java/src/main/com/google/appengine/api/search/checkers/CursorChecker.java

   1 // Copyright 2012 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.search.checkers;
   4
   5 /**
   6  * Checks values of {@link com.google.appengine.api.search.Cursor}.
   7  *
   8  */
   9 public final class CursorChecker {
  10
  11   /**
  12    * The maximum length of a cursor.
  13    */
  14   public static final int MAXIMUM_CURSOR_LENGTH = 10000;
  15
  16   /**
  17    * Checks the cursor string if provided is not empty nor too long.
  18    *
  19    * @param cursor the search cursor to check
  20    * @return the checked cursor
  21    * @throws IllegalArgumentException if the cursor is empty or is too long
  22    */
  23   public static String checkCursor(String cursor) {
  24     if (cursor != null) {
  25       Preconditions.checkArgument(!cursor.isEmpty(),
  26           "cursor cannot be empty");
  27       Preconditions.checkArgument(cursor.length() <= MAXIMUM_CURSOR_LENGTH,
  28           String.format("cursor cannot be longer than %d characters", MAXIMUM_CURSOR_LENGTH));
  29     }
  30     return cursor;
  31   }
  32 }