edu.princeton.cs.algs4.Transaction Maven / Gradle / Ivy
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/******************************************************************************
* Compilation: javac Transaction.java
* Execution: java Transaction
* Dependencies: StdOut.java
*
* Data type for commercial transactions.
*
******************************************************************************/
package edu.princeton.cs.algs4;
import java.util.Arrays;
import java.util.Comparator;
/**
* The {@code 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.
*
* @author Robert Sedgewick
* @author Kevin Wayne
*/
public class Transaction implements Comparable {
private final String who; // customer
private final Date when; // date
private final double amount; // amount
/**
* Initializes a new transaction from the given arguments.
*
* @param who the person involved in this transaction
* @param when the date of this transaction
* @param amount the amount of this transaction
* @throws IllegalArgumentException if {@code amount}
* is {@code Double.NaN}, {@code Double.POSITIVE_INFINITY},
* or {@code Double.NEGATIVE_INFINITY}
*/
public Transaction(String who, Date when, double amount) {
if (Double.isNaN(amount) || Double.isInfinite(amount))
throw new IllegalArgumentException("Amount cannot be NaN or infinite");
this.who = who;
this.when = when;
this.amount = amount;
}
/**
* Initializes a new transaction by parsing a string of the form NAME DATE AMOUNT.
*
* @param transaction the string to parse
* @throws IllegalArgumentException if {@code amount}
* is {@code Double.NaN}, {@code Double.POSITIVE_INFINITY},
* or {@code Double.NEGATIVE_INFINITY}
*/
public Transaction(String transaction) {
String[] a = transaction.split("\\s+");
who = a[0];
when = new Date(a[1]);
amount = Double.parseDouble(a[2]);
if (Double.isNaN(amount) || Double.isInfinite(amount))
throw new IllegalArgumentException("Amount cannot be NaN or infinite");
}
/**
* Returns the name of the customer involved in this transaction.
*
* @return the name of the customer involved in this transaction
*/
public String who() {
return who;
}
/**
* Returns the date of this transaction.
*
* @return the date of this transaction
*/
public Date when() {
return when;
}
/**
* Returns the amount of this transaction.
*
* @return the amount of this transaction
*/
public double amount() {
return amount;
}
/**
* Returns a string representation of this transaction.
*
* @return a string representation of this transaction
*/
@Override
public String toString() {
return String.format("%-10s %10s %8.2f", who, when, amount);
}
/**
* Compares two transactions by amount.
*
* @param that the other transaction
* @return { 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
*/
public int compareTo(Transaction that) {
return Double.compare(this.amount, that.amount);
}
/**
* Compares this transaction to the specified object.
*
* @param other the other transaction
* @return true if this transaction is equal to {@code other}; false otherwise
*/
@Override
public boolean equals(Object other) {
if (other == this) return true;
if (other == null) return false;
if (other.getClass() != this.getClass()) return false;
Transaction that = (Transaction) other;
return (this.amount == that.amount) && (this.who.equals(that.who))
&& (this.when.equals(that.when));
}
/**
* Returns a hash code for this transaction.
*
* @return a hash code for this transaction
*/
public int hashCode() {
int hash = 1;
hash = 31*hash + who.hashCode();
hash = 31*hash + when.hashCode();
hash = 31*hash + ((Double) amount).hashCode();
return hash;
// return Objects.hash(who, when, amount);
}
/**
* Compares two transactions by customer name.
*/
public static class WhoOrder implements Comparator {
@Override
public int compare(Transaction v, Transaction w) {
return v.who.compareTo(w.who);
}
}
/**
* Compares two transactions by date.
*/
public static class WhenOrder implements Comparator {
@Override
public int compare(Transaction v, Transaction w) {
return v.when.compareTo(w.when);
}
}
/**
* Compares two transactions by amount.
*/
public static class HowMuchOrder implements Comparator {
@Override
public int compare(Transaction v, Transaction w) {
return Double.compare(v.amount, w.amount);
}
}
/**
* Unit tests the {@code Transaction} data type.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
Transaction[] a = new Transaction[4];
a[0] = new Transaction("Turing 6/17/1990 644.08");
a[1] = new Transaction("Tarjan 3/26/2002 4121.85");
a[2] = new Transaction("Knuth 6/14/1999 288.34");
a[3] = new Transaction("Dijkstra 8/22/2007 2678.40");
StdOut.println("Unsorted");
for (int i = 0; i < a.length; i++)
StdOut.println(a[i]);
StdOut.println();
StdOut.println("Sort by date");
Arrays.sort(a, new Transaction.WhenOrder());
for (int i = 0; i < a.length; i++)
StdOut.println(a[i]);
StdOut.println();
StdOut.println("Sort by customer");
Arrays.sort(a, new Transaction.WhoOrder());
for (int i = 0; i < a.length; i++)
StdOut.println(a[i]);
StdOut.println();
StdOut.println("Sort by amount");
Arrays.sort(a, new Transaction.HowMuchOrder());
for (int i = 0; i < a.length; i++)
StdOut.println(a[i]);
StdOut.println();
}
}
/******************************************************************************
* Copyright 2002-2018, Robert Sedgewick and Kevin Wayne.
*
* This file is part of algs4.jar, which accompanies the textbook
*
* Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne,
* Addison-Wesley Professional, 2011, ISBN 0-321-57351-X.
* http://algs4.cs.princeton.edu
*
*
* algs4.jar is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* algs4.jar is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with algs4.jar. If not, see http://www.gnu.org/licenses.
******************************************************************************/