/*
* 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;
import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.expression.visitor.ExpressionVisitor;
import org.apache.phoenix.schema.SortOrder;
import org.apache.phoenix.schema.PDataType;
import org.apache.phoenix.schema.tuple.Tuple;
import org.apache.phoenix.util.ByteUtil;
/**
*
* Implementation for || string concatenation expression.
*
* @since 0.1
*/
public class StringConcatExpression extends BaseCompoundExpression {
public StringConcatExpression() {
}
public StringConcatExpression(List<Expression> children) {
super(children);
}
@Override
public 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));
buf.append(')');
return buf.toString();
}
@Override
public final <T> T accept(ExpressionVisitor<T> visitor) {
List<T> l = acceptChildren(visitor, visitor.visitEnter(this));
T t = visitor.visitLeave(this, l);
if (t == null) {
t = visitor.defaultReturn(this, l);
}
return t;
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
byte[] result = ByteUtil.EMPTY_BYTE_ARRAY;
for (int i=0; i<children.size(); i++) {
if (children.get(i).getDataType() == null || !children.get(i).evaluate(tuple, ptr)) {
continue;
}
PDataType childType = children.get(i).getDataType();
SortOrder sortOrder = children.get(i).getSortOrder();
// We could potentially not invert the bytes, but we might as well since we're allocating
// additional space here anyway.
if (childType.isCoercibleTo(PDataType.VARCHAR)) {
result = ByteUtil.concat(result, ByteUtil.concat(sortOrder, ptr));
} else {
result = ByteUtil.concat(result, PDataType.VARCHAR.toBytes(childType.toObject(ptr, sortOrder).toString()));
}
}
ptr.set(result);
return true;
}
@Override
public PDataType getDataType() {
return PDataType.VARCHAR;
}
}