Java tutorial
/** * (c) Copyright 2012 WibiData, Inc. * * See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * Licensed 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 com.moz.fiji.schema.hbase; import java.util.regex.Pattern; import com.google.common.base.Joiner; import org.apache.commons.lang.StringUtils; import org.apache.hadoop.hbase.util.Bytes; import com.moz.fiji.annotations.ApiAudience; import com.moz.fiji.annotations.ApiStability; import com.moz.fiji.schema.NotAFijiManagedTableException; /** * <p>Multiple instances of Fiji can be installed on a single HBase * cluster. Within a Fiji instance, several HBase tables are created * to manage system, metadata, schemas, and user-space tables. This * class represents the name of one of those HBase tables that are * created and managed by Fiji. This class should only be used internally * in Fiji modules, or by framework application developers who need * direct access to HBase tables managed by Fiji.</p> * * <p> * The names of tables in HBase created and managed by Fiji are * made of a list of delimited components. There are at least 3 * components of a name: * </p> * * <ol> * <li> * Prefix: a literal string "fiji" used to mark that this table * is managed by Fiji. * </li> * <li> * FijiInstance: the name of fiji instance managing this table. * </li> * <li> * Type: the type of table (system, schema, meta, table). * </li> * </ol> * * <p> * If the type of the table is "table", then it's name (the name users * of Fiji would use to refer to it) is the fourth and final component. * </p> * * <p> * For example, an HBase cluster might have the following tables: * </p> * <pre> * devices * fiji.default.meta * fiji.default.schema * fiji.default.schema_hash * fiji.default.schema_id * fiji.default.system * fiji.default.table.foo * fiji.default.table.bar * fiji.experimental.meta * fiji.experimental.schema * fiji.experimental.schema_hash * fiji.experimental.schema_id * fiji.experimental.system * fiji.experimental.table.baz * </pre> * * <p> * In this example, there is an HBase table completely unrelated to * fiji called "devices." There are two fiji installations, one * called "default" and another called "experimental." Within the * "default" installation, there are two Fiji tables, "foo" and * "bar." Within the "experimental" installation, there is a single * Fiji table "baz." * </p> */ @ApiAudience.Framework @ApiStability.Evolving public final class FijiManagedHBaseTableName { /** The delimited used to separate the components of an HBase table name. */ private static final char DELIMITER = '.'; private static final Joiner DELIMITER_JOINER = Joiner.on(DELIMITER); /** The first component of all HBase table names managed by Fiji. */ public static final String FIJI_COMPONENT = "fiji"; /** Regexp matching Fiji system tables. */ public static final Pattern FIJI_SYSTEM_TABLES_REGEX = Pattern .compile("fiji[.](.*)[.](meta|system|schema_hash|schema_id)"); /** The name component used for the Fiji meta table. */ private static final String FIJI_META_COMPONENT = "meta"; /** The name component used for the Fiji schema hash table. */ private static final String FIJI_SCHEMA_HASH_COMPONENT = "schema_hash"; /** The name component used for the Fiji schema IDs table. */ private static final String FIJI_SCHEMA_ID_COMPONENT = "schema_id"; /** The name component used for the Fiji system table. */ private static final String FIJI_SYSTEM_COMPONENT = "system"; /** The name component used for all user-space Fiji tables. */ private static final String FIJI_TABLE_COMPONENT = "table"; /** The HBase table name. */ private final String mHBaseTableName; /** The Fiji instance name. */ private final String mFijiInstanceName; /** The Fiji table name, or null if it is not a user-space Fiji table. */ private final String mFijiTableName; /** * Constructs a Fiji-managed HBase table name. * * @param fijiInstanceName The fiji instance name. * @param type The type component of the HBase table name (meta, schema, system, table). */ private FijiManagedHBaseTableName(String fijiInstanceName, String type) { mHBaseTableName = DELIMITER_JOINER.join(FIJI_COMPONENT, fijiInstanceName, type); mFijiInstanceName = fijiInstanceName; mFijiTableName = null; } /** * Constructs a Fiji-managed HBase table name. * * @param fijiInstanceName The fiji instance name. * @param type The type component of the HBase table name. * @param fijiTableName The name of the user-space Fiji table. */ private FijiManagedHBaseTableName(String fijiInstanceName, String type, String fijiTableName) { mHBaseTableName = DELIMITER_JOINER.join(FIJI_COMPONENT, fijiInstanceName, type, fijiTableName); mFijiInstanceName = fijiInstanceName; mFijiTableName = fijiTableName; } /** * Constructs using an HBase HTable name. * * @param hbaseTableName The HBase HTable name. * @return A new fiji-managed HBase table name. * @throws NotAFijiManagedTableException If the HBase table is not managed by fiji. */ public static FijiManagedHBaseTableName get(String hbaseTableName) throws NotAFijiManagedTableException { // Split it into components. String[] components = StringUtils.splitPreserveAllTokens(hbaseTableName, Character.toString(DELIMITER), 4); // Make sure the first component is 'fiji'. if (!components[0].equals(FIJI_COMPONENT)) { throw new NotAFijiManagedTableException(hbaseTableName, "Doesn't start with fiji name component."); } if (components.length == 3) { // It's a managed fiji meta/schema/system table. return new FijiManagedHBaseTableName(components[1], components[2]); } else if (components.length == 4) { // It's a user-space fiji table. return new FijiManagedHBaseTableName(components[1], components[2], components[3]); } else { // Wrong number of components... must not be a fiji table. throw new NotAFijiManagedTableException(hbaseTableName, "Invalid number of name components."); } } /** * Gets a new instance of a Fiji-managed HBase table that holds the Fiji meta table. * * @param fijiInstanceName The name of the Fiji instance. * @return The name of the HBase table used to store the Fiji meta table. */ public static FijiManagedHBaseTableName getMetaTableName(String fijiInstanceName) { return new FijiManagedHBaseTableName(fijiInstanceName, FIJI_META_COMPONENT); } /** * Gets a new instance of a Fiji-managed HBase table that holds the Fiji schema hash table. * * @param fijiInstanceName The name of the Fiji instance. * @return The name of the HBase table used to store the Fiji schema hash table. */ public static FijiManagedHBaseTableName getSchemaHashTableName(String fijiInstanceName) { return new FijiManagedHBaseTableName(fijiInstanceName, FIJI_SCHEMA_HASH_COMPONENT); } /** * Gets a new instance of a Fiji-managed HBase table that holds the Fiji schema IDs table. * * @param fijiInstanceName The name of the Fiji instance. * @return The name of the HBase table used to store the Fiji schema IDs table. */ public static FijiManagedHBaseTableName getSchemaIdTableName(String fijiInstanceName) { return new FijiManagedHBaseTableName(fijiInstanceName, FIJI_SCHEMA_ID_COMPONENT); } /** * Gets a new instance of a Fiji-managed HBase table that holds the Fiji system table. * * @param fijiInstanceName The name of the Fiji instance. * @return The name of the HBase table used to store the Fiji system table. */ public static FijiManagedHBaseTableName getSystemTableName(String fijiInstanceName) { return new FijiManagedHBaseTableName(fijiInstanceName, FIJI_SYSTEM_COMPONENT); } /** * Gets a new instance of a Fiji-managed HBase table that holds a user-space Fiji table. * * @param fijiInstanceName The name of the Fiji instance. * @param fijiTableName The name of the user-space Fiji table. * @return The name of the HBase table used to store the user-space Fiji table. */ public static FijiManagedHBaseTableName getFijiTableName(String fijiInstanceName, String fijiTableName) { return new FijiManagedHBaseTableName(fijiInstanceName, FIJI_TABLE_COMPONENT, fijiTableName); } /** * Gets the name of the Fiji instance this named table belongs to. * * @return The name of the fiji instance. */ public String getFijiInstanceName() { return mFijiInstanceName; } /** * Gets the name of the Fiji table. * A user defined fiji table named "foo" in the default fiji instance will be stored in HBase * with the FijiManaged name "fiji.default.table.foo". This method will return only "foo". * * @return The name of the fiji table, or null if this is not a user-space Fiji table. */ public String getFijiTableName() { return mFijiTableName; } /** * Gets the name of the HBase table that stores the data for this Fiji table. * * @return The HBase table name as a UTF-8 encoded byte array. */ public byte[] toBytes() { return Bytes.toBytes(mHBaseTableName); } @Override public String toString() { return mHBaseTableName; } @Override public boolean equals(Object other) { if (!(other instanceof FijiManagedHBaseTableName)) { return false; } return toString().equals(other.toString()); } @Override public int hashCode() { return toString().hashCode(); } }