1 files changed, 184 insertions, 0 deletions
diff --git a/sql/hive-thriftserver/src/main/java/org/apache/hive/service/AbstractService.java b/sql/hive-thriftserver/src/main/java/org/apache/hive/service/AbstractService.java
new file mode 100644
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+++ b/sql/hive-thriftserver/src/main/java/org/apache/hive/service/AbstractService.java
@@ -0,0 +1,184 @@
+/**
+ * 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.hive.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hive.conf.HiveConf;
+
+/**
+ * AbstractService.
+ *
+ */
+public abstract class AbstractService implements Service {
+
+  private static final Log LOG = LogFactory.getLog(AbstractService.class);
+
+  /**
+   * Service state: initially {@link STATE#NOTINITED}.
+   */
+  private STATE state = STATE.NOTINITED;
+
+  /**
+   * Service name.
+   */
+  private final String name;
+  /**
+   * Service start time. Will be zero until the service is started.
+   */
+  private long startTime;
+
+  /**
+   * The configuration. Will be null until the service is initialized.
+   */
+  private HiveConf hiveConf;
+
+  /**
+   * List of state change listeners; it is final to ensure
+   * that it will never be null.
+   */
+  private final List<ServiceStateChangeListener> listeners =
+      new ArrayList<ServiceStateChangeListener>();
+
+  /**
+   * Construct the service.
+   *
+   * @param name
+   *          service name
+   */
+  public AbstractService(String name) {
+    this.name = name;
+  }
+
+  @Override
+  public synchronized STATE getServiceState() {
+    return state;
+  }
+
+  /**
+   * {@inheritDoc}
+   *
+   * @throws IllegalStateException
+   *           if the current service state does not permit
+   *           this action
+   */
+  @Override
+  public synchronized void init(HiveConf hiveConf) {
+    ensureCurrentState(STATE.NOTINITED);
+    this.hiveConf = hiveConf;
+    changeState(STATE.INITED);
+    LOG.info("Service:" + getName() + " is inited.");
+  }
+
+  /**
+   * {@inheritDoc}
+   *
+   * @throws IllegalStateException
+   *           if the current service state does not permit
+   *           this action
+   */
+  @Override
+  public synchronized void start() {
+    startTime = System.currentTimeMillis();
+    ensureCurrentState(STATE.INITED);
+    changeState(STATE.STARTED);
+    LOG.info("Service:" + getName() + " is started.");
+  }
+
+  /**
+   * {@inheritDoc}
+   *
+   * @throws IllegalStateException
+   *           if the current service state does not permit
+   *           this action
+   */
+  @Override
+  public synchronized void stop() {
+    if (state == STATE.STOPPED ||
+        state == STATE.INITED ||
+        state == STATE.NOTINITED) {
+      // already stopped, or else it was never
+      // started (eg another service failing canceled startup)
+      return;
+    }
+    ensureCurrentState(STATE.STARTED);
+    changeState(STATE.STOPPED);
+    LOG.info("Service:" + getName() + " is stopped.");
+  }
+
+  @Override
+  public synchronized void register(ServiceStateChangeListener l) {
+    listeners.add(l);
+  }
+
+  @Override
+  public synchronized void unregister(ServiceStateChangeListener l) {
+    listeners.remove(l);
+  }
+
+  @Override
+  public String getName() {
+    return name;
+  }
+
+  @Override
+  public synchronized HiveConf getHiveConf() {
+    return hiveConf;
+  }
+
+  @Override
+  public long getStartTime() {
+    return startTime;
+  }
+
+  /**
+   * Verify that that a service is in a given state.
+   *
+   * @param currentState
+   *          the desired state
+   * @throws IllegalStateException
+   *           if the service state is different from
+   *           the desired state
+   */
+  private void ensureCurrentState(STATE currentState) {
+    ServiceOperations.ensureCurrentState(state, currentState);
+  }
+
+  /**
+   * Change to a new state and notify all listeners.
+   * This is a private method that is only invoked from synchronized methods,
+   * which avoid having to clone the listener list. It does imply that
+   * the state change listener methods should be short lived, as they
+   * will delay the state transition.
+   *
+   * @param newState
+   *          new service state
+   */
+  private void changeState(STATE newState) {
+    state = newState;
+    // notify listeners
+    for (ServiceStateChangeListener l : listeners) {
+      l.stateChanged(this);
+    }
+  }
+
+}