/*******************************************************************************
* Copyright (c) 2010, 2015 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
* Simon Scholz <simon.scholz@vogella.com> - Bug 460405
*******************************************************************************/
package org.eclipse.e4.ui.internal.workbench.swt;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.eclipse.core.expressions.ICountable;
import org.eclipse.core.expressions.IIterable;
import org.eclipse.core.runtime.IAdapterFactory;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
/**
* Adapts ISelection instances to either IIterable or ICountable. For use with
* core expressions.
*
* @since 3.3
*/
public class SelectionAdapterFactory implements IAdapterFactory {
private static final ICountable ICOUNT_0 = () -> 0;
private static final ICountable ICOUNT_1 = () -> 1;
private static final IIterable<?> ITERATE_EMPTY = () -> Collections.emptyList().iterator();
/**
* The classes we can adapt to.
*/
private static final Class<?>[] CLASSES = new Class[] { IIterable.class, ICountable.class };
@Override
public <T> T getAdapter(Object adaptableObject, Class<T> adapterType) {
if (adaptableObject instanceof ISelection) {
if (adapterType == IIterable.class) {
return adapterType.cast(iterable((ISelection) adaptableObject));
} else if (adapterType == ICountable.class) {
return adapterType.cast(countable((ISelection) adaptableObject));
}
}
return null;
}
private IIterable<?> iterable(final ISelection sel) {
if (sel.isEmpty()) {
return ITERATE_EMPTY;
}
if (sel instanceof IStructuredSelection) {
return ((IStructuredSelection) sel)::iterator;
}
final List<Object> list = Arrays.asList(new Object[] { sel });
return list::iterator;
}
private ICountable countable(final ISelection sel) {
if (sel.isEmpty()) {
return ICOUNT_0;
}
if (sel instanceof IStructuredSelection) {
final IStructuredSelection ss = (IStructuredSelection) sel;
return ss::size;
}
return ICOUNT_1;
}
@Override
public Class<?>[] getAdapterList() {
return CLASSES;
}
}