Applying my patch to LANG-355, making StrBuilder implement Appendable

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@795604 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/text/StrBuilder.java

@@ -71,7 +71,7 @@ import org.apache.commons.lang.SystemUtils;
  * @since 2.2
  * @version $Id$
  */
-public class StrBuilder implements CharSequence {
+public class StrBuilder implements CharSequence, Appendable {
 
     /**
      * The extra capacity for new builders.
@@ -462,6 +462,36 @@ public class StrBuilder implements CharSequence {
         return append(obj.toString());        
     }
 
+    /**
+     * Appends a CharSequence to this string builder.
+     * Appending null will call {@link #appendNull()}.
+     *
+     * @param seq  the CharSequence to append
+     * @return this, to enable chaining
+     */
+    public StrBuilder append(CharSequence seq) {
+        if (seq == null) {
+            return appendNull();
+        } 
+        return append(seq.toString());        
+    }
+
+    /**
+     * Appends part of a CharSequence to this string builder.
+     * Appending null will call {@link #appendNull()}.
+     *
+     * @param seq  the CharSequence to append
+     * @param startIndex  the start index, inclusive, must be valid
+     * @param length  the length to append, must be valid
+     * @return this, to enable chaining
+     */
+    public StrBuilder append(CharSequence seq, int startIndex, int length) {
+        if (seq == null) {
+            return appendNull();
+        } 
+        return append(seq.toString(), startIndex, length);
+    }
+
     /**
      * Appends a string to this string builder.
      * Appending null will call {@link #appendNull()}.

src/test/org/apache/commons/lang/text/StrBuilderAppendInsertTest.java

@@ -138,6 +138,9 @@ public class StrBuilderAppendInsertTest extends TestCase {
 
         sb.append(new StrBuilder("yes"));
         assertEquals("foobazyes", sb.toString());
+
+        sb.append((CharSequence) "Seq");
+        assertEquals("foobazyesSeq", sb.toString());
     }
 
     //-----------------------------------------------------------------------
@@ -214,6 +217,9 @@ public class StrBuilderAppendInsertTest extends TestCase {
 
         sb.append("abcbardef", 3, 3);
         assertEquals("foobar", sb.toString());
+
+        sb.append( (CharSequence)"abcbardef", 4, 3);
+        assertEquals("foobarard", sb.toString());
     }
 
     //-----------------------------------------------------------------------