| /* |
| * 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.hive.metastore; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| import org.apache.hadoop.hive.metastore.api.Table; |
| import org.apache.thrift.TException; |
| |
| /** |
| * Use this to get Table objects for a table list. It provides an iterator to |
| * on the resulting Table objects. It batches the calls to |
| * IMetaStoreClient.getTableObjectsByName to avoid OOM issues in HS2 (with |
| * embedded metastore) or MetaStore server (if HS2 is using remote metastore). |
| * |
| */ |
| public class TableIterable implements Iterable<Table> { |
| |
| @Override |
| public Iterator<Table> iterator() { |
| return new Iterator<Table>() { |
| |
| private final Iterator<String> tableNamesIter = tableNames.iterator(); |
| private Iterator<org.apache.hadoop.hive.metastore.api.Table> batchIter = null; |
| |
| @Override |
| public boolean hasNext() { |
| return ((batchIter != null) && batchIter.hasNext()) || tableNamesIter.hasNext(); |
| } |
| |
| @Override |
| public Table next() { |
| if ((batchIter == null) || !batchIter.hasNext()) { |
| getNextBatch(); |
| } |
| return batchIter.next(); |
| } |
| |
| private void getNextBatch() { |
| // get next batch of table names in this list |
| List<String> nameBatch = new ArrayList<String>(); |
| int batchCounter = 0; |
| while (batchCounter < batchSize && tableNamesIter.hasNext()) { |
| nameBatch.add(tableNamesIter.next()); |
| batchCounter++; |
| } |
| // get the Table objects for this batch of table names and get iterator |
| // on it |
| |
| try { |
| if (catName != null) { |
| batchIter = msc.getTableObjectsByName(catName, dbname, nameBatch).iterator(); |
| } else { |
| batchIter = msc.getTableObjectsByName(dbname, nameBatch).iterator(); |
| } |
| } catch (TException e) { |
| throw new RuntimeException(e); |
| } |
| |
| } |
| |
| @Override |
| public void remove() { |
| throw new IllegalStateException( |
| "TableIterable is a read-only iterable and remove() is unsupported"); |
| } |
| }; |
| } |
| |
| private final IMetaStoreClient msc; |
| private final String dbname; |
| private final List<String> tableNames; |
| private final int batchSize; |
| private final String catName; |
| |
| /** |
| * Primary constructor that fetches all tables in a given msc, given a Hive |
| * object,a db name and a table name list. |
| */ |
| public TableIterable(IMetaStoreClient msc, String dbname, List<String> tableNames, int batchSize) |
| throws TException { |
| this.msc = msc; |
| this.catName = null; |
| this.dbname = dbname; |
| this.tableNames = tableNames; |
| this.batchSize = batchSize; |
| } |
| |
| public TableIterable(IMetaStoreClient msc, String catName, String dbname, List<String> |
| tableNames, int batchSize) throws TException { |
| this.msc = msc; |
| this.catName = catName; |
| this.dbname = dbname; |
| this.tableNames = tableNames; |
| this.batchSize = batchSize; |
| } |
| } |