| /** |
| * 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.lib; |
| |
| import java.util.Map; |
| import java.util.LinkedHashMap; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.metrics2.MetricsInfo; |
| import org.apache.hadoop.metrics2.MetricsTag; |
| |
| /** |
| * Helpers to create interned metrics info |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| public class Interns { |
| private static final Log LOG = LogFactory.getLog(Interns.class); |
| |
| // A simple intern cache with two keys |
| // (to avoid creating new (combined) key objects for lookup) |
| private static abstract class CacheWith2Keys<K1, K2, V> { |
| private final Map<K1, Map<K2, V>> k1Map = |
| new LinkedHashMap<K1, Map<K2, V>>() { |
| private static final long serialVersionUID = 1L; |
| private boolean gotOverflow = false; |
| @Override |
| protected boolean removeEldestEntry(Map.Entry<K1, Map<K2, V>> e) { |
| boolean overflow = expireKey1At(size()); |
| if (overflow && !gotOverflow) { |
| LOG.warn("Metrics intern cache overflow at "+ size() +" for "+ e); |
| gotOverflow = true; |
| } |
| return overflow; |
| } |
| }; |
| |
| abstract protected boolean expireKey1At(int size); |
| abstract protected boolean expireKey2At(int size); |
| abstract protected V newValue(K1 k1, K2 k2); |
| |
| synchronized V add(K1 k1, K2 k2) { |
| Map<K2, V> k2Map = k1Map.get(k1); |
| if (k2Map == null) { |
| k2Map = new LinkedHashMap<K2, V>() { |
| private static final long serialVersionUID = 1L; |
| private boolean gotOverflow = false; |
| @Override protected boolean removeEldestEntry(Map.Entry<K2, V> e) { |
| boolean overflow = expireKey2At(size()); |
| if (overflow && !gotOverflow) { |
| LOG.warn("Metrics intern cache overflow at "+ size() +" for "+ e); |
| gotOverflow = true; |
| } |
| return overflow; |
| } |
| }; |
| k1Map.put(k1, k2Map); |
| } |
| V v = k2Map.get(k2); |
| if (v == null) { |
| v = newValue(k1, k2); |
| k2Map.put(k2, v); |
| } |
| return v; |
| } |
| } |
| |
| // Sanity limits in case of misuse/abuse. |
| static final int MAX_INFO_NAMES = 2010; |
| static final int MAX_INFO_DESCS = 100; // distinct per name |
| |
| enum Info { |
| INSTANCE; |
| |
| final CacheWith2Keys<String, String, MetricsInfo> cache = |
| new CacheWith2Keys<String, String, MetricsInfo>() { |
| |
| @Override protected boolean expireKey1At(int size) { |
| return size > MAX_INFO_NAMES; |
| } |
| |
| @Override protected boolean expireKey2At(int size) { |
| return size > MAX_INFO_DESCS; |
| } |
| |
| @Override protected MetricsInfo newValue(String name, String desc) { |
| return new MetricsInfoImpl(name, desc); |
| } |
| }; |
| } |
| |
| /** |
| * Get a metric info object |
| * @param name |
| * @param description |
| * @return an interned metric info object |
| */ |
| public static MetricsInfo info(String name, String description) { |
| return Info.INSTANCE.cache.add(name, description); |
| } |
| |
| // Sanity limits |
| static final int MAX_TAG_NAMES = 100; |
| static final int MAX_TAG_VALUES = 1000; // distinct per name |
| |
| enum Tags { |
| INSTANCE; |
| |
| final CacheWith2Keys<MetricsInfo, String, MetricsTag> cache = |
| new CacheWith2Keys<MetricsInfo, String, MetricsTag>() { |
| |
| @Override protected boolean expireKey1At(int size) { |
| return size > MAX_TAG_NAMES; |
| } |
| |
| @Override protected boolean expireKey2At(int size) { |
| return size > MAX_TAG_VALUES; |
| } |
| |
| @Override protected MetricsTag newValue(MetricsInfo info, String value) { |
| return new MetricsTag(info, value); |
| } |
| }; |
| } |
| |
| /** |
| * Get a metrics tag |
| * @param info of the tag |
| * @param value of the tag |
| * @return an interned metrics tag |
| */ |
| public static MetricsTag tag(MetricsInfo info, String value) { |
| return Tags.INSTANCE.cache.add(info, value); |
| } |
| |
| /** |
| * Get a metrics tag |
| * @param name of the tag |
| * @param description of the tag |
| * @param value of the tag |
| * @return an interned metrics tag |
| */ |
| public static MetricsTag tag(String name, String description, String value) { |
| return Tags.INSTANCE.cache.add(info(name, description), value); |
| } |
| } |