bank

Class TransactionListNIL

java.lang.Object

bank.TransactionList

bank.TransactionListNIL

public class TransactionListNIL
extends TransactionList

Singleton class for empty lists of transactions

Field Summary

Fields inherited from class bank.TransactionList

EMPTY_LIST

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TransactionListNIL() This class is a singleton, to access the only object use TransactionList.EMPTY_LIST

Method Summary

Methods

Modifier and Type	Method and Description
Transaction	head()
boolean	isEmpty()
int	length()
TransactionList	tail()

Methods inherited from class bank.TransactionList

prepend

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransactionListNIL

protected TransactionListNIL()

This class is a singleton, to access the only object use TransactionList.EMPTY_LIST

Method Detail

head

public Transaction head()

Specified by:

head in class TransactionList

Returns:

the first element of this list, or null iff this list is empty

tail

public TransactionList tail()

Specified by:

tail in class TransactionList

Returns:

the tail (the list without its first element) of this list, or null iff this list is empty

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in class TransactionList

Returns:

true iff this list is empty

length

public int length()

Specified by:

length in class TransactionList

Returns:

the length of this list