Identifier.java
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/*
* 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.onlab.util;
import java.util.Objects;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* Abstract identifier backed by another value, e.g. string, int.
*/
public class Identifier<T> {
protected final T identifier; // backing identifier value
/**
* Constructor for serialization.
*/
protected Identifier() {
this.identifier = null;
}
/**
* Constructs an identifier backed by the specified value.
*
* @param value the backing value
*/
protected Identifier(T value) {
this.identifier = checkNotNull(value, "Identifier cannot be null.");
}
/**
* Returns the backing identifier value.
*
* @return identifier
*/
public T id() {
return identifier;
}
/**
* Returns the hashcode of the identifier.
*
* @return hashcode
*/
@Override
public int hashCode() {
return identifier.hashCode();
}
/**
* Compares two device key identifiers for equality.
*
* @param obj to compare against
* @return true if the objects are equal, false otherwise.
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof Identifier) {
Identifier that = (Identifier) obj;
return this.getClass() == that.getClass() &&
Objects.equals(this.identifier, that.identifier);
}
return false;
}
/**
* Returns a string representation of a DeviceKeyId.
*
* @return string
*/
public String toString() {
return identifier.toString();
}
}