[BAEL-1847] Iterate Backwards through a List (#4540)

* [BAEL-1847] Iterate Backwards through a List * [BAEL-1847] Updated unit tests
2018-07-01 16:11:31 +05:30
parent bafa1678eb
commit 92340e9ca5
2 changed files with 167 additions and 0 deletions
@@ -0,0 +1,80 @@
+package com.baeldung.java.list;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.ListIterator;
+
+import org.apache.commons.collections4.iterators.ReverseListIterator;
+
+import com.google.common.collect.Lists;
+
+/**
+ * Provides methods for iterating backward over a list.
+ */
+public class ReverseIterator {
+
+    /**
+     * Iterate using the for loop.
+     *
+     * @param list the list
+     */
+    public void iterateUsingForLoop(final List<String> list) {
+
+        for (int i = list.size(); i-- > 0; ) {
+            System.out.println(list.get(i));
+        }
+    }
+
+    /**
+     * Iterate using the Java {@link ListIterator}.
+     *
+     * @param list the list
+     */
+    public void iterateUsingListIterator(final List<String> list) {
+
+        final ListIterator listIterator = list.listIterator(list.size());
+        while (listIterator.hasPrevious()) {
+            System.out.println(listIterator.previous());
+        }
+    }
+
+    /**
+     * Iterate using Java {@link Collections} API.
+     *
+     * @param list the list
+     */
+    public void iterateUsingCollections(final List<String> list) {
+
+        Collections.reverse(list);
+        for (final String item : list) {
+            System.out.println(item);
+        }
+    }
+
+    /**
+     * Iterate using Apache Commons {@link ReverseListIterator}.
+     *
+     * @param list the list
+     */
+    public void iterateUsingApacheReverseListIterator(final List<String> list) {
+
+        final ReverseListIterator listIterator = new ReverseListIterator(list);
+        while (listIterator.hasNext()) {
+            System.out.println(listIterator.next());
+        }
+    }
+
+    /**
+     * Iterate using Guava {@link Lists} API.
+     *
+     * @param list the list
+     */
+    public void iterateUsingGuava(final List<String> list) {
+
+        final List<String> reversedList = Lists.reverse(list);
+        for (final String item : reversedList) {
+            System.out.println(item);
+        }
+    }
+
+}