Adding isNotEmpty property to collection and string.

sdk/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.
 
 part of dart.core;
 
 /**
  * The StringBuffer class is useful for concatenating strings
  * efficiently. Only on a call to [toString] are the strings
  * concatenated to a single String.
  */
 class StringBuffer implements StringSink {
 
   /** Creates the string buffer with an initial content. */
   external StringBuffer([Object content = ""]);
 
   /**
    * Returns the length of the content that has been accumulated so far.
    * This is a constant-time operation.
    */
   external int get length;
 
   /** Returns whether the buffer is empty. This is a constant-time operation. */
   bool get isEmpty => length == 0;
 
+  /**
+   * Returns whether the buffer is not empty. This is a constant-time
+   * operation.
+   */
+  bool get isNotEmpty => !isEmpty;
+
   /// Adds the contents of [obj], converted to a string, to the buffer.
   external void write(Object obj);
 
   /// Adds the string representation of [charCode] to the buffer.
   external void writeCharCode(int charCode);
 
   void writeAll(Iterable objects, [String separator = ""]) {
     Iterator iterator = objects.iterator;
     if (!iterator.moveNext()) return;
     if (separator.isEmpty) {
@@ skipping 15 matching lines @@
   }
 
   /**
    * Clears the string buffer.
    */
   external void clear();
 
   /// Returns the contents of buffer as a concatenated string.
   external String toString();
 }