com.github.hilcode.versionator.Zipper.java Source code

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Here is the source code for com.github.hilcode.versionator.Zipper.java

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/*
 * Copyright (C) 2016 H.C. Wijbenga
 *
 * 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 com.github.hilcode.versionator;

import java.util.Collection;
import java.util.Iterator;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

public final class Zipper<T> implements Iterable<Tuple._2<T, T>> {
    private final Collection<T> a;

    private final Collection<T> b;

    private Zipper(final Collection<T> a, final Collection<T> b) {
        Preconditions.checkNotNull(a, "Missing 'a'.");
        Preconditions.checkNotNull(b, "Missing 'b'.");
        this.a = a;
        this.b = b;
    }

    @Override
    public Iterator<Tuple._2<T, T>> iterator() {
        final ImmutableList.Builder<Tuple._2<T, T>> zipper = ImmutableList.builder();
        final Iterator<T> as = this.a.iterator();
        final Iterator<T> bs = this.b.iterator();
        while (as.hasNext() && bs.hasNext()) {
            final Tuple._2<T, T> tuple = new Tuple._2<>(as.next(), bs.next());
            zipper.add(tuple);
        }
        return zipper.build().iterator();
    }

    public interface Builder {
        <T> Zipper<T> zip(Collection<T> a, Collection<T> b);
    }

    public static final Zipper.Builder BUILDER = new Builder() {
        @Override
        public <T> Zipper<T> zip(final Collection<T> a, final Collection<T> b) {
            return new Zipper<>(a, b);
        }
    };
}