com.google.common.collect.ConsumingQueueIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of guava Show documentation

Builds the guava lib. Requires the jsr305 be built first.

There is a newer version: 33.3.0-jre-r3

/*
 * Copyright (C) 2015 The Guava Authors
 *
 * 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.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An Iterator implementation which draws elements from a queue, removing them from the queue as it
 * iterates. This class is not thread safe.
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class ConsumingQueueIterator extends AbstractIterator {
  private final Queue queue;

  ConsumingQueueIterator(Queue queue) {
    this.queue = checkNotNull(queue);
  }

  @Override
  @CheckForNull
  protected T computeNext() {
    // TODO(b/192579700): Use a ternary once it no longer confuses our nullness checker.
    if (queue.isEmpty()) {
      return endOfData();
    }
    return queue.remove();
  }
}