/**
* 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 org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
import org.apache.hadoop.hbase.io.HbaseObjectWritable;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
/**
* This filter is used to filter cells based on value. It takes a {@link CompareFilter.CompareOp}
* operator (equal, greater, not equal, etc), and either a byte [] value or
* a WritableByteArrayComparable.
* <p>
* If we have a byte [] value then we just do a lexicographic compare. For
* example, if passed value is 'b' and cell has 'a' and the compare operator
* is LESS, then we will filter out this cell (return true). If this is not
* sufficient (eg you want to deserialize a long and then compare it to a fixed
* long value), then you can pass in your own comparator instead.
* <p>
* You must also specify a family and qualifier. Only the value of this column
* will be tested. When using this filter on a {@link Scan} with specified
* inputs, the column to be tested should also be added as input (otherwise
* the filter will regard the column as missing).
* <p>
* To prevent the entire row from being emitted if the column is not found
* on a row, use {@link #setFilterIfMissing}.
* Otherwise, if the column is found, the entire row will be emitted only if
* the value passes. If the value fails, the row will be filtered out.
* <p>
* In order to test values of previous versions (timestamps), set
* {@link #setLatestVersionOnly} to false. The default is true, meaning that
* only the latest version's value is tested and all previous versions are ignored.
* <p>
* To filter based on the value of all scanned columns, use {@link ValueFilter}.
*/
public class SingleColumnValueFilter extends FilterBase {
static final Log LOG = LogFactory.getLog(SingleColumnValueFilter.class);
protected byte [] columnFamily;
protected byte [] columnQualifier;
private CompareOp compareOp;
private WritableByteArrayComparable comparator;
private boolean foundColumn = false;
private boolean matchedColumn = false;
private boolean filterIfMissing = false;
private boolean latestVersionOnly = true;
/**
* Writable constructor, do not use.
*/
public SingleColumnValueFilter() {
}
/**
* Constructor for binary compare of the value of a single column. If the
* column is found and the condition passes, all columns of the row will be
* emitted. If the column is not found or the condition fails, the row will
* not be emitted.
*
* @param family name of column family
* @param qualifier name of column qualifier
* @param compareOp operator
* @param value value to compare column values against
*/
public SingleColumnValueFilter(final byte [] family, final byte [] qualifier,
final CompareOp compareOp, final byte[] value) {
this(family, qualifier, compareOp, new BinaryComparator(value));
}
/**
* Constructor for binary compare of the value of a single column. If the
* column is found and the condition passes, all columns of the row will be
* emitted. If the condition fails, the row will not be emitted.
* <p>
* Use the filterIfColumnMissing flag to set whether the rest of the columns
* in a row will be emitted if the specified column to check is not found in
* the row.
*
* @param family name of column family
* @param qualifier name of column qualifier
* @param compareOp operator
* @param comparator Comparator to use.
*/
public SingleColumnValueFilter(final byte [] family, final byte [] qualifier,
final CompareOp compareOp, final WritableByteArrayComparable comparator) {
this.columnFamily = family;
this.columnQualifier = qualifier;
this.compareOp = compareOp;
this.comparator = comparator;
}
/**
* @return operator
*/
public CompareOp getOperator() {
return compareOp;
}
/**
* @return the comparator
*/
public WritableByteArrayComparable getComparator() {
return comparator;
}
/**
* @return the family
*/
public byte[] getFamily() {
return columnFamily;
}
/**
* @return the qualifier
*/
public byte[] getQualifier() {
return columnQualifier;
}
public ReturnCode filterKeyValue(KeyValue keyValue) {
// System.out.println("REMOVE KEY=" + keyValue.toString() + ", value=" + Bytes.toString(keyValue.getValue()));
if (this.matchedColumn) {
// We already found and matched the single column, all keys now pass
return ReturnCode.INCLUDE;
} else if (this.latestVersionOnly && this.foundColumn) {
// We found but did not match the single column, skip to next row
return ReturnCode.NEXT_ROW;
}
if (!keyValue.matchingColumn(this.columnFamily, this.columnQualifier)) {
return ReturnCode.INCLUDE;
}
foundColumn = true;
if (filterColumnValue(keyValue.getBuffer(),
keyValue.getValueOffset(), keyValue.getValueLength())) {
return this.latestVersionOnly? ReturnCode.NEXT_ROW: ReturnCode.INCLUDE;
}
this.matchedColumn = true;
return ReturnCode.INCLUDE;
}
private boolean filterColumnValue(final byte [] data, final int offset,
final int length) {
// TODO: Can this filter take a rawcomparator so don't have to make this
// byte array copy?
int compareResult =
this.comparator.compareTo(Arrays.copyOfRange(data, offset, offset + length));
switch (this.compareOp) {
case LESS:
return compareResult <= 0;
case LESS_OR_EQUAL:
return compareResult < 0;
case EQUAL:
return compareResult != 0;
case NOT_EQUAL:
return compareResult == 0;
case GREATER_OR_EQUAL:
return compareResult > 0;
case GREATER:
return compareResult >= 0;
default:
throw new RuntimeException("Unknown Compare op " + compareOp.name());
}
}
public boolean filterRow() {
// If column was found, return false if it was matched, true if it was not
// If column not found, return true if we filter if missing, false if not
return this.foundColumn? !this.matchedColumn: this.filterIfMissing;
}
public void reset() {
foundColumn = false;
matchedColumn = false;
}
/**
* Get whether entire row should be filtered if column is not found.
* @return true if row should be skipped if column not found, false if row
* should be let through anyways
*/
public boolean getFilterIfMissing() {
return filterIfMissing;
}
/**
* Set whether entire row should be filtered if column is not found.
* <p>
* If true, the entire row will be skipped if the column is not found.
* <p>
* If false, the row will pass if the column is not found. This is default.
* @param filterIfMissing flag
*/
public void setFilterIfMissing(boolean filterIfMissing) {
this.filterIfMissing = filterIfMissing;
}
/**
* Get whether only the latest version of the column value should be compared.
* If true, the row will be returned if only the latest version of the column
* value matches. If false, the row will be returned if any version of the
* column value matches. The default is true.
* @return return value
*/
public boolean getLatestVersionOnly() {
return latestVersionOnly;
}
/**
* Set whether only the latest version of the column value should be compared.
* If true, the row will be returned if only the latest version of the column
* value matches. If false, the row will be returned if any version of the
* column value matches. The default is true.
* @param latestVersionOnly flag
*/
public void setLatestVersionOnly(boolean latestVersionOnly) {
this.latestVersionOnly = latestVersionOnly;
}
public void readFields(final DataInput in) throws IOException {
this.columnFamily = Bytes.readByteArray(in);
if(this.columnFamily.length == 0) {
this.columnFamily = null;
}
this.columnQualifier = Bytes.readByteArray(in);
if(this.columnQualifier.length == 0) {
this.columnQualifier = null;
}
this.compareOp = CompareOp.valueOf(in.readUTF());
this.comparator =
(WritableByteArrayComparable)HbaseObjectWritable.readObject(in, null);
this.foundColumn = in.readBoolean();
this.matchedColumn = in.readBoolean();
this.filterIfMissing = in.readBoolean();
this.latestVersionOnly = in.readBoolean();
}
public void write(final DataOutput out) throws IOException {
Bytes.writeByteArray(out, this.columnFamily);
Bytes.writeByteArray(out, this.columnQualifier);
out.writeUTF(compareOp.name());
HbaseObjectWritable.writeObject(out, comparator,
WritableByteArrayComparable.class, null);
out.writeBoolean(foundColumn);
out.writeBoolean(matchedColumn);
out.writeBoolean(filterIfMissing);
out.writeBoolean(latestVersionOnly);
}
}