org.apache.hadoop.metrics2.AbstractMetric.java Source code

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Here is the source code for org.apache.hadoop.metrics2.AbstractMetric.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.hadoop.metrics2;

import com.google.common.base.Objects;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

import java.util.StringJoiner;

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

/**
 * The immutable metric
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public abstract class AbstractMetric implements MetricsInfo {
    private final MetricsInfo info;

    /**
     * Construct the metric
     * @param info  about the metric
     */
    protected AbstractMetric(MetricsInfo info) {
        this.info = checkNotNull(info, "metric info");
    }

    @Override
    public String name() {
        return info.name();
    }

    @Override
    public String description() {
        return info.description();
    }

    protected MetricsInfo info() {
        return info;
    }

    /**
     * Get the value of the metric
     * @return the value of the metric
     */
    public abstract Number value();

    /**
     * Get the type of the metric
     * @return the type of the metric
     */
    public abstract MetricType type();

    /**
     * Accept a visitor interface
     * @param visitor of the metric
     */
    public abstract void visit(MetricsVisitor visitor);

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof AbstractMetric) {
            final AbstractMetric other = (AbstractMetric) obj;
            return Objects.equal(info, other.info()) && Objects.equal(value(), other.value());
        }
        return false;
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(info, value());
    }

    @Override
    public String toString() {
        return new StringJoiner(", ", this.getClass().getSimpleName() + "{", "}").add("info=" + info)
                .add("value=" + value()).toString();
    }
}