Added stringToFloat to NumberUtils

Patch contributed by Fredrik Westermarck
Reviewed by Phil Steitz


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@137661 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/math/NumberUtils.java

@@ -69,8 +69,9 @@ import org.apache.commons.lang.StringUtils;
  * @author Phil Steitz
  * @author Matthew Hawthorne
  * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
+ * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
  * @since 2.0
- * @version $Id: NumberUtils.java,v 1.10 2003/08/18 02:22:24 bayard Exp $
+ * @version $Id: NumberUtils.java,v 1.11 2003/09/04 07:27:12 psteitz Exp $
  */
 public class NumberUtils {
     
@@ -154,6 +155,47 @@ public class NumberUtils {
         }
     }
 
+    /**
+     * <p>Convert a <code>String</code> to a <code>float</code>, returning
+     * <code>0.0f</code> if the conversion fails.</p>
+     *
+     * <p>If the string <code>str</code> is <code>null</code>,
+     * <code>0.0f</code> is returned.</p>
+     *
+     * @param str the string to convert, may be <code>null</code>
+     * @return the float represented by the string, or <code>0.0f</code>
+     *  if conversion fails
+     * @since 2.1
+     */
+    public static float stringToFloat(String str) {
+        return stringToFloat(str, 0.0f);
+    }
+
+    /**
+     * <p>Convert a <code>String</code> to a <code>float</code>, returning a
+     * default value if the conversion fails.</p>
+     *
+     * <p>If the string <code>str</code> is <code>null</code>, the default
+     * value is returned.</p>
+     *
+     * @param str the string to convert, may be <code>null</code>
+     * @param defaultValue the default value
+     * @return the float represented by the string, or defaultValue
+     *  if conversion fails
+     * @since 2.1
+     */
+    public static float stringToFloat(String str, float defaultValue) {
+      if(str==null) {
+          return defaultValue;
+      }
+      
+      try {
+          return Float.parseFloat(str);
+      } catch (NumberFormatException nfe) {
+          return defaultValue;
+      }
+    }
+
     //-----------------------------------------------------------------------
     // must handle Long, Float, Integer, Float, Short,
     //                  BigDecimal, BigInteger and Byte

src/test/org/apache/commons/lang/math/NumberUtilsTest.java

@@ -75,7 +75,7 @@ import org.apache.commons.lang.SystemUtils;
  * @author Stephen Colebourne
  * @author Matthew Hawthorne
  * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
- * @version $Id: NumberUtilsTest.java,v 1.7 2003/08/18 02:22:27 bayard Exp $
+ * @version $Id: NumberUtilsTest.java,v 1.8 2003/09/04 07:27:12 psteitz Exp $
  */
 public class NumberUtilsTest extends TestCase {
 
@@ -123,6 +123,25 @@ public class NumberUtilsTest extends TestCase {
         assertTrue("stringToInt(String,int) 2 failed", NumberUtils.stringToInt("1234.5", 5) == 5);
     }
 
+    /**
+     * Test for float stringToFloat(String)
+     */
+    public void testStringToFloatString() {
+        assertTrue("stringToFloat(String) 1 failed", NumberUtils.stringToFloat("-1.2345") == -1.2345f);
+        assertTrue("stringToFloat(String) 2 failed", NumberUtils.stringToFloat("1.2345") == 1.2345f);
+        assertTrue("stringToFloat(String) 3 failed", NumberUtils.stringToFloat("abc") == 0.0f);
+        assertTrue("stringToFloat(empty) failed", NumberUtils.stringToFloat("") == 0.0f);
+        assertTrue("stringToFloat(null) failed", NumberUtils.stringToFloat(null) == 0.0f);
+    }
+
+    /**
+     * Test for float stringToFloat(String, float)
+     */
+    public void testStringToFloatStringF() {
+        assertTrue("stringToFloat(String,int) 1 failed", NumberUtils.stringToFloat("1.2345", 5.1f) == 1.2345f);
+        assertTrue("stringToFloat(String,int) 2 failed", NumberUtils.stringToFloat("a", 5.0f) == 5.0f);
+    }
+
     public void testCreateNumber() {
         //a lot of things can go wrong
         assertEquals("createNumber(String) 1 failed", new Float("1234.5"), NumberUtils.createNumber("1234.5"));