata;
020
021import java.io.File;
022import java.nio.file.Path;
023import java.util.Collections;
024import java.util.HashMap;
025import java.util.Map;
026import java.util.Objects;
027
028/**
029 * A skeleton class for metadata.
030 */
031public abstract class AbstractMetadata implements Metadata {
032
033    private Metadata newInstance(Map<String, String> properties, Path path) {
034        return new DefaultMetadata(
035                getGroupId(), getArtifactId(), getVersion(), getType(), getNature(), path, properties);
036    }
037
038    @Deprecated
039    @Override
040    public Metadata setFile(File file) {
041        File current = getFile();
042        if (Objects.equals(current, file)) {
043            return this;
044        }
045        return newInstance(getProperties(), file != null ? file.toPath() : null);
046    }
047
048    @Override
049    public Metadata setPath(Path path) {
050        Path current = getPath();
051        if (Objects.equals(current, path)) {
052            return this;
053        }
054        return newInstance(getProperties(), path);
055    }
056
057    @Override
058    public Metadata setProperties(Map<String, String> properties) {
059        Map<String, String> current = getProperties();
060        if (current.equals(properties) || (properties == null && current.isEmpty())) {
061            return this;
062        }
063        return newInstance(copyProperties(properties), getPath());
064    }
065
066    @Override
067    public String getProperty(String key, String defaultValue) {
068        String value = getProperties().get(key);
069        return (value != null) ? value : defaultValue;
070    }
071
072    /**
073     * Copies the specified metadata properties. This utility method should be used when creating new metadata instances
074     * with caller-supplied properties.
075     *
076     * @param properties The properties to copy, may be {@code null}.
077     * @return The copied and read-only properties, never {@code null}.
078     */
079    protected static Map<String, String> copyProperties(Map<String, String> properties) {
080        if (properties != null && !properties.isEmpty()) {
081            return Collections.unmodifiableMap(new HashMap<>(properties));
082        } else {
083            return Collections.emptyMap();
084        }
085    }
086
087    @Override
088    public String toString() {
089        StringBuilder buffer = new StringBuilder(128);
090        if (!getGroupId().isEmpty()) {
091            buffer.append(getGroupId());
092        }
093        if (!getArtifactId().isEmpty()) {
094            buffer.append(':').append(getArtifactId());
095        }
096        if (!getVersion().isEmpty()) {
097            buffer.append(':').append(getVersion());
098        }
099        buffer.append('/').append(getType());
100        return buffer.toString();
101    }
102
103    /**
104     * Compares this metadata with the specified object.
105     *
106     * @param obj The object to compare this metadata against, may be {@code null}.
107     * @return {@code true} if and only if the specified object is another {@link Metadata} with equal coordinates,
108     *         type, nature, properties and file, {@code false} otherwise.
109     */
110    @Override
111    public boolean equals(Object obj) {
112        if (obj == this) {
113            return true;
114        } else if (!(obj instanceof Metadata)) {
115            return false;
116        }
117
118        Metadata that = (Metadata) obj;
119
120        return Objects.equals(getArtifactId(), that.getArtifactId())
121                && Objects.equals(getGroupId(), that.getGroupId())
122                && Objects.equals(getVersion(), that.getVersion())
123                && Objects.equals(getType(), that.getType())
124                && Objects.equals(getNature(), that.getNature())
125                && Objects.equals(getPath(), that.getPath())
126                && Objects.equals(getProperties(), that.getProperties());
127    }
128
129    /**
130     * Returns a hash code for this metadata.
131     *
132     * @return A hash code for the metadata.
133     */
134    @Override
135    public int hashCode() {
136        int hash = 17;
137        hash = hash * 31 + getGroupId().hashCode();
138        hash = hash * 31 + getArtifactId().hashCode();
139        hash = hash * 31 + getType().hashCode();
140        hash = hash * 31 + getNature().hashCode();
141        hash = hash * 31 + getVersion().hashCode();
142        hash = hash * 31 + hash(getPath());
143        return hash;
144    }
145
146    private static int hash(Object obj) {
147        return (obj != null) ? obj.hashCode() : 0;
148    }
149}