001 /*
002 * Copyright 2005 Stephen McConnell
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
013 * implied.
014 *
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package net.dpml.transit.tools;
020
021 import java.io.File;
022 import java.net.URI;
023 import java.net.URL;
024
025 import net.dpml.transit.artifact.Handler;
026
027 import org.apache.tools.ant.BuildException;
028 import org.apache.tools.ant.Project;
029
030 /**
031 * The get task handles the retrival of a rresource and the binding of the resource filename
032 * to a project property.
033 *
034 * @author <a href="http://www.dpml.net">The Digital Product Meta Library</a>
035 * @version 1.0.0
036 */
037 public class GetTask extends TransitTask
038 {
039 /**
040 * The uri of the artifact to load.
041 */
042 private String m_uri;
043
044 /**
045 * The name of a property under which the locally cached artifact filename will be bound.
046 */
047 private String m_name;
048
049 /**
050 * Set the project.
051 * @param project the current project
052 */
053 public void setProject( Project project )
054 {
055 setTaskName( "get" );
056 super.setProject( project );
057 }
058
059 /**
060 * Set the artifact uri of the plugin from which the task is to be loaded.
061 * @param uri an artifact plugin uri
062 */
063 public void setUri( String uri )
064 {
065 m_uri = uri;
066 }
067
068 /**
069 * Set the name of a property into which the local file path will be assigned.
070 * @param name the ant property name
071 */
072 public void setProperty( String name )
073 {
074 m_name = name;
075 }
076
077 /**
078 * Return the artifact uri of the plugin.
079 * @return the artifact uri
080 */
081 private URI getURI()
082 {
083 try
084 {
085 return new URI( m_uri.toString() );
086 }
087 catch( Throwable e )
088 {
089 final String error =
090 "Cound not convert the supplied uri spec ["
091 + m_uri
092 + "] to a formal URI.";
093 throw new BuildException( error, e, getLocation() );
094 }
095 }
096
097 /**
098 * Return the ant property name.
099 * @return the property name
100 */
101 private String getPropertyName()
102 {
103 if( null == m_name )
104 {
105 final String error =
106 "The required 'property' attribute is not declared.";
107 throw new BuildException( error, getLocation() );
108 }
109 else
110 {
111 return m_name;
112 }
113 }
114
115 /**
116 * Load the resource and assign the locally cached file path to the supplied property name.
117 * @exception BuildException if an error occurs during resource resolution
118 */
119 public void execute() throws BuildException
120 {
121 if( null == m_uri )
122 {
123 final String error =
124 "Missing uri attribute.";
125 throw new BuildException( error, getLocation() );
126 }
127
128 String name = getPropertyName();
129
130 try
131 {
132 String spec = getURI().toString();
133 log( "artifact: " + spec );
134 URL url = new URL( (URL) null, spec, new Handler() );
135 File file = (File) url.getContent( new Class[]{File.class} );
136 getProject().setNewProperty( name, file.getAbsolutePath() );
137 }
138 catch( Throwable e )
139 {
140 final String error =
141 "Unexpected error while attempting to resolve artifact uri ["
142 + m_uri
143 + "]";
144 throw new BuildException( error, e, getLocation() );
145 }
146 }
147 }