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/*
* 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.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 List<Object> resources;
public static final ResourcePath ROOT = new ResourcePath(ImmutableList.of());
public static ResourcePath child(ResourcePath parent, Object child) {
ImmutableList<Object> components = ImmutableList.builder()
.addAll(parent.components())
.add(child)
.build();
return new ResourcePath(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(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);
this.resources = ImmutableList.copyOf(components);
}
// for serialization
private ResourcePath() {
this.resources = null;
}
/**
* Returns the components of this resource path.
*
* @return the components of this resource path
*/
public List<Object> components() {
return resources;
}
/**
* 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() {
if (!isRoot()) {
return Optional.of(new ResourcePath(resources.subList(0, resources.size() - 1)));
}
return Optional.empty();
}
/**
* Returns true if the path represents root.
*
* @return true if the path represents root, false otherwise.
*/
public boolean isRoot() {
return resources.size() == 0;
}
/**
* 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 lastComponent() {
int last = resources.size() - 1;
return resources.get(last);
}
@Override
public int hashCode() {
return resources.hashCode();
}
@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.resources, that.resources);
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("resources", resources)
.toString();
}
}
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