/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.server.types.texpressions;
import com.foundationdb.qp.operator.QueryBindings;
import com.foundationdb.qp.operator.QueryContext;
import com.foundationdb.qp.row.Row;
import com.foundationdb.server.explain.*;
import com.foundationdb.server.explain.std.TExpressionExplainer;
import com.foundationdb.server.types.TCast;
import com.foundationdb.server.types.TExecutionContext;
import com.foundationdb.server.types.TInstance;
import com.foundationdb.server.types.TPreptimeValue;
import com.foundationdb.server.types.value.Value;
import com.foundationdb.server.types.value.ValueSource;
import com.foundationdb.util.SparseArray;
import java.util.Collections;
public final class TCastExpression implements TPreparedExpression {
@Override
public TPreptimeValue evaluateConstant(QueryContext queryContext) {
TPreptimeValue inputValue = input.evaluateConstant(queryContext);
Value value;
if (inputValue == null || inputValue.value() == null) {
value = null;
}
else {
value = new Value(targetInstance);
TExecutionContext context = new TExecutionContext(
new SparseArray<>(),
Collections.singletonList(input.resultType()),
targetInstance,
queryContext,
null,
null,
null
);
cast.evaluate(context, inputValue.value(), value);
}
return new TPreptimeValue(targetInstance, value);
}
@Override
public TInstance resultType() {
return targetInstance;
}
@Override
public TEvaluatableExpression build() {
return new CastEvaluation(input.build(), cast, sourceInstance, targetInstance);
}
@Override
public CompoundExplainer getExplainer(ExplainContext context) {
CompoundExplainer ex = new TExpressionExplainer(Type.FUNCTION, "CAST", context);
ex.addAttribute(Label.OPERAND, input.getExplainer(context));
ex.addAttribute(Label.OUTPUT_TYPE, PrimitiveExplainer.getInstance(targetInstance.toStringConcise(false)));
return ex;
}
@Override
public String toString() {
return "CAST(" + input + " AS " + targetInstance + ")";
}
public TCastExpression(TPreparedExpression input, TCast cast, TInstance targetInstance) {
this.input = input;
this.cast = cast;
this.targetInstance = targetInstance;
this.sourceInstance = input.resultType();
assert sourceInstance.typeClass() == cast.sourceClass()
: sourceInstance + " not an acceptable source for cast " + cast;
}
private final TInstance sourceInstance;
private final TInstance targetInstance;
private final TPreparedExpression input;
private final TCast cast;
private static class CastEvaluation implements TEvaluatableExpression {
@Override
public ValueSource resultValue() {
return value;
}
@Override
public void evaluate() {
inputEval.evaluate();
ValueSource inputVal = inputEval.resultValue();
cast.evaluate(executionContext, inputVal, value);
}
@Override
public void with(Row row) {
inputEval.with(row);
}
@Override
public void with(QueryContext context) {
inputEval.with(context);
this.executionContext.setQueryContext(context);
}
@Override
public void with(QueryBindings bindings) {
inputEval.with(bindings);
}
private CastEvaluation(TEvaluatableExpression inputEval, TCast cast,
TInstance sourceInstance, TInstance targetInstance)
{
this.inputEval = inputEval;
this.cast = cast;
this.value = new Value(targetInstance);
this.executionContext = new TExecutionContext(
Collections.singletonList(sourceInstance),
targetInstance,
null);
}
private final TExecutionContext executionContext;
private final TEvaluatableExpression inputEval;
private final TCast cast;
private final Value value;
}
}