package coprocessor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.coprocessor.BaseMasterObserver;
import org.apache.hadoop.hbase.coprocessor.MasterCoprocessorEnvironment;
import org.apache.hadoop.hbase.coprocessor.ObserverContext;
import org.apache.hadoop.hbase.master.MasterFileSystem;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.regionserver.HRegion;
import java.io.IOException;
// cc MasterObserverExample Example master observer that creates a separate directory on the file system when a table is created.
// vv MasterObserverExample
public class MasterObserverExample extends BaseMasterObserver {
// ^^ MasterObserverExample
public static final Log LOG = LogFactory.getLog(HRegion.class);
// vv MasterObserverExample
@Override
public void postCreateTable(
ObserverContext<MasterCoprocessorEnvironment> env,
HRegionInfo[] regions, boolean sync)
throws IOException {
// ^^ MasterObserverExample
LOG.debug("Got postCreateTable callback");
// vv MasterObserverExample
String tableName = regions[0].getTableDesc().getNameAsString(); // co MasterObserverExample-1-GetName Get the new table's name from the table descriptor.
// ^^ MasterObserverExample
LOG.debug("Created table: " + tableName + ", region count: " + regions.length);
// vv MasterObserverExample
MasterServices services = env.getEnvironment().getMasterServices();
MasterFileSystem masterFileSystem = services.getMasterFileSystem(); // co MasterObserverExample-2-Services Get the available services and retrieve a reference to the actual file system.
FileSystem fileSystem = masterFileSystem.getFileSystem();
Path blobPath = new Path(tableName + "-blobs"); // co MasterObserverExample-3-Path Create a new directory that will store binary data from the client application.
fileSystem.mkdirs(blobPath);
// ^^ MasterObserverExample
LOG.debug("Created " + blobPath + ": " + fileSystem.exists(blobPath));
// vv MasterObserverExample
}
}
// ^^ MasterObserverExample