/*

* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

* Represents a location in source

*

*/

package com.nokia.tracebuilder.source;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

/**

 * Represents a location in source

 * 

 */

public class SourceLocation extends SourceLocationBase {

	/**

	 * Location listeners

	 */

	private ArrayList<SourceLocationListener> locationListeners;

	/**

	 * Temporary array for callback purposes. Prevents concurrent modifications

	 * if listeners are removed during a callback

	 */

	private ArrayList<SourceLocationListener> tempListeners;

	/**

	 * Offset that was used in last notification

	 */

	private int notifiedOffset;

	/**

	 * Length that was used in last notification

	 */

	private int notifiedLength;

	/**

	 * Reference count

	 */

	private int refCount = 0;

	/**

	 * Listener change flag

	 */

	private boolean listenersChanged = true;

	/**

	 * Constructor

	 * 

	 * @param parser

	 *            the parser owning this location

	 * @param offset

	 *            offset of location

	 * @param length

	 *            length of location

	 */

	public SourceLocation(SourceParser parser, int offset, int length) {

		super(parser, offset, length);

		this.notifiedOffset = offset;

		this.notifiedLength = length;

		parser.addLocation(this);

		refCount = 1;

	}

	/**

	 * Selects the source code represented by this location. This does not work

	 * if the source has not been associated with a selector.

	 */

	public void selectFromSource() {

		if (getParser() != null && !isDeleted()) {

			SourceDocumentInterface owner = getParser().getSource();

			if (owner != null) {

				SourceSelector selector = owner.getSourceSelector();

				if (selector != null) {

					selector.setSelection(getOffset(), getLength());

				}

			}

		}

	}

	/**

	 * Gets the name of the class which owns this location

	 * 

	 * @return the class name

	 */

	public String getClassName() {

		String retval = null;

		if (getParser() != null) {

			SourceContext context = getParser().getContext(getOffset());

			if (context != null) {

				retval = context.getClassName();

			}

		}

		return retval;

	}

	/**

	 * Gets the name of function which owns this location

	 * 

	 * @return the function name

	 */

	public String getFunctionName() {

		String retval = null;

		if (getParser() != null) {

			SourceContext context = getParser().getContext(getOffset());

			if (context != null) {

				retval = context.getFunctionName();

			}

		}

		return retval;

	}

	/**

	 * Adds a location listener to this location

	 * 

	 * @param listener

	 *            the location listener

	 */

	public void addLocationListener(SourceLocationListener listener) {

		if (locationListeners == null) {

			locationListeners = new ArrayList<SourceLocationListener>();

		}

		locationListeners.add(listener);

		listenersChanged = true;

	}

	/**

	 * Removes a location listener from this location

	 * 

	 * @param listener

	 *            the location listener

	 */

	public void removeLocationListener(SourceLocationListener listener) {

		if (locationListeners != null) {

			if (locationListeners.remove(listener)) {

				listenersChanged = true;

			}

		}

	}

	/**

	 * Gets the listener interfaces

	 * 

	 * @return the listeners

	 */

	protected Iterator<SourceLocationListener> getListeners() {

		List<SourceLocationListener> list;

		if (locationListeners != null) {

			if (listenersChanged) {

				listenersChanged = false;

				if (tempListeners == null) {

					tempListeners = new ArrayList<SourceLocationListener>();

				}

				tempListeners.clear();

				tempListeners.addAll(locationListeners);

			}

			list = tempListeners;

		} else {

			list = Collections.emptyList();

		}

		return list.iterator();

	}

	/**

	 * Fires a location deleted event to registered listeners.

	 * 

	 * @see SourceLocationListener

	 */

	void notifyLocationDeleted() {

		if (locationListeners != null) {

			Iterator<SourceLocationListener> listeners = getListeners();

			locationListeners = null;

			resetParser();

			while (listeners.hasNext()) {

				listeners.next().locationDeleted(this);

			}

		}

	}

	/**

	 * Sends locationChanged notifications to listeners if this location has

	 * changed.

	 */

	protected void notifyLocationChanged() {

		if (locationListeners != null) {

			if (notifiedOffset != getOffset() || notifiedLength != getLength()) {

				notifiedOffset = getOffset();

				notifiedLength = getLength();

				resetLineNumber();

				Iterator<SourceLocationListener> itr = locationListeners

						.iterator();

				while (itr.hasNext()) {

					itr.next().locationChanged(this);

				}

			}

		}

	}

	/**

	 * Increases the reference count of this location.

	 * 

	 * @see #dereference()

	 */

	public void reference() {

		refCount++;

	}

	/**

	 * Decrements the reference count of this location. When reference count is

	 * 0, this is removed from source. Note that a location can also be removed

	 * from source even if it has outstanding references left. In that case it

	 * can no longer be selected.

	 */

	public void dereference() {

		if (--refCount <= 0) {

			removeFromSource();

		}

	}

	/**

	 * Removes this location from the source

	 */

	private void removeFromSource() {

		delete();

		if (getParser() != null) {

			getParser().removeLocation(this);

			resetParser();

		}

		notifyLocationDeleted();

	}

}