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    /**
034     * Constructor for subclasses.
035     */
036    public AbstractMetadata() {}
037
038    private Metadata newInstance(Map<String, String> properties, Path path) {
039        return new DefaultMetadata(
040                getGroupId(), getArtifactId(), getVersion(), getType(), getNature(), path, properties);
041    }
042
043    @Deprecated
044    @Override
045    public Metadata setFile(File file) {
046        File current = getFile();
047        if (Objects.equals(current, file)) {
048            return this;
049        }
050        return newInstance(getProperties(), file != null ? file.toPath() : null);
051    }
052
053    @Override
054    public Metadata setPath(Path path) {
055        Path current = getPath();
056        if (Objects.equals(current, path)) {
057            return this;
058        }
059        return newInstance(getProperties(), path);
060    }
061
062    @Override
063    public Metadata setProperties(Map<String, String> properties) {
064        Map<String, String> current = getProperties();
065        if (current.equals(properties) || (properties == null && current.isEmpty())) {
066            return this;
067        }
068        return newInstance(copyProperties(properties), getPath());
069    }
070
071    @Override
072    public String getProperty(String key, String defaultValue) {
073        String value = getProperties().get(key);
074        return (value != null) ? value : defaultValue;
075    }
076
077    /**
078     * Copies the specified metadata properties. This utility method should be used when creating new metadata instances
079     * with caller-supplied properties.
080     *
081     * @param properties The properties to copy, may be {@code null}.
082     * @return The copied and read-only properties, never {@code null}.
083     */
084    protected static Map<String, String> copyProperties(Map<String, String> properties) {
085        if (properties != null && !properties.isEmpty()) {
086            return Collections.unmodifiableMap(new HashMap<>(properties));
087        } else {
088            return Collections.emptyMap();
089        }
090    }
091
092    @Override
093    public String toString() {
094        StringBuilder buffer = new StringBuilder(128);
095        if (!getGroupId().isEmpty()) {
096            buffer.append(getGroupId());
097        }
098        if (!getArtifactId().isEmpty()) {
099            buffer.append(':').append(getArtifactId());
100        }
101        if (!getVersion().isEmpty()) {
102            buffer.append(':').append(getVersion());
103        }
104        buffer.append('/').append(getType());
105        return buffer.toString();
106    }
107
108    /**
109     * Compares this metadata with the specified object.
110     *
111     * @param obj The object to compare this metadata against, may be {@code null}.
112     * @return {@code true} if and only if the specified object is another {@link Metadata} with equal coordinates,
113     *         type, nature, properties and file, {@code false} otherwise.
114     */
115    @Override
116    public boolean equals(Object obj) {
117        if (obj == this) {
118            return true;
119        } else if (!(obj instanceof Metadata)) {
120            return false;
121        }
122
123        Metadata that = (Metadata) obj;
124
125        return Objects.equals(getArtifactId(), that.getArtifactId())
126                && Objects.equals(getGroupId(), that.getGroupId())
127                && Objects.equals(getVersion(), that.getVersion())
128                && Objects.equals(getType(), that.getType())
129                && Objects.equals(getNature(), that.getNature())
130                && Objects.equals(getPath(), that.getPath())
131                && Objects.equals(getProperties(), that.getProperties());
132    }
133
134    /**
135     * Returns a hash code for this metadata.
136     *
137     * @return A hash code for the metadata.
138     */
139    @Override
140    public int hashCode() {
141        int hash = 17;
142        hash = hash * 31 + getGroupId().hashCode();
143        hash = hash * 31 + getArtifactId().hashCode();
144        hash = hash * 31 + getType().hashCode();
145        hash = hash * 31 + getNature().hashCode();
146        hash = hash * 31 + getVersion().hashCode();
147        hash = hash * 31 + hash(getPath());
148        return hash;
149    }
150
151    private static int hash(Object obj) {
152        return (obj != null) ? obj.hashCode() : 0;
153    }
154}