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ixjava developed by David Karnok

There is a newer version: 1.0.0

/*
 * Copyright 2011-2016 David Karnok
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ix;

import java.util.Iterator;

/**
 * Suppress or throw when the remove() is called.
 *
 * @param  the value type
 */
final class IxReadOnly extends IxSource {

    final boolean silent;

    IxReadOnly(Iterable source, boolean silent) {
        super(source);
        this.silent = silent;
    }

    @Override
    public Iterator iterator() {
        if (silent) {
            return new ReadOnlySilentIterator(source.iterator());
        }
        return new ReadOnlyThrowingIterator(source.iterator());
    }

    static final class ReadOnlySilentIterator implements Iterator {

        final Iterator source;

        ReadOnlySilentIterator(Iterator source) {
            this.source = source;
        }

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

        @Override
        public T next() {
            return source.next();
        }

        @Override
        public void remove() {
            // deliberately ignored
        }
    }

    static final class ReadOnlyThrowingIterator implements Iterator {

        final Iterator source;

        ReadOnlyThrowingIterator(Iterator source) {
            this.source = source;
        }

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

        @Override
        public T next() {
            return source.next();
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException();
        }
    }
}