bundles/org.eclipse.wst.sse.ui/src/org/eclipse/wst/sse/ui/internal/openon/OpenOnBuilder.java

/*
* Copyright (c) 2002 IBM Corporation and others.
* All rights reserved.   This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
* 
* Contributors:
*   IBM - Initial API and implementation
*   Jens Lukowski/Innoopract - initial renaming/restructuring
* 
*/
package org.eclipse.wst.sse.ui.internal.openon;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IPluginRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.wst.sse.ui.internal.extension.RegistryReader;


/**
 * Reads extensions for open on extension point, org.eclipse.wst.sse.ui.extensions.openon
 */
public class OpenOnBuilder extends RegistryReader {
	// extension point ID
	public static final String PL_OPENON = "openon"; //$NON-NLS-1$

	public static final String PLUGIN_ID = "org.eclipse.wst.sse.ui.extensions"; //$NON-NLS-1$

	public static final String TAG_OPENON = "openon"; //$NON-NLS-1$
	public static final String TAG_CONTENT_TYPE_IDENTIFIER = "contenttypeidentifier"; //$NON-NLS-1$
	public static final String TAG_PARTITION_TYPE = "partitiontype"; //$NON-NLS-1$

	public static final String ATT_ID = "id"; //$NON-NLS-1$
	public static final String ATT_CLASS = "class"; //$NON-NLS-1$

	protected String targetContributionTag;

	private static OpenOnBuilder fInstance;

	private List fOpenOnDefs = null;
	private OpenOnDefinition fCurrentOpenOnDefinition = null;
	private String fCurrentContentType;

	/**
	 * returns singleton instance of OpenOnBuilder
	 * 
	 * @return OpenOnBuilder
	 */
	public synchronized static OpenOnBuilder getInstance() {
		if (fInstance == null) {
			fInstance = new OpenOnBuilder();
		}
		return fInstance;
	}

	/**
	 * Returns the name of the part ID attribute that is expected
	 * in the target extension.
	 * 
	 * @param element
	 * @return String
	 */
	protected String getId(IConfigurationElement element) {
		String value = element.getAttribute(ATT_ID);
		return value;
	}

	protected String getOpenOnClass(IConfigurationElement element) {
		String value = element.getAttribute(ATT_CLASS);
		return value;
	}

	/**
	 * Processes element which should be a configuration element specifying an
	 * open on object.  Creates a new open on definition object and adds it to the
	 * list of open on definition objects
	 * 
	 * @param element openon configuration element
	 */
	private void processOpenOnTag(IConfigurationElement element) {
		String theId = getId(element);
		String theClass = getOpenOnClass(element);

		if (theId != null && theClass != null) {
			// start building new OpenOnDefinition
			fCurrentOpenOnDefinition = new OpenOnDefinition(theId, theClass, element);

			// create a new list of open on definitions if it hasnt been created yet
			if (fOpenOnDefs == null) {
				fOpenOnDefs = new ArrayList();
			}
			fOpenOnDefs.add(fCurrentOpenOnDefinition);
		}
		else {
			fCurrentOpenOnDefinition = null;
		}
	}

	/**
	 * Processes element which should be a configuration element specifying a content
	 * type for the current open on tag.  Assumes that there is a valid current open
	 * on definition object.
	 * 
	 * @param element contenttypeidentifier configuration element
	 */
	private void processContentTypeTag(IConfigurationElement element) {
		// add to current openOnDefinition
		String theId = getId(element);

		if (theId != null) {
			fCurrentContentType = theId;
			fCurrentOpenOnDefinition.addContentTypeId(fCurrentContentType);
		}
		else {
			fCurrentContentType = null;
		}
	}

	/**
	 * Processes element which should be a configuration element specifying a partition
	 * type for the current open on/content type tag.  Assumes that there is a valid
	 * current open on/content type tag.
	 * 
	 * @param element partitiontype configuration element
	 */
	private void processPartitionTypeTag(IConfigurationElement element) {
		// add to current openOnDefinition/contentType
		String theId = getId(element);

		if (theId != null) {
			fCurrentOpenOnDefinition.addPartitionType(fCurrentContentType, theId);
		}
	}

	/* (non-Javadoc)
	 */
	protected boolean readElement(IConfigurationElement element) {
		String tag = element.getName();

		if (tag.equals(targetContributionTag)) {
			processOpenOnTag(element);

			// make sure processing of current open on tag resulted in a current open on definition
			// before continue reading the children
			if (fCurrentOpenOnDefinition != null) {
				readElementChildren(element);
			}
			return true;
		}
		else if (tag.equals(TAG_CONTENT_TYPE_IDENTIFIER)) {
			processContentTypeTag(element);

			// make sure processing of current content type resulted in a valid content type
			// before reading the children
			if (fCurrentContentType != null) {
				readElementChildren(element);
			}
			return true;
		}
		else if (tag.equals(TAG_PARTITION_TYPE)) {
			processPartitionTypeTag(element);
			return true;
		}

		return false;
	}

	private void initCache() {
		if (fOpenOnDefs == null) {
			readContributions(TAG_OPENON, PL_OPENON);
		}
	}

	/**
	 * Reads the contributions from the registry for the provided workbench
	 * part and the provided extension point ID.
	 * @param tag
	 * @param extensionPoint
	 */
	protected void readContributions(String tag, String extensionPoint) {
		targetContributionTag = tag;
		IPluginRegistry registry = Platform.getPluginRegistry();
		readRegistry(registry, PLUGIN_ID, extensionPoint);
	}

	/**
	 * Returns all the open on definition objects
	 * @return
	 */
	public OpenOnDefinition[] getOpenOnDefinitions() {
		initCache();
		if( fOpenOnDefs == null )
			fOpenOnDefs = new ArrayList();
		return (OpenOnDefinition[]) fOpenOnDefs.toArray(new OpenOnDefinition[fOpenOnDefs.size()]);
	}

	/**
	 * Returns all the open on definition objects valid for contentType/partitionType
	 * @param contentType
	 * @param partitionType
	 * @return if either contentType or partitionType is null, null is returned 
	 */
	public OpenOnDefinition[] getOpenOnDefinitions(String contentType, String partitionType) {
		if (contentType == null || partitionType == null) {
			// should not be able to define an openon without a content type
			// but if it were possible then would need to search all openon definitions for
			// definitions with empty contentType list
			return null;
		}

		// entire list of openon definition objects
		OpenOnDefinition[] allDefs = getOpenOnDefinitions();
		// current list of open on definitions valid for contentType/partitionType
		List defs = new ArrayList();
		// default definitions that should be added to end of list of open on definitions
		List lastDefs = new ArrayList();

		for (int i = 0; i < allDefs.length; ++i) {
			// for each one check if it contains contentType
			List partitions = (List) allDefs[i].getContentTypes().get(contentType);
			if (partitions != null) {
				// this openon definition is valid for all partition types for this content type
				if (partitions.isEmpty()) {
					// this will be added to end of list because this is considered a default openon
					lastDefs.add(allDefs[i]);
				}
				else {
					// examine the partition types of this openon
					int j = 0; // current index in list of partitions
					boolean added = false; // openon has been added to list
					while (j < partitions.size() && !added) {
						// this openon definition applies to partitionType so add to list of valid openons
						if (partitionType.equals(partitions.get(j))) {
							defs.add(allDefs[i]);
							added = true;
						}
						else {
							// continue checking to see if this openon definition is valid for current partitionType
							++j;
						}
					}
				}
			}
		}
		// append the default openon definitions
		defs.addAll(lastDefs);

		// return the list
		return (OpenOnDefinition[]) defs.toArray(new OpenOnDefinition[defs.size()]);
	}
}