core/store/dist/src/main/java/org/onosproject/store/resource/impl/ResourceStoreUtil.java

/*
 * Copyright 2016-present Open Networking Laboratory
 *
 * 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 org.onosproject.store.resource.impl;

import org.onosproject.net.resource.ContinuousResource;

final class ResourceStoreUtil {
    // prohibit construction
    private ResourceStoreUtil() {}

    /**
     * Checks if there is enough resource volume to allocated the requested resource
     * against the specified resource.
     *
     * @param original   original resource
     * @param request    requested resource
     * @param allocation current allocation of the resource
     * @return true if there is enough resource volume. Otherwise, false.
     */
    // computational complexity: O(n) where n is the number of allocations
    static boolean hasEnoughResource(ContinuousResource original,
                                     ContinuousResource request,
                                     ContinuousResourceAllocation allocation) {
        if (allocation == null) {
            return request.value() <= original.value();
        }

        double allocated = allocation.allocations().stream()
                .filter(x -> x.resource() instanceof ContinuousResource)
                .map(x -> (ContinuousResource) x.resource())
                .mapToDouble(ContinuousResource::value)
                .sum();
        double left = original.value() - allocated;
        return request.value() <= left;
    }
}