/**
* Copyright The Apache Software Foundation
*
* 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.hadoop.hbase.zookeeper;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
import org.apache.zookeeper.KeeperException;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* Non-instantiable class that provides helper functions for
* clients other than AssignmentManager for reading the
* state of a table in ZK.
*
* <p>Does not cache state like {@link ZKTable}, actually reads from ZK each call.
*/
public class ZKTableReadOnly {
private ZKTableReadOnly() {}
/**
* Go to zookeeper and see if state of table is {@code ZooKeeperProtos.Table.State#DISABLED}.
* This method does not use cache.
* This method is for clients other than AssignmentManager
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isDisabledTable(final ZooKeeperWatcher zkw,
final TableName tableName)
throws KeeperException {
ZooKeeperProtos.Table.State state = getTableState(zkw, tableName);
return isTableState(ZooKeeperProtos.Table.State.DISABLED, state);
}
/**
* Go to zookeeper and see if state of table is {@code ZooKeeperProtos.Table.State#ENABLED}.
* This method does not use cache.
* This method is for clients other than AssignmentManager
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isEnabledTable(final ZooKeeperWatcher zkw,
final TableName tableName)
throws KeeperException {
return getTableState(zkw, tableName) == ZooKeeperProtos.Table.State.ENABLED;
}
/**
* Go to zookeeper and see if state of table is {@code ZooKeeperProtos.Table.State#DISABLING}
* of {@code ZooKeeperProtos.Table.State#DISABLED}.
* This method does not use cache.
* This method is for clients other than AssignmentManager.
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isDisablingOrDisabledTable(final ZooKeeperWatcher zkw,
final TableName tableName)
throws KeeperException {
ZooKeeperProtos.Table.State state = getTableState(zkw, tableName);
return isTableState(ZooKeeperProtos.Table.State.DISABLING, state) ||
isTableState(ZooKeeperProtos.Table.State.DISABLED, state);
}
/**
* Gets a list of all the tables set as disabled in zookeeper.
* @return Set of disabled tables, empty Set if none
* @throws KeeperException
*/
public static Set<TableName> getDisabledTables(ZooKeeperWatcher zkw)
throws KeeperException {
Set<TableName> disabledTables = new HashSet<TableName>();
List<String> children =
ZKUtil.listChildrenNoWatch(zkw, zkw.tableZNode);
for (String child: children) {
TableName tableName =
TableName.valueOf(child);
ZooKeeperProtos.Table.State state = getTableState(zkw, tableName);
if (state == ZooKeeperProtos.Table.State.DISABLED) disabledTables.add(tableName);
}
return disabledTables;
}
/**
* Gets a list of all the tables set as disabled in zookeeper.
* @return Set of disabled tables, empty Set if none
* @throws KeeperException
*/
public static Set<TableName> getDisabledOrDisablingTables(ZooKeeperWatcher zkw)
throws KeeperException {
Set<TableName> disabledTables = new HashSet<TableName>();
List<String> children =
ZKUtil.listChildrenNoWatch(zkw, zkw.tableZNode);
for (String child: children) {
TableName tableName =
TableName.valueOf(child);
ZooKeeperProtos.Table.State state = getTableState(zkw, tableName);
if (state == ZooKeeperProtos.Table.State.DISABLED ||
state == ZooKeeperProtos.Table.State.DISABLING)
disabledTables.add(tableName);
}
return disabledTables;
}
static boolean isTableState(final ZooKeeperProtos.Table.State expectedState,
final ZooKeeperProtos.Table.State currentState) {
return currentState != null && currentState.equals(expectedState);
}
/**
* @param zkw
* @param tableName
* @return Null or {@link ZooKeeperProtos.Table.State} found in znode.
* @throws KeeperException
*/
static ZooKeeperProtos.Table.State getTableState(final ZooKeeperWatcher zkw,
final TableName tableName)
throws KeeperException {
String znode = ZKUtil.joinZNode(zkw.tableZNode, tableName.getNameAsString());
byte [] data = ZKUtil.getData(zkw, znode);
if (data == null || data.length <= 0) return ZooKeeperProtos.Table.State.ENABLED;
try {
ProtobufUtil.expectPBMagicPrefix(data);
ZooKeeperProtos.Table.Builder builder = ZooKeeperProtos.Table.newBuilder();
int magicLen = ProtobufUtil.lengthOfPBMagic();
ZooKeeperProtos.Table t = builder.mergeFrom(data, magicLen, data.length - magicLen).build();
return t.getState();
} catch (InvalidProtocolBufferException e) {
KeeperException ke = new KeeperException.DataInconsistencyException();
ke.initCause(e);
throw ke;
} catch (DeserializationException e) {
throw ZKUtil.convert(e);
}
}
}