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The Java Data Objects API (JDO) : a standard interface-based Java model abstraction of persistence, developed by the JCP.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
/*
* LongIdentity.java
*
*/
package javax.jdo.identity;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/** This class is for identity with a single long field.
* @version 2.0
*/
public class LongIdentity extends SingleFieldIdentity {
/** The key.
*/
private long key;
private void construct(long key) {
this.key = key;
hashCode = hashClassName() ^ (int)key;
}
/** Constructor with class and key.
* @param pcClass the class
* @param key the key
*/
public LongIdentity (Class pcClass, long key) {
super (pcClass);
construct(key);
}
/** Constructor with class and key.
* @param pcClass the class
* @param key the key
*/
public LongIdentity (Class pcClass, Long key) {
super(pcClass);
setKeyAsObject(key);
construct(key.longValue());
}
/** Constructor with class and key.
* @param pcClass the class
* @param str the key
*/
public LongIdentity (Class pcClass, String str) {
super(pcClass);
assertKeyNotNull(str);
construct(Long.parseLong(str));
}
/** Constructor only for Externalizable.
*/
public LongIdentity () {
}
/** Return the key.
* @return the key
*/
public long getKey () {
return key;
}
/** Return the String form of the key.
* @return the String form of the key
*/
public String toString () {
return Long.toString(key);
}
/** Determine if the other object represents the same object id.
* @param obj the other object
* @return true if both objects represent the same object id
*/
public boolean equals (Object obj) {
if (this == obj) {
return true;
} else if (!super.equals (obj)) {
return false;
} else {
LongIdentity other = (LongIdentity) obj;
return key == other.key;
}
}
/** Determine the ordering of identity objects.
* @param o Other identity
* @return The relative ordering between the objects
* @since 2.2
*/
public int compareTo(Object o) {
if (o instanceof LongIdentity) {
LongIdentity other = (LongIdentity)o;
int result = super.compare(other);
if (result == 0) {
long diff = key - other.key;
if (diff == 0) {
return 0;
} else {
if (diff < 0) {
return -1;
} else {
return 1;
}
}
} else {
return result;
}
}
else if (o == null) {
throw new ClassCastException("object is null");
}
throw new ClassCastException(this.getClass().getName() + " != " + o.getClass().getName());
}
/** Create the key as an Object.
* @return the key as an Object
* @since 2.0
*/
protected Object createKeyAsObject() {
return new Long(key);
}
/** Write this object. Write the superclass first.
* @param out the output
*/
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal (out);
out.writeLong(key);
}
/** Read this object. Read the superclass first.
* @param in the input
*/
public void readExternal(ObjectInput in)
throws IOException, ClassNotFoundException {
super.readExternal (in);
key = in.readLong();
}
}