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/**
* 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.master;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.ServiceNotRunningException;
import org.apache.hadoop.hbase.master.procedure.ProcedurePrepareLatch;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.util.NonceKey;
/**
* View and edit the current cluster schema. Use this API making any modification to
* namespaces, tables, etc.
*
* Implementation Notes
* Nonces are for when operation is non-idempotent to ensure once-only semantic, even
* across process failures.
*/
// ClusterSchema is introduced to encapsulate schema modification. Currently the different aspects
// are spread about the code base. This effort is about cleanup, shutting down access, and
// coalescing common code. In particular, we'd contain filesystem modification. Other
// benefits are to make all schema modification work the same way (one way to do an operation only
// rather than the current approach where how an operation is done varies with context) and to make
// it so clusterschema modification can stand apart from Master to faciliate standalone
// testing. It is part of the filesystem refactor project that undoes the dependency on a
// layout in HDFS that mimics our model of tables have regions have column families have files.
// With this Interface in place, with all modifications going via this route where no filesystem
// particulars are exposed, redoing our internals will take less effort.
//
// Currently ClusterSchema Interface will include namespace and table manipulation. Ideally a
// form of this Interface will go all the ways down to the file manipulation level but currently
// TBD.
//
// ClusterSchema is private to the Master; only the Master knows current cluster state and has
// means of editing/altering it.
//
// TODO: Remove Server argument when MasterServices are passed.
// TODO: We return Future in the below from most methods. It may change to return
// a ProcedureFuture subsequently.
@InterfaceAudience.Private
public interface ClusterSchema {
/**
* Timeout for cluster operations in milliseconds.
*/
public static final String HBASE_MASTER_CLUSTER_SCHEMA_OPERATION_TIMEOUT_KEY =
"hbase.master.cluster.schema.operation.timeout";
/**
* Default operation timeout in milliseconds.
*/
public static final int DEFAULT_HBASE_MASTER_CLUSTER_SCHEMA_OPERATION_TIMEOUT =
5 * 60 * 1000;
/**
* For internals use only. Do not use! Provisionally part of this Interface.
* Prefer the high-level APIs available elsewhere in this API.
* @return Instance of {@link TableNamespaceManager}
*/
// TODO: Remove from here. Keep internal. This Interface is too high-level to host this accessor.
TableNamespaceManager getTableNamespaceManager();
/**
* Create a new Namespace.
* @param namespaceDescriptor descriptor for new Namespace
* @param nonceKey A unique identifier for this operation from the client or process.
* @param latch A latch to block on for precondition validation
* @return procedure id
* @throws IOException if service is not running see {@link ServiceNotRunningException}
*/
long createNamespace(NamespaceDescriptor namespaceDescriptor, NonceKey nonceKey, ProcedurePrepareLatch latch)
throws IOException;
/**
* Modify an existing Namespace.
* @param nonceKey A unique identifier for this operation from the client or process.
* @param latch A latch to block on for precondition validation
* @return procedure id
* @throws IOException if service is not running see {@link ServiceNotRunningException}
*/
long modifyNamespace(NamespaceDescriptor descriptor, NonceKey nonceKey, ProcedurePrepareLatch latch)
throws IOException;
/**
* Delete an existing Namespace.
* Only empty Namespaces (no tables) can be removed.
* @param nonceKey A unique identifier for this operation from the client or process.
* @param latch A latch to block on for precondition validation
* @return procedure id
* @throws IOException if service is not running see {@link ServiceNotRunningException}
*/
long deleteNamespace(String name, NonceKey nonceKey, ProcedurePrepareLatch latch)
throws IOException;
/**
* Get a Namespace
* @param name Name of the Namespace
* @return Namespace descriptor for name
* @throws IOException if namespace does not exist
*/
// No Future here because presumption is that the request will go against cached metadata so
// return immediately -- no need of running a Procedure.
NamespaceDescriptor getNamespace(String name) throws IOException;
/**
* Get all Namespaces
* @return All Namespace descriptors
*/
List getNamespaces() throws IOException;
}