org.apache.mahout.math.random.WeightedThing.java Source code

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Here is the source code for org.apache.mahout.math.random.WeightedThing.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.mahout.math.random;

import com.google.common.base.Preconditions;
import org.apache.mahout.common.RandomUtils;

/**
 * Handy for creating multinomial distributions of things.
 */
public final class WeightedThing<T> implements Comparable<WeightedThing<T>> {
    private double weight;
    private final T value;

    public WeightedThing(T thing, double weight) {
        this.value = Preconditions.checkNotNull(thing);
        this.weight = weight;
    }

    public WeightedThing(double weight) {
        this.value = null;
        this.weight = weight;
    }

    public T getValue() {
        return value;
    }

    public double getWeight() {
        return weight;
    }

    public void setWeight(double weight) {
        this.weight = weight;
    }

    @Override
    public int compareTo(WeightedThing<T> other) {
        return Double.compare(this.weight, other.weight);
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof WeightedThing) {
            @SuppressWarnings("unchecked")
            WeightedThing<T> other = (WeightedThing<T>) o;
            return weight == other.weight && value.equals(other.value);
        }
        return false;
    }

    @Override
    public int hashCode() {
        return 31 * RandomUtils.hashDouble(weight) + value.hashCode();
    }
}