BAEL-9192 (#18447)

* BAEL-9192

* BAEL-9192

* BAEL-9192

* BAEL-9192

---------

Co-authored-by: Neetika Khandelwal <[email protected]>

Author: Neetika23

core-java-modules/core-java-collections-7/pom.xml

@@ -25,6 +25,12 @@
             <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-lambda</artifactId>
+            <version>${stefanbirkner.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -42,6 +48,7 @@
 
     <properties>
         <junit.version>5.9.2</junit.version>
+        <stefanbirkner.version>1.2.1</stefanbirkner.version>
     </properties>
 
 </project>

core-java-modules/core-java-collections-7/src/main/java/com/baeldung/PrintStack.java

@@ -0,0 +1,86 @@
+package com.baeldung;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Stack;
+
+public class PrintStack {
+
+    public static void givenStack_whenUsingToString_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+        System.out.print(stack.toString());
+    }
+
+    public static void givenStack_whenUsingForEach_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        List<Integer> result = new ArrayList<>();
+        for (Integer value : stack) {
+            System.out.print(value + " ");
+        }
+    }
+
+    public static void givenStack_whenUsingDirectForEach_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        stack.forEach(element -> System.out.println(element));
+    }
+
+    public static void givenStack_whenUsingStreamReverse_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        stack.stream()
+            .sorted(Comparator.reverseOrder())
+            .forEach(System.out::println);
+    }
+
+    public static void givenStack_whenUsingIterator_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        Iterator<Integer> iterator = stack.iterator();
+        while (iterator.hasNext()) {
+            System.out.print(iterator.next() + " ");
+        }
+    }
+
+    public static void givenStack_whenUsingListIteratorReverseOrder_thenPrintStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        ListIterator<Integer> iterator = stack.listIterator(stack.size());
+        while (iterator.hasPrevious()) {
+            System.out.print(iterator.previous() + " ");
+        }
+    }
+
+    public static void givenStack_whenUsingDeque_thenPrintStack() {
+        Deque<Integer> stack = new ArrayDeque<>();
+        stack.push(10);
+        stack.push(20);
+        stack.push(30);
+
+        stack.forEach(e -> System.out.print(e + " "));
+    }
+}

core-java-modules/core-java-collections-7/src/test/java/com/baeldung/printstack/PrintStackUnitTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.printstack;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.tapSystemOut;
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.PrintStack;
+
+class PrintStackUnitTest {
+
+    @Test
+    void givenStack_whenUsingToString_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingToString_thenPrintStack());
+        assertEquals("[10, 20, 30]", output);
+    }
+
+    @Test
+    void givenStack_whenUsingForEach_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingForEach_thenPrintStack());
+        assertEquals("10 20 30 ", output);
+    }
+
+    @Test
+    void givenStack_whenUsingDirectForEach_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingDirectForEach_thenPrintStack());
+        assertEquals("10\n20\n30\n", output.replace("\r\n", "\n"));
+    }
+
+    @Test
+    void givenStack_whenUsingStreamReverse_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingStreamReverse_thenPrintStack());
+        assertEquals("30\n20\n10\n", output.replace("\r\n", "\n"));
+    }
+
+    @Test
+    void givenStack_whenUsingIterator_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingIterator_thenPrintStack());
+        assertEquals("10 20 30 ", output);
+    }
+
+    @Test
+    void givenStack_whenUsingListIteratorReverseOrder_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingListIteratorReverseOrder_thenPrintStack());
+        assertEquals("30 20 10 ", output);
+    }
+
+    @Test
+    void givenStack_whenUsingDeque_thenPrintStack() throws Exception {
+        String output = tapSystemOut(() -> PrintStack.givenStack_whenUsingDeque_thenPrintStack());
+        assertEquals("30 20 10 ", output);
+    }
+}