de.unentscheidbar.validation.internal.Collections3.java Source code

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Here is the source code for de.unentscheidbar.validation.internal.Collections3.java

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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2009 Sun Microsystems, Inc. All rights reserved. Portions Copyrighted 2012 Daniel
 * Huss.
 * 
 * The contents of this file are subject to the terms of either the GNU General Public License
 * Version 2 only ("GPL") or the Common Development and Distribution License("CDDL") (collectively,
 * the "License"). You may not use this file except in compliance with the License. You can obtain a
 * copy of the License at http://www.netbeans.org/cddl-gplv2.html or nbbuild/licenses/CDDL-GPL-2-CP.
 * See the License for the specific language governing permissions and limitations under the
 * License. When distributing the software, include this License Header Notice in each file and
 * include the License file at nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this particular file
 * as subject to the "Classpath" exception as provided by Sun in the GPL Version 2 section of the
 * License file that accompanied this code. If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyrighted [year] [name of copyright owner]"
 * 
 * Contributor(s):
 * 
 * The Original Software is NetBeans. The Initial Developer of the Original Software is Sun
 * Microsystems, Inc. Portions Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * If you wish your version of this file to be governed by only the CDDL or only the GPL Version 2,
 * indicate your decision by adding "[Contributor] elects to include this software in this
 * distribution under the [CDDL or GPL Version 2] license." If you do not indicate a single choice
 * of license, a recipient has the option to distribute your version of this file under either the
 * CDDL, the GPL Version 2 or to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL Version 2 license, then the
 * option applies only if the new code is made subject to such option by the copyright holder.
 */
package de.unentscheidbar.validation.internal;

import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;

import javax.annotation.Nullable;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultiset;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Multiset;

import de.unentscheidbar.validation.swing.Validation;

public final class Collections3 implements Serializable {

    private static final long serialVersionUID = Validation.VERSION;

    /**
     * Returns an immutable version of the given collection and tries to preserve any special
     * properties of that collection. Lists are converted to immutable lists, Sets are converted to
     * immutable sets, sorted sets to immutable sorted sets, etc.
     * <p>
     * If the specialization of the given collection is not recognized, it is converted to an
     * immutable list.
     * </p>
     * 
     * @param c
     *            The collection that
     * @return An immutable version of the given collection or {@code null} iff {@code c} was
     *         {@code null}.
     */
    public static <C> Collection<C> immutableCopyOf(@Nullable Collection<C> c) {

        if (c == null)
            return null;
        /* Most common cases first */
        if (c instanceof List<?>) {
            return ImmutableList.copyOf(c);
        } else if (c instanceof Set<?>) {
            return ImmutableSet.copyOf(c);
        } else if (c instanceof SortedSet<?>) {
            return ImmutableSortedSet.copyOf(c);
        } else if (c instanceof Multiset<?>) {
            return ImmutableMultiset.copyOf(c);
        } else {
            return ImmutableList.copyOf(c);
        }
    }

    private Collections3() {

        /* Do not instantiate */
    }

}