feature: #1261 Added collecting parameter design pattern (#2134)

* #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 :)

collecting-parameter/src/test/java/com/iluwatar/collectingparameter/PrinterQueueTest.java

@@ -0,0 +1,34 @@
+package com.iluwatar.collectingparameter;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PrinterQueueTest {
+
+  @Test
+  @Timeout(1000)
+  void singletonTest() {
+    PrinterQueue printerQueue1 = PrinterQueue.getInstance();
+    PrinterQueue printerQueue2 = PrinterQueue.getInstance();
+    assertSame(printerQueue1, printerQueue2);
+  }
+
+  @Test()
+  @Timeout(1000)
+  void negativePageCount() throws IllegalArgumentException {
+    Assertions.assertThrows(IllegalArgumentException.class, () -> new PrinterItem(PaperSizes.A4, -1, true, true));
+  }
+
+  @Test()
+  @Timeout(1000)
+  void nullPageSize() throws IllegalArgumentException {
+    Assertions.assertThrows(IllegalArgumentException.class, () -> new PrinterItem(null, 1, true, true));
+  }
+
+}