AbstractMetadata.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012 Sonatype, Inc.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *    Sonatype, Inc. - initial API and implementation
  10  *******************************************************************************/
  11 package org.eclipse.aether.metadata;
  12
  13 import java.io.File;
  14 import java.util.Collections;
  15 import java.util.HashMap;
  16 import java.util.Map;
  17
  18 /**
  19  * A skeleton class for metadata.
  20  */
  21 public abstract class AbstractMetadata
  22     implements Metadata
  23 {
  24
  25     private Metadata newInstance( Map<String, String> properties, File file )
  26     {
  27         return new DefaultMetadata( getGroupId(), getArtifactId(), getVersion(), getType(), getNature(), file,
  28                                     properties );
  29     }
  30
  31     public Metadata setFile( File file )
  32     {
  33         File current = getFile();
  34         if ( ( current == null ) ? file == null : current.equals( file ) )
  35         {
  36             return this;
  37         }
  38         return newInstance( getProperties(), file );
  39     }
  40
  41     public Metadata setProperties( Map<String, String> properties )
  42     {
  43         Map<String, String> current = getProperties();
  44         if ( current.equals( properties ) || ( properties == null && current.isEmpty() ) )
  45         {
  46             return this;
  47         }
  48         return newInstance( copyProperties( properties ), getFile() );
  49     }
  50
  51     public String getProperty( String key, String defaultValue )
  52     {
  53         String value = getProperties().get( key );
  54         return ( value != null ) ? value : defaultValue;
  55     }
  56
  57     /**
  58      * Copies the specified metadata properties. This utility method should be used when creating new metadata instances
  59      * with caller-supplied properties.
  60      *
  61      * @param properties The properties to copy, may be {@code null}.
  62      * @return The copied and read-only properties, never {@code null}.
  63      */
  64     protected static Map<String, String> copyProperties( Map<String, String> properties )
  65     {
  66         if ( properties != null && !properties.isEmpty() )
  67         {
  68             return Collections.unmodifiableMap( new HashMap<String, String>( properties ) );
  69         }
  70         else
  71         {
  72             return Collections.emptyMap();
  73         }
  74     }
  75
  76     @Override
  77     public String toString()
  78     {
  79         StringBuilder buffer = new StringBuilder( 128 );
  80         if ( getGroupId().length() > 0 )
  81         {
  82             buffer.append( getGroupId() );
  83         }
  84         if ( getArtifactId().length() > 0 )
  85         {
  86             buffer.append( ':' ).append( getArtifactId() );
  87         }
  88         if ( getVersion().length() > 0 )
  89         {
  90             buffer.append( ':' ).append( getVersion() );
  91         }
  92         buffer.append( '/' ).append( getType() );
  93         return buffer.toString();
  94     }
  95
  96     /**
  97      * Compares this metadata with the specified object.
  98      *
  99      * @param obj The object to compare this metadata against, may be {@code null}.
 100      * @return {@code true} if and only if the specified object is another {@link Metadata} with equal coordinates,
 101      *         type, nature, properties and file, {@code false} otherwise.
 102      */
 103     @Override
 104     public boolean equals( Object obj )
 105     {
 106         if ( obj == this )
 107         {
 108             return true;
 109         }
 110         else if ( !( obj instanceof Metadata ) )
 111         {
 112             return false;
 113         }
 114
 115         Metadata that = (Metadata) obj;
 116
 117         return getArtifactId().equals( that.getArtifactId() ) && getGroupId().equals( that.getGroupId() )
 118             && getVersion().equals( that.getVersion() ) && getType().equals( that.getType() )
 119             && getNature().equals( that.getNature() ) && eq( getFile(), that.getFile() )
 120             && eq( getProperties(), that.getProperties() );
 121     }
 122
 123     private static <T> boolean eq( T s1, T s2 )
 124     {
 125         return s1 != null ? s1.equals( s2 ) : s2 == null;
 126     }
 127
 128     /**
 129      * Returns a hash code for this metadata.
 130      *
 131      * @return A hash code for the metadata.
 132      */
 133     @Override
 134     public int hashCode()
 135     {
 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( getFile() );
 143         return hash;
 144     }
 145
 146     private static int hash( Object obj )
 147     {
 148         return ( obj != null ) ? obj.hashCode() : 0;
 149     }
 150
 151 }