org.apache.phoenix.expression.RowValueConstructorExpression Maven / Gradle / Ivy
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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.
*/
/**
* Implementation for row value constructor (a,b,c) expression.
*
*
* @since 0.1
*/
package org.apache.phoenix.expression;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Arrays;
import java.util.BitSet;
import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.expression.visitor.ExpressionVisitor;
import org.apache.phoenix.query.QueryConstants;
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.PVarbinary;
import org.apache.phoenix.util.ByteUtil;
import org.apache.phoenix.util.SchemaUtil;
import org.apache.phoenix.util.TrustedByteArrayOutputStream;
public class RowValueConstructorExpression extends BaseCompoundExpression {
private ImmutableBytesWritable ptrs[];
private ImmutableBytesWritable literalExprPtr;
private int partialEvalIndex = -1;
private int estimatedByteSize;
// The boolean field that indicated the object is a literal constant,
// has been repurposed to a bitset and now holds additional information.
// This is to facilitate b/w compat to 4.13 clients.
// @see PHOENIX-5122
private BitSet extraFields;
// Important : When you want to add new bits make sure to add those towards the end,
// else will break b/w compat again.
private enum ExtraFieldPosition {
LITERAL_CONSTANT(0),
STRIP_TRAILING_SEPARATOR_BYTE(1);
private int bitPosition;
private ExtraFieldPosition(int position) {
bitPosition = position;
}
private int getBitPosition() {
return bitPosition;
}
}
public RowValueConstructorExpression() {
}
public RowValueConstructorExpression(List children, boolean isConstant) {
super(children);
extraFields = new BitSet(8);
extraFields.set(ExtraFieldPosition.STRIP_TRAILING_SEPARATOR_BYTE.getBitPosition());
if (isConstant) {
extraFields.set(ExtraFieldPosition.LITERAL_CONSTANT.getBitPosition());
}
estimatedByteSize = 0;
init();
}
public RowValueConstructorExpression clone(List children) {
return new RowValueConstructorExpression(children, literalExprPtr != null);
}
public int getEstimatedSize() {
return estimatedByteSize;
}
@Override
public boolean isStateless() {
return literalExprPtr != null;
}
@Override
public final T accept(ExpressionVisitor visitor) {
List l = acceptChildren(visitor, visitor.visitEnter(this));
T t = visitor.visitLeave(this, l);
if (t == null) {
t = visitor.defaultReturn(this, l);
}
return t;
}
@Override
public void readFields(DataInput input) throws IOException {
super.readFields(input);
extraFields = BitSet.valueOf(new byte[] {input.readByte()});
init();
}
@Override
public void write(DataOutput output) throws IOException {
super.write(output);
byte[] b = extraFields.toByteArray();
output.writeByte((int)(b.length > 0 ? b[0] & 0xff : 0));
}
private void init() {
this.ptrs = new ImmutableBytesWritable[children.size()];
if (isConstant()) {
ImmutableBytesWritable ptr = new ImmutableBytesWritable();
this.evaluate(null, ptr);
literalExprPtr = ptr;
}
}
private boolean isConstant() {
return extraFields.get(ExtraFieldPosition.LITERAL_CONSTANT.getBitPosition());
}
private boolean isStripTrailingSepByte() {
return extraFields.get(ExtraFieldPosition.STRIP_TRAILING_SEPARATOR_BYTE.getBitPosition());
}
@Override
public PDataType getDataType() {
return PVarbinary.INSTANCE;
}
@Override
public void reset() {
partialEvalIndex = 0;
estimatedByteSize = 0;
Arrays.fill(ptrs, null);
super.reset();
}
private static int getExpressionByteCount(Expression e) {
PDataType childType = e.getDataType();
if (childType != null && !childType.isFixedWidth()) {
return 1;
} else {
// Write at least one null byte in the case of the child being null with a childType of null
return childType == null || !childType.isFixedWidth() ? 1 : SchemaUtil.getFixedByteSize(e);
}
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
if(literalExprPtr != null) {
// if determined during construction that the row value constructor is just comprised of literal expressions,
// let's just return the ptr we have already computed and be done with evaluation.
ptr.set(literalExprPtr.get(), literalExprPtr.getOffset(), literalExprPtr.getLength());
return true;
}
try {
boolean isPartialEval = this.partialEvalIndex >= 0;
int evalIndex = isPartialEval ? this.partialEvalIndex : 0;
int expressionCount = evalIndex;
for(; evalIndex < ptrs.length; evalIndex++) {
final Expression expression = children.get(evalIndex);
// TODO: handle overflow and underflow
if (expression.evaluate(tuple, ptr)) {
if (ptr.getLength() == 0) {
estimatedByteSize += getExpressionByteCount(expression);
} else {
expressionCount = evalIndex+1;
ptrs[evalIndex] = new ImmutableBytesWritable();
ptrs[evalIndex].set(ptr.get(), ptr.getOffset(), ptr.getLength());
estimatedByteSize += ptr.getLength() + (expression.getDataType().isFixedWidth() ? 0 : 1); // 1 extra for the separator byte.
}
} else if (tuple == null || tuple.isImmutable()) {
estimatedByteSize += getExpressionByteCount(expression);
} else { // Cannot yet be evaluated
return false;
}
}
if (isPartialEval) {
this.partialEvalIndex = evalIndex; // Move counter forward
}
if (evalIndex == ptrs.length) {
if (expressionCount == 0) {
ptr.set(ByteUtil.EMPTY_BYTE_ARRAY);
return true;
}
if (expressionCount == 1) {
ptr.set(ptrs[0].get(), ptrs[0].getOffset(), ptrs[0].getLength());
return true;
}
TrustedByteArrayOutputStream output = new TrustedByteArrayOutputStream(estimatedByteSize);
try {
boolean previousCarryOver = false;
for (int i = 0; i< expressionCount; i++) {
Expression child = getChildren().get(i);
PDataType childType = child.getDataType();
ImmutableBytesWritable tempPtr = ptrs[i];
if (tempPtr == null) {
// Since we have a null and have no representation for null,
// we must decrement the value of the current. Otherwise,
// we'd have an ambiguity if this value happened to be the
// min possible value.
previousCarryOver = childType == null || childType.isFixedWidth();
int bytesToWrite = getExpressionByteCount(child);
for (int m = 0; m < bytesToWrite; m++) {
output.write(QueryConstants.SEPARATOR_BYTE);
}
} else {
output.write(tempPtr.get(), tempPtr.getOffset(), tempPtr.getLength());
if (!childType.isFixedWidth()) {
output.write(SchemaUtil.getSeparatorByte(true, false, child));
}
if (previousCarryOver) {
previousCarryOver = !ByteUtil.previousKey(output.getBuffer(), output.size());
}
}
}
int outputSize = output.size();
byte[] outputBytes = output.getBuffer();
// Don't remove trailing separator byte unless it's the one for ASC
// as otherwise we need it to ensure sort order is correct.
// Additionally for b/w compat with clients older than 4.14.1 -
// If SortOorder.ASC then always strip trailing separator byte (as before)
// else only strip for >= 4.14 client (when STRIP_TRAILING_SEPARATOR_BYTE bit is set)
for (int k = expressionCount -1 ;
k >=0 && getChildren().get(k).getDataType() != null
&& !getChildren().get(k).getDataType().isFixedWidth()
&& outputBytes[outputSize-1] == SchemaUtil.getSeparatorByte(true, false, getChildren().get(k))
&& (getChildren().get(k).getSortOrder() == SortOrder.ASC ? true : isStripTrailingSepByte()) ; k--) {
outputSize--;
}
ptr.set(outputBytes, 0, outputSize);
return true;
} finally {
output.close();
}
}
return false;
} catch (IOException e) {
throw new RuntimeException(e); //Impossible.
}
}
@Override
public final String toString() {
StringBuilder buf = new StringBuilder("(");
for (int i = 0; i < children.size() - 1; i++) {
buf.append(children.get(i) + ", ");
}
buf.append(children.get(children.size()-1) + ")");
return buf.toString();
}
@Override
public boolean requiresFinalEvaluation() {
return true;
}
}
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