com.hazelcast.sql.impl.expression.predicate.TernaryLogic Maven / Gradle / Ivy
/*
* Copyright 2024 Hazelcast Inc.
*
* Licensed under the Hazelcast Community License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://hazelcast.com/hazelcast-community-license
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.sql.impl.expression.predicate;
import com.hazelcast.sql.impl.expression.Expression;
import com.hazelcast.sql.impl.expression.ExpressionEvalContext;
import com.hazelcast.sql.impl.row.Row;
/**
* Implements ternary boolean logic according to SQL standard.
*
* SQL BOOLEAN type is represented by Java {@link Boolean} type, SQL BOOLEAN NULL,
* also known as UNKNOWN, is represented as Java {@code null}.
*/
public final class TernaryLogic {
private TernaryLogic() {
// No-op.
}
/**
* Performs AND for the given operands acting on the given row in the given
* context.
*
* The method exhibits a short-circuiting behaviour: there is no guarantee
* all of the passed operands would be evaluated. Operand evaluation order
* is unspecified.
*
* @param row the row to evaluate the operands on.
* @param context the context to evaluate the operands in.
* @param operands the boolean operands to evaluate.
* @return {@code true} if all of the operands were evaluated to {@code true},
* {@code false} if at least one of the operands was evaluated to {@code false},
* {@code null} otherwise.
*/
public static Boolean and(Row row, ExpressionEvalContext context, Expression... operands) {
boolean seenUnknown = false;
for (Expression operand : operands) {
Boolean result = (Boolean) operand.eval(row, context);
if (isFalse(result)) {
return Boolean.FALSE;
}
if (isNull(result)) {
seenUnknown = true;
}
}
return seenUnknown ? null : Boolean.TRUE;
}
/**
* Performs OR for the given operands acting on the given row in the given
* context.
*
* The method exhibits a short-circuiting behaviour: there is no guarantee
* all of the passed operands would be evaluated. Operand evaluation order
* is unspecified.
*
* @param row the row to evaluate the operands on.
* @param context the context to evaluate the operands in.
* @param operands the boolean operands to evaluate.
* @return {@code false} if all of the operands were evaluated to {@code false},
* {@code true} if at least one of the operands was evaluated to {@code true},
* {@code null} otherwise.
*/
public static Boolean or(Row row, ExpressionEvalContext context, Expression... operands) {
boolean seenUnknown = false;
for (Expression operand : operands) {
Boolean result = (Boolean) operand.eval(row, context);
if (isTrue(result)) {
return Boolean.TRUE;
}
if (isNull(result)) {
seenUnknown = true;
}
}
return seenUnknown ? null : Boolean.FALSE;
}
/**
* Negates the given boolean value.
*
* @param value the value to negate.
* @return {@code true} if the passed value was {@code false}, {@code false}
* if it was {@code true}, {@code null} if it was {@code null}.
*/
public static Boolean not(Boolean value) {
return value == null ? null : !value;
}
/**
* Checks whether the given value is {@code null}.
*
* @param value the value to check.
* @return {@code true} if the passed value is {@code null}, {@code false}
* otherwise.
*/
public static boolean isNull(Object value) {
return value == null;
}
/**
* Checks whether the given value is not {@code null}.
*
* @param value the value to check.
* @return {@code false} if the passed value is {@code null}, {@code true}
* otherwise.
*/
public static boolean isNotNull(Object value) {
return value != null;
}
/**
* Checks whether the given value is {@code true}.
*
* @param value the value to check.
* @return {@code true} if the passed value is {@code true}; {@code false}
* otherwise, i.e. the passed value is either {@code false} or {@code null}.
*/
public static boolean isTrue(Boolean value) {
return value != null && value;
}
/**
* Checks whether the given value is not {@code true}.
*
* @param value the value to check.
* @return {@code true} if the passed value is either {@code false} or
* {@code null}; {@code false} otherwise, i.e. the passed value is {@code
* true}.
*/
public static boolean isNotTrue(Boolean value) {
return value == null || !value;
}
/**
* Checks whether the given value is {@code false}.
*
* @param value the value to check.
* @return {@code true} if the passed value is {@code false}; {@code false}
* otherwise, i.e. the passed value is either {@code true} or {@code null}.
*/
public static boolean isFalse(Boolean value) {
return value != null && !value;
}
/**
* Checks whether the given value is not {@code false}.
*
* @param value the value to check.
* @return {@code true} if the passed value is either {@code true} or
* {@code null}; {@code false} otherwise, i.e. the passed value is {@code
* false}.
*/
public static boolean isNotFalse(Boolean value) {
return value == null || value;
}
}