| /* |
| * Copyright 2015 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.net.newresource; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.base.MoreObjects; |
| import com.google.common.collect.ImmutableList; |
| |
| import java.util.Arrays; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Objects; |
| import java.util.Optional; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| /** |
| * An object that is used to locate a resource in a network. |
| * A ResourcePath represents a path that is hierarchical and composed of a sequence |
| * of elementary resources that are not globally identifiable. A ResourcePath can be a globally |
| * unique resource identifier. |
| * |
| * Users of this class must keep the semantics of resources regarding the hierarchical structure. |
| * For example, resource path, Link:1/VLAN ID:100, is valid, but resource path, VLAN ID:100/Link:1 |
| * is not valid because a link is not a sub-component of a VLAN ID. |
| */ |
| @Beta |
| public final class ResourcePath { |
| |
| private final ResourcePath parent; |
| private final Object last; |
| |
| public static final ResourcePath ROOT = new ResourcePath(ImmutableList.of()); |
| |
| /** |
| * Creates an resource path from the specified components. |
| * |
| * @param components components of the path. The order represents hierarchical structure of the resource. |
| */ |
| public ResourcePath(Object... components) { |
| this(Arrays.asList(components)); |
| } |
| |
| /** |
| * Creates an resource path from the specified components. |
| * |
| * @param components components of the path. The order represents hierarchical structure of the resource. |
| */ |
| public ResourcePath(List<Object> components) { |
| checkNotNull(components); |
| if (components.isEmpty()) { |
| this.parent = null; |
| this.last = null; |
| return; |
| } |
| |
| LinkedList<Object> children = new LinkedList<>(components); |
| this.last = children.pollLast(); |
| this.parent = new ResourcePath(children); |
| } |
| |
| /** |
| * Creates an resource path from the specified parent and child. |
| * |
| * @param parent the parent of this resource |
| * @param last a child of the parent |
| */ |
| public ResourcePath(ResourcePath parent, Object last) { |
| this.parent = checkNotNull(parent); |
| this.last = checkNotNull(last); |
| } |
| |
| // for serialization |
| private ResourcePath() { |
| this.parent = null; |
| this.last = null; |
| } |
| |
| /** |
| * Returns the components of this resource path. |
| * |
| * @return the components of this resource path |
| */ |
| public List<Object> components() { |
| LinkedList<Object> components = new LinkedList<>(); |
| |
| ResourcePath parentPath = parent; |
| while (parentPath != null) { |
| components.addFirst(last); |
| parentPath = parent.parent; |
| } |
| |
| return components; |
| } |
| |
| /** |
| * Returns the parent resource path of this instance. |
| * E.g. if this path is Link:1/VLAN ID:100, the return value is the resource path for Link:1. |
| * |
| * @return the parent resource path of this instance. |
| * If there is no parent, empty instance will be returned. |
| */ |
| public Optional<ResourcePath> parent() { |
| return Optional.ofNullable(parent); |
| } |
| |
| public ResourcePath child(Object child) { |
| return new ResourcePath(this, child); |
| } |
| |
| /** |
| * Returns the last component of this instance. |
| * |
| * @return the last component of this instance. |
| * The return value is equal to the last object of {@code components()}. |
| */ |
| public Object last() { |
| return last; |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(this.parent, this.last); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (!(obj instanceof ResourcePath)) { |
| return false; |
| } |
| final ResourcePath that = (ResourcePath) obj; |
| return Objects.equals(this.parent, that.parent) |
| && Objects.equals(this.last, that.last); |
| } |
| |
| @Override |
| public String toString() { |
| return MoreObjects.toStringHelper(this) |
| .add("parent", parent) |
| .add("last", last) |
| .toString(); |
| } |
| } |