Java tutorial
/** * 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.drill.exec.ops; import io.netty.buffer.DrillBuf; import java.io.IOException; import java.security.PrivilegedExceptionAction; import java.util.concurrent.Callable; import java.util.concurrent.ExecutorService; import org.apache.drill.common.exceptions.DrillRuntimeException; import org.apache.drill.exec.exception.OutOfMemoryException; import org.apache.drill.exec.memory.BufferAllocator; import org.apache.drill.exec.physical.base.PhysicalOperator; import org.apache.drill.exec.store.dfs.DrillFileSystem; import org.apache.drill.exec.testing.ExecutionControls; import org.apache.drill.exec.work.WorkManager; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.security.UserGroupInformation; import com.google.common.base.Preconditions; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; class OperatorContextImpl extends OperatorContext implements AutoCloseable { static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(OperatorContextImpl.class); private final BufferAllocator allocator; private final ExecutionControls executionControls; private boolean closed = false; private final PhysicalOperator popConfig; private final OperatorStats stats; private final BufferManager manager; private DrillFileSystem fs; private final ExecutorService executor; /** * This lazily initialized executor service is used to submit a {@link Callable task} that needs a proxy user. There * is no pool that is created; this pool is a decorator around {@link WorkManager#executor the worker pool} that * returns a {@link ListenableFuture future} for every task that is submitted. For the shutdown sequence, * see {@link WorkManager#close}. */ private ListeningExecutorService delegatePool; public OperatorContextImpl(PhysicalOperator popConfig, FragmentContext context) throws OutOfMemoryException { this.allocator = context.getNewChildAllocator(popConfig.getClass().getSimpleName(), popConfig.getOperatorId(), popConfig.getInitialAllocation(), popConfig.getMaxAllocation()); this.popConfig = popConfig; this.manager = new BufferManagerImpl(allocator); OpProfileDef def = new OpProfileDef(popConfig.getOperatorId(), popConfig.getOperatorType(), getChildCount(popConfig)); stats = context.getStats().newOperatorStats(def, allocator); executionControls = context.getExecutionControls(); executor = context.getDrillbitContext().getExecutor(); } public OperatorContextImpl(PhysicalOperator popConfig, FragmentContext context, OperatorStats stats) throws OutOfMemoryException { this.allocator = context.getNewChildAllocator(popConfig.getClass().getSimpleName(), popConfig.getOperatorId(), popConfig.getInitialAllocation(), popConfig.getMaxAllocation()); this.popConfig = popConfig; this.manager = new BufferManagerImpl(allocator); this.stats = stats; executionControls = context.getExecutionControls(); executor = context.getDrillbitContext().getExecutor(); } public DrillBuf replace(DrillBuf old, int newSize) { return manager.replace(old, newSize); } public DrillBuf getManagedBuffer() { return manager.getManagedBuffer(); } public DrillBuf getManagedBuffer(int size) { return manager.getManagedBuffer(size); } public ExecutionControls getExecutionControls() { return executionControls; } public BufferAllocator getAllocator() { if (allocator == null) { throw new UnsupportedOperationException("Operator context does not have an allocator"); } return allocator; } public boolean isClosed() { return closed; } @Override public void close() { if (closed) { logger.debug("Attempted to close Operator context for {}, but context is already closed", popConfig != null ? popConfig.getClass().getName() : null); return; } logger.debug("Closing context for {}", popConfig != null ? popConfig.getClass().getName() : null); manager.close(); if (allocator != null) { allocator.close(); } if (fs != null) { try { fs.close(); } catch (IOException e) { throw new DrillRuntimeException(e); } } closed = true; } public OperatorStats getStats() { return stats; } public <RESULT> ListenableFuture<RESULT> runCallableAs(final UserGroupInformation proxyUgi, final Callable<RESULT> callable) { synchronized (this) { if (delegatePool == null) { delegatePool = MoreExecutors.listeningDecorator(executor); } } return delegatePool.submit(new Callable<RESULT>() { @Override public RESULT call() throws Exception { final Thread currentThread = Thread.currentThread(); final String originalThreadName = currentThread.getName(); currentThread.setName(proxyUgi.getUserName() + ":task-delegate-thread"); final RESULT result; try { result = proxyUgi.doAs(new PrivilegedExceptionAction<RESULT>() { @Override public RESULT run() throws Exception { return callable.call(); } }); } finally { currentThread.setName(originalThreadName); } return result; } }); } @Override public DrillFileSystem newFileSystem(Configuration conf) throws IOException { Preconditions.checkState(fs == null, "Tried to create a second FileSystem. Can only be called once per OperatorContext"); fs = new DrillFileSystem(conf, getStats()); return fs; } }