com.hazelcast.org.apache.calcite.rel.metadata.NullSentinel 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.rel.metadata;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
/** Placeholder for null values. */
public enum NullSentinel {
/** Placeholder for a null value. */
INSTANCE {
@Override public String toString() {
return "NULL";
}
},
/** Placeholder that means that a request for metadata is already active,
* therefore this request forms a cycle. */
ACTIVE;
public static Comparable mask(@Nullable Comparable value) {
if (value == null) {
return INSTANCE;
}
return value;
}
public static Object mask(@Nullable Object value) {
if (value == null) {
return INSTANCE;
}
return value;
}
}