com.rcpcompany.uibindings.utils.SelectionUtils.java Source code

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Here is the source code for com.rcpcompany.uibindings.utils.SelectionUtils.java

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/*******************************************************************************
 * Copyright (c) 2006-2013 The RCP Company 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:
 *     The RCP Company - initial API and implementation
 *******************************************************************************/
package com.rcpcompany.uibindings.utils;

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

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;

/**
 * A number of utility methods used to manage selections.
 * 
 * @author Tonny Madsen, The RCP Company
 */
public final class SelectionUtils {
    private SelectionUtils() {
    }

    private static final List EMPTY_LIST = new ArrayList();

    /**
     * Computes and returns a list with the objects of the selection that are - or can adapt to -
     * the specified base class.
     * 
     * @param <T> the type of the baseClass
     * @param selection the selection to handle
     * @param baseClass the wanted base class
     * @return a list with the found objects
     */
    public static <T> List<T> computeSelection(ISelection selection, Class<T> baseClass) {
        if (!(selection instanceof IStructuredSelection))
            return EMPTY_LIST;
        final IStructuredSelection ss = (IStructuredSelection) selection;
        List<T> list = null;
        for (final Iterator e = ss.iterator(); e.hasNext();) {
            final Object next = e.next();
            T c = (T) Platform.getAdapterManager().getAdapter(next, baseClass);
            if (c != null) {
                // OK
            } else if (baseClass.isInstance(next)) {
                c = (T) next;
            } else if (next instanceof IAdaptable) {
                c = (T) ((IAdaptable) next).getAdapter(baseClass);
            }
            if (c != null) {
                if (list == null) {
                    list = new ArrayList<T>(ss.size());
                }
                list.add(c);
            }
        }
        if (list == null)
            return EMPTY_LIST;
        return list;
    }
}