/*-
 *******************************************************************************
 * Copyright (c) 2011, 2014 Diamond Light Source Ltd.
 * 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:
 *    Matthew Gerring - initial API and implementation and/or initial documentation
 *******************************************************************************/
package org.eclipse.dawnsci.hdf5.editor;

import java.util.HashSet;
import java.util.Set;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;


public class H5SelectionProvider implements ISelectionProvider {

	private Set<ISelectionChangedListener> listeners;
	private ISelection currentSelection;
	
	public H5SelectionProvider() {
		listeners = new HashSet<ISelectionChangedListener>(11);
	}
	
	@Override
	public void addSelectionChangedListener(ISelectionChangedListener listener) {
		listeners.add(listener);
	}

	/**
	 * You cannot return a null currentSelection as eclipse does not
	 * like it.
	 */
	@Override
	public ISelection getSelection() {
		if (currentSelection==null) currentSelection = new StructuredSelection(); // Cannot be null
		return currentSelection;
	}

	@Override
	public void removeSelectionChangedListener(ISelectionChangedListener listener) {
		listeners.remove(listener);
	}

	@Override
	public void setSelection(ISelection selection) {
		this.currentSelection = selection;
		SelectionChangedEvent e = new SelectionChangedEvent(this, selection);
		for (ISelectionChangedListener s : listeners) s.selectionChanged(e);
	}

}