/**
*
* Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
*
* 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.speedment.runtime.config.trait;
import com.speedment.runtime.config.Document;
import java.util.Optional;
/**
* Trait for {@link Document} implementations that is not the root. More
* concretely this means that they implement the {@link #getParent()} method.
*
* @param <PARENT> the type of the parent document
* @author Emil Forslund
* @version 2.3.0
*/
public interface HasParent<PARENT extends Document> extends Document {
/**
* Returns the parent of this document. That is the document that is located
* exactly one step above this document in the tree. If this is a root node,
* an empty {@code Optional} is returned.
*
* @return the parent or {@code empty} if this is the root
* @see #getParentOrThrow()
*/
@Override
Optional<PARENT> getParent();
/**
* Returns the parent of this document or throws an exception if this was
* the root. This method can be used if you know beforehand that this
* document is never the root.
*
* @return the parent document
* @throws IllegalStateException if this was the root
* @see #getParent()
*/
default PARENT getParentOrThrow() throws IllegalStateException {
return getParent().orElseThrow(
() -> new IllegalStateException(
"Unable to get parent for " + toString()
)
);
}
}