plugins/org.eclipse.wst.common.project.facet.core/src/org/eclipse/wst/common/project/facet/core/internal/PresetsExtensionPoint.java - webtools-common/webtools.common.fproj - Git at Google

 /******************************************************************************
  * Copyright (c) 2008 BEA Systems, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *    Konstantin Komissarchik - initial implementation and ongoing maintenance
  ******************************************************************************/

 package org.eclipse.wst.common.project.facet.core.internal;

 import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.PLUGIN_ID;
 import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.createErrorStatus;
 import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.log;
 import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.logError;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findExtensions;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findOptionalElement;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findRequiredAttribute;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findRequiredElement;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.getElementValue;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.getTopLevelElements;
 import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.instantiate;

 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.wst.common.project.facet.core.IDynamicPreset;
 import org.eclipse.wst.common.project.facet.core.IPreset;
 import org.eclipse.wst.common.project.facet.core.IPresetFactory;
 import org.eclipse.wst.common.project.facet.core.IProjectFacet;
 import org.eclipse.wst.common.project.facet.core.IProjectFacetVersion;
 import org.eclipse.wst.common.project.facet.core.PresetDefinition;
 import org.eclipse.wst.common.project.facet.core.ProjectFacetsManager;
 import org.eclipse.wst.common.project.facet.core.util.internal.IndexedSet;
 import org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.InvalidExtensionException;

 /**
  * Contains the logic for processing the <code>presets</code> extension point.
  *
  * @author <a href="mailto:kosta@bea.com">Konstantin Komissarchik</a>
  */

 public final class PresetsExtensionPoint
 {
     public static final String EXTENSION_POINT_ID = "presets"; //$NON-NLS-1$
     private static final String OLD_EXTENSION_POINT_ID = "facets"; //$NON-NLS-1$

     private static final String EL_DESCRIPTION = "description"; //$NON-NLS-1$
     private static final String EL_DYNAMIC_PRESET = "dynamic-preset"; //$NON-NLS-1$
     private static final String EL_FACET = "facet"; //$NON-NLS-1$
     private static final String EL_FACTORY = "factory"; //$NON-NLS-1$
     private static final String EL_LABEL = "label"; //$NON-NLS-1$
     private static final String EL_PRESET = "preset"; //$NON-NLS-1$
     private static final String EL_STATIC_PRESET = "static-preset"; //$NON-NLS-1$
     private static final String ATTR_CLASS = "class"; //$NON-NLS-1$
     private static final String ATTR_EXTENDS = "extends"; //$NON-NLS-1$
     private static final String ATTR_ID = "id"; //$NON-NLS-1$
     private static final String ATTR_VERSION = "version"; //$NON-NLS-1$

     private static final String DEFAULT_DESCRIPTION = ""; //$NON-NLS-1$

     private static IndexedSet<String,IPreset> presets = null;

     public static Set<IPreset> getPresets()
     {
         readExtensions();
         return presets.getItemSet();
     }

     public static IPreset getPreset( final String id )
     {
         readExtensions();
         return presets.getItemByKey( id );
     }

     private static synchronized void readExtensions()
     {
         if( presets != null )
         {
             return;
         }

         presets = new IndexedSet<String,IPreset>();

         for( IConfigurationElement element
              : getTopLevelElements( findExtensions( PLUGIN_ID, EXTENSION_POINT_ID ) ) )
         {
             final String elName = element.getName();

             if( elName.equals( EL_STATIC_PRESET ) )
             {
                 try
                 {
                     readStaticPreset( element );
                 }
                 catch( InvalidExtensionException e )
                 {
                     // Continue. The problem has been reported to the user via the log.
                 }
             }
             else if( elName.equals( EL_DYNAMIC_PRESET ) )
             {
                 try
                 {
                     readDynamicPreset( element );
                 }
                 catch( InvalidExtensionException e )
                 {
                     // Continue. The problem has been reported to the user via the log.
                 }
             }
         }

         for( IConfigurationElement element
              : getTopLevelElements( findExtensions( PLUGIN_ID, OLD_EXTENSION_POINT_ID ) ) )
         {
             if( element.getName().equals( EL_PRESET ) )
             {
                 try
                 {
                     readStaticPreset( element );
                 }
                 catch( InvalidExtensionException e )
                 {
                     // Continue. The problem has been reported to the user via the log.
                 }
             }
         }

         // Resolve the base presets. Make sure that no presets are extending presets that do not
         // exist, check for circular references, etc.

         Set<IPreset> copy = new HashSet<IPreset>( presets.getItemSet() );

         for( IPreset preset : copy )
         {
             if( presets.containsItem( preset ) )
             {
                 resolveBasePreset( preset, new HashSet<IPreset>() );
             }
         }

         // Find static presets that are extending dynamic presets and make them into dynamic
         // presets (StaticExtendingDynamicPreset class).

         boolean doAnotherPass = true;

         while( doAnotherPass )
         {
             doAnotherPass = false;

             for( IPreset preset : presets.getItemSet() )
             {
                 if( preset.getType() == IPreset.Type.STATIC )
                 {
                     final StaticPreset stPreset = (StaticPreset) preset;
                     final String basePresetId = stPreset.getBasePresetId();

                     if( basePresetId != null )
                     {
                         final IPreset basePreset = getPreset( basePresetId );

                         if( basePreset.getType() == IPreset.Type.DYNAMIC )
                         {
                             final StaticExtendingDynamicPreset stPresetNew
                                 = new StaticExtendingDynamicPreset( stPreset.getId(),
                                                                     stPreset.getPluginId(),
                                                                     stPreset.getLabel(),
                                                                     stPreset.getDescription(),
                                                                     stPreset.getBasePresetId(),
                                                                     stPreset.getProjectFacets() );

                             presets.removeItem( stPreset );
                             presets.addItemWithKey( stPresetNew.getId(), stPresetNew );

                             doAnotherPass = true;
                             break;
                         }
                     }
                 }
             }
         }
     }

     private static void readStaticPreset( final IConfigurationElement el )

         throws InvalidExtensionException

     {
         final String pluginId = el.getContributor().getName();
         final String id = findRequiredAttribute( el, ATTR_ID );

         final IConfigurationElement elLabel = findOptionalElement( el, EL_LABEL );
         final String label = getElementValue( elLabel, id );

         final IConfigurationElement elDesc = findOptionalElement( el, EL_DESCRIPTION );
         final String description = getElementValue( elDesc, DEFAULT_DESCRIPTION );

         String basePreset = el.getAttribute( ATTR_EXTENDS );

         if( basePreset != null )
         {
             basePreset = basePreset.trim();

             if( basePreset.length() == 0 )
             {
                 basePreset = null;
             }
         }

         final Set<IProjectFacetVersion> facets = new HashSet<IProjectFacetVersion>();

         for( IConfigurationElement child : el.getChildren() )
         {
             final String childName = child.getName();

             if( childName.equals( EL_FACET ) )
             {
                 final String fid = findRequiredAttribute( child, ATTR_ID );
                 final String fver = findRequiredAttribute( child, ATTR_VERSION );

                 if( ! ProjectFacetsManager.isProjectFacetDefined( fid ) )
                 {
                     final String msg
                         = Resources.bind( Resources.presetUsesUnknownFacet, id, pluginId, fid );

                     logError( msg );

                     return;
                 }

                 final IProjectFacet f = ProjectFacetsManager.getProjectFacet( fid );

                 if( ! f.hasVersion( fver ) )
                 {
                     final String msg
                         = Resources.bind( Resources.presetUsesUnknownFacetVersion, id, pluginId,
                                           fid, fver );

                     logError( msg );

                     return;
                 }

                 final IProjectFacetVersion fv = f.getVersion( fver );

                 facets.add( fv );
             }
         }

         final StaticPreset preset
             = new StaticPreset( id, pluginId, label, description, basePreset, facets );

         presets.addItemWithKey( id, preset );
     }

     private static void readDynamicPreset( final IConfigurationElement el )

         throws InvalidExtensionException

     {
         final String pluginId = el.getContributor().getName();
         final String id = findRequiredAttribute( el, ATTR_ID );
         final IConfigurationElement elFactory = findRequiredElement( el, EL_FACTORY );
         final String factoryClassName = findRequiredAttribute( elFactory, ATTR_CLASS );

         final DynamicPreset preset = new DynamicPreset( id, pluginId, factoryClassName );
         presets.addItemWithKey( id, preset );
     }

     private static boolean resolveBasePreset( final IPreset preset,
                                               final Set<IPreset> visitedPresets )
     {
         if( preset.getType() == IPreset.Type.STATIC )
         {
             final StaticPreset stPreset = (StaticPreset) preset;
             final String basePresetId = stPreset.getBasePresetId();

             if( basePresetId != null )
             {
                 final IPreset basePreset = getPreset( basePresetId );
                 boolean problem = false;

                 visitedPresets.add( preset );

                 if( basePreset == null )
                 {
                     final String msg
                         = Resources.bind( Resources.basePresetNotFound, stPreset.getId(),
                                           stPreset.getPluginId(), basePresetId );

                     logError( msg );

                     problem = true;
                 }
                 else if( visitedPresets.contains( basePreset ) )
                 {
                     final StringBuilder cycle = new StringBuilder();
                     final int cycleSize = visitedPresets.size();
                     int count = 0;

                     for( IPreset vp : visitedPresets )
                     {
                         count++;

                         if( count > 1 )
                         {
                             if( count == cycleSize )
                             {
                                 cycle.append( " and " ); //$NON-NLS-1$
                             }
                             else
                             {
                                 cycle.append( ", " ); //$NON-NLS-1$
                             }
                         }

                         cycle.append( '"' );
                         cycle.append( vp.getId() );
                         cycle.append( '"' );
                     }

                     final String msg = Resources.bind( Resources.cycleDetected, cycle.toString() );

                     logError( msg );

                     problem = true;
                 }
                 else if( ! resolveBasePreset( basePreset, visitedPresets ) )
                 {
                     problem = true;
                 }

                 if( problem )
                 {
                     PresetsExtensionPoint.presets.removeItemByKey( preset.getId() );
                     return false;
                 }
             }
         }

         return true;
     }

     private static class StaticPreset

         implements IPreset

     {
         private final String id;
         private final String pluginId;
         private final String label;
         private final String description;
         private final String basePresetId;
         private final Set<IProjectFacet> facets;
         private final Set<IProjectFacetVersion> facetVersions;
         private final Set<IProjectFacetVersion> facetVersionsReadOnly;

         public StaticPreset( final String id,
                              final String pluginId,
                              final String label,
                              final String description,
                              final String basePreset,
                              final Set<IProjectFacetVersion> facets )
         {
             this.id = id;
             this.pluginId = pluginId;
             this.label = label;
             this.description = description;
             this.basePresetId = basePreset;
             this.facetVersions = facets;
             this.facetVersionsReadOnly = Collections.unmodifiableSet( this.facetVersions );

             this.facets = new HashSet<IProjectFacet>( this.facetVersions.size() );

             for( IProjectFacetVersion fv : this.facetVersions )
             {
                 this.facets.add( fv.getProjectFacet() );
             }
         }

         public final String getId()
         {
             return this.id;
         }

         public final String getPluginId()
         {
             return this.pluginId;
         }

         public Type getType()
         {
             return Type.STATIC;
         }

         public final String getLabel()
         {
             return this.label;
         }

         public final String getDescription()
         {
             return this.description;
         }

         public final String getBasePresetId()
         {
             return this.basePresetId;
         }

         public Set<IProjectFacetVersion> getProjectFacets()
         {
             if( this.basePresetId == null )
             {
                 return this.facetVersionsReadOnly;
             }
             else
             {
                 final IPreset basePreset = getPreset( this.basePresetId );
                 return createCombinedFacetSet( basePreset );
             }
         }

         public final boolean isUserDefined()
         {
             return false;
         }

         public final String toString()
         {
             return this.id;
         }

         public boolean equals( final Object obj )
         {
             if( ! ( obj instanceof StaticPreset ) )
             {
                 return false;
             }

             final StaticPreset p = (StaticPreset) obj;

             return this.id.equals( p.id ) &&
                    this.pluginId.equals( p.pluginId ) &&
                    this.label.equals( p.label ) &&
                    this.description.equals( p.description ) &&
                    this.facetVersions.equals( p.facetVersions );
         }

         protected final Set<IProjectFacetVersion> createCombinedFacetSet( final IPreset basePreset )
         {
             final Set<IProjectFacetVersion> result
                 = new HashSet<IProjectFacetVersion>( this.facetVersions );

             for( IProjectFacetVersion fv : basePreset.getProjectFacets() )
             {
                 if( ! this.facets.contains( fv.getProjectFacet() ) )
                 {
                     result.add( fv );
                 }
             }

             return Collections.unmodifiableSet( result );
         }
     }

     private static final class StaticExtendingDynamicPreset

         extends StaticPreset
         implements IDynamicPreset

     {
         public StaticExtendingDynamicPreset( final String id,
                                              final String pluginId,
                                              final String label,
                                              final String description,
                                              final String basePresetId,
                                              final Set<IProjectFacetVersion> facets )
         {
             super( id, pluginId, label, description, basePresetId, facets );
         }

         @Override
         public Type getType()
         {
             return Type.DYNAMIC;
         }

         @Override
         public Set<IProjectFacetVersion> getProjectFacets()
         {
             return Collections.emptySet();
         }

         public IPreset resolve( final Map<String,Object> context )
         {
             final IDynamicPreset basePreset = (IDynamicPreset) getPreset( getBasePresetId() );
             final IPreset resBasePreset = basePreset.resolve( context );

             if( resBasePreset == null )
             {
                 return null;
             }
             else
             {
                 final Set<IProjectFacetVersion> facets = createCombinedFacetSet( resBasePreset );

                 return new StaticPreset( getId(), getPluginId(), getLabel(), getDescription(),
                                          getBasePresetId(), facets );
             }
         }
     }

     private static final class DynamicPreset

         implements IDynamicPreset

     {
         private final String id;
         private final String pluginId;
         private final String factoryClassName;

         public DynamicPreset( final String id,
                               final String pluginId,
                               final String factoryClassName )
         {
             this.id = id;
             this.pluginId = pluginId;
             this.factoryClassName = factoryClassName;
         }

         public String getId()
         {
             return this.id;
         }

         public Type getType()
         {
             return Type.DYNAMIC;
         }

         public String getLabel()
         {
             return this.id;
         }

         public String getDescription()
         {
             return ""; //$NON-NLS-1$
         }

         public Set<IProjectFacetVersion> getProjectFacets()
         {
             return Collections.emptySet();
         }

         public boolean isUserDefined()
         {
             return false;
         }

         public IPreset resolve( final Map<String,Object> context )
         {
             IPresetFactory factory = null;

             try
             {
                 factory = instantiate( this.pluginId, this.factoryClassName, IPresetFactory.class );
             }
             catch( CoreException e )
             {
                 log( e.getStatus() );
             }

             if( factory != null )
             {
                 PresetDefinition def = null;

                 try
                 {
                     def = factory.createPreset( this.id, context );
                 }
                 catch( Exception e )
                 {
                     final String msg
                         = Resources.bind( Resources.failedWhileInvokingPresetFactory,
                                           this.pluginId );

                     log( createErrorStatus( msg, e ) );
                 }

                 if( def != null )
                 {
                     final StaticPreset staticPreset
                         = new StaticPreset( this.id, this.pluginId, def.getLabel(),
                                             def.getDescription(), null, def.getProjectFacets() );

                     return staticPreset;
                 }
             }

             return null;
         }

         public String toString()
         {
             return this.id;
         }
     }

     private static final class Resources

         extends NLS

     {
         public static String presetUsesUnknownFacet;
         public static String presetUsesUnknownFacetVersion;
         public static String basePresetNotFound;
         public static String cycleDetected;
         public static String failedWhileInvokingPresetFactory;

         static
         {
             initializeMessages( PresetsExtensionPoint.class.getName(), Resources.class );
         }

         public static String bind( final String template,
                                    final Object arg1,
                                    final Object arg2,
                                    final Object arg3 )
         {
             return NLS.bind( template, new Object[] { arg1, arg2, arg3 } );
         }

         public static String bind( final String template,
                                    final Object arg1,
                                    final Object arg2,
                                    final Object arg3,
                                    final Object arg4 )
         {
             return NLS.bind( template, new Object[] { arg1, arg2, arg3, arg4 } );
         }
     }

 }
	/******************************************************************************
	* Copyright (c) 2008 BEA Systems, Inc.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Konstantin Komissarchik - initial implementation and ongoing maintenance
	******************************************************************************/

	package org.eclipse.wst.common.project.facet.core.internal;

	import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.PLUGIN_ID;
	import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.createErrorStatus;
	import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.log;
	import static org.eclipse.wst.common.project.facet.core.internal.FacetCorePlugin.logError;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findExtensions;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findOptionalElement;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findRequiredAttribute;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.findRequiredElement;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.getElementValue;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.getTopLevelElements;
	import static org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.instantiate;

	import java.util.Collections;
	import java.util.HashSet;
	import java.util.Map;
	import java.util.Set;

	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.osgi.util.NLS;
	import org.eclipse.wst.common.project.facet.core.IDynamicPreset;
	import org.eclipse.wst.common.project.facet.core.IPreset;
	import org.eclipse.wst.common.project.facet.core.IPresetFactory;
	import org.eclipse.wst.common.project.facet.core.IProjectFacet;
	import org.eclipse.wst.common.project.facet.core.IProjectFacetVersion;
	import org.eclipse.wst.common.project.facet.core.PresetDefinition;
	import org.eclipse.wst.common.project.facet.core.ProjectFacetsManager;
	import org.eclipse.wst.common.project.facet.core.util.internal.IndexedSet;
	import org.eclipse.wst.common.project.facet.core.util.internal.PluginUtil.InvalidExtensionException;

	/**
	* Contains the logic for processing the <code>presets</code> extension point.
	*
	* @author <a href="mailto:kosta@bea.com">Konstantin Komissarchik</a>
	*/

	public final class PresetsExtensionPoint
	{
	public static final String EXTENSION_POINT_ID = "presets"; //$NON-NLS-1$
	private static final String OLD_EXTENSION_POINT_ID = "facets"; //$NON-NLS-1$

	private static final String EL_DESCRIPTION = "description"; //$NON-NLS-1$
	private static final String EL_DYNAMIC_PRESET = "dynamic-preset"; //$NON-NLS-1$
	private static final String EL_FACET = "facet"; //$NON-NLS-1$
	private static final String EL_FACTORY = "factory"; //$NON-NLS-1$
	private static final String EL_LABEL = "label"; //$NON-NLS-1$
	private static final String EL_PRESET = "preset"; //$NON-NLS-1$
	private static final String EL_STATIC_PRESET = "static-preset"; //$NON-NLS-1$
	private static final String ATTR_CLASS = "class"; //$NON-NLS-1$
	private static final String ATTR_EXTENDS = "extends"; //$NON-NLS-1$
	private static final String ATTR_ID = "id"; //$NON-NLS-1$
	private static final String ATTR_VERSION = "version"; //$NON-NLS-1$

	private static final String DEFAULT_DESCRIPTION = ""; //$NON-NLS-1$

	private static IndexedSet<String,IPreset> presets = null;

	public static Set<IPreset> getPresets()
	{
	readExtensions();
	return presets.getItemSet();
	}

	public static IPreset getPreset( final String id )
	{
	readExtensions();
	return presets.getItemByKey( id );
	}

	private static synchronized void readExtensions()
	{
	if( presets != null )
	{
	return;
	}

	presets = new IndexedSet<String,IPreset>();

	for( IConfigurationElement element
	: getTopLevelElements( findExtensions( PLUGIN_ID, EXTENSION_POINT_ID ) ) )
	{
	final String elName = element.getName();

	if( elName.equals( EL_STATIC_PRESET ) )
	{
	try
	{
	readStaticPreset( element );
	}
	catch( InvalidExtensionException e )
	{
	// Continue. The problem has been reported to the user via the log.
	}
	}
	else if( elName.equals( EL_DYNAMIC_PRESET ) )
	{
	try
	{
	readDynamicPreset( element );
	}
	catch( InvalidExtensionException e )
	{
	// Continue. The problem has been reported to the user via the log.
	}
	}
	}

	for( IConfigurationElement element
	: getTopLevelElements( findExtensions( PLUGIN_ID, OLD_EXTENSION_POINT_ID ) ) )
	{
	if( element.getName().equals( EL_PRESET ) )
	{
	try
	{
	readStaticPreset( element );
	}
	catch( InvalidExtensionException e )
	{
	// Continue. The problem has been reported to the user via the log.
	}
	}
	}

	// Resolve the base presets. Make sure that no presets are extending presets that do not
	// exist, check for circular references, etc.

	Set<IPreset> copy = new HashSet<IPreset>( presets.getItemSet() );

	for( IPreset preset : copy )
	{
	if( presets.containsItem( preset ) )
	{
	resolveBasePreset( preset, new HashSet<IPreset>() );
	}
	}

	// Find static presets that are extending dynamic presets and make them into dynamic
	// presets (StaticExtendingDynamicPreset class).

	boolean doAnotherPass = true;

	while( doAnotherPass )
	{
	doAnotherPass = false;

	for( IPreset preset : presets.getItemSet() )
	{
	if( preset.getType() == IPreset.Type.STATIC )
	{
	final StaticPreset stPreset = (StaticPreset) preset;
	final String basePresetId = stPreset.getBasePresetId();

	if( basePresetId != null )
	{
	final IPreset basePreset = getPreset( basePresetId );

	if( basePreset.getType() == IPreset.Type.DYNAMIC )
	{
	final StaticExtendingDynamicPreset stPresetNew
	= new StaticExtendingDynamicPreset( stPreset.getId(),
	stPreset.getPluginId(),
	stPreset.getLabel(),
	stPreset.getDescription(),
	stPreset.getBasePresetId(),
	stPreset.getProjectFacets() );

	presets.removeItem( stPreset );
	presets.addItemWithKey( stPresetNew.getId(), stPresetNew );

	doAnotherPass = true;
	break;
	}
	}
	}
	}
	}
	}

	private static void readStaticPreset( final IConfigurationElement el )

	throws InvalidExtensionException

	{
	final String pluginId = el.getContributor().getName();
	final String id = findRequiredAttribute( el, ATTR_ID );

	final IConfigurationElement elLabel = findOptionalElement( el, EL_LABEL );
	final String label = getElementValue( elLabel, id );

	final IConfigurationElement elDesc = findOptionalElement( el, EL_DESCRIPTION );
	final String description = getElementValue( elDesc, DEFAULT_DESCRIPTION );

	String basePreset = el.getAttribute( ATTR_EXTENDS );

	if( basePreset != null )
	{
	basePreset = basePreset.trim();

	if( basePreset.length() == 0 )
	{
	basePreset = null;
	}
	}

	final Set<IProjectFacetVersion> facets = new HashSet<IProjectFacetVersion>();

	for( IConfigurationElement child : el.getChildren() )
	{
	final String childName = child.getName();

	if( childName.equals( EL_FACET ) )
	{
	final String fid = findRequiredAttribute( child, ATTR_ID );
	final String fver = findRequiredAttribute( child, ATTR_VERSION );

	if( ! ProjectFacetsManager.isProjectFacetDefined( fid ) )
	{
	final String msg
	= Resources.bind( Resources.presetUsesUnknownFacet, id, pluginId, fid );

	logError( msg );

	return;
	}

	final IProjectFacet f = ProjectFacetsManager.getProjectFacet( fid );

	if( ! f.hasVersion( fver ) )
	{
	final String msg
	= Resources.bind( Resources.presetUsesUnknownFacetVersion, id, pluginId,
	fid, fver );

	logError( msg );

	return;
	}

	final IProjectFacetVersion fv = f.getVersion( fver );

	facets.add( fv );
	}
	}

	final StaticPreset preset
	= new StaticPreset( id, pluginId, label, description, basePreset, facets );

	presets.addItemWithKey( id, preset );
	}

	private static void readDynamicPreset( final IConfigurationElement el )

	throws InvalidExtensionException

	{
	final String pluginId = el.getContributor().getName();
	final String id = findRequiredAttribute( el, ATTR_ID );
	final IConfigurationElement elFactory = findRequiredElement( el, EL_FACTORY );
	final String factoryClassName = findRequiredAttribute( elFactory, ATTR_CLASS );

	final DynamicPreset preset = new DynamicPreset( id, pluginId, factoryClassName );
	presets.addItemWithKey( id, preset );
	}

	private static boolean resolveBasePreset( final IPreset preset,
	final Set<IPreset> visitedPresets )
	{
	if( preset.getType() == IPreset.Type.STATIC )
	{
	final StaticPreset stPreset = (StaticPreset) preset;
	final String basePresetId = stPreset.getBasePresetId();

	if( basePresetId != null )
	{
	final IPreset basePreset = getPreset( basePresetId );
	boolean problem = false;

	visitedPresets.add( preset );

	if( basePreset == null )
	{
	final String msg
	= Resources.bind( Resources.basePresetNotFound, stPreset.getId(),
	stPreset.getPluginId(), basePresetId );

	logError( msg );

	problem = true;
	}
	else if( visitedPresets.contains( basePreset ) )
	{
	final StringBuilder cycle = new StringBuilder();
	final int cycleSize = visitedPresets.size();
	int count = 0;

	for( IPreset vp : visitedPresets )
	{
	count++;

	if( count > 1 )
	{
	if( count == cycleSize )
	{
	cycle.append( " and " ); //$NON-NLS-1$
	}
	else
	{
	cycle.append( ", " ); //$NON-NLS-1$
	}
	}

	cycle.append( '"' );
	cycle.append( vp.getId() );
	cycle.append( '"' );
	}

	final String msg = Resources.bind( Resources.cycleDetected, cycle.toString() );

	logError( msg );

	problem = true;
	}
	else if( ! resolveBasePreset( basePreset, visitedPresets ) )
	{
	problem = true;
	}

	if( problem )
	{
	PresetsExtensionPoint.presets.removeItemByKey( preset.getId() );
	return false;
	}
	}
	}

	return true;
	}

	private static class StaticPreset

	implements IPreset

	{
	private final String id;
	private final String pluginId;
	private final String label;
	private final String description;
	private final String basePresetId;
	private final Set<IProjectFacet> facets;
	private final Set<IProjectFacetVersion> facetVersions;
	private final Set<IProjectFacetVersion> facetVersionsReadOnly;

	public StaticPreset( final String id,
	final String pluginId,
	final String label,
	final String description,
	final String basePreset,
	final Set<IProjectFacetVersion> facets )
	{
	this.id = id;
	this.pluginId = pluginId;
	this.label = label;
	this.description = description;
	this.basePresetId = basePreset;
	this.facetVersions = facets;
	this.facetVersionsReadOnly = Collections.unmodifiableSet( this.facetVersions );

	this.facets = new HashSet<IProjectFacet>( this.facetVersions.size() );

	for( IProjectFacetVersion fv : this.facetVersions )
	{
	this.facets.add( fv.getProjectFacet() );
	}
	}

	public final String getId()
	{
	return this.id;
	}

	public final String getPluginId()
	{
	return this.pluginId;
	}

	public Type getType()
	{
	return Type.STATIC;
	}

	public final String getLabel()
	{
	return this.label;
	}

	public final String getDescription()
	{
	return this.description;
	}

	public final String getBasePresetId()
	{
	return this.basePresetId;
	}

	public Set<IProjectFacetVersion> getProjectFacets()
	{
	if( this.basePresetId == null )
	{
	return this.facetVersionsReadOnly;
	}
	else
	{
	final IPreset basePreset = getPreset( this.basePresetId );
	return createCombinedFacetSet( basePreset );
	}
	}

	public final boolean isUserDefined()
	{
	return false;
	}

	public final String toString()
	{
	return this.id;
	}

	public boolean equals( final Object obj )
	{
	if( ! ( obj instanceof StaticPreset ) )
	{
	return false;
	}

	final StaticPreset p = (StaticPreset) obj;

	return this.id.equals( p.id ) &&
	this.pluginId.equals( p.pluginId ) &&
	this.label.equals( p.label ) &&
	this.description.equals( p.description ) &&
	this.facetVersions.equals( p.facetVersions );
	}

	protected final Set<IProjectFacetVersion> createCombinedFacetSet( final IPreset basePreset )
	{
	final Set<IProjectFacetVersion> result
	= new HashSet<IProjectFacetVersion>( this.facetVersions );

	for( IProjectFacetVersion fv : basePreset.getProjectFacets() )
	{
	if( ! this.facets.contains( fv.getProjectFacet() ) )
	{
	result.add( fv );
	}
	}

	return Collections.unmodifiableSet( result );
	}
	}

	private static final class StaticExtendingDynamicPreset

	extends StaticPreset
	implements IDynamicPreset

	{
	public StaticExtendingDynamicPreset( final String id,
	final String pluginId,
	final String label,
	final String description,
	final String basePresetId,
	final Set<IProjectFacetVersion> facets )
	{
	super( id, pluginId, label, description, basePresetId, facets );
	}

	@Override
	public Type getType()
	{
	return Type.DYNAMIC;
	}

	@Override
	public Set<IProjectFacetVersion> getProjectFacets()
	{
	return Collections.emptySet();
	}

	public IPreset resolve( final Map<String,Object> context )
	{
	final IDynamicPreset basePreset = (IDynamicPreset) getPreset( getBasePresetId() );
	final IPreset resBasePreset = basePreset.resolve( context );

	if( resBasePreset == null )
	{
	return null;
	}
	else
	{
	final Set<IProjectFacetVersion> facets = createCombinedFacetSet( resBasePreset );

	return new StaticPreset( getId(), getPluginId(), getLabel(), getDescription(),
	getBasePresetId(), facets );
	}
	}
	}

	private static final class DynamicPreset

	implements IDynamicPreset

	{
	private final String id;
	private final String pluginId;
	private final String factoryClassName;

	public DynamicPreset( final String id,
	final String pluginId,
	final String factoryClassName )
	{
	this.id = id;
	this.pluginId = pluginId;
	this.factoryClassName = factoryClassName;
	}

	public String getId()
	{
	return this.id;
	}

	public Type getType()
	{
	return Type.DYNAMIC;
	}

	public String getLabel()
	{
	return this.id;
	}

	public String getDescription()
	{
	return ""; //$NON-NLS-1$
	}

	public Set<IProjectFacetVersion> getProjectFacets()
	{
	return Collections.emptySet();
	}

	public boolean isUserDefined()
	{
	return false;
	}

	public IPreset resolve( final Map<String,Object> context )
	{
	IPresetFactory factory = null;

	try
	{
	factory = instantiate( this.pluginId, this.factoryClassName, IPresetFactory.class );
	}
	catch( CoreException e )
	{
	log( e.getStatus() );
	}

	if( factory != null )
	{
	PresetDefinition def = null;

	try
	{
	def = factory.createPreset( this.id, context );
	}
	catch( Exception e )
	{
	final String msg
	= Resources.bind( Resources.failedWhileInvokingPresetFactory,
	this.pluginId );

	log( createErrorStatus( msg, e ) );
	}

	if( def != null )
	{
	final StaticPreset staticPreset
	= new StaticPreset( this.id, this.pluginId, def.getLabel(),
	def.getDescription(), null, def.getProjectFacets() );

	return staticPreset;
	}
	}

	return null;
	}

	public String toString()
	{
	return this.id;
	}
	}

	private static final class Resources

	extends NLS

	{
	public static String presetUsesUnknownFacet;
	public static String presetUsesUnknownFacetVersion;
	public static String basePresetNotFound;
	public static String cycleDetected;
	public static String failedWhileInvokingPresetFactory;

	static
	{
	initializeMessages( PresetsExtensionPoint.class.getName(), Resources.class );
	}

	public static String bind( final String template,
	final Object arg1,
	final Object arg2,
	final Object arg3 )
	{
	return NLS.bind( template, new Object[] { arg1, arg2, arg3 } );
	}

	public static String bind( final String template,
	final Object arg1,
	final Object arg2,
	final Object arg3,
	final Object arg4 )
	{
	return NLS.bind( template, new Object[] { arg1, arg2, arg3, arg4 } );
	}
	}

	}