235 lines
10 KiB
Java
235 lines
10 KiB
Java
|
|
/**
|
|
* Class to create objects of a Library, which can hold and report on assets held within
|
|
*
|
|
* @George Wilkinson
|
|
* @3.0
|
|
*/
|
|
|
|
// Import all required libraries. Not using .* as it is not good practice due to potential conflicts.
|
|
import java.util.ArrayList;
|
|
import java.util.HashSet;
|
|
import java.util.Scanner;
|
|
import java.util.Random;
|
|
import java.io.File;
|
|
import java.io.IOException;
|
|
import java.awt.FileDialog;
|
|
import java.awt.Frame;
|
|
import java.io.PrintWriter;
|
|
|
|
public class Library
|
|
{
|
|
private ArrayList<LibraryItem> itemList; // Initialise an ArrayList of name itemList to store Library Items
|
|
private ArrayList<LibraryUser> userList; // Initialise an ArrayList of name userList to store Library Users
|
|
private HashSet<String> uuidSet; // Initialise a Hash Set of name uuidSet ( unique user identifier ) to store unique user IDs for efficient O(1) searching
|
|
|
|
/*
|
|
* Constructor for objects of class Library
|
|
*/
|
|
public Library()
|
|
{
|
|
itemList = new ArrayList<LibraryItem>();
|
|
userList = new ArrayList<LibraryUser>();
|
|
uuidSet = new HashSet<String>();
|
|
}
|
|
|
|
/*
|
|
* Appends a LibraryItem to the itemList.
|
|
*/
|
|
public void storeItem( LibraryItem item )
|
|
{
|
|
itemList.add( item );
|
|
}
|
|
|
|
/*
|
|
* Appends a LibraryUser to the userList.
|
|
*/
|
|
public void storeUser( LibraryUser user )
|
|
{
|
|
userList.add( user );
|
|
if ( user.getUserID().equals( "unknown" ) )
|
|
{
|
|
user.setUserID( generateUserID( "AB-", 6 ) );
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Returns a random unique user ID by specifying
|
|
* @prefix - arbitrary alphanumeric prefix
|
|
* @length - length of numeric ID
|
|
* and returning a unique user id
|
|
* @uuid - a unique string starting with @prefix, and concat. with a random number
|
|
*
|
|
* Example: length = 6, expected result should be under 999,999 and above 99,999.
|
|
* If we just use 10^(length), this would generate any number under 1,000,000.
|
|
* This is an issue since any integers below 100,000 can be used, which would be incorrect.
|
|
* By using the offset of a factor of 10 below the desired length we can generate between 0 and 899,999.
|
|
* After this, we can add 100,000 back to the number to ensure a baseline length is maintained.
|
|
*
|
|
* Note: I am aware that this is overengineered, and that several random integers of amount @length could be used,
|
|
* but this is considerably more efficient since there is no iteration involved in the creation of the ID. O(1)
|
|
*/
|
|
public String generateUserID( String prefix, int length )
|
|
{
|
|
Random random = new Random();
|
|
final int offset = (int) Math.pow( 10, (length-1) ); // Static integer equal to 10^(length-1) lower than length. This will allow for the factor to be consistent.
|
|
int intLength = (int) ( Math.pow( 10, length ) ) - offset ; // Integer equal to 10^(length) minus the offset. This creates a ceiling for the ID range.
|
|
|
|
if ( uuidSet.size() > ( intLength - 1 ) ) { // No idea why I get an error for equals FIX LATER
|
|
System.out.println("Too many user IDs delegated for current range, increasing ID range by a factor of 10");
|
|
return generateUserID( prefix, length+1 );
|
|
/*
|
|
* This is essential for eliminating a stack overflow error when the specified range is full. This would be incorrect to catch.
|
|
* By incrementing the length value when the ID range is full, roughly 2.1 billion users can be created without running into an overflow error.
|
|
*/
|
|
}
|
|
|
|
String uuid = prefix + ( random.nextInt( intLength ) + offset );
|
|
/*
|
|
* Sets the uid to the prefix, concat. with a random integer of specified length
|
|
* Add the offset to a random number, to create a floor to the ID range.
|
|
*/
|
|
|
|
if ( uuidSet.contains( uuid ) )
|
|
{
|
|
generateUserID( prefix, length ); // If the ID generated is already contained in the hashset, the method should be called again.
|
|
}
|
|
|
|
uuidSet.add( uuid ); // Add the UUID to the hash set so it cannot be returned from this method more than once.
|
|
return uuid;
|
|
}
|
|
|
|
/*
|
|
* A method to output all user data to a file using a fileDialog to specify file location.
|
|
*
|
|
* Note: Potentially could implement the HashSet made for GenerateUserID to avoid unnecessary recursion.
|
|
*/
|
|
public void writeUserData()
|
|
{
|
|
try {
|
|
Frame frame = null; // Initialise null frame
|
|
FileDialog fileBox = new FileDialog( frame, "Save", FileDialog.SAVE ); // Initialise file dialog box to save written data.
|
|
fileBox.setVisible( true );
|
|
PrintWriter writer = new PrintWriter( new File( fileBox.getDirectory() + fileBox.getFile() ) );
|
|
for ( LibraryUser user : userList ){
|
|
user.writeData( writer );
|
|
}
|
|
writer.close();
|
|
}
|
|
catch( IOException e ) { // Catch any IO Exceptions that may occur from improper file selection.
|
|
System.err.println( "Caught IOException: " + e.getMessage() + "\nAn I/O Exception has occurred, please check file is readable and correct format." );
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Prints to the terminal, in a human-readable format, all items in the itemList
|
|
*
|
|
* Contains a marker at the start and end to visualise in terminal output.
|
|
*/
|
|
public void printAll()
|
|
{
|
|
System.out.println("\n\nStart Detail Print");
|
|
for( LibraryItem item : itemList )
|
|
{
|
|
System.out.println("---------------");
|
|
item.printDetails();
|
|
}
|
|
System.out.println("End Detail Print\n");
|
|
}
|
|
|
|
/*
|
|
* A method to read all data from files using a fileDialog to specify file location.
|
|
* This will create the corresponding objects depending on flags contained in the file
|
|
* and populate it's fields.
|
|
*
|
|
* Default flag value: "book", to support legacy files. This will not interfere with
|
|
* files of different flag orders.
|
|
*/
|
|
public void readData()
|
|
{
|
|
Frame frame = null; // Initialise a null frame
|
|
FileDialog fileBox = new FileDialog( frame, "Open", FileDialog.LOAD ); // Initialise filebox with the null frame pointer
|
|
fileBox.setVisible( true ); // Open a file selection dialog to the user.
|
|
|
|
try {
|
|
Scanner fileScanner = new Scanner( new File( fileBox.getDirectory() + fileBox.getFile() ) );
|
|
String typeFlag = "book"; // Set a default flag to support legacy files.
|
|
|
|
while( fileScanner.hasNextLine() ){
|
|
|
|
String lineItem = fileScanner.nextLine();
|
|
|
|
// Ensure no comments or empty lines are included
|
|
if ( lineItem.contains( "//" ) || lineItem.trim().isEmpty() ){}
|
|
|
|
// Check current line is a candidate flag
|
|
else if ( lineItem.startsWith("[" ) ) {
|
|
|
|
if ( lineItem.toLowerCase().contains("book") )
|
|
typeFlag = "book";
|
|
else if ( lineItem.toLowerCase().contains("periodical") )
|
|
typeFlag = "periodical";
|
|
else if ( lineItem.toLowerCase().contains("cd") )
|
|
typeFlag = "cd";
|
|
else if ( lineItem.toLowerCase().contains("dvd") )
|
|
typeFlag = "dvd";
|
|
else if ( lineItem.toLowerCase().contains("user") )
|
|
typeFlag = "user";
|
|
else {
|
|
System.out.println( "Flag detected, but no accepted format...\n Cannot store item in Library. Changing Flag to generic and skipping the following: ");
|
|
typeFlag = "generic";
|
|
}
|
|
|
|
}
|
|
|
|
// Could be a switch case to be more efficient
|
|
// Check current flag for data processing.
|
|
else {
|
|
if ( typeFlag.equals( "book" ) ) {
|
|
// Process Book Data
|
|
Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(","); // Create a new scanner to grab the values in a comma separated list
|
|
LibraryItem book = new Book();
|
|
book.readItemData( detailScanner );
|
|
storeItem( book ); // Store the new LibraryItem in the itemList
|
|
}
|
|
else if ( typeFlag.equals( "periodical" ) ) {
|
|
// Process Periodic Data
|
|
Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
|
|
LibraryItem periodical = new Periodical();
|
|
periodical.readItemData( detailScanner );
|
|
storeItem( periodical );
|
|
}
|
|
else if ( typeFlag.equals( "cd" ) ) {
|
|
//Process CD Data
|
|
Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
|
|
LibraryItem cd = new CD();
|
|
cd.readItemData( detailScanner );
|
|
storeItem( cd );
|
|
}
|
|
else if ( typeFlag.equals( "dvd" ) ) {
|
|
//Process DVD Data
|
|
Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
|
|
LibraryItem dvd = new DVD();
|
|
dvd.readItemData( detailScanner );
|
|
storeItem( dvd );
|
|
}
|
|
else if ( typeFlag.equals( "user" ) ) {
|
|
//Process User Data
|
|
Scanner detailScanner = new Scanner ( lineItem ).useDelimiter(",");
|
|
LibraryUser user = new LibraryUser();
|
|
user.readData( detailScanner );
|
|
storeUser( user );
|
|
}
|
|
else if ( typeFlag.equals( "generic" ) ) {
|
|
// Output unaccepted lines to terminal
|
|
System.out.println( lineItem );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
catch( IOException e ) { // Catch any IO Exceptions that may occur from improper file selection.
|
|
System.err.println( "Caught IOException: " + e.getMessage() + "\nAn I/O Exception has occurred, please check file is readable and correct format." );
|
|
}
|
|
}
|
|
}
|