com.google.appengine.tools.mapreduce.MockClock.java Source code

Introduction

Here is the source code for com.google.appengine.tools.mapreduce.MockClock.java

Source

/*
 * Copyright 2010 Google Inc.
 *
 * 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.appengine.tools.mapreduce;

import com.google.appengine.tools.mapreduce.util.Clock;
import com.google.common.base.Preconditions;

import java.util.Arrays;
import java.util.List;

/**
 * Mock clock that returns a predefined sequence of times.
 *
 * Package visible because it's a utility class for mapreduce.
 *
 *
 */
public class MockClock implements Clock {
    private List<Long> times;
    private int currentOffset = 0;
    private boolean repeatLastTime;

    /**
     * Makes the clock return the given time repeatedly.
     */
    public MockClock(long time) {
        times = Arrays.asList(new Long(time));
        repeatLastTime = true;
    }

    /**
     * Initializes a clock that returns a sequence of predefined times.
     *
     * @param times the sequence of times to return
     * @param repeatLastTime defines the behavior if more than times.sizes() calls
     * to {@link #currentTimeMillis()} are made. If true, then the last time
     * is repeatedly returned. Otherwise, an exception is thrown.
     */
    public MockClock(List<Long> times, boolean repeatLastTime) {
        this.times = times;
        this.repeatLastTime = repeatLastTime;
    }

    /**
     * Returns the next time in the sequence.
     */
    @Override
    public long currentTimeMillis() {
        Preconditions.checkNotNull(times);
        Preconditions.checkState(times.size() > 0);
        Preconditions.checkElementIndex(currentOffset, times.size());

        long timeToReturn = times.get(currentOffset).longValue();

        if (!repeatLastTime || currentOffset < times.size() - 1) {
            currentOffset++;
        }

        return timeToReturn;
    }
}