bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/registry/PreferenceTransferRegistryReader.java

/*******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.ui.internal.registry;

import com.ibm.icu.text.Collator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.preferences.PreferenceFilterEntry;
import org.eclipse.ui.internal.WorkbenchPlugin;
import org.eclipse.ui.internal.preferences.PreferenceTransferElement;

/**
 * Preference Transfer registry reader to read extenders of the preferenceTranser schema.
 * 
 * @since 3.1
 */
public class PreferenceTransferRegistryReader extends RegistryReader {
    private List preferenceTransfers;

    private String pluginPoint;

    /**
     *  Create an instance of this class.
     *
     *  @param pluginPointId java.lang.String
     */
    public PreferenceTransferRegistryReader(String pluginPointId) {
        pluginPoint = pluginPointId;
    }

    /**
     * Adds new wizard to the provided collection. Override to
     * provide more logic.
     * 
     * TODO: remove the config parameter?
     */
    protected void addNewElementToResult(PreferenceTransferElement element,
            IConfigurationElement config) {
        preferenceTransfers.add(element);
    }


    /**
     * Returns a new PreferenceTransferElement configured according to the parameters
     * contained in the passed Registry.  
     *
     * May answer null if there was not enough information in the Extension to create 
     * an adequate wizard
     */
    protected PreferenceTransferElement createPreferenceTransferElement(
            IConfigurationElement element) {
        // PreferenceTransfers must have a name and class attribute
        if (element.getAttribute(IWorkbenchRegistryConstants.ATT_NAME) == null) {
            logMissingAttribute(element, IWorkbenchRegistryConstants.ATT_NAME);
            return null;
        }
        
        // must specifiy a mapping
        if (element.getChildren(IWorkbenchRegistryConstants.TAG_MAPPING) == null) {
            logMissingElement(element, IWorkbenchRegistryConstants.TAG_MAPPING);
            return null;
        }
        
        
        return new PreferenceTransferElement(element);
    }

    /**
     * Returns a sorted list of preference transfers.
     *
     *@return an array of <code>IPreferenceTransfer</code> objects
     */
    public PreferenceTransferElement[] getPreferenceTransfers() {
        readPreferenceTransfers();
        PreferenceTransferElement[] transfers = new PreferenceTransferElement[preferenceTransfers.size()];
        Collections.sort(preferenceTransfers, new Comparator() {
            public int compare(Object o1, Object o2) {
                String name1 = ((PreferenceTransferElement)o1).getName();
                String name2 = ((PreferenceTransferElement)o2).getName();
                              
                return Collator.getInstance().compare(name1, name2);
            }});
        preferenceTransfers.toArray(transfers);
        return transfers;
    }

    /**
     * Implement this method to read element attributes.
     */
    public boolean readElement(IConfigurationElement element) {
        if (!element.getName().equals(IWorkbenchRegistryConstants.TAG_TRANSFER)) {
			return false;
		}
        PreferenceTransferElement transfer = createPreferenceTransferElement(element);
        if (transfer != null) {
			addNewElementToResult(transfer, element);
		}
        return true;
    }

    /**
     * Reads the wizards in a registry.  
     */
    protected void readPreferenceTransfers() {
        preferenceTransfers = new ArrayList();
        IExtensionRegistry registry = Platform.getExtensionRegistry();
        readRegistry(registry, WorkbenchPlugin.PI_WORKBENCH, pluginPoint);
    }
    


   /**
     * @param configElement
     * @return the child configuration elements
     */
    public static IConfigurationElement[] getMappings(IConfigurationElement configElement) {
        IConfigurationElement[] children = configElement.getChildren(IWorkbenchRegistryConstants.TAG_MAPPING);
        if (children.length < 1) {
            logMissingElement(configElement, IWorkbenchRegistryConstants.TAG_MAPPING);
            return null;
        } 
        return children;
    }

    /**
     * @param element
     * @return the scope attribute for this element
     */
    public static String getScope(IConfigurationElement element) {
        return element.getAttribute(IWorkbenchRegistryConstants.ATT_SCOPE);
    }

    /**
     * @param element
     * @return the maps mapping nodes to keys for this element
     */
    public static Map getEntry(IConfigurationElement element) {
        IConfigurationElement[] entries = element.getChildren(IWorkbenchRegistryConstants.TAG_ENTRY);
        if (entries.length == 0) {
			return null;
		}
        Map map = new HashMap(entries.length);
        for (int i = 0; i < entries.length; i++) {
            IConfigurationElement entry = entries[i];
            IConfigurationElement[] keys = entry.getChildren(IWorkbenchRegistryConstants.ATT_KEY);
            PreferenceFilterEntry[] prefFilters = null;
            if (keys.length > 0) {
                prefFilters = new PreferenceFilterEntry[keys.length];
                for (int j = 0; j < keys.length; j++) {
					IConfigurationElement keyElement = keys[j];
					prefFilters[j] = new PreferenceFilterEntry(keyElement.getAttribute(IWorkbenchRegistryConstants.ATT_NAME));
				}
            }
            map.put(entry.getAttribute(IWorkbenchRegistryConstants.ATT_NODE), prefFilters);            
        }
        return map;
    }

}