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

   1 // Copyright 2011 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.search.checkers;
   4
   5 import com.google.apphosting.api.AppEngineInternal;
   6 import com.google.common.base.Strings;
   7
   8 /**
   9  * Checks values of {@link com.google.appengine.api.search.Index Indexes}.
  10  *
  11  */
  12 @AppEngineInternal
  13 public class IndexChecker {
  14
  15   /**
  16    * Checks whether an index name is valid. It must be a ASCII visible
  17    * printable string of length between 1 and {@literal
  18    * #MAXIMUM_INDEX_NAME_LENGTH}, not start with '!', and not be of
  19    * the format __.*__, which are reserved sequences for internal
  20    * index names.
  21    *
  22    * @param indexName the index name to check
  23    * @return the checked index name
  24    * @throws IllegalArgumentException if the index name is not valid.
  25    */
  26   public static String checkName(String indexName) {
  27     Preconditions.checkArgument(!Strings.isNullOrEmpty(indexName), "Index name null or empty");
  28     Preconditions.checkArgument(indexName.length() <= SearchApiLimits.MAXIMUM_INDEX_NAME_LENGTH,
  29         "Index name longer than %d characters: %s",
  30         SearchApiLimits.MAXIMUM_INDEX_NAME_LENGTH, indexName);
  31     Preconditions.checkArgument(isAsciiVisiblePrintable(indexName),
  32         "Index name must be ASCII visible printable: %s", indexName);
  33     Preconditions.checkArgument(!isReserved(indexName),
  34         "Index name must not start with !: %s", indexName);
  35     return indexName;
  36   }
  37
  38   /**
  39    * @return true if all characters are visible ascii printable: that is,
  40    * between 33 ('!') and 126 ('~'), inclusive
  41    */
  42   static boolean isAsciiVisiblePrintable(String str) {
  43     for (int i = 0; i < str.length(); ++i) {
  44       if (str.charAt(i) < 33 || str.charAt(i) > 126) {
  45         return false;
  46       }
  47     }
  48     return true;
  49   }
  50
  51   /**
  52    * @return true if str represents a reserved index name
  53    */
  54   static boolean isReserved(String str) {
  55     return str.startsWith("!")
  56       || (str.length() > 3 && str.startsWith("__") && str.endsWith("__"));
  57   }
  58 }