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* 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.phoenix.expression.function;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.compile.KeyPart;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.parse.FunctionParseNode.Argument;
import org.apache.phoenix.parse.FunctionParseNode.BuiltInFunction;
import org.apache.phoenix.query.KeyRange;
import org.apache.phoenix.query.QueryConstants;
import org.apache.phoenix.schema.PColumn;
import org.apache.phoenix.schema.PTable;
import org.apache.phoenix.schema.SortOrder;
import org.apache.phoenix.schema.tuple.Tuple;
import org.apache.phoenix.schema.types.PDataType;
import org.apache.phoenix.schema.types.PVarchar;
import org.apache.phoenix.util.ByteUtil;
import org.apache.phoenix.util.StringUtil;
/**
*
* Implementation of the RTrim() build-in function. It removes from the right end of
* space character and other function bytes in single byte utf8 characters set
*
*
* @since 0.1
*/
@BuiltInFunction(name=RTrimFunction.NAME, args={
@Argument(allowedTypes={PVarchar.class})})
public class RTrimFunction extends ScalarFunction {
public static final String NAME = "RTRIM";
public RTrimFunction() { }
public RTrimFunction(List children) throws SQLException {
super(children);
}
private Expression getStringExpression() {
return children.get(0);
}
@Override
public SortOrder getSortOrder() {
return children.get(0).getSortOrder();
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
// Starting from the end of the byte, look for all single bytes at the end of the string
// that is below SPACE_UTF8 (space and control characters) or above (control chars).
if (!getStringExpression().evaluate(tuple, ptr)) {
return false;
}
if (ptr.getLength() == 0) {
ptr.set(ByteUtil.EMPTY_BYTE_ARRAY);
return true;
}
byte[] string = ptr.get();
int offset = ptr.getOffset();
int length = ptr.getLength();
SortOrder sortOrder = getStringExpression().getSortOrder();
int i = StringUtil.getFirstNonBlankCharIdxFromEnd(string, offset, length, sortOrder);
if (i == offset - 1) {
ptr.set(ByteUtil.EMPTY_BYTE_ARRAY);
return true;
}
ptr.set(string, offset, i - offset + 1);
return true;
}
@Override
public OrderPreserving preservesOrder() {
return OrderPreserving.YES_IF_LAST;
}
@Override
public int getKeyFormationTraversalIndex() {
return 0;
}
@Override
public KeyPart newKeyPart(final KeyPart childPart) {
return new KeyPart() {
@Override
public KeyRange getKeyRange(CompareOp op, Expression rhs) {
byte[] lowerRange = KeyRange.UNBOUND;
byte[] upperRange = KeyRange.UNBOUND;
boolean lowerInclusive = true;
boolean upperInclusive = false;
PDataType type = getColumn().getDataType();
SortOrder sortOrder = getColumn().getSortOrder();
switch (op) {
case LESS_OR_EQUAL:
lowerInclusive = false;
case EQUAL:
upperRange = evaluateExpression(rhs);
if (op == CompareOp.EQUAL) {
lowerRange = upperRange;
}
if (sortOrder == SortOrder.ASC || !getTable().rowKeyOrderOptimizable()) {
upperRange = Arrays.copyOf(upperRange, upperRange.length + 1);
upperRange[upperRange.length-1] = StringUtil.SPACE_UTF8;
ByteUtil.nextKey(upperRange, upperRange.length);
} else {
upperInclusive = true;
if (op == CompareOp.LESS_OR_EQUAL) {
// Nothing more to do here, as the biggest value for DESC
// will be the RHS value.
break;
}
/*
* Somewhat tricky to get the range correct for the DESC equality case.
* The lower range is the RHS value followed by any number of inverted spaces.
* We need to add a zero byte as the lower range will have an \xFF byte
* appended to it and otherwise we'd skip past any rows where there is more
* than one space following the RHS.
* The upper range should span up to and including the RHS value. We need
* to add our own \xFF as otherwise this will look like a degenerate query
* since the lower would be bigger than the upper range.
*/
lowerRange = Arrays.copyOf(lowerRange, lowerRange.length + 2);
lowerRange[lowerRange.length-2] = StringUtil.INVERTED_SPACE_UTF8;
lowerRange[lowerRange.length-1] = QueryConstants.SEPARATOR_BYTE;
upperRange = Arrays.copyOf(upperRange, upperRange.length + 1);
upperRange[upperRange.length-1] = QueryConstants.DESC_SEPARATOR_BYTE;
}
break;
default:
// TOOD: Is this ok for DESC?
return childPart.getKeyRange(op, rhs);
}
Integer length = getColumn().getMaxLength();
if (type.isFixedWidth() && length != null) {
// Don't pad based on current sort order, but instead use our
// minimum byte as otherwise we'll end up skipping rows in
// the case of descending, since rows with more padding appear
// *after* rows with no padding.
if (lowerRange != KeyRange.UNBOUND) {
lowerRange = type.pad(lowerRange, length, SortOrder.ASC);
}
if (upperRange != KeyRange.UNBOUND) {
upperRange = type.pad(upperRange, length, SortOrder.ASC);
}
}
KeyRange range = KeyRange.getKeyRange(lowerRange, lowerInclusive, upperRange, upperInclusive);
if (getColumn().getSortOrder() == SortOrder.DESC) {
range = range.invert();
}
return range;
}
@Override
public List getExtractNodes() {
// We cannot extract the node, as we may have false positives with trailing
// non blank characters such as 'foo bar' where the RHS constant is 'foo'.
return Collections.emptyList();
}
@Override
public PColumn getColumn() {
return childPart.getColumn();
}
@Override
public PTable getTable() {
return childPart.getTable();
}
};
}
@Override
public Integer getMaxLength() {
return getStringExpression().getMaxLength();
}
@Override
public PDataType getDataType() {
return PVarchar.INSTANCE;
}
@Override
public String getName() {
return NAME;
}
}