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@@ -52,24 +52,13 @@ import org.apache.zookeeper.proto.SetDataRequest;
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import org.apache.zookeeper.proto.SetDataResponse;
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import org.apache.zookeeper.proto.SyncRequest;
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import org.apache.zookeeper.proto.SyncResponse;
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-import org.apache.zookeeper.proto.WatcherEvent;
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import org.apache.zookeeper.server.DataTree;
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-import org.apache.zookeeper.Watcher.Event.EventType;
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-import org.apache.zookeeper.Watcher.Event.KeeperState;
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/**
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* This is the main class of ZooKeeper client library. To use a ZooKeeper
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* service, an application must first instantiate an object of ZooKeeper class.
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* All the iterations will be done by calling the methods of ZooKeeper class.
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* <p>
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- * To create a client(ZooKeeper) object, the application needs to pass a string
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- * containing a list of host:port pairs, each corresponding to a ZooKeeper
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- * server; a sessionTimeout; and an object of Watcher type.
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- * <p>
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- * The client object will pick an arbitrary server and try to connect to it. If
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- * failed, it will try the next one in the list, until a connection is
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- * established, or all the servers have been tried.
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- * <p>
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* Once a connection to a server is established, a session ID is assigned to the
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* client. The client will send heart beats to the server periodically to keep
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* the session valid.
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@@ -109,10 +98,10 @@ public class ZooKeeper {
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private static final Logger LOG = Logger.getLogger(ZooKeeper.class);
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private final ZKWatchManager watchManager = new ZKWatchManager();
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-
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+
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/**
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* Manage watchers & handle events generated by the ClientCnxn object.
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- *
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+ *
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* We are implementing this as a nested class of ZooKeeper so that
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* the public methods will not be exposed as part of the ZooKeeper client
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* API.
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@@ -128,10 +117,10 @@ public class ZooKeeper {
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/* (non-Javadoc)
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* @see org.apache.zookeeper.ClientWatchManager#materialize(Event.KeeperState, Event.EventType, java.lang.String)
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*/
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- public Set<Watcher> materialize(Watcher.Event.KeeperState state,
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+ public Set<Watcher> materialize(Watcher.Event.KeeperState state,
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Watcher.Event.EventType type, String path) {
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Set<Watcher> result = new HashSet<Watcher>();
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-
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+
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// clear the watches if we are not connected
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if (state != Watcher.Event.KeeperState.SyncConnected) {
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@@ -152,9 +141,9 @@ public class ZooKeeper {
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childWatches.clear();
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}
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}
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-
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+
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Set<Watcher> watchers = null;
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-
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+
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switch (type) {
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case None:
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result.add(defaultWatcher);
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@@ -192,7 +181,7 @@ public class ZooKeeper {
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LOG.error(msg);
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throw new RuntimeException(msg);
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}
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-
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+
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result.addAll(watchers);
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return result;
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}
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@@ -268,12 +257,46 @@ public class ZooKeeper {
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protected ClientCnxn cnxn;
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+ /**
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+ * @see ZooKeeper(String, int, Watcher, long, byte[])
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+ */
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public ZooKeeper(String host, int sessionTimeout, Watcher watcher)
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throws IOException {
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watchManager.defaultWatcher = watcher;
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cnxn = new ClientCnxn(host, sessionTimeout, this, watchManager);
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}
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+ /**
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+ * To create a client(ZooKeeper) object, the application needs to pass a
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+ * string containing a list of host:port pairs, each corresponding to a
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+ * ZooKeeper server.
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+ * <p>
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+ * The client object will pick an arbitrary server and try to connect to it.
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+ * If failed, it will try the next one in the list, until a connection is
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+ * established, or all the servers have been tried.
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+ * <p>
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+ * Use {@link #getSessionId} and {@link #getSessionPasswd} on an established
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+ * client connection, these values must be passed as sessionId and
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+ * sessionPasswd respectively if reconnecting. Otherwise, if not
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+ * reconnecting, use the other constructor which does not require these
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+ * parameters.
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+ *
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+ * @param host
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+ * comma separated host:port pairs, each corresponding to a zk
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+ * server. eg. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"
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+ * @param sessionTimeout
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+ * session timeout in milliseconds
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+ * @param watcher
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+ * a watcher object which will be notified of state changes, may
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+ * also be notified for node events
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+ * @param sessionId
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+ * specific session id to use if reconnecting
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+ * @param sessionPasswd
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+ * password for this session
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+ *
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+ * @throws IOException
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+ * in cases of network failure
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+ */
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public ZooKeeper(String host, int sessionTimeout, Watcher watcher,
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long sessionId, byte[] sessionPasswd) throws IOException {
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watchManager.defaultWatcher = watcher;
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@@ -282,16 +305,23 @@ public class ZooKeeper {
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}
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/**
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- * The session id for this ZooKeeper client instance. The value returned
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- * is not valid until the client connects to a server and may change
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- * after a re-connect.
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- *
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+ * The session id for this ZooKeeper client instance. The value returned is
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+ * not valid until the client connects to a server and may change after a
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+ * re-connect.
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+ *
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* @return current session id
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*/
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public long getSessionId() {
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return cnxn.getSessionId();
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}
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+ /**
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+ * The session password for this ZooKeeper client instance. The value
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+ * returned is not valid until the client connects to a server and may
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+ * change after a re-connect.
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+ *
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+ * @return current session password
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+ */
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public byte[] getSessionPasswd() {
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return cnxn.getSessionPasswd();
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}
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@@ -363,7 +393,7 @@ public class ZooKeeper {
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* watches on the path left by exists calls, and the watches on the parent
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* of the node by getChildren calls.
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* <p>
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- * The maximum allowable size of the data array is 1 MB (1,048,576 bytes).
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+ * The maximum allowable size of the data array is 1 MB (1,048,576 bytes).
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* Arrays larger than this will cause a KeeperExecption to be thrown.
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*
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* @param path
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@@ -402,7 +432,7 @@ public class ZooKeeper {
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return response.getPath();
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}
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- /**
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+ /**
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* The Asynchronous version of create. The request doesn't actually until
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* the asynchronous callback is called.
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*
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@@ -686,7 +716,7 @@ public class ZooKeeper {
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* A KeeperException with error code KeeperException.BadVersion will be
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* thrown if the given version does not match the node's version.
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* <p>
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- * The maximum allowable size of the data array is 1 MB (1,048,576 bytes).
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+ * The maximum allowable size of the data array is 1 MB (1,048,576 bytes).
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* Arrays larger than this will cause a KeeperExecption to be thrown.
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*
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* @param path
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Patrick D. Hunt