Source code: javax/ide/extension/spi/DefaultElementContext.java

   package javax.ide.extension.spi;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.Collections;
   import java.util.HashMap;
   import java.util.Iterator;
   import java.util.List;
   import java.util.Map;
  import java.util.logging.LogRecord;
  import java.util.logging.Logger;
  
  import javax.ide.extension.ElementContext;
  import javax.ide.extension.ElementEndContext;
  import javax.ide.extension.ElementName;
  import javax.ide.extension.ElementStartContext;
  import javax.ide.extension.ElementVisitor;
  import javax.ide.extension.ElementVisitorFactory;
  
  import javax.ide.extension.ExtensionHook;
  import org.xml.sax.Attributes;
  import javax.ide.extension.Extension;
  import java.net.URI;
  
  /**
   * A default XML context implementation. This provides access to methods that 
   * change the context and should only be used by ExtensibleSAXHandler.
   */
  public class DefaultElementContext
    implements ElementContext, ElementStartContext, ElementEndContext
  {
    private Attributes _attributes;
    private ElementName _name;
    private final Stack _elementPathStack = new Stack();
    private final ScopedMap _contextMap = new ScopedMap();
    private final Stack _elementText = new Stack();
    
    private final Stack _childHandlers = new Stack();
    private Map _ceChildHandlers = null;
    
    private Logger _logger;
  
    private final List _visitorFactories = new ArrayList();
  
    public DefaultElementContext()
    {
      // Initialize the "global" value map.
      _childHandlers.push( null );
    }
      
    /**
     * Get the local name of the current element.
     * 
     * @return the local name of the current element.
     */
    public ElementName getElementName()
    {
      return _name;
    }
      
    /**
     * Get the text contained in this element. It's only valid to call this from
     * EDDElementHandler.handleEndElement.
     */
    public String getText()
    {
      StringBuffer buffer = (StringBuffer) _elementText.peek();
      
      if ( buffer == null )
      {
        return null;
      }
      
      return buffer.toString();
    }
    
    /**
     * Get the value of an attribute for this element. It's only valid to call
     * this from EDDElementHandler.handleStartElement.
     * 
     * @param attributeName the local name of an XML attribute, must not be
     *    null.
     * @return the value of the specified attribute, or null if not present.
     */
    public String getAttributeValue( String attributeName )
    {
      if ( _attributes == null )
      {
        throw new IllegalStateException(
          "Cannot call from handleEndElement"
        );
      }
      
      if ( attributeName == null )
      {
        throw new IllegalArgumentException( "attributeName must not be null" );
      }
      
      return _attributes.getValue( attributeName );  
   }
   
   public Collection getAttributeNames()
   {
     if (_attributes == null)
     {
       throw new IllegalStateException();
     }
     ArrayList al = new ArrayList( _attributes.getLength() );
     for ( int i=0; i < _attributes.getLength(); i++ )
     {
       al.add( _attributes.getLocalName( i ) );
     }
     
     return Collections.unmodifiableCollection( al );
   }
   
   public Map getScopeData()
   {
     return _contextMap;
   }
       
   /**
    * Register a handler that will be used only for immediate children of the
    * current element.
    * 
    * @param name the element name.
    * @param visitor the {@link ElementVisitor}.
    */
   public void registerChildVisitor( ElementName name, ElementVisitor visitor )
   {
     if ( _ceChildHandlers == null )
     {
       _ceChildHandlers = new HashMap();
     }
     _ceChildHandlers.put( name, visitor );  
   }
 
   
   public void registerVisitorFactory( ElementVisitorFactory factory )
   {
     _visitorFactories.add( factory );
   }
   
   /**
    * Get a scoped handler for the current element (if any)
    */
   public ElementVisitor getScopedHandler()
   {
     ElementName qualified = _name;
     ElementName unqualified = new ElementName( null, _name.getLocalName() );
     ElementVisitor handler = null;
     
     // Look for child-only handlers first.
     Map childHandlerMap = (Map) _childHandlers.peek();
     if ( childHandlerMap != null )
     {
       handler = (ElementVisitor) childHandlerMap.get( qualified );
       if ( handler == null )
       {
         handler = (ElementVisitor) childHandlerMap.get( unqualified );
       }
       
       if ( handler != null )
       {
         return handler;
       }
 
     } 
     
     for ( Iterator i = _visitorFactories.iterator(); i.hasNext(); )
     {
       ElementVisitorFactory factory = (ElementVisitorFactory) i.next();
       
       ElementVisitor visitor = factory.getVisitor( _name );
       if ( visitor != null )
       {
         return visitor;
       }
     }
     
 
     return handler;
   }
 
   private void setElement( String uri, String name )
   {
     _name = new ElementName( uri, name );
   }
 
   void beginElement( String uri, String name, Attributes attributes )
   {
     setElement( uri, name );
     _attributes = attributes;
     
     _contextMap.enterScope();  
 
     _childHandlers.push( _ceChildHandlers );
     _ceChildHandlers = null;
   }
   
   void appendCharacters( char[] characters, int start, int length )
   {
     if ( _elementText.isEmpty() )
     {
       throw new IllegalStateException();
     }
 
     StringBuffer buffer = (StringBuffer) _elementText.peek();
     if ( buffer == null )
     {
       buffer = new StringBuffer();
       _elementText.replace( buffer );
     }
     
     buffer.append( characters, start, length );
   }
   
   void postEndElement()
   {
     _contextMap.exitScope();
     _elementText.pop();
     _ceChildHandlers = (Map) _childHandlers.peek();
     _childHandlers.pop();    
 
 
     _name = null;
     _attributes = null;
   }
   
   void endElement( String uri, String name )
   {
     setElement( uri, name );
     _attributes = null;    
     _elementPathStack.pop();
   }
   
   /**
    * Push the current element onto the element stack.
    */
   void postBeginElement()
   {
     _elementPathStack.push( _name );
     _elementText.push( null );    // StringBuffer is created lazily.    
   }
     
   public Logger getLogger()
   {
     if ( _logger == null )
     {
       _logger = new NullLogger();
     }
     return _logger;
   }
   
   public void setMessageReporter( Logger logger )
   {
     _logger = logger;
   }
 
   /**
    * Get the extension currently being processed.
    * 
    * @return the exetnsion currently being processed.
    */
   public Extension getExtension()
   {
     return (Extension) getScopeData().get( ExtensionHook.KEY_EXTENSION );
   }
   
   
   /**
    * Get the URI of the source of the extension. For extensions packaged in
    * JAR files, this is the URI of the JAR file.
    * 
    * @return the URI of the exension source.
    */
   public URI getExtensionSourceURI()
   {
     ExtensionSource source = (ExtensionSource) getScopeData().get(
       ExtensionVisitor.KEY_EXTENSION_SOURCE
     );
     return source.getURI();
   }
   
   private class NullLogger extends Logger
   {
     public NullLogger( )
     {
       super( null, null );
     }
   
     public void log( LogRecord logRecord )
     {
       // NO-OP
     }
   }
 
 }