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.appengine.api.search.Util;
   6
   7 /**
   8  * Checks values of {@link com.google.appengine.api.search.Index Indexes}.
   9  *
  10  */
  11 public class IndexChecker {
  12
  13   /**
  14    * The maximum length for an index name.
  15    */
  16   public static final int MAXIMUM_INDEX_NAME_LENGTH = 100;
  17
  18   /**
  19    * The maximum number of documents allowed per index and delete request.
  20    */
  21   public static final int MAXIMUM_DOCS_PER_REQUEST = 200;
  22
  23   /**
  24    * Checks whether an index name is valid. It must be a ASCII visible
  25    * printable string of length between 1 and {@literal
  26    * #MAXIMUM_INDEX_NAME_LENGTH}, not start with '!', and not be of
  27    * the format __.*__, which are reserved sequences for internal
  28    * index names.
  29    *
  30    * @param indexName the index name to check
  31    * @return the checked index name
  32    * @throws IllegalArgumentException if the index name is not valid.
  33    */
  34   public static String checkName(String indexName) {
  35     Preconditions.checkArgument(!Util.isNullOrEmpty(indexName), "Index name null or empty");
  36     Preconditions.checkArgument(indexName.length() <= MAXIMUM_INDEX_NAME_LENGTH,
  37         "Index name longer than %d characters: %s", MAXIMUM_INDEX_NAME_LENGTH, indexName);
  38     Preconditions.checkArgument(isAsciiVisiblePrintable(indexName),
  39         "indexName must be ASCII visible printable: %s", indexName);
  40     Preconditions.checkArgument(!isReserved(indexName),
  41         "indexName must not start with !: %s", indexName);
  42     return indexName;
  43   }
  44
  45   /**
  46    * @return true if all characters are visible ascii printable: that is,
  47    * between 33 ('!') and 126 ('~'), inclusive
  48    */
  49   static boolean isAsciiVisiblePrintable(String str) {
  50     for (int i = 0; i < str.length(); ++i) {
  51       if (str.charAt(i) < 33 || str.charAt(i) > 126) {
  52         return false;
  53       }
  54     }
  55     return true;
  56   }
  57
  58   /**
  59    * @return true if str represents a reserved index name
  60    */
  61   static boolean isReserved(String str) {
  62     return str.startsWith("!")
  63       || (str.length() > 3 && str.startsWith("__") && str.endsWith("__"));
  64   }
  65 }