Conainers in Depth: Exercise 34

ContainersInDepth/README.md

@@ -234,3 +234,10 @@ because an `ArrayList` must create space and copy all its references forward dur
 **Note**:
 1. We can instantiate an abstract class by implementing the abstract method in an anonymous class, like 
 [ListPerformance.java](https://github.com/kean0212/Thinking-In-Java-Notes/blob/master/ContainersInDepth/ListPerformance.java#L22).
+
+### Choosing between Sets
+1. `HashSet` is used for 'insertion' and 'searching'.
+
+2. `TreeSet` is used for sorted set.
+
+3. `LinkedHashSet` is for maintaining inserted order.

ContainersInDepth/SetPerformance.java

@@ -0,0 +1,61 @@
+import java.util.List;
+import java.util.Set;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.HashSet;
+import java.util.TreeSet;
+import java.util.LinkedHashSet;
+
+public class SetPerformance {
+    static List<Test<Set<String>>> tests = new ArrayList<>();
+
+    static {
+        tests.add(new Test<Set<String>>("add") {
+            int test(Set<String> set, TestParam testParam) {
+                int loops = testParam.loops;
+                int size = testParam.size;
+                for (int i = 0; i < loops; ++i) {
+                    set.clear();
+                    for (int j = 0; j < size; ++j) {
+                        set.add("hello");
+                    }
+                }
+                return loops * size;
+            }
+        });
+        tests.add(new Test<Set<String>>("contains") {
+            int test(Set<String> set, TestParam testParam) {
+                int loops = testParam.loops;
+                int size = testParam.size * 2;
+                for (int i = 0; i < loops; ++i) {
+                    for (int j = 0; j < size; ++j) {
+                        set.contains("hello");
+                    }
+                }
+                return loops * size;
+            }
+        });
+        tests.add(new Test<Set<String>>("iterate") {
+            int test(Set<String> set, TestParam testParam) {
+                int loops = testParam.loops * 10;
+                for (int i = 0; i < loops; ++i) {
+                    Iterator<String> iterator = set.iterator();
+                    while (iterator.hasNext()) {
+                        iterator.next();
+                    }
+                }
+                return loops * set.size();
+            }
+        });
+    }
+
+    public static void main(String[] args) {
+        if (args.length > 0) {
+            Tester.defaultTestParams = TestParam.array(args);
+        }
+        Tester.fieldWidth = 10;
+        Tester.run(new HashSet<String>(), tests);
+        Tester.run(new TreeSet<String>(), tests);
+        Tester.run(new LinkedHashSet<String>(), tests);
+    }
+}