mirror of
https://github.com/tiennm99/java-design-patterns.git
synced 2026-05-20 10:24:53 +00:00
* #1261 Added base directories, folders, and file for the collecting parameter design pattern. * #1261 Added initial comment * #1261 Added Maven Dependencies * #1261 Added Maven Dependencies * #1261 Finished README.md file * #1261 Added tests * #1261 Code adheres to the standard * #1261 Code adheres to the standard * #1261 Code adheres to the standard * #1261 - Added table to README.md - Explicitly state that result is the collecting parameter - Improved applicability - Separated PrinterItem.java from PrinterQueue.java - Tests work now - Giant comment split * #1261 fixed programmatic example in README.md. * #1261 updated class diagram * #1261 Fixed everything. * #1261 Minor edit to README.md. * #1261 Minor edit to README.md. * #1261 Minor updates. * #1261 Fixed code style. * #1261 Removed getPrinterQueue test * #1261 Removed code smells * #1261 Added UML plugin. * #1261 Dependencies resolved. * #1261 Specified the UML diagram paths. Perhaps this will work. * #1261 pom.xml updated with UML wrapper. Maybe this will create class diagram when built? * #1261 UML added. * #1261 - README.md obeys the YAML requirements - Typo in README.md fixed - UMLWrapper removed from module pom.xml - More comments added Should be able to merge now :)
This commit is contained in:
JoshuaSinglaANU
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/*
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* This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
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*
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* The MIT License
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* Copyright © 2014-2022 Ilkka Seppälä
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.collectingparameter;
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import java.util.LinkedList;
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import java.util.Queue;
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/**
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* The Collecting Parameter Design Pattern aims to return a result that is the collaborative result of several
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* methods. This design pattern uses a 'collecting parameter' that is passed to several functions, accumulating results
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* as it travels from method-to-method. This is different to the Composed Method design pattern, where a single
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* collection is modified via several methods.
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*
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* <p>This example is inspired by Kent Beck's example in his book, 'Smalltalk Best Practice Patterns'. The context for this
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* situation is that there is a single printer queue {@link PrinterQueue} that holds numerous print jobs
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* {@link PrinterItem} that must be distributed to various print centers.
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* Each print center has its own requirements and printing limitations. In this example, the following requirements are:
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* If an A4 document is coloured, it must also be single-sided. All other non-coloured A4 documents are accepted.
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* All A3 documents must be non-coloured and single sided. All A2 documents must be a single page, single sided, and
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* non-coloured.
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*
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* <p>A collecting parameter (the result variable) is used to filter the global printer queue so that it meets the
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* requirements for this centre,
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**/
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public class App {
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static PrinterQueue printerQueue = PrinterQueue.getInstance();
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/**
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* Program entry point.
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*
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* @param args command line args
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*/
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public static void main(String[] args) {
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/*
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Initialising the printer queue with jobs
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*/
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printerQueue.addPrinterItem(new PrinterItem(PaperSizes.A4, 5, false, false));
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printerQueue.addPrinterItem(new PrinterItem(PaperSizes.A3, 2, false, false));
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printerQueue.addPrinterItem(new PrinterItem(PaperSizes.A2, 5, false, false));
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/*
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This variable is the collecting parameter, and will store the policy abiding print jobs.
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*/
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var result = new LinkedList<PrinterItem>();
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/*
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Adding A4, A3, and A2 papers that obey the policy
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*/
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addValidA4Papers(result);
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addValidA3Papers(result);
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addValidA2Papers(result);
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}
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/**
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* Adds A4 document jobs to the collecting parameter according to some policy that can be whatever the client
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* (the print center) wants.
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*
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* @param printerItemsCollection the collecting parameter
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*/
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public static void addValidA4Papers(Queue<PrinterItem> printerItemsCollection) {
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/*
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Iterate through the printer queue, and add A4 papers according to the correct policy to the collecting parameter,
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which is 'printerItemsCollection' in this case.
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*/
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for (PrinterItem nextItem : printerQueue.getPrinterQueue()) {
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if (nextItem.paperSize.equals(PaperSizes.A4)) {
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var isColouredAndSingleSided = nextItem.isColour && !nextItem.isDoubleSided;
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if (isColouredAndSingleSided || !nextItem.isColour) {
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printerItemsCollection.add(nextItem);
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}
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}
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}
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}
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/**
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* Adds A3 document jobs to the collecting parameter according to some policy that can be whatever the client
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* (the print center) wants. The code is similar to the 'addA4Papers' method. The code can be changed to accommodate
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* the wants of the client.
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*
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* @param printerItemsCollection the collecting parameter
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*/
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public static void addValidA3Papers(Queue<PrinterItem> printerItemsCollection) {
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for (PrinterItem nextItem : printerQueue.getPrinterQueue()) {
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if (nextItem.paperSize.equals(PaperSizes.A3)) {
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// Encoding the policy into a Boolean: the A3 paper cannot be coloured and double-sided at the same time
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var isNotColouredAndSingleSided = !nextItem.isColour && !nextItem.isDoubleSided;
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if (isNotColouredAndSingleSided) {
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printerItemsCollection.add(nextItem);
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}
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}
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}
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}
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/**
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* Adds A2 document jobs to the collecting parameter according to some policy that can be whatever the client
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* (the print center) wants. The code is similar to the 'addA4Papers' method. The code can be changed to accommodate
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* the wants of the client.
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*
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* @param printerItemsCollection the collecting parameter
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*/
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public static void addValidA2Papers(Queue<PrinterItem> printerItemsCollection) {
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for (PrinterItem nextItem : printerQueue.getPrinterQueue()) {
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if (nextItem.paperSize.equals(PaperSizes.A2)) {
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// Encoding the policy into a Boolean: the A2 paper must be single page, single-sided, and non-coloured.
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var isNotColouredSingleSidedAndOnePage = nextItem.pageCount == 1 && !nextItem.isDoubleSided
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&& !nextItem.isColour;
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if (isNotColouredSingleSidedAndOnePage) {
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printerItemsCollection.add(nextItem);
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}
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}
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}
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}
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}
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package com.iluwatar.collectingparameter;
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enum PaperSizes {
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A2,
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A3,
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A4
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}
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package com.iluwatar.collectingparameter;
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import java.util.Objects;
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/**
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* This class represents a Print Item, that should be added to the queue.
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**/
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public class PrinterItem {
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PaperSizes paperSize;
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int pageCount;
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boolean isDoubleSided;
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boolean isColour;
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/**
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* The {@link PrinterItem} constructor.
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**/
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public PrinterItem(PaperSizes paperSize, int pageCount, boolean isDoubleSided, boolean isColour) {
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if (!Objects.isNull(paperSize)) {
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this.paperSize = paperSize;
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} else {
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throw new IllegalArgumentException();
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}
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if (pageCount > 0) {
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this.pageCount = pageCount;
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} else {
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throw new IllegalArgumentException();
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}
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this.isColour = isColour;
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this.isDoubleSided = isDoubleSided;
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}
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}
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package com.iluwatar.collectingparameter;
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import java.util.LinkedList;
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import java.util.Objects;
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import java.util.Queue;
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/**
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* This class represents a singleton Printer Queue. It contains a queue that can be filled up with {@link PrinterItem}.
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**/
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public class PrinterQueue {
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static PrinterQueue currentInstance = null;
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private final Queue<PrinterItem> printerItemQueue;
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/**
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* This class is a singleton. The getInstance method will ensure that only one instance exists at a time.
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*/
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public static PrinterQueue getInstance() {
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if (Objects.isNull(currentInstance)) {
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currentInstance = new PrinterQueue();
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}
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return currentInstance;
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}
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/**
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* Empty the printer queue.
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*/
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public void emptyQueue() {
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currentInstance.getPrinterQueue().clear();
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}
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/**
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* Private constructor prevents instantiation, unless using the getInstance() method.
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*/
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private PrinterQueue() {
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printerItemQueue = new LinkedList<>();
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}
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public Queue<PrinterItem> getPrinterQueue() {
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return currentInstance.printerItemQueue;
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}
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/**
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* Adds a single print job to the queue.
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*
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* @param printerItem The printing job to be added to the queue
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*/
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public void addPrinterItem(PrinterItem printerItem) {
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currentInstance.getPrinterQueue().add(printerItem);
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}
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}
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/*
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* This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
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*
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* The MIT License
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* Copyright © 2014-2022 Ilkka Seppälä
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.collectingparameter;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
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class AppTest {
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/**
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* Checks whether {@link App} executes without throwing exception
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*/
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@Test
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void executesWithoutException() {
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assertDoesNotThrow(() -> App.main(new String[]{}));
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}
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}
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+55
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package com.iluwatar.collectingparameter;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.api.Timeout;
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import java.util.LinkedList;
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import java.util.Queue;
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class CollectingParameterTest {
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@Test
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@Timeout(1000)
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void testCollectingParameter() {
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PrinterQueue printerQueue = PrinterQueue.getInstance();
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printerQueue.emptyQueue();
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PrinterItem item1 = new PrinterItem(PaperSizes.A4, 1, false, true);
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PrinterItem item2 = new PrinterItem(PaperSizes.A4, 10, true, false);
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PrinterItem item3 = new PrinterItem(PaperSizes.A4, 4, true, true);
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PrinterItem item4 = new PrinterItem(PaperSizes.A3, 9, false, false);
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PrinterItem item5 = new PrinterItem(PaperSizes.A3, 3, true, true);
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PrinterItem item6 = new PrinterItem(PaperSizes.A3, 3, false, true);
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PrinterItem item7 = new PrinterItem(PaperSizes.A3, 3, true, false);
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PrinterItem item8 = new PrinterItem(PaperSizes.A2, 1, false, false);
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PrinterItem item9 = new PrinterItem(PaperSizes.A2, 2, false, false);
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PrinterItem item10 = new PrinterItem(PaperSizes.A2, 1, true, false);
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PrinterItem item11 = new PrinterItem(PaperSizes.A2, 1, false, true);
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printerQueue.addPrinterItem(item1);
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printerQueue.addPrinterItem(item2);
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printerQueue.addPrinterItem(item3);
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printerQueue.addPrinterItem(item4);
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printerQueue.addPrinterItem(item5);
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printerQueue.addPrinterItem(item6);
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printerQueue.addPrinterItem(item7);
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printerQueue.addPrinterItem(item8);
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printerQueue.addPrinterItem(item9);
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printerQueue.addPrinterItem(item10);
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printerQueue.addPrinterItem(item11);
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Queue<PrinterItem> result = new LinkedList<>();
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App.addValidA4Papers(result);
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App.addValidA3Papers(result);
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App.addValidA2Papers(result);
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Queue<PrinterItem> testResult = new LinkedList<>();
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testResult.add(item1);
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testResult.add(item2);
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testResult.add(item4);
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testResult.add(item8);
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Assertions.assertArrayEquals(testResult.toArray(), result.toArray());
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}
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}
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+34
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package com.iluwatar.collectingparameter;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.api.Timeout;
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import java.util.LinkedList;
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import java.util.Queue;
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import static org.junit.jupiter.api.Assertions.*;
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class PrinterQueueTest {
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@Test
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@Timeout(1000)
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void singletonTest() {
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PrinterQueue printerQueue1 = PrinterQueue.getInstance();
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PrinterQueue printerQueue2 = PrinterQueue.getInstance();
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assertSame(printerQueue1, printerQueue2);
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}
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@Test()
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@Timeout(1000)
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void negativePageCount() throws IllegalArgumentException {
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Assertions.assertThrows(IllegalArgumentException.class, () -> new PrinterItem(PaperSizes.A4, -1, true, true));
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}
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@Test()
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@Timeout(1000)
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void nullPageSize() throws IllegalArgumentException {
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Assertions.assertThrows(IllegalArgumentException.class, () -> new PrinterItem(null, 1, true, true));
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}
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}
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