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reactive4java developed by David Karnok
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/*
 * Copyright 2011-2013 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 hu.akarnokd.reactive4java.base;

import java.text.SimpleDateFormat;
import java.util.Date;

import javax.annotation.Nonnull;

// #GWT-ACCEPT-START
//import com.google.gwt.i18n.client.DateTimeFormat;
// #GWT-ACCEPT-END
/**
 * An immutable record holding a value and timestamp pairs.
 * @author akarnokd, 2011.01.29.
 * @param  the contained type
 */
public final class Timestamped implements Comparable> {
    /** The value. */
    private final T value;
    /** The timestamp. */
    private final long timestamp;
    /**
     * Construct a new timestamped value.
     * @param value the value
     * @param timestamp the timestamp
     */
    public Timestamped(T value, long timestamp) {
        this.value = value;
        this.timestamp = timestamp;
    }
    /** @return the contained value */
    public T value() {
        return value;
    }
    /** @return the associated timestamp. */
    public long timestamp() {
        return timestamp;
    }
    /**
     * A type inference helper to construct a new timestamped value.
     * @param  the type of the value
     * @param value the value
     * @param timestamp the timestamp
     * @return the timestamped object
     */
    @Nonnull
    public static  Timestamped of(T value, long timestamp) {
        return new Timestamped(value, timestamp);
    }
    /**
     * A type inference helper to construct a new timestamped value from another
     * timestamped value by keeping the value and assigning a new value.
     * @param  the type of the value
     * @param value the value
     * @param timestamp the timestamp
     * @return the timestamped object
     */
    @Nonnull
    public static  Timestamped of(
            @Nonnull Timestamped value,
            long timestamp) {
        return new Timestamped(value.value(), timestamp);
    }
    /**
     * A type inference helper to construct a new timestamped value where the timestamp
     * is the System.currentTimeMillis().
     * @param  the type of the value
     * @param value the value
     * @return the timestamped object
     */
    @Nonnull
    public static  Timestamped of(T value) {
        return of(value, System.currentTimeMillis());
    }
    /**
     * A type inference helper to construct a new timestamped value from another timestamped value
     * where the new timestamp is the System.currentTimeMillis().
     * @param  the type of the value
     * @param value the value
     * @return the timestamped object
     */
    public static  Timestamped of(
            @Nonnull Timestamped value) {
        return of(value, System.currentTimeMillis());
    }
    @Override
    public String toString() {
        // #GWT-IGNORE-START
        return value + " @ " + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date(timestamp));
        // #GWT-IGNORE-END
        // #GWT-ACCEPT-START
        //return DateTimeFormat.getFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date(timestamp));
        // #GWT-ACCEPT-END
    }
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Timestamped) {
            Timestamped that = (Timestamped)obj;
            return (this.value == that.value || (this.value != null && this.value.equals(that.value)))
            && this.timestamp == that.timestamp;
        }
        return false;
    }
    @Override
    public int hashCode() {
        return (17 + (value != null ? value.hashCode() : 0)) * 31 + (int)((timestamp >> 32) ^ (timestamp & 0xFFFFFFFFL));
    }
    @Override
    public int compareTo(Timestamped that) {
        long t1 = this.timestamp();
        long t2 = that.timestamp();
        return t1 < t2 ? -1 : (t1 == t2) ? 0 : 1;
    }
}