From d776d2688968a3da89f050235819936fae1436ae Mon Sep 17 00:00:00 2001
From: Stephen Colebourne <scolebourne@apache.org>
Date: Tue, 21 Oct 2003 23:23:06 +0000
Subject: [PATCH] Improve performance of BooleanUtils.toBoolean(String)

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@137686 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/commons/lang/BooleanUtils.java | 80 ++++++++++++++++---
 .../apache/commons/lang/BooleanUtilsTest.java | 38 +++++++--
 2 files changed, 103 insertions(+), 15 deletions(-)

diff --git a/src/java/org/apache/commons/lang/BooleanUtils.java b/src/java/org/apache/commons/lang/BooleanUtils.java
index 4b2a06fe1..14b160770 100644
--- a/src/java/org/apache/commons/lang/BooleanUtils.java
+++ b/src/java/org/apache/commons/lang/BooleanUtils.java
@@ -66,7 +66,7 @@
  * @author Matthew Hawthorne
  * @author Gary Gregory
  * @since 2.0
- * @version $Id: BooleanUtils.java,v 1.16 2003/09/23 19:45:14 fredrik Exp $
+ * @version $Id: BooleanUtils.java,v 1.17 2003/10/21 23:23:06 scolebourne Exp $
  */
 public class BooleanUtils {
 
@@ -502,12 +502,14 @@ public static Integer toIntegerObject(Boolean bool, Integer trueValue, Integer f
      * Otherwise, <code>null</code> is returned.</p>
      *
      * <pre>
+     *   BooleanUtils.toBooleanObject(null)    = null
      *   BooleanUtils.toBooleanObject("true")  = Boolean.TRUE
      *   BooleanUtils.toBooleanObject("false") = Boolean.FALSE
      *   BooleanUtils.toBooleanObject("on")    = Boolean.TRUE
      *   BooleanUtils.toBooleanObject("ON")    = Boolean.TRUE
      *   BooleanUtils.toBooleanObject("off")   = Boolean.FALSE
      *   BooleanUtils.toBooleanObject("oFf")   = Boolean.FALSE
+     *   BooleanUtils.toBooleanObject("blue")  = null
      * </pre>
      *
      * @param str  the String to check
@@ -574,34 +576,94 @@ public static Boolean toBooleanObject(String str, String trueString, String fals
     // String to boolean methods
     //-----------------------------------------------------------------------
     /**
-     * <p>Converts a String to a boolean.</p>
+     * <p>Converts a String to a boolean (optimised for performance).</p>
      * 
      * <p><code>'true'</code>, <code>'on'</code> or <code>'yes'</code>
      * (case insensitive) will return <code>true</code>. Otherwise,
      * <code>false</code> is returned.</p>
+     * 
+     * <p>This method performs 4 times faster (JDK1.4) than
+     * <code>Boolean.valueOf(String)</code>. However, this method accepts
+     * 'on' and 'yes' as true values.
      *
      * <pre>
+     *   BooleanUtils.toBoolean(null)    = false
      *   BooleanUtils.toBoolean("true")  = true
+     *   BooleanUtils.toBoolean("TRUE")  = true
+     *   BooleanUtils.toBoolean("tRUe")  = true
      *   BooleanUtils.toBoolean("on")    = true
      *   BooleanUtils.toBoolean("yes")   = true
      *   BooleanUtils.toBoolean("false") = false
+     *   BooleanUtils.toBoolean("x gti") = false
      * </pre>
      *
      * @param str  the String to check
      * @return the boolean value of the string, <code>false</code> if no match
      */
     public static boolean toBoolean(String str) {
-        if ("true".equalsIgnoreCase(str)) {
-            return true;
-        } else if ("on".equalsIgnoreCase(str)) {
-            return true;
-        } else if ("yes".equalsIgnoreCase(str)) {
+        // Previously used equalsIgnoreCase, which was fast for interned 'true'.
+        // Non interned 'true' matched 15 times slower.
+        // 
+        // Optimisation provides same performance as before for interned 'true'.
+        // Similar performance for null, 'false', and other strings not length 2/3/4.
+        // 'true'/'TRUE' match 4 times slower, 'tRUE'/'True' 7 times slower.
+        if (str == "true") {
             return true;
         }
-        // no match
+        if (str == null) {
+            return false;
+        }
+        switch (str.length()) {
+            case 2: {
+                char ch0 = str.charAt(0);
+                char ch1 = str.charAt(1);
+                return 
+                    (ch0 == 'o' || ch0 == 'O') &&
+                    (ch1 == 'n' || ch1 == 'N');
+            }
+            case 3: {
+                char ch = str.charAt(0);
+                if (ch == 'y') {
+                    return 
+                        (str.charAt(1) == 'e' || str.charAt(1) == 'E') &&
+                        (str.charAt(2) == 's' || str.charAt(2) == 'S');
+                }
+                if (ch == 'Y') {
+                    return 
+                        (str.charAt(1) == 'E' || str.charAt(1) == 'e') &&
+                        (str.charAt(2) == 'S' || str.charAt(2) == 's');
+                }
+            }
+            case 4: {
+                char ch = str.charAt(0);
+                if (ch == 't') {
+                    return 
+                        (str.charAt(1) == 'r' || str.charAt(1) == 'R') &&
+                        (str.charAt(2) == 'u' || str.charAt(2) == 'U') &&
+                        (str.charAt(3) == 'e' || str.charAt(3) == 'E');
+                }
+                if (ch == 'T') {
+                    return 
+                        (str.charAt(1) == 'R' || str.charAt(1) == 'r') &&
+                        (str.charAt(2) == 'U' || str.charAt(2) == 'u') &&
+                        (str.charAt(3) == 'E' || str.charAt(3) == 'e');
+                }
+            }
+        }
         return false;
     }
-
+    
+//    public static void main(String[] args) {
+//        long start = System.currentTimeMillis();
+//        boolean flag = true;
+//        int count = 0;
+//        for (int i = 0; i < 100000000; i++) {
+//            flag = toBoolean("YES");
+//        }
+//        long end = System.currentTimeMillis();
+//        System.out.println((end - start) + " " + flag + " " + count);
+//    }
+    
     /**
      * <p>Converts a String to a Boolean throwing an exception if no match found.</p>
      * 
diff --git a/src/test/org/apache/commons/lang/BooleanUtilsTest.java b/src/test/org/apache/commons/lang/BooleanUtilsTest.java
index c2db56e5b..ee35b6847 100644
--- a/src/test/org/apache/commons/lang/BooleanUtilsTest.java
+++ b/src/test/org/apache/commons/lang/BooleanUtilsTest.java
@@ -66,7 +66,7 @@
  *
  * @author Stephen Colebourne
  * @author Matthew Hawthorne
- * @version $Id: BooleanUtilsTest.java,v 1.7 2003/08/18 02:22:25 bayard Exp $
+ * @version $Id: BooleanUtilsTest.java,v 1.8 2003/10/21 23:23:06 scolebourne Exp $
  */
 public class BooleanUtilsTest extends TestCase {
 
@@ -308,13 +308,39 @@ public void test_toBoolean_String() {
         assertEquals(false, BooleanUtils.toBoolean(""));
         assertEquals(false, BooleanUtils.toBoolean("off"));
         assertEquals(false, BooleanUtils.toBoolean("oof"));
-        assertEquals(true, BooleanUtils.toBoolean("true"));
-        assertEquals(true, BooleanUtils.toBoolean("yes"));
-        assertEquals(true, BooleanUtils.toBoolean("on"));
+        assertEquals(false, BooleanUtils.toBoolean("yep"));
+        assertEquals(false, BooleanUtils.toBoolean("trux"));
+        assertEquals(false, BooleanUtils.toBoolean("false"));
+        assertEquals(false, BooleanUtils.toBoolean("a"));
+        assertEquals(true, BooleanUtils.toBoolean("true")); // interned handled differently
+        assertEquals(true, BooleanUtils.toBoolean(new StringBuffer("tr").append("ue").toString()));
+        assertEquals(true, BooleanUtils.toBoolean("truE"));
+        assertEquals(true, BooleanUtils.toBoolean("trUe"));
+        assertEquals(true, BooleanUtils.toBoolean("trUE"));
+        assertEquals(true, BooleanUtils.toBoolean("tRue"));
+        assertEquals(true, BooleanUtils.toBoolean("tRuE"));
+        assertEquals(true, BooleanUtils.toBoolean("tRUe"));
+        assertEquals(true, BooleanUtils.toBoolean("tRUE"));
         assertEquals(true, BooleanUtils.toBoolean("TRUE"));
-        assertEquals(true, BooleanUtils.toBoolean("ON"));
-        assertEquals(true, BooleanUtils.toBoolean("YES"));
+        assertEquals(true, BooleanUtils.toBoolean("TRUe"));
+        assertEquals(true, BooleanUtils.toBoolean("TRuE"));
+        assertEquals(true, BooleanUtils.toBoolean("TRue"));
+        assertEquals(true, BooleanUtils.toBoolean("TrUE"));
+        assertEquals(true, BooleanUtils.toBoolean("TrUe"));
         assertEquals(true, BooleanUtils.toBoolean("TruE"));
+        assertEquals(true, BooleanUtils.toBoolean("True"));
+        assertEquals(true, BooleanUtils.toBoolean("on"));
+        assertEquals(true, BooleanUtils.toBoolean("oN"));
+        assertEquals(true, BooleanUtils.toBoolean("On"));
+        assertEquals(true, BooleanUtils.toBoolean("ON"));
+        assertEquals(true, BooleanUtils.toBoolean("yes"));
+        assertEquals(true, BooleanUtils.toBoolean("yeS"));
+        assertEquals(true, BooleanUtils.toBoolean("yEs"));
+        assertEquals(true, BooleanUtils.toBoolean("yES"));
+        assertEquals(true, BooleanUtils.toBoolean("Yes"));
+        assertEquals(true, BooleanUtils.toBoolean("YeS"));
+        assertEquals(true, BooleanUtils.toBoolean("YEs"));
+        assertEquals(true, BooleanUtils.toBoolean("YES"));
     }
 
     public void test_toBoolean_String_String_String() {