org.apache.flink.util.TernaryBoolean Maven / Gradle / Ivy
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* 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.flink.util;
import org.apache.flink.annotation.PublicEvolving;
import javax.annotation.Nullable;
/**
* A ternary boolean, which can have the values 'true', 'false', or 'undefined'.
*
* A ternary boolean can for example be used to configuration switches that
* may be not configured (undefined), in which case a default value should be assumed.
*/
@PublicEvolving
public enum TernaryBoolean {
/** The value for 'true'. */
TRUE,
/** The value for 'false'. */
FALSE,
/** The value for 'undefined'. In a configuration setting, this typically means that the
* default value will be used, or the value from a deployment-wide configuration.*/
UNDEFINED;
// ------------------------------------------------------------------------
/**
* Gets the boolean value corresponding to this value. If this is the 'undefined' value,
* the method returns the given default.
*
* @param defaultValue The value to be returned in case this ternary value is 'undefined'.
*/
public boolean getOrDefault(boolean defaultValue) {
return this == UNDEFINED ? defaultValue : (this == TRUE);
}
/**
* Gets the boolean value corresponding to this value. If this is the 'UNDEFINED' value,
* the method returns the given valueForUndefined.
*
* @param valueForUndefined The value to be returned in case this ternary value is 'undefined'.
*/
public TernaryBoolean resolveUndefined(boolean valueForUndefined) {
return this != UNDEFINED ? this : fromBoolean(valueForUndefined);
}
/**
* Gets this ternary boolean as a boxed boolean. The value 'undefined' results
* in 'null.
*/
@Nullable
public Boolean getAsBoolean() {
return this == UNDEFINED ? null : (this == TRUE ? Boolean.TRUE : Boolean.FALSE);
}
// ------------------------------------------------------------------------
/**
* Converts the given boolean to a TernaryBoolean, {@link #TRUE} or {@link #FALSE} respectively.
*/
public static TernaryBoolean fromBoolean(boolean bool) {
return bool ? TRUE : FALSE;
}
/**
* Converts the given boxed Boolean to a TernaryBoolean. A null value results in
* {@link #UNDEFINED}, while a non-null value results in {@link #TRUE} or {@link #FALSE} respectively.
*/
public static TernaryBoolean fromBoxedBoolean(@Nullable Boolean bool) {
return bool == null ? UNDEFINED : fromBoolean(bool);
}
}