001    /*
002     * Copyright 2005 Stephen J. 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.tools.tasks;
020    
021    import net.dpml.library.ResourceNotFoundException;
022    import net.dpml.library.Resource;
023    
024    import net.dpml.tools.Context;
025    
026    import org.apache.tools.ant.BuildException;
027    
028    /**
029     * Locate a named feature of the a project or resource.
030     *
031     * @author <a href="http://www.dpml.net">Digital Product Meta Library</a>
032     * @version 1.1.1
033     */
034    public abstract class ResourceTask extends GenericTask
035    {
036        private String m_key;
037        private String m_ref;
038    
039       /**
040        * Set the key of the target project or resource description from which features will be 
041        * resolved from.  If not declared the key defaults to the current defintion.
042        *
043        * @param key the resource key
044        */
045        public void setKey( final String key )
046        {
047            m_key = key;
048        }
049    
050       /**
051        * Set the ref of the target project or resource description from which features will be 
052        * resolved from.
053        *
054        * @param ref the resource reference
055        */
056        public void setRef( final String ref )
057        {
058            m_ref = ref;
059        }
060    
061       /**
062        * Get the project definition.
063        * @return the resource
064        */
065        protected Resource getResource()
066        {
067            if( null != m_ref )
068            {
069                return getResource( m_ref );
070            }
071            else if( null != m_key )
072            {
073                Context context = getContext();
074                Resource resource = context.getResource();
075                Resource parent = resource.getParent();
076                String ref = parent.getResourcePath() + "/" + m_key;
077                return getResource( ref );
078            }
079            else
080            {
081                return getContext().getResource();
082            }
083        }
084    
085        private Resource getResource( String ref )
086        {
087            try
088            {
089                return getContext().getLibrary().getResource( ref );
090            }
091            catch( ResourceNotFoundException e )
092            {
093                final String error = 
094                  "Feature reference ["
095                  + ref
096                  + "] in the project [" 
097                  + getResource()
098                  + "] is unknown.";
099                throw new BuildException( error, e );
100            }
101        }
102    }