/**
* 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 java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.Map;
import org.apache.hadoop.hbase.master.AssignmentManager;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.zookeeper.ZKTable;
import org.apache.hadoop.hbase.zookeeper.ZKTable.TableState;
import org.apache.zookeeper.KeeperException;
/**
* Non-instantiable class that provides helper functions for
* clients other than {@link 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 {@link TableState#DISABLED}.
* This method does not use cache as {@link #isDisabledTable(String)} does.
* This method is for clients other than {@link AssignmentManager}
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isDisabledTable(final ZooKeeperWatcher zkw,
final String tableName)
throws KeeperException {
TableState state = getTableState(zkw, tableName);
return isTableState(TableState.DISABLED, state);
}
/**
* Go to zookeeper and see if state of table is {@link TableState#ENABLED}.
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isEnabledTable(final ZooKeeperWatcher zkw,
final String tableName) throws KeeperException {
TableState state = getTableState(zkw, tableName);
// If a table is ENABLED then we are removing table state znode in 0.92
// but in 0.94 we keep it in ENABLED state.
return state == null || state == TableState.ENABLED;
}
/**
* Go to zookeeper and see if state of table is {@link TableState#DISABLING}
* of {@link TableState#DISABLED}.
* @param zkw
* @param tableName
* @return True if table is enabled.
* @throws KeeperException
*/
public static boolean isDisablingOrDisabledTable(final ZooKeeperWatcher zkw,
final String tableName) throws KeeperException {
TableState state = getTableState(zkw, tableName);
return isTableState(TableState.DISABLING, state) ||
isTableState(TableState.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<String> getDisabledTables(ZooKeeperWatcher zkw)
throws KeeperException {
Set<String> disabledTables = new HashSet<String>();
List<String> children =
ZKUtil.listChildrenNoWatch(zkw, zkw.clientTableZNode);
for (String child: children) {
TableState state = getTableState(zkw, child);
if (state == TableState.DISABLED) disabledTables.add(child);
}
return disabledTables;
}
/**
* Gets a list of all the tables set as disabled in zookeeper.
* @return Map of disabled tables, empty MAP if none
* @throws KeeperException
*/
public static Map<TableState, Set<String>> getDisabledOrDisablingTables(ZooKeeperWatcher zkw)
throws KeeperException {
Map<TableState, Set<String>> disabledTables = new HashMap<TableState, Set<String>>();
List<String> children = ZKUtil.listChildrenNoWatch(zkw, zkw.clientTableZNode);
for (String child : children) {
TableState state = getTableState(zkw, child);
if (state == TableState.DISABLED) {
Set<String> tables = disabledTables.get(state);
if (tables == null) {
tables = new HashSet<String>();
disabledTables.put(TableState.DISABLED, tables);
}
tables.add(child);
continue;
}
if (state == TableState.DISABLING) {
Set<String> tables = disabledTables.get(state);
if (tables == null) {
tables = new HashSet<String>();
disabledTables.put(TableState.DISABLING, tables);
}
tables.add(child);
continue;
}
}
return disabledTables;
}
/**
* Gets a list of all the tables set as enabled or enabling in zookeeper.
* @return Map of enabled tables, empty map if none
* @throws KeeperException
*/
public static Map<TableState, Set<String>> getEnabledOrEnablingTables(ZooKeeperWatcher zkw)
throws KeeperException {
Map<TableState, Set<String>> enabledTables = new HashMap<TableState, Set<String>>();
List<String> children = ZKUtil.listChildrenNoWatch(zkw, zkw.clientTableZNode);
for (String child : children) {
TableState state = getTableState(zkw, child);
if (state == TableState.ENABLED) {
Set<String> tables = enabledTables.get(state);
if (tables == null) {
tables = new HashSet<String>();
enabledTables.put(TableState.ENABLED, tables);
}
tables.add(child);
continue;
}
if (state == TableState.ENABLING) {
Set<String> tables = enabledTables.get(state);
if (tables == null) {
tables = new HashSet<String>();
enabledTables.put(TableState.ENABLING, tables);
}
tables.add(child);
continue;
}
}
return enabledTables;
}
static boolean isTableState(final TableState expectedState,
final TableState currentState) {
return currentState != null && currentState.equals(expectedState);
}
/**
* Read the TableState from ZooKeeper
* @throws KeeperException
*/
static TableState getTableState(final ZooKeeperWatcher zkw,
final String child) throws KeeperException {
return getTableState(zkw, zkw.clientTableZNode, child);
}
/**
* @deprecated Only for 0.92/0.94 compatibility. Use getTableState(zkw, child) instead.
*/
static TableState getTableState(final ZooKeeperWatcher zkw,
final String parent, final String child) throws KeeperException {
String znode = ZKUtil.joinZNode(parent, child);
byte [] data = ZKUtil.getData(zkw, znode);
if (data == null || data.length <= 0) {
return null;
}
String str = Bytes.toString(data);
try {
return TableState.valueOf(str);
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException(str);
}
}
}