/*
* 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.ambari.view.hive2.internal;
import com.google.common.base.Optional;
/**
* Simple implementation of a container class which can
* hold one of two values
* <p>
* Callers should check if the value if left or right before
* trying to get the value
*
* @param <L> Left Value
* @param <R> Right value
*/
public class Either<L, R> {
private final Optional<L> left;
private final Optional<R> right;
public boolean isLeft() {
return left.isPresent() && !right.isPresent();
}
public boolean isRight() {
return !left.isPresent() && right.isPresent();
}
public boolean isNone() { return !(left.isPresent() || right.isPresent()); }
public L getLeft() {
return left.orNull();
}
public R getRight() {
return right.orNull();
}
private Either(Optional<L> left, Optional<R> right) {
this.left = left;
this.right = right;
}
public static <L, R> Either<L, R> left(L value) {
return new Either<>(Optional.of(value), Optional.<R>absent());
}
public static <L, R> Either<L, R> right(R value) {
return new Either<>(Optional.<L>absent(), Optional.of(value));
}
public static <L, R> Either<L, R> none() {
return new Either<>(Optional.<L>absent(), Optional.<R>absent());
}
}