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

   1 // Copyright 2010 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.search.checkers;
   4
   5 import com.google.appengine.api.search.SearchQueryException;
   6 import com.google.appengine.api.search.SearchServicePb.SearchParams;
   7 import com.google.appengine.api.search.query.QueryTreeBuilder;
   8 import com.google.apphosting.api.AppEngineInternal;
   9
  10 import org.antlr.runtime.RecognitionException;
  11
  12 import java.io.UnsupportedEncodingException;
  13
  14 /**
  15  * Checks values of {@link com.google.appengine.api.search.Query}.
  16  *
  17  */
  18 @AppEngineInternal
  19 public final class QueryChecker {
  20
  21   /**
  22    * Checks that query is not null and is parsable.
  23    * @param query the query to check
  24    * @return the checked query
  25    * @throws SearchQueryException if the query is not parsable
  26    * @throws IllegalArgumentException if the query is too long
  27    */
  28   public static String checkQuery(String query) {
  29     checkQueryFast(query);
  30     return checkQueryParses(query);
  31   }
  32
  33   /**
  34    * Checks if the given query parses. This method assumes that the
  35    * other checks, such as length, non-null, etc., were already
  36    * performed.
  37    *
  38    * @param query the query to check
  39    * @return the checked query
  40    * @throws SearchQueryException if the query is not parsable
  41    */
  42   private static String checkQueryParses(String query) {
  43     try {
  44       new QueryTreeBuilder().parse(query);
  45     } catch (RecognitionException e) {
  46       throw new SearchQueryException("Unable to parse query: " + query);
  47     }
  48     return query;
  49   }
  50
  51   /**
  52    * Checks the search specification is valid, specifically, has a valid
  53    * index specification, a non-null query, a non-null number of documents
  54    * to return specification, a valid cursor if present, valid sort
  55    * specification list, a valid collection of field names for sorting,
  56    * and a valid scorer specification.
  57    *
  58    * @param params the SearchParams to check
  59    * @return this checked SearchParams
  60    * @throws IllegalArgumentException if some part of the specification is
  61    * invalid
  62    * @throws SearchQueryException if the query is unparsable
  63    */
  64   public static SearchParams checkValid(SearchParams params) {
  65     checkValidFast(params);
  66     checkQueryParses(params.getQuery());
  67     return params;
  68   }
  69
  70   /**
  71    * Performs a fast check of the search parameters. This method does not
  72    * check if the query stored in the parameters parses.
  73    *
  74    * @param params the search parameters to check
  75    * @return this checked SearchParams
  76    * @throws IllegalArgumentException if parameters are not valid
  77    */
  78   public static SearchParams checkValidFast(SearchParams params) {
  79     IndexChecker.checkName(params.getIndexSpec().getName());
  80     checkQueryFast(params.getQuery());
  81     QueryOptionsChecker.checkValid(params);
  82     return params;
  83   }
  84
  85   /**
  86    * Checks if the query is not null, and not overly long. This method
  87    * does not check if the query is parsable.
  88    *
  89    * @param query the query to check
  90    * @return the checked query
  91    */
  92   private static String checkQueryFast(String query) {
  93     Preconditions.checkNotNull(query, "query cannot be null");
  94     int length;
  95     try {
  96       length = query.getBytes("UTF-8").length;
  97     } catch (UnsupportedEncodingException e){
  98       throw new IllegalArgumentException("Unsupported encoding UTF-8. Shouldn't  happen, ever!");
  99     }
 100     Preconditions.checkArgument(
 101         length <= SearchApiLimits.MAXIMUM_QUERY_LENGTH,
 102         String.format("query string must not be longer than %d bytes, was %d",
 103                       SearchApiLimits.MAXIMUM_QUERY_LENGTH, length));
 104     return query;
 105   }
 106 }