ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/util/PostSelectionProviderProxy.java

/*=============================================================================#
 # Copyright (c) 2012, 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ecommons.ui.util;

import org.eclipse.jface.viewers.IPostSelectionProvider;
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 PostSelectionProviderProxy extends AbstractPostSelectionProvider {
	
	
	private final ISelectionChangedListener fSelectionChangedListener = new ISelectionChangedListener() {
		@Override
		public void selectionChanged(final SelectionChangedEvent event) {
			fireSelectionChanged(new SelectionChangedEvent(PostSelectionProviderProxy.this,
					getSelection(event.getSelection()) ));
		}
	};
	private final ISelectionChangedListener fPostSelectionChangedListener = new ISelectionChangedListener() {
		@Override
		public void selectionChanged(final SelectionChangedEvent event) {
			firePostSelectionChanged(new SelectionChangedEvent(PostSelectionProviderProxy.this,
					getSelection(event.getSelection()) ));
		}
	};
	
	protected ISelectionProvider fSelectionProvider;
	
	
	public PostSelectionProviderProxy(final ISelectionProvider selectionProvider) {
		setSelectionProvider(selectionProvider);
	}
	
	public PostSelectionProviderProxy() {
	}
	
	
	protected void setSelectionProvider(final ISelectionProvider selectionProvider) {
		if (fSelectionProvider == selectionProvider) {
			return;
		}
		if (fSelectionProvider != null) {
			fSelectionProvider.removeSelectionChangedListener(fSelectionChangedListener);
			if (fSelectionProvider instanceof IPostSelectionProvider) {
				((IPostSelectionProvider) fSelectionProvider).removePostSelectionChangedListener(fPostSelectionChangedListener);
			}
			else {
				fSelectionProvider.removeSelectionChangedListener(fPostSelectionChangedListener);
			}
		}
		fSelectionProvider = selectionProvider;
		if (fSelectionProvider != null) {
			fSelectionProvider.addSelectionChangedListener(fSelectionChangedListener);
			if (fSelectionProvider instanceof IPostSelectionProvider) {
				((IPostSelectionProvider) fSelectionProvider).addPostSelectionChangedListener(fPostSelectionChangedListener);
			}
			else {
				fSelectionProvider.addSelectionChangedListener(fPostSelectionChangedListener);
			}
		}
		
		{	final SelectionChangedEvent event = new SelectionChangedEvent(
					this, getSelection(getSelection()) );
			
			fireSelectionChanged(event);
			firePostSelectionChanged(event);
		}
	}
	
	protected ISelectionProvider getSelectionProvider() {
		return fSelectionProvider;
	}
	
	
	@Override
	public void setSelection(final ISelection selection) {
		if (fSelectionProvider != null) {
			fSelectionProvider.setSelection(selection);
		}
	}
	
	@Override
	public ISelection getSelection() {
		return getSelection((fSelectionProvider != null) ? fSelectionProvider.getSelection() : null);
	}
	
	protected ISelection getSelection(final ISelection originalSelection) {
		return (originalSelection != null) ? originalSelection : StructuredSelection.EMPTY;
	}
	
}