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2.5 Implementing a Remote Interface

The general rules for a class that implements a remote interface are as follows:

For example, the following class BankAcctImpl implements the BankAccount remote interface and extends the java.rmi.server.UnicastRemoteObject class:

package mypackage;

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

public class BankAccountImpl
	extends UnicastRemoteObject
	implements BankAccount
{
	private float balance = 0.0;

	public BankAccountImpl(float initialBalance) 
		throws RemoteException 
	{
		balance = initialBalance;
	}
	public void deposit(float amount) throws RemoteException {
		...
	}
	public void withdraw(float amount) throws OverdrawnException,
		RemoteException {
		...
	}
	public float getBalance() throws RemoteException {
		...
	}
}


Note that if necessary, a class that implements a remote interface can extend some other class besides java.rmi.server.UnicastRemoteObject. However, the implementation class must then assume the responsibility for exporting the object (taken care of by the UnicastRemoteObject constructor) and for implementing (if needed) the correct remote semantics of the hashCode, equals, and toString methods inherited from the java.lang.Object class.



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