/**
* 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.tajo.engine.eval;
import com.google.gson.annotations.Expose;
import org.apache.tajo.catalog.CatalogUtil;
import org.apache.tajo.catalog.Column;
import org.apache.tajo.catalog.Schema;
import org.apache.tajo.common.TajoDataTypes;
import org.apache.tajo.common.TajoDataTypes.DataType;
import org.apache.tajo.datum.BooleanDatum;
import org.apache.tajo.datum.Datum;
import org.apache.tajo.datum.DatumFactory;
import org.apache.tajo.datum.NullDatum;
import org.apache.tajo.storage.Tuple;
public class IsNullEval extends BinaryEval {
// it's just a hack to emulate a binary expression
private final static ConstEval DUMMY_EVAL = new ConstEval(DatumFactory.createBool(true));
private static final DataType RES_TYPE = CatalogUtil.newSimpleDataType(TajoDataTypes.Type.BOOLEAN);
// persistent variables
@Expose private boolean isNot;
public IsNullEval(boolean not, EvalNode predicand) {
super(EvalType.IS_NULL, predicand, DUMMY_EVAL);
this.isNot = not;
}
@Override
public EvalContext newContext() {
IsNullEvalCtx context = new IsNullEvalCtx();
context.predicandContext = leftExpr.newContext();
return context;
}
@Override
public DataType getValueType() {
return RES_TYPE;
}
@Override
public String getName() {
return "?";
}
@Override
public void eval(EvalContext ctx, Schema schema, Tuple tuple) {
IsNullEvalCtx isNullCtx = (IsNullEvalCtx) ctx;
leftExpr.eval(isNullCtx.predicandContext, schema, tuple);
Datum result = leftExpr.terminate(((IsNullEvalCtx)ctx).predicandContext);
((IsNullEvalCtx) ctx).result = DatumFactory.createBool(isNot ^ (result.type() == TajoDataTypes.Type.NULL));
}
@Override
public Datum terminate(EvalContext ctx) {
return ((IsNullEvalCtx)ctx).result;
}
public boolean isNot() {
return isNot;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof IsNullEval) {
IsNullEval other = (IsNullEval) obj;
return super.equals(other) && isNot == other.isNot();
} else {
return false;
}
}
public Object clone() throws CloneNotSupportedException {
IsNullEval isNullEval = (IsNullEval) super.clone();
isNullEval.isNot = isNot;
return isNullEval;
}
private class IsNullEvalCtx implements EvalContext {
EvalContext predicandContext;
BooleanDatum result;
IsNullEvalCtx() {
this.result = DatumFactory.createBool(false);
}
}
}