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