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.accumulo.test; import static org.junit.Assert.assertEquals; import java.util.Collections; import java.util.Iterator; import java.util.Map; import org.apache.accumulo.core.client.Accumulo; import org.apache.accumulo.core.client.AccumuloClient; import org.apache.accumulo.core.client.BatchScanner; import org.apache.accumulo.core.client.BatchWriter; import org.apache.accumulo.core.client.BatchWriterConfig; import org.apache.accumulo.core.client.IteratorSetting; import org.apache.accumulo.core.client.Scanner; import org.apache.accumulo.core.data.Key; import org.apache.accumulo.core.data.Mutation; import org.apache.accumulo.core.data.Range; import org.apache.accumulo.core.data.Value; import org.apache.accumulo.core.security.Authorizations; import org.apache.accumulo.harness.AccumuloClusterHarness; import org.apache.accumulo.miniclusterImpl.MiniAccumuloConfigImpl; import org.apache.accumulo.test.functional.YieldingIterator; import org.apache.commons.lang.StringUtils; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.Text; import org.junit.Test; import org.slf4j.Logger; import org.slf4j.LoggerFactory; // ACCUMULO-4643 public class YieldScannersIT extends AccumuloClusterHarness { Logger log = LoggerFactory.getLogger(YieldScannersIT.class); private static final char START_ROW = 'a'; @Override public int defaultTimeoutSeconds() { return 60; } @Override public void configureMiniCluster(MiniAccumuloConfigImpl cfg, Configuration hadoopCoreSite) { cfg.setNumTservers(1); } @Test public void testScan() throws Exception { // make a table final String tableName = getUniqueNames(1)[0]; try (AccumuloClient client = Accumulo.newClient().from(getClientProps()).build()) { client.tableOperations().create(tableName); final BatchWriter writer = client.createBatchWriter(tableName, new BatchWriterConfig()); for (int i = 0; i < 10; i++) { byte[] row = { (byte) (START_ROW + i) }; Mutation m = new Mutation(new Text(row)); m.put(new Text(), new Text(), new Value()); writer.addMutation(m); } writer.flush(); writer.close(); log.info("Creating scanner"); // make a scanner for a table with 10 keys try (Scanner scanner = client.createScanner(tableName, Authorizations.EMPTY)) { final IteratorSetting cfg = new IteratorSetting(100, YieldingIterator.class); scanner.addScanIterator(cfg); log.info("iterating"); Iterator<Map.Entry<Key, Value>> it = scanner.iterator(); int keyCount = 0; int yieldNextCount = 0; int yieldSeekCount = 0; while (it.hasNext()) { Map.Entry<Key, Value> next = it.next(); log.info(Integer.toString(keyCount) + ": Got key " + next.getKey() + " with value " + next.getValue()); // verify we got the expected key char expected = (char) (START_ROW + keyCount); assertEquals("Unexpected row", Character.toString(expected), next.getKey().getRow().toString()); // determine whether we yielded on a next and seek if ((keyCount & 1) != 0) { yieldNextCount++; yieldSeekCount++; } String[] value = StringUtils.split(next.getValue().toString(), ','); assertEquals("Unexpected yield next count", Integer.toString(yieldNextCount), value[0]); assertEquals("Unexpected yield seek count", Integer.toString(yieldSeekCount), value[1]); assertEquals("Unexpected rebuild count", Integer.toString(yieldNextCount + yieldSeekCount), value[2]); keyCount++; } assertEquals("Did not get the expected number of results", 10, keyCount); } } } @Test public void testBatchScan() throws Exception { // make a table final String tableName = getUniqueNames(1)[0]; try (AccumuloClient client = Accumulo.newClient().from(getClientProps()).build()) { client.tableOperations().create(tableName); final BatchWriter writer = client.createBatchWriter(tableName, new BatchWriterConfig()); for (int i = 0; i < 10; i++) { byte[] row = { (byte) (START_ROW + i) }; Mutation m = new Mutation(new Text(row)); m.put(new Text(), new Text(), new Value()); writer.addMutation(m); } writer.flush(); writer.close(); log.info("Creating batch scanner"); // make a scanner for a table with 10 keys try (BatchScanner scanner = client.createBatchScanner(tableName)) { final IteratorSetting cfg = new IteratorSetting(100, YieldingIterator.class); scanner.addScanIterator(cfg); scanner.setRanges(Collections.singleton(new Range())); log.info("iterating"); Iterator<Map.Entry<Key, Value>> it = scanner.iterator(); int keyCount = 0; int yieldNextCount = 0; int yieldSeekCount = 0; while (it.hasNext()) { Map.Entry<Key, Value> next = it.next(); log.info(Integer.toString(keyCount) + ": Got key " + next.getKey() + " with value " + next.getValue()); // verify we got the expected key char expected = (char) (START_ROW + keyCount); assertEquals("Unexpected row", Character.toString(expected), next.getKey().getRow().toString()); // determine whether we yielded on a next and seek if ((keyCount & 1) != 0) { yieldNextCount++; yieldSeekCount++; } String[] value = StringUtils.split(next.getValue().toString(), ','); assertEquals("Unexpected yield next count", Integer.toString(yieldNextCount), value[0]); assertEquals("Unexpected yield seek count", Integer.toString(yieldSeekCount), value[1]); assertEquals("Unexpected rebuild count", Integer.toString(yieldNextCount + yieldSeekCount), value[2]); keyCount++; } assertEquals("Did not get the expected number of results", 10, keyCount); } } } }