| /* |
| * 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.iceberg; |
| |
| import java.io.Closeable; |
| import java.util.ArrayDeque; |
| import java.util.Deque; |
| import org.apache.iceberg.relocated.com.google.common.base.Preconditions; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public abstract class ClientPoolImpl<C, E extends Exception> |
| implements Closeable, ClientPool<C, E> { |
| private static final Logger LOG = LoggerFactory.getLogger(ClientPoolImpl.class); |
| |
| private final int poolSize; |
| private final Deque<C> clients; |
| private final Class<? extends E> reconnectExc; |
| private final Object signal = new Object(); |
| private final boolean retryByDefault; |
| private volatile int currentSize; |
| private boolean closed; |
| |
| public ClientPoolImpl(int poolSize, Class<? extends E> reconnectExc, boolean retryByDefault) { |
| this.poolSize = poolSize; |
| this.reconnectExc = reconnectExc; |
| this.clients = new ArrayDeque<>(poolSize); |
| this.currentSize = 0; |
| this.closed = false; |
| this.retryByDefault = retryByDefault; |
| } |
| |
| @Override |
| public <R> R run(Action<R, C, E> action) throws E, InterruptedException { |
| return run(action, retryByDefault); |
| } |
| |
| @Override |
| public <R> R run(Action<R, C, E> action, boolean retry) throws E, InterruptedException { |
| C client = get(); |
| try { |
| return action.run(client); |
| |
| } catch (Exception exc) { |
| if (retry && isConnectionException(exc)) { |
| try { |
| client = reconnect(client); |
| } catch (Exception ignored) { |
| // if reconnection throws any exception, rethrow the original failure |
| throw reconnectExc.cast(exc); |
| } |
| |
| return action.run(client); |
| } |
| |
| throw exc; |
| |
| } finally { |
| release(client); |
| } |
| } |
| |
| protected abstract C newClient(); |
| |
| protected abstract C reconnect(C client); |
| |
| protected boolean isConnectionException(Exception exc) { |
| return reconnectExc.isInstance(exc); |
| } |
| |
| protected abstract void close(C client); |
| |
| @Override |
| public void close() { |
| this.closed = true; |
| try { |
| while (currentSize > 0) { |
| if (!clients.isEmpty()) { |
| synchronized (this) { |
| if (!clients.isEmpty()) { |
| C client = clients.removeFirst(); |
| close(client); |
| currentSize -= 1; |
| } |
| } |
| } |
| if (clients.isEmpty() && currentSize > 0) { |
| // wake every second in case this missed the signal |
| synchronized (signal) { |
| signal.wait(1000); |
| } |
| } |
| } |
| |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| LOG.warn("Interrupted while shutting down pool. Some clients may not be closed.", e); |
| } |
| } |
| |
| private C get() throws InterruptedException { |
| Preconditions.checkState(!closed, "Cannot get a client from a closed pool"); |
| while (true) { |
| if (!clients.isEmpty() || currentSize < poolSize) { |
| synchronized (this) { |
| if (!clients.isEmpty()) { |
| return clients.removeFirst(); |
| } else if (currentSize < poolSize) { |
| C client = newClient(); |
| currentSize += 1; |
| return client; |
| } |
| } |
| } |
| synchronized (signal) { |
| // wake every second in case this missed the signal |
| signal.wait(1000); |
| } |
| } |
| } |
| |
| private void release(C client) { |
| synchronized (this) { |
| clients.addFirst(client); |
| } |
| synchronized (signal) { |
| signal.notify(); |
| } |
| } |
| |
| public int poolSize() { |
| return poolSize; |
| } |
| |
| public boolean isClosed() { |
| return closed; |
| } |
| } |