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 import com.google.apphosting.api.AppEngineInternal;
   6
   7 /**
   8  * Checks values of {@link com.google.appengine.api.search.Cursor}.
   9  *
  10  */
  11 @AppEngineInternal
  12 public final class CursorChecker {
  13
  14   /**
  15    * Checks the cursor string if provided is not empty nor too long.
  16    *
  17    * @param cursor the search cursor to check
  18    * @return the checked cursor
  19    * @throws IllegalArgumentException if the cursor is empty or is too long
  20    */
  21   public static String checkCursor(String cursor) {
  22     if (cursor != null) {
  23       Preconditions.checkArgument(!cursor.isEmpty(),
  24           "cursor cannot be empty");
  25       Preconditions.checkArgument(cursor.length() <= SearchApiLimits.MAXIMUM_CURSOR_LENGTH,
  26           String.format("cursor cannot be longer than %d characters",
  27                         SearchApiLimits.MAXIMUM_CURSOR_LENGTH));
  28     }
  29     return cursor;
  30   }
  31 }