| /* |
| * Copyright 2010 The Apache Software Foundation |
| * |
| * 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.rest; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.HColumnDescriptor; |
| import org.apache.hadoop.hbase.KeyValue; |
| import org.apache.hadoop.hbase.UnknownScannerException; |
| import org.apache.hadoop.hbase.client.HTableInterface; |
| import org.apache.hadoop.hbase.client.HTablePool; |
| import org.apache.hadoop.hbase.client.Result; |
| import org.apache.hadoop.hbase.client.ResultScanner; |
| import org.apache.hadoop.hbase.client.Scan; |
| import org.apache.hadoop.hbase.filter.Filter; |
| import org.apache.hadoop.hbase.rest.model.ScannerModel; |
| import org.apache.hadoop.util.StringUtils; |
| |
| public class ScannerResultGenerator extends ResultGenerator { |
| |
| private static final Log LOG = |
| LogFactory.getLog(ScannerResultGenerator.class); |
| |
| public static Filter buildFilterFromModel(final ScannerModel model) |
| throws Exception { |
| String filter = model.getFilter(); |
| if (filter == null || filter.length() == 0) { |
| return null; |
| } |
| return buildFilter(filter); |
| } |
| |
| private String id; |
| private Iterator<KeyValue> rowI; |
| private KeyValue cache; |
| private ResultScanner scanner; |
| private Result cached; |
| |
| public ScannerResultGenerator(final String tableName, final RowSpec rowspec, |
| final Filter filter) throws IllegalArgumentException, IOException { |
| HTablePool pool = RESTServlet.getInstance().getTablePool(); |
| HTableInterface table = pool.getTable(tableName); |
| try { |
| Scan scan; |
| if (rowspec.hasEndRow()) { |
| scan = new Scan(rowspec.getStartRow(), rowspec.getEndRow()); |
| } else { |
| scan = new Scan(rowspec.getStartRow()); |
| } |
| if (rowspec.hasColumns()) { |
| byte[][] columns = rowspec.getColumns(); |
| for (byte[] column: columns) { |
| byte[][] split = KeyValue.parseColumn(column); |
| if (split.length > 1 && (split[1] != null && split[1].length != 0)) { |
| scan.addColumn(split[0], split[1]); |
| } else { |
| scan.addFamily(split[0]); |
| } |
| } |
| } else { |
| for (HColumnDescriptor family: |
| table.getTableDescriptor().getFamilies()) { |
| scan.addFamily(family.getName()); |
| } |
| } |
| scan.setTimeRange(rowspec.getStartTime(), rowspec.getEndTime()); |
| scan.setMaxVersions(rowspec.getMaxVersions()); |
| if (filter != null) { |
| scan.setFilter(filter); |
| } |
| // always disable block caching on the cluster when scanning |
| scan.setCacheBlocks(false); |
| scanner = table.getScanner(scan); |
| cached = null; |
| id = Long.toString(System.currentTimeMillis()) + |
| Integer.toHexString(scanner.hashCode()); |
| } finally { |
| pool.putTable(table); |
| } |
| } |
| |
| public String getID() { |
| return id; |
| } |
| |
| public void close() { |
| } |
| |
| public boolean hasNext() { |
| if (cache != null) { |
| return true; |
| } |
| if (rowI != null && rowI.hasNext()) { |
| return true; |
| } |
| if (cached != null) { |
| return true; |
| } |
| try { |
| Result result = scanner.next(); |
| if (result != null && !result.isEmpty()) { |
| cached = result; |
| } |
| } catch (UnknownScannerException e) { |
| throw new IllegalArgumentException(e); |
| } catch (IOException e) { |
| LOG.error(StringUtils.stringifyException(e)); |
| } |
| return cached != null; |
| } |
| |
| public KeyValue next() { |
| if (cache != null) { |
| KeyValue kv = cache; |
| cache = null; |
| return kv; |
| } |
| boolean loop; |
| do { |
| loop = false; |
| if (rowI != null) { |
| if (rowI.hasNext()) { |
| return rowI.next(); |
| } else { |
| rowI = null; |
| } |
| } |
| if (cached != null) { |
| rowI = cached.list().iterator(); |
| loop = true; |
| cached = null; |
| } else { |
| Result result = null; |
| try { |
| result = scanner.next(); |
| } catch (UnknownScannerException e) { |
| throw new IllegalArgumentException(e); |
| } catch (IOException e) { |
| LOG.error(StringUtils.stringifyException(e)); |
| } |
| if (result != null && !result.isEmpty()) { |
| rowI = result.list().iterator(); |
| loop = true; |
| } |
| } |
| } while (loop); |
| return null; |
| } |
| |
| public void putBack(KeyValue kv) { |
| this.cache = kv; |
| } |
| |
| public void remove() { |
| throw new UnsupportedOperationException("remove not supported"); |
| } |
| } |