Package com.stardog.stark.query

Class QueryResults

java.lang.Object
com.stardog.stark.query.QueryResults
public final class QueryResults extends Object

Utilities for working with QueryResults

Since:
1.0
Version:
1.0
Author:
Michael Grove, Jeen Broekstra

  • Method Details

    • toList

      public static <T> List<T> toList(QueryResult<T> theResult)
      Return the results as a List
      Parameters:
      theResult - the query result
      Returns:
      the results as a `List`
      Implementation Notes:
      * This pulls all of the results into memory so it is not appropriate for a large result set. * The side effect of this call is that `theResult` is closed.

    • report

      public static void report(@Nonnull SelectQueryResult theResult, @Nonnull SelectQueryResultHandler theHandler)
      Iterate over the query result and send the results to the given handler
      Parameters:
      theResult - the result
      theHandler - the result handler
      Throws:
      QueryExecutionFailure - if the next result could not be computed
      Implementation Notes:
      The side effect of this call is that `theResult` is closed.

    • singleResult

      @Nonnull public static <T> Optional<T> singleResult(@Nonnull QueryResult<T> theResult)
      Return the next result from the results and close the results.
      Parameters:
      theResult - the result
      Returns:
      the next result
      Throws:
      QueryExecutionFailure - if the next result could not be computed
      Implementation Notes:
      The side effect of this call is that `theResult` is closed.

    • size

      public static long size(@Nonnull QueryResult<?> theResult)
      Return the number of results present in this result set
      Parameters:
      theResult - the results
      Returns:
      the number of results
      Throws:
      QueryExecutionFailure - if the results count not be computed
      Implementation Notes:
      The side effect of this call is that `theResult` is exhausted and closed.

    • consume

      public static void consume(@Nonnull QueryResult<?> theResult)
      Iterate over all of the results and close the result set. The results of the query are simply thrown away.
      Parameters:
      theResult - the results
      Throws:
      QueryExecutionFailure - if the execution failed in any way

    • closeQuietly

      public static void closeQuietly(@Nonnull QueryResult<?> theResult)
      "Quietly" close the QueryResult; any exception throw while closing will simply be logged.
      Parameters:
      theResult - the result to close

    • equals

      public static boolean equals(@Nonnull SelectQueryResult tqr1, @Nonnull SelectQueryResult tqr2) throws QueryExecutionFailure
      Compares two tuple query results and returns true if they are equal. Tuple query results are equal if they contain the same set of BindingSets and have the same headers. Blank nodes identifiers are not relevant for equality, they are matched by trying to find compatible mappings between BindingSets. Note that the method consumes both query results fully.
      Parameters:
      tqr1 - the first SelectQueryResult to compare.
      tqr2 - the second SelectQueryResult to compare.
      Throws:
      QueryExecutionFailure
      Implementation Notes:
      This will consume both sets of results and they will both be closed as a side effect of calling this method. The results are also pulled into memory for the comparison, so this may not be suitable for use for large result sets.

    • equalsWithOrder

      public static boolean equalsWithOrder(@Nonnull SelectQueryResult tqr1, @Nonnull SelectQueryResult tqr2)
      Similar to equals(SelectQueryResult, SelectQueryResult) but also checks the order of binding sets.

    • isSubset

      public static boolean isSubset(@Nonnull SelectQueryResult tqr1, @Nonnull SelectQueryResult tqr2) throws QueryExecutionFailure
      Compares two tuple query results and returns true if the the first is a subset of the other. Uses the same notion of BindingSet equality as equals(SelectQueryResult, SelectQueryResult).
      Parameters:
      tqr1 - the first SelectQueryResult to compare.
      tqr2 - the second SelectQueryResult to compare.
      Throws:
      QueryExecutionFailure
      Implementation Notes:
      This will consume both sets of results and they will both be closed as a side effect of calling this method. The results are also pulled into memory for the comparison, so this may not be suitable for use for large result sets.