org.apache.hadoop.hdfs.util.EnumCounters Maven / Gradle / Ivy
/**
* 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.hdfs.util;
import java.util.Arrays;
import java.util.HashMap;
import com.google.common.base.Preconditions;
import org.apache.commons.lang.ArrayUtils;
/**
* Counters for an enum type.
*
* For example, suppose there is an enum type
*
* enum Fruit { APPLE, ORANGE, GRAPE }
*
* An {@link EnumCounters} object can be created for counting the numbers of
* APPLE, ORANGLE and GRAPE.
*
* @param the enum type
*/
public class EnumCounters> {
/** The class of the enum. */
private final Class enumClass;
/** An array of longs corresponding to the enum type. */
private final long[] counters;
/**
* Construct counters for the given enum constants.
* @param enumClass the enum class of the counters.
*/
public EnumCounters(final Class enumClass) {
final E[] enumConstants = enumClass.getEnumConstants();
Preconditions.checkNotNull(enumConstants);
this.enumClass = enumClass;
this.counters = new long[enumConstants.length];
}
public EnumCounters(final Class enumClass, long defaultVal) {
final E[] enumConstants = enumClass.getEnumConstants();
Preconditions.checkNotNull(enumConstants);
this.enumClass = enumClass;
this.counters = new long[enumConstants.length];
reset(defaultVal);
}
/** @return the value of counter e. */
public final long get(final E e) {
return counters[e.ordinal()];
}
/** @return the values of counter as a shadow copy of array*/
public long[] asArray() {
return ArrayUtils.clone(counters);
}
/** Negate all counters. */
public final void negation() {
for(int i = 0; i < counters.length; i++) {
counters[i] = -counters[i];
}
}
/** Set counter e to the given value. */
public final void set(final E e, final long value) {
counters[e.ordinal()] = value;
}
/** Set this counters to that counters. */
public final void set(final EnumCounters that) {
for(int i = 0; i < counters.length; i++) {
this.counters[i] = that.counters[i];
}
}
/** Reset all counters to zero. */
public final void reset() {
reset(0L);
}
/** Add the given value to counter e. */
public final void add(final E e, final long value) {
counters[e.ordinal()] += value;
}
/** Add that counters to this counters. */
public final void add(final EnumCounters that) {
for(int i = 0; i < counters.length; i++) {
this.counters[i] += that.counters[i];
}
}
/** Subtract the given value from counter e. */
public final void subtract(final E e, final long value) {
counters[e.ordinal()] -= value;
}
/** Subtract this counters from that counters. */
public final void subtract(final EnumCounters that) {
for(int i = 0; i < counters.length; i++) {
this.counters[i] -= that.counters[i];
}
}
/** @return the sum of all counters. */
public final long sum() {
long sum = 0;
for(int i = 0; i < counters.length; i++) {
sum += counters[i];
}
return sum;
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
} else if (obj == null || !(obj instanceof EnumCounters)) {
return false;
}
final EnumCounters that = (EnumCounters)obj;
return this.enumClass == that.enumClass
&& Arrays.equals(this.counters, that.counters);
}
@Override
public int hashCode() {
return Arrays.hashCode(counters);
}
@Override
public String toString() {
final E[] enumConstants = enumClass.getEnumConstants();
final StringBuilder b = new StringBuilder();
for(int i = 0; i < counters.length; i++) {
final String name = enumConstants[i].name();
b.append(name).append("=").append(counters[i]).append(", ");
}
return b.substring(0, b.length() - 2);
}
public final void reset(long val) {
for(int i = 0; i < counters.length; i++) {
this.counters[i] = val;
}
}
public boolean allLessOrEqual(long val) {
for (long c : counters) {
if (c > val) {
return false;
}
}
return true;
}
public boolean anyGreaterOrEqual(long val) {
for (long c: counters) {
if (c >= val) {
return true;
}
}
return false;
}
/**
* A factory for creating counters.
*
* @param the enum type
* @param the counter type
*/
public static interface Factory,
C extends EnumCounters> {
/** Create a new counters instance. */
public C newInstance();
}
/**
* A key-value map which maps the keys to {@link EnumCounters}.
* Note that null key is supported.
*
* @param the key type
* @param the enum type
* @param the counter type
*/
public static class Map, C extends EnumCounters> {
/** The factory for creating counters. */
private final Factory factory;
/** Key-to-Counts map. */
private final java.util.Map counts = new HashMap();
/** Construct a map. */
public Map(final Factory factory) {
this.factory = factory;
}
/** @return the counters for the given key. */
public final C getCounts(final K key) {
C c = counts.get(key);
if (c == null) {
c = factory.newInstance();
counts.put(key, c);
}
return c;
}
/** @return the sum of the values of all the counters. */
public final C sum() {
final C sum = factory.newInstance();
for(C c : counts.values()) {
sum.add(c);
}
return sum;
}
/** @return the sum of the values of all the counters for e. */
public final long sum(final E e) {
long sum = 0;
for(C c : counts.values()) {
sum += c.get(e);
}
return sum;
}
@Override
public String toString() {
return counts.toString();
}
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy