diff --git a/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java b/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java new file mode 100644 index 00000000000..f5f9734bb9a --- /dev/null +++ b/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java @@ -0,0 +1,47 @@ +/* + * 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.filter; + +import java.io.DataInput; +import java.io.DataOutput; +import java.io.IOException; +import org.apache.hadoop.hbase.KeyValue; + +/** + * A filter that will only return the key component of each KV (the value will + * be rewritten as empty). + *

+ * This filter can be used to grab all of the keys without having to also grab + * the values. + */ +public class KeyOnlyFilter extends FilterBase { + + public KeyOnlyFilter() {} + + @Override + public ReturnCode filterKeyValue(KeyValue kv) { + kv.convertToKeyOnly(); + return ReturnCode.INCLUDE; + } + + public void write(DataOutput out) throws IOException {} + + public void readFields(DataInput in) throws IOException {} +}