/*
* 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 com.facebook.giraph.hive;
import org.apache.hadoop.conf.Configuration;
import org.apache.log4j.Logger;
import com.facebook.giraph.hive.impl.HiveApiTableSchema;
import com.facebook.giraph.hive.impl.common.Writables;
import com.google.common.base.Function;
/**
* Helpers for Hive schemas
*/
public class HiveTableSchemas {
/** Key for table schema for a name */
public static final String TABLE_KEY_PREFIX = "hive.api.schema.table.";
/** Key for table schema for a profile */
public static final String PROFILE_KEY_PREFIX = "hive.api.schema.profile.";
/** Logger */
private static final Logger LOG = Logger.getLogger(HiveTableSchemas.class);
/** Don't construct */
protected HiveTableSchemas() { }
/**
* Configure object with hive table schema, if it supports it
* @param obj Object
* @param schema Hive table schema
*/
public static void configure(Object obj, HiveTableSchema schema) {
if (obj instanceof HiveTableSchemaAware) {
((HiveTableSchemaAware) obj).setTableSchema(schema);
}
}
/**
* Configure object with hive table schema
* @param obj Object
* @param schema Hive table schema
*/
public static void configure(HiveTableSchemaAware obj, HiveTableSchema schema) {
obj.setTableSchema(schema);
}
/**
* Get schema for a table
* @param conf Configuration
* @param dbName Database name
* @param tableName Table name
* @return schema
*/
public static HiveTableSchema getForTable(Configuration conf, String dbName,
String tableName) {
return getImpl(conf, tableNameKey(dbName, tableName));
}
/**
* Get schema for a profile
* @param conf Configuration
* @param profile Profile ID
* @return schema
*/
public static HiveTableSchema getForProfile(Configuration conf,
String profile) {
return getImpl(conf, profileKey(profile));
}
/**
* Get function to lookup names in the table schema given
*
* @param tableSchema Hive table schema to use
* @return Function that does lookup
*/
public static Function<String, Integer> schemaLookupFunc(final HiveTableSchema tableSchema) {
return new Function<String, Integer>() {
@Override
public Integer apply(String input) {
return tableSchema.positionOf(input);
}
};
}
/**
* Get schema from Configuration using key
* @param conf Configuration
* @param key String key
* @return schema
*/
private static HiveTableSchema getImpl(Configuration conf, String key) {
String value = conf.get(key);
if (value == null) {
throw new NullPointerException("No HiveTableSchema with key " +
key + " found");
}
HiveTableSchema hiveTableSchema = new HiveApiTableSchema();
Writables.readFieldsFromEncodedStr(value, hiveTableSchema);
return hiveTableSchema;
}
/**
* Put schema for table
* @param conf Configuration
* @param dbName Database name
* @param tableName Table name
* @param hiveTableSchema schema
*/
public static void putForName(Configuration conf, String dbName,
String tableName, HiveTableSchema hiveTableSchema) {
putImpl(conf, tableNameKey(dbName, tableName), hiveTableSchema);
}
/**
* Put schema for profile
* @param conf Configuraiton
* @param profile Profile ID
* @param hiveTableSchema schema
*/
public static void putForProfile(Configuration conf, String profile,
HiveTableSchema hiveTableSchema) {
putImpl(conf, profileKey(profile), hiveTableSchema);
}
/**
* Put schema for given key into Configuration
* @param conf Configuration
* @param key String key
* @param schema Hive table schema
*/
private static void putImpl(Configuration conf, String key,
HiveTableSchema schema) {
conf.set(key, Writables.writeToEncodedStr(schema));
}
/**
* Key for Configuration for a table
*
* @param dbName database name
* @param tableName table name
* @return key
*/
private static String tableNameKey(String dbName, String tableName) {
return TABLE_KEY_PREFIX + dbName + "." + tableName;
}
/**
* Key for Configuration for a profile
*
* @param profile Profile ID
* @return key
*/
private static String profileKey(String profile) {
return PROFILE_KEY_PREFIX + profile;
}
}