Make isEmpty a getter.

lib/core/string_buffer.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * The StringBuffer class is useful for concatenating strings
  * efficiently. Only on a call to [toString] are the strings
  * concatenated to a single String.
  */
 abstract class StringBuffer {
   /**
    * Creates the string buffer with an initial content.
    */
   factory StringBuffer([Object content = ""])
     => new _StringBufferImpl(content);
 
   /**
    * Returns the length of the buffer.
    */
   int get length;
 
   /**
    * Returns whether the buffer is empty.
    */
-  bool isEmpty();
+  bool get isEmpty;
 
   /**
    * Converts [obj] to a string and adds it to the buffer. Returns [:this:].
    */
   StringBuffer add(Object obj);
 
   /**
    * Adds the string representation of [charCode] to the buffer.
    * Returns [this].
    */
@@ skipping 24 matching lines @@
     add(content);
   }
 
   /**
    * Returns the length of the buffer.
    */
   int get length {
     return _length;
   }
 
-  bool isEmpty() {
+  bool get isEmpty {
     return _length === 0;
   }
 
   /**
    * Adds [obj] to the buffer. Returns [this].
    */
   StringBuffer add(Object obj) {
     String str = obj.toString();
-    if (str === null || str.isEmpty()) {
+    if (str === null || str.isEmpty) {
       return this;
     }
     _buffer.add(str);
     _length += str.length;
     return this;
   }
 
   /**
    * Adds all items in [objects] to the buffer. Returns [this].
    */
@@ skipping 31 matching lines @@
     _buffer.clear();
     _buffer.add(result);
     // Since we track the length at each add operation, there is no
     // need to update it in this function.
     return result;
   }
 
   List<String> _buffer;
   int _length;
 }