/**
* Copyright 2013 Cloudera Inc.
*
* 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.cloudera.cdk.examples.data;
import com.cloudera.cdk.data.DatasetReader;
import com.cloudera.cdk.data.DatasetRepositories;
import com.cloudera.cdk.data.Key;
import com.cloudera.cdk.data.RandomAccessDataset;
import com.cloudera.cdk.data.RandomAccessDatasetRepository;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
/**
* Read the user objects from the users dataset by key lookup, and by scanning.
*/
public class ReadUserDataset extends Configured implements Tool {
@Override
public int run(String[] args) throws Exception {
// Construct an HBase dataset repository using the local HBase database
RandomAccessDatasetRepository repo =
DatasetRepositories.openRandomAccess("repo:hbase:localhost.localdomain");
// Load the users dataset
RandomAccessDataset<User> users = repo.load("users");
// Get an accessor for the dataset and look up a user by username
Key key = new Key.Builder(users).add("username", "bill").build();
System.out.println(users.get(key));
// Get a reader for the dataset and read all the users
DatasetReader<User> reader = users.newReader();
try {
reader.open();
for (User user : reader) {
System.out.println(user);
}
} finally {
reader.close();
}
return 0;
}
public static void main(String... args) throws Exception {
int rc = ToolRunner.run(new ReadUserDataset(), args);
System.exit(rc);
}
}