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/*
* Copyright (C) 2014-2024 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed 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.helger.commons.functional;
import javax.annotation.Nonnull;
import com.helger.commons.ValueEnforcer;
/**
* Represents a predicate (boolean-valued function) of one
* {@code boolean}-valued argument. This is the {@code boolean}-consuming
* primitive type specialization of {@link java.util.function.Predicate}.
*
* This is a functional interface whose
* functional method is {@link #test(boolean)}.
*
* @see java.util.function.Predicate
* @since 8.5.2
*/
@FunctionalInterface
public interface IBooleanPredicate
{
/**
* Evaluates this predicate on the given argument.
*
* @param bValue
* the input argument
* @return {@code true} if the input argument matches the predicate, otherwise
* {@code false}
*/
boolean test (boolean bValue);
/**
* Returns a predicate that represents the logical negation of this predicate.
*
* @return a predicate that represents the logical negation of this predicate
*/
@Nonnull
default IBooleanPredicate negate ()
{
return x -> !test (x);
}
/**
* Returns a composed predicate that represents a short-circuiting logical AND
* of this predicate and another. When evaluating the composed predicate, if
* this predicate is {@code false}, then the {@code other} predicate is not
* evaluated.
*
* Any exceptions thrown during evaluation of either predicate are relayed to
* the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param aOther
* a predicate that will be logically-ANDed with this predicate
* @return a composed predicate that represents the short-circuiting logical
* AND of this predicate and the {@code other} predicate
* @throws NullPointerException
* if other is null
*/
@Nonnull
default IBooleanPredicate and (@Nonnull final IBooleanPredicate aOther)
{
ValueEnforcer.notNull (aOther, "Other");
return x -> test (x) && aOther.test (x);
}
/**
* Returns a composed predicate that represents a short-circuiting logical OR
* of this predicate and another. When evaluating the composed predicate, if
* this predicate is {@code true}, then the {@code other} predicate is not
* evaluated.
*
* Any exceptions thrown during evaluation of either predicate are relayed to
* the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param aOther
* a predicate that will be logically-ORed with this predicate
* @return a composed predicate that represents the short-circuiting logical
* OR of this predicate and the {@code other} predicate
* @throws NullPointerException
* if other is null
*/
@Nonnull
default IBooleanPredicate or (@Nonnull final IBooleanPredicate aOther)
{
ValueEnforcer.notNull (aOther, "Other");
return x -> test (x) || aOther.test (x);
}
@Nonnull
static IBooleanPredicate all ()
{
return x -> true;
}
@Nonnull
static IBooleanPredicate none ()
{
return x -> false;
}
@Nonnull
static IBooleanPredicate ifTrue ()
{
// This is a brainer ;) "if true" is the identity function
return x -> x;
}
@Nonnull
static IBooleanPredicate ifFalse ()
{
return x -> !x;
}
}