Class Transaction

java.lang.Object

Transaction

All Implemented Interfaces:

java.lang.Comparable<Transaction>

public class Transaction
extends java.lang.Object
implements java.lang.Comparable<Transaction>

The Transaction class is an immutable data type to encapsulate a commercial transaction with a customer name, date, and amount.

For additional documentation, see Section 1.2 of Algorithms, 4th Edition, by Robert Sedgewick and Kevin Wayne.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Transaction.HowMuchOrder Compares two transactions by amount.
static class	Transaction.WhenOrder Compares two transactions by date.
static class	Transaction.WhoOrder Compares two transactions by customer name.

Constructor Summary

Constructors

Constructor and Description
Transaction(java.lang.String transaction) Initializes a new transaction by parsing a string of the form NAME DATE AMOUNT.
Transaction(java.lang.String who, Date when, double amount) Initializes a new transaction from the given arguments.

Method Summary

Methods

Modifier and Type	Method and Description
double	amount() Returns the amount of the transaction.
int	compareTo(Transaction that) Compares this transaction to that transaction.
boolean	equals(java.lang.Object x) Is this transaction equal to x?
int	hashCode() Returns a hash code for this transaction.
static void	main(java.lang.String[] args) Unit tests the transaction data type.
java.lang.String	toString() Returns a string representation of the transaction.
Date	when() Returns the date of the transaction.
java.lang.String	who() Returns the name of the customer involved in the transaction.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Transaction

public Transaction(java.lang.String who,
           Date when,
           double amount)

Initializes a new transaction from the given arguments.

Parameters:

who - the person involved in the transaction

when - the date of the transaction

amount - the amount of the transaction

Throws:

java.lang.IllegalArgumentException - if amount is Double.NaN, Double.POSITIVE_INFINITY or Double.NEGATIVE_INFINITY

Transaction

public Transaction(java.lang.String transaction)

Initializes a new transaction by parsing a string of the form NAME DATE AMOUNT.

Parameters:

transaction - the string to parse

Throws:

java.lang.IllegalArgumentException - if amount is Double.NaN, Double.POSITIVE_INFINITY or Double.NEGATIVE_INFINITY

Method Detail

who

public java.lang.String who()

Returns the name of the customer involved in the transaction.

Returns:

the name of the customer involved in the transaction

when

public Date when()

Returns the date of the transaction.

Returns:

the date of the transaction

amount

public double amount()

Returns the amount of the transaction.

Returns:

the amount of the transaction

toString

public java.lang.String toString()

Returns a string representation of the transaction.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the transaction

compareTo

public int compareTo(Transaction that)

Compares this transaction to that transaction.

Specified by:

compareTo in interface java.lang.Comparable<Transaction>

Returns:

{ a negative integer, zero, a positive integer}, depending on whether the amount of this transaction is { less than, equal to, or greater than } the amount of that transaction

equals

public boolean equals(java.lang.Object x)

Is this transaction equal to x?

Overrides:

equals in class java.lang.Object

Parameters:

x - the other transaction

Returns:

true if this transaction is equal to x; false otherwise

hashCode

public int hashCode()

Returns a hash code for this transaction.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code for this transaction

main

public static void main(java.lang.String[] args)

Unit tests the transaction data type.