de.dhke.projects.cutil.collections.immutable.ImmutableIterator.java Source code

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Here is the source code for de.dhke.projects.cutil.collections.immutable.ImmutableIterator.java

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/**
 * (c) 2009-2014 Peter Wullinger
 *
 * $Id$
 *
 * Use, modification and restribution of this file are covered by the
 * terms of the Artistic License 2.0.
 *
 * You should have received a copy of the license terms in a file named
 * "LICENSE" together with this software package.
 *
 * Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT
 * HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
 * A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE
 * EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO
 * COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT
 * OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 **/
package de.dhke.projects.cutil.collections.immutable;

import de.dhke.projects.cutil.IDecorator;
import java.util.Iterator;
import org.apache.commons.collections15.Transformer;

public class ImmutableIterator<T> implements Iterator<T>, IDecorator<Iterator<T>> {
    private final Iterator<T> _baseIter;
    private final Transformer<T, T> _valueTransformer;

    public ImmutableIterator(final Iterator<T> baseIter, final Transformer<T, T> valueTransformer) {
        _baseIter = baseIter;
        _valueTransformer = valueTransformer;
    }

    @Override
    public Iterator<T> getDecoratee() {
        return _baseIter;
    }

    public static <T> ImmutableIterator<T> decorate(final Iterator<T> baseIter) {
        return new ImmutableIterator<>(baseIter, null);
    }

    public static <T> ImmutableIterator<T> decorate(final Iterator<T> baseIter,
            final Transformer<T, T> valueTransformer) {
        return new ImmutableIterator<>(baseIter, valueTransformer);
    }

    @Override
    public boolean hasNext() {
        return _baseIter.hasNext();
    }

    @Override
    public T next() {
        if (_valueTransformer == null)
            return _baseIter.next();
        else
            return _valueTransformer.transform(_baseIter.next());
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("Cannot modify ImmutableIterator.");
    }
}