Java tutorial
/* * 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 com.google.common.base.MoreObjects; import com.google.common.collect.Sets; import org.onosproject.net.resource.DiscreteResource; import org.onosproject.net.resource.DiscreteResourceId; import org.onosproject.net.resource.Resources; import java.util.LinkedHashSet; import java.util.Objects; import java.util.Optional; import java.util.Set; import java.util.stream.Collectors; final class GenericDiscreteResources implements DiscreteResources { private final Set<DiscreteResource> values; static DiscreteResources of(Set<DiscreteResource> resources) { if (resources.isEmpty()) { return DiscreteResources.empty(); } return new GenericDiscreteResources(resources); } private GenericDiscreteResources(Set<DiscreteResource> values) { this.values = values; } // for serializer private GenericDiscreteResources() { this.values = null; } @Override public Optional<DiscreteResource> lookup(DiscreteResourceId id) { DiscreteResource resource = Resources.discrete(id).resource(); if (values.contains(resource)) { return Optional.of(resource); } else { return Optional.empty(); } } @Override public DiscreteResources difference(DiscreteResources other) { if (other instanceof GenericDiscreteResources) { // make sure that the set is serializable return of(new LinkedHashSet<>(Sets.difference(this.values(), other.values()))); } else if (other instanceof EmptyDiscreteResources) { return this; } return DiscreteResources.of(Sets.difference(this.values(), other.values())); } @Override public boolean isEmpty() { return values.isEmpty(); } @Override public boolean containsAny(Set<DiscreteResource> other) { return !Sets.intersection(this.values(), other).isEmpty(); } // returns a new instance, not mutate the current instance @Override public DiscreteResources add(DiscreteResources other) { if (other instanceof GenericDiscreteResources) { // make sure that the set is serializable return of(new LinkedHashSet<>(Sets.union(this.values(), other.values()))); } else if (other instanceof EmptyDiscreteResources) { return this; } return DiscreteResources.of(Sets.union(this.values(), other.values())); } @Override public Set<DiscreteResource> values() { // breaks immutability, but intentionally returns the field // because this class is transient return values; } @Override public <T> Set<DiscreteResource> valuesOf(Class<T> cls) { return values.stream().filter(x -> x.isTypeOf(cls)).collect(Collectors.toCollection(LinkedHashSet::new)); } @Override public int hashCode() { return Objects.hash(values); } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null || getClass() != obj.getClass()) { return false; } final GenericDiscreteResources other = (GenericDiscreteResources) obj; return Objects.equals(this.values, other.values); } @Override public String toString() { return MoreObjects.toStringHelper(this).add("values", values).toString(); } }