Java tutorial
/** * 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.hdfs.server.namenode; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.*; /** * Op codes for edits file */ @InterfaceAudience.Private @InterfaceStability.Unstable public enum FSEditLogOpCodes { // last op code in file OP_ADD((byte) 0, AddOp.class), // deprecated operation OP_RENAME_OLD((byte) 1, RenameOldOp.class), OP_DELETE((byte) 2, DeleteOp.class), OP_MKDIR((byte) 3, MkdirOp.class), OP_SET_REPLICATION((byte) 4, SetReplicationOp.class), @Deprecated OP_DATANODE_ADD((byte) 5), // obsolete @Deprecated OP_DATANODE_REMOVE((byte) 6), // obsolete OP_SET_PERMISSIONS((byte) 7, SetPermissionsOp.class), OP_SET_OWNER((byte) 8, SetOwnerOp.class), OP_CLOSE( (byte) 9, CloseOp.class), OP_SET_GENSTAMP_V1((byte) 10, SetGenstampV1Op.class), OP_SET_NS_QUOTA((byte) 11, SetNSQuotaOp.class), // obsolete OP_CLEAR_NS_QUOTA((byte) 12, ClearNSQuotaOp.class), // obsolete OP_TIMES((byte) 13, TimesOp.class), // set atime, mtime OP_SET_QUOTA((byte) 14, SetQuotaOp.class), // filecontext rename OP_RENAME((byte) 15, RenameOp.class), // concat files OP_CONCAT_DELETE((byte) 16, ConcatDeleteOp.class), OP_SYMLINK((byte) 17, SymlinkOp.class), OP_GET_DELEGATION_TOKEN((byte) 18, GetDelegationTokenOp.class), OP_RENEW_DELEGATION_TOKEN((byte) 19, RenewDelegationTokenOp.class), OP_CANCEL_DELEGATION_TOKEN((byte) 20, CancelDelegationTokenOp.class), OP_UPDATE_MASTER_KEY((byte) 21, UpdateMasterKeyOp.class), OP_REASSIGN_LEASE((byte) 22, ReassignLeaseOp.class), OP_END_LOG_SEGMENT((byte) 23, EndLogSegmentOp.class), OP_START_LOG_SEGMENT((byte) 24, StartLogSegmentOp.class), OP_UPDATE_BLOCKS( (byte) 25, UpdateBlocksOp.class), OP_CREATE_SNAPSHOT( (byte) 26, CreateSnapshotOp.class), OP_DELETE_SNAPSHOT( (byte) 27, DeleteSnapshotOp.class), OP_RENAME_SNAPSHOT( (byte) 28, RenameSnapshotOp.class), OP_ALLOW_SNAPSHOT( (byte) 29, AllowSnapshotOp.class), OP_DISALLOW_SNAPSHOT( (byte) 30, DisallowSnapshotOp.class), OP_SET_GENSTAMP_V2( (byte) 31, SetGenstampV2Op.class), OP_ALLOCATE_BLOCK_ID( (byte) 32, AllocateBlockIdOp.class), OP_ADD_BLOCK( (byte) 33, AddBlockOp.class), OP_ADD_CACHE_DIRECTIVE( (byte) 34, AddCacheDirectiveInfoOp.class), OP_REMOVE_CACHE_DIRECTIVE( (byte) 35, RemoveCacheDirectiveInfoOp.class), OP_ADD_CACHE_POOL( (byte) 36, AddCachePoolOp.class), OP_MODIFY_CACHE_POOL( (byte) 37, ModifyCachePoolOp.class), OP_REMOVE_CACHE_POOL( (byte) 38, RemoveCachePoolOp.class), OP_MODIFY_CACHE_DIRECTIVE( (byte) 39, ModifyCacheDirectiveInfoOp.class), OP_SET_ACL( (byte) 40, SetAclOp.class), OP_ROLLING_UPGRADE_START( (byte) 41, RollingUpgradeStartOp.class), OP_ROLLING_UPGRADE_FINALIZE( (byte) 42, RollingUpgradeFinalizeOp.class), OP_SET_XATTR( (byte) 43, SetXAttrOp.class), OP_REMOVE_XATTR( (byte) 44, RemoveXAttrOp.class), OP_SET_STORAGE_POLICY( (byte) 45, SetStoragePolicyOp.class), OP_TRUNCATE( (byte) 46, TruncateOp.class), OP_APPEND( (byte) 47, AppendOp.class), OP_SET_QUOTA_BY_STORAGETYPE( (byte) 48, SetQuotaByStorageTypeOp.class), OP_ADD_ERASURE_CODING_POLICY( (byte) 49, AddErasureCodingPolicyOp.class), OP_ENABLE_ERASURE_CODING_POLICY( (byte) 50, EnableErasureCodingPolicyOp.class), OP_DISABLE_ERASURE_CODING_POLICY( (byte) 51, DisableErasureCodingPolicyOp.class), OP_REMOVE_ERASURE_CODING_POLICY( (byte) 52, RemoveErasureCodingPolicyOp.class), // Note that the current range of the valid OP code is 0~127 OP_INVALID((byte) -1); private final byte opCode; private final Class<? extends FSEditLogOp> opClass; /** * Constructor * * @param opCode byte value of constructed enum */ FSEditLogOpCodes(byte opCode) { this(opCode, null); } FSEditLogOpCodes(byte opCode, Class<? extends FSEditLogOp> opClass) { this.opCode = opCode; this.opClass = opClass; } /** * return the byte value of the enum * * @return the byte value of the enum */ public byte getOpCode() { return opCode; } public Class<? extends FSEditLogOp> getOpClass() { return opClass; } private static final FSEditLogOpCodes[] VALUES; static { byte max = 0; for (FSEditLogOpCodes code : FSEditLogOpCodes.values()) { if (code.getOpCode() > max) { max = code.getOpCode(); } } VALUES = new FSEditLogOpCodes[max + 1]; for (FSEditLogOpCodes code : FSEditLogOpCodes.values()) { if (code.getOpCode() >= 0) { VALUES[code.getOpCode()] = code; } } } /** * Converts byte to FSEditLogOpCodes enum value * * @param opCode get enum for this opCode * @return enum with byte value of opCode */ public static FSEditLogOpCodes fromByte(byte opCode) { if (opCode >= 0 && opCode < VALUES.length) { return VALUES[opCode]; } return opCode == -1 ? OP_INVALID : null; } }