Hbase 协处理器（二）之RowCount代码

时间：2015-08-16 16:41:23 阅读：275 评论：0 收藏：0 [点我收藏+]

public class RowCountEndpoint extends ExampleProtos.RowCountService
implements Coprocessor, CoprocessorService {
private RegionCoprocessorEnvironment env;

public RowCountEndpoint() {
}

@Override
public Service getService() {
return this;
}

@Override
public void getRowCount(RpcController controller, ExampleProtos.CountRequest request,
RpcCallback<ExampleProtos.CountResponse> done) {
Scan scan = new Scan();
scan.setFilter(new FirstKeyOnlyFilter());
ExampleProtos.CountResponse response = null;
InternalScanner scanner = null;
try {
scanner = env.getRegion().getScanner(scan);
List<Cell> results = new ArrayList<Cell>();
boolean hasMore = false;
byte[] lastRow = null;
long count = 0;
do {
hasMore = scanner.next(results);
for (Cell kv : results) {
byte[] currentRow = CellUtil.cloneRow(kv);
if (lastRow == null || !Bytes.equals(lastRow, currentRow)) {
lastRow = currentRow;
count++;
}
}
results.clear();
} while (hasMore);

response = ExampleProtos.CountResponse.newBuilder()
.setCount(count).build();
} catch (IOException ioe) {
ResponseConverter.setControllerException(controller, ioe);
} finally {
if (scanner != null) {
try {
scanner.close();
} catch (IOException ignored) {}
}
}
done.run(response);
}

/**
* Returns a count of all KeyValues in the region where this coprocessor is loaded.
*/
@Override
public void getKeyValueCount(RpcController controller, ExampleProtos.CountRequest request,
RpcCallback<ExampleProtos.CountResponse> done) {
ExampleProtos.CountResponse response = null;
InternalScanner scanner = null;
try {
scanner = env.getRegion().getScanner(new Scan());
List<Cell> results = new ArrayList<Cell>();
boolean hasMore = false;
long count = 0;
do {
hasMore = scanner.next(results);
for (Cell kv : results) {
count++;
}
results.clear();
} while (hasMore);

response = ExampleProtos.CountResponse.newBuilder()
.setCount(count).build();
} catch (IOException ioe) {
ResponseConverter.setControllerException(controller, ioe);
} finally {
if (scanner != null) {
try {
scanner.close();
} catch (IOException ignored) {}
}
}
done.run(response);
}

@Override
public void start(CoprocessorEnvironment env) throws IOException {
if (env instanceof RegionCoprocessorEnvironment) {
this.env = (RegionCoprocessorEnvironment)env;
} else {
throw new CoprocessorException("Must be loaded on a table region!");
}
}

@Override
public void stop(CoprocessorEnvironment env) throws IOException {
// nothing to do
}
}

标签：hbase1.0 api 处理器 coprocessor hbase

原文地址：http://blog.csdn.net/dhtx_wzgl/article/details/47702923

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