com.hazelcast.org.apache.calcite.sql2rel.AuxiliaryConverter Maven / Gradle / Ivy
/*
* 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 com.hazelcast.org.apache.calcite.sql2rel;
import com.hazelcast.org.apache.calcite.rex.RexBuilder;
import com.hazelcast.org.apache.calcite.rex.RexCall;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.sql.SqlFunction;
import com.hazelcast.org.apache.calcite.sql.fun.SqlStdOperatorTable;
/** Converts an expression for a group window function (e.g. TUMBLE)
* into an expression for an auxiliary group function (e.g. TUMBLE_START).
*
* @see SqlStdOperatorTable#TUMBLE_OLD
*/
public interface AuxiliaryConverter {
/** Converts an expression.
*
* @param rexBuilder Rex builder
* @param groupCall Call to the group function, e.g. "TUMBLE($2, 36000)"
* @param e Expression holding result of the group function, e.g. "$0"
*
* @return Expression for auxiliary function, e.g. "$0 + 36000" converts
* the result of TUMBLE to the result of TUMBLE_END
*/
RexNode convert(RexBuilder rexBuilder, RexNode groupCall, RexNode e);
/** Simple implementation of {@link AuxiliaryConverter}. */
class Impl implements AuxiliaryConverter {
private final SqlFunction f;
public Impl(SqlFunction f) {
this.f = f;
}
@Override public RexNode convert(RexBuilder rexBuilder, RexNode groupCall,
RexNode e) {
switch (f.getKind()) {
case TUMBLE_START:
case HOP_START:
case SESSION_START:
case SESSION_END:
return e;
case TUMBLE_END:
return rexBuilder.makeCall(
SqlStdOperatorTable.PLUS, e,
((RexCall) groupCall).operands.get(1));
case HOP_END:
return rexBuilder.makeCall(
SqlStdOperatorTable.PLUS, e,
((RexCall) groupCall).operands.get(2));
default:
throw new AssertionError("unknown: " + f);
}
}
}
}