| /* |
| * 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.cassandra.io.sstable; |
| |
| import java.util.Objects; |
| import java.util.function.Function; |
| |
| import com.google.common.collect.Iterables; |
| |
| import com.codahale.metrics.Gauge; |
| import org.apache.cassandra.db.ColumnFamilyStore; |
| import org.apache.cassandra.db.Keyspace; |
| import org.apache.cassandra.io.sstable.format.SSTableReader; |
| |
| public class SimpleGaugeProvider<T extends Number, R extends SSTableReader> extends GaugeProvider<T> |
| { |
| private final Function<SSTableReader, R> mapper; |
| private final Function<Iterable<R>, T> combiner; |
| |
| public SimpleGaugeProvider(Function<SSTableReader, R> mapper, String name, Function<Iterable<R>, T> combiner) |
| { |
| super(name); |
| this.mapper = mapper; |
| this.combiner = combiner; |
| } |
| |
| @Override |
| public Gauge<T> getTableGauge(ColumnFamilyStore cfs) |
| { |
| return () -> combine(cfs.getLiveSSTables()); |
| } |
| |
| @Override |
| public Gauge<T> getKeyspaceGauge(Keyspace keyspace) |
| { |
| return () -> combine(getAllReaders(keyspace)); |
| } |
| |
| @Override |
| public Gauge<T> getGlobalGauge() |
| { |
| return () -> combine(Iterables.concat(Iterables.transform(Keyspace.all(), SimpleGaugeProvider::getAllReaders))); |
| } |
| |
| private T combine(Iterable<SSTableReader> allReaders) |
| { |
| Iterable<R> readers = Iterables.filter(Iterables.transform(allReaders, mapper::apply), Objects::nonNull); |
| return combiner.apply(readers); |
| } |
| |
| private static Iterable<SSTableReader> getAllReaders(Keyspace keyspace) |
| { |
| return Iterables.concat(Iterables.transform(keyspace.getColumnFamilyStores(), ColumnFamilyStore::getLiveSSTables)); |
| } |
| } |