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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.*;

final class IxUnion extends IxSource {

    final Iterable other;

    IxUnion(Iterable source, Iterable other) {
        super(source);
        this.other = other;
    }

    @Override
    public Iterator iterator() {
        return new UnionIterator(source.iterator(), other.iterator());
    }

    static final class UnionIterator extends IxSourceIterator {

        final Iterator other;

        final Set set;

        boolean second;

        UnionIterator(Iterator it, Iterator other) {
            super(it);
            this.other = other;
            this.set = new HashSet();
        }

        @Override
        protected boolean moveNext() {
            Set set = this.set;
            for (;;) {
                if (second) {
                    Iterator other = this.other;
                    while (other.hasNext()) {
                        T v = other.next();
                        if (set.add(v)) {
                            value = v;
                            hasValue = true;
                            return true;
                        }
                    }

                    done = true;
                    return false;
                }

                Iterator it = this.it;
                while (it.hasNext()) {
                    T v = it.next();
                    if (set.add(v)) {
                        value = v;
                        hasValue = true;
                        return true;
                    }
                }

                second = true;
            }
        }
    }
}