/*
*
* 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 com.google.common.base.Preconditions;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
import java.util.ArrayList;
/**
* Simple filter that returns first N columns on row only.
* This filter was written to test filters in Get and as soon as it gets
* its quota of columns, {@link #filterAllRemaining()} returns true. This
* makes this filter unsuitable as a Scan filter.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class ColumnCountGetFilter extends FilterBase {
private int limit = 0;
private int count = 0;
public ColumnCountGetFilter(final int n) {
Preconditions.checkArgument(n >= 0, "limit be positive %s", n);
this.limit = n;
}
public int getLimit() {
return limit;
}
@Override
public boolean filterAllRemaining() {
return this.count > this.limit;
}
@Override
public ReturnCode filterKeyValue(KeyValue v) {
this.count++;
return filterAllRemaining() ? ReturnCode.NEXT_COL : ReturnCode.INCLUDE_AND_NEXT_COL;
}
@Override
public void reset() {
this.count = 0;
}
public static Filter createFilterFromArguments(ArrayList<byte []> filterArguments) {
Preconditions.checkArgument(filterArguments.size() == 1,
"Expected 1 but got: %s", filterArguments.size());
int limit = ParseFilter.convertByteArrayToInt(filterArguments.get(0));
return new ColumnCountGetFilter(limit);
}
/**
* @return The filter serialized using pb
*/
public byte [] toByteArray() {
FilterProtos.ColumnCountGetFilter.Builder builder =
FilterProtos.ColumnCountGetFilter.newBuilder();
builder.setLimit(this.limit);
return builder.build().toByteArray();
}
/**
* @param pbBytes A pb serialized {@link ColumnCountGetFilter} instance
* @return An instance of {@link ColumnCountGetFilter} made from <code>bytes</code>
* @throws org.apache.hadoop.hbase.exceptions.DeserializationException
* @see #toByteArray
*/
public static ColumnCountGetFilter parseFrom(final byte [] pbBytes)
throws DeserializationException {
FilterProtos.ColumnCountGetFilter proto;
try {
proto = FilterProtos.ColumnCountGetFilter.parseFrom(pbBytes);
} catch (InvalidProtocolBufferException e) {
throw new DeserializationException(e);
}
return new ColumnCountGetFilter(proto.getLimit());
}
/**
* @param other
* @return true if and only if the fields of the filter that are serialized
* are equal to the corresponding fields in other. Used for testing.
*/
boolean areSerializedFieldsEqual(Filter o) {
if (o == this) return true;
if (!(o instanceof ColumnCountGetFilter)) return false;
ColumnCountGetFilter other = (ColumnCountGetFilter)o;
return this.getLimit() == other.getLimit();
}
@Override
public String toString() {
return this.getClass().getSimpleName() + " " + this.limit;
}
}