/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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
 *
 *      https://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.
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package org.springframework.beans;

import org.springframework.lang.Nullable;

Interface representing an object whose value set can be merged with
that of a parent object.
Author:
Rob Harrop
See Also:
ManagedSet
ManagedList
ManagedMap
ManagedProperties
Since:
2.0/**
 * Interface representing an object whose value set can be merged with
 * that of a parent object.
 *
 * @author Rob Harrop
 * @since 2.0
 * @see org.springframework.beans.factory.support.ManagedSet
 * @see org.springframework.beans.factory.support.ManagedList
 * @see org.springframework.beans.factory.support.ManagedMap
 * @see org.springframework.beans.factory.support.ManagedProperties
 */
public interface Mergeable {

	
Is merging enabled for this particular instance?
/**
	 * Is merging enabled for this particular instance?
	 */
	boolean isMergeEnabled();

	
Merge the current value set with that of the supplied object.
The supplied object is considered the parent, and values in
the callee's value set must override those of the supplied object.
Params:
parent – the object to merge with
Throws:
IllegalArgumentException – if the supplied parent is null
IllegalStateException – if merging is not enabled for this instance (i.e. mergeEnabled equals false).
Returns:
the result of the merge operation/**
	 * Merge the current value set with that of the supplied object.
	 * <p>The supplied object is considered the parent, and values in
	 * the callee's value set must override those of the supplied object.
	 * @param parent the object to merge with
	 * @return the result of the merge operation
	 * @throws IllegalArgumentException if the supplied parent is {@code null}
	 * @throws IllegalStateException if merging is not enabled for this instance
	 * (i.e. {@code mergeEnabled} equals {@code false}).
	 */
	Object merge(@Nullable Object parent);

}