/*
* Copyright © 2014 Cask Data, Inc.
*
* 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 co.cask.cdap.common.zookeeper.coordination;
import com.google.common.base.Function;
import javax.annotation.Nullable;
/**
* A function to modify a {@link ResourceRequirement}.
*/
public interface ResourceModifier extends Function<ResourceRequirement, ResourceRequirement> {
/**
* Called to produce a new {@link ResourceRequirement}.
*
* @param existingRequirement The existing requirement or {@code null} if no existing requirement
* @return The new requirement to submit or {@code null} if no modification wanted to be made
*/
@Nullable
@Override
ResourceRequirement apply(@Nullable ResourceRequirement existingRequirement);
}