Package org.datanucleus.store.query.inmemory

Class JavaQueryInMemoryEvaluator

  • Direct Known Subclasses:
    JDOQLInMemoryEvaluator, JPQLInMemoryEvaluator
    public abstract class JavaQueryInMemoryEvaluator
extends java.lang.Object
    Class to evaluate a Java "string-based" query in whole or part. Takes in the "generic" compilation, a list of instances and applies the required restrictions to the input giving a final result. Typically extended for JDOQL, JPQL specifics.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected java.lang.String candidateAlias  
      protected java.util.Collection<java.lang.Object> candidates
      Candidates objects to evaluate.
      protected ClassLoaderResolver clr  
      protected QueryCompilation compilation
      Compilation of the underlying query, that we are evaluating.
      protected InMemoryExpressionEvaluator evaluator
      The evaluator.
      protected java.lang.String language  
      protected java.util.Map parameterValues
      Map of input parameter values, keyed by the parameter name.
      protected Query query
      Underlying "string-based" query.
      static java.lang.String RESULTS_SET
      Name under which any set of results are stored in the state map.
      protected java.util.Map<java.lang.String,​java.lang.Object> state
      Map of state symbols for the query evaluation.

    • Constructor Summary

      Constructors 
      Constructor Description
      JavaQueryInMemoryEvaluator​(java.lang.String language, Query query, QueryCompilation compilation, java.util.Map<java.lang.Object,​java.lang.Object> parameterValues, ClassLoaderResolver clr, java.util.Collection<java.lang.Object> candidates)
      Constructor for the evaluator of a query in the specified language.

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      private java.lang.Boolean evaluateBooleanExpression​(Expression expr, InMemoryExpressionEvaluator eval)
      Convenience method to evaluate the provided expression returning a boolean.
      protected abstract java.util.Collection<java.lang.Object> evaluateSubquery​(Query subquery, QueryCompilation compilation, java.util.Collection<java.lang.Object> candidates, java.lang.Object outerCandidate)
      Method to evaluate a subquery of the query being evaluated.
      java.util.Collection<java.lang.Object> execute​(boolean applyFilter, boolean applyOrdering, boolean applyResult, boolean applyResultClass, boolean applyRange)
      Method to perform the evaluation, applying the query restrictions that are required.
      private java.util.List<java.lang.Object> handleAggregates​(java.util.List<java.lang.Object> resultSet)
      Checks if there are aggregates and handle it.
      private java.util.List<java.lang.Object> handleFilter​(java.util.List<java.lang.Object> set)  
      private java.util.List<java.lang.Object> handleRange​(java.util.List<java.lang.Object> set, long fromIncl, long toExcl)  
      private java.util.List<java.lang.Object> handleResult​(java.util.List<java.lang.Object> resultSet)
      Checks if there are aggregates and handles it.
      (package private) abstract java.util.Collection<java.lang.Object> mapResultClass​(java.util.Collection<java.lang.Object> resultSet)
      Constructs ResultClassMapper and calls its map function
      private java.util.List<java.lang.Object> ordering​(java.util.List<java.lang.Object> set)  
      private java.lang.Object[] result​(java.lang.Object obj)  
      private java.lang.Object[] result​(java.util.List<java.lang.Object> set)  
      private boolean satisfiesHavingClause​(java.util.List set)
      Checks if the results set fulfils the having clause.
      private java.util.List<java.lang.Object> sortByGrouping​(java.util.List<java.lang.Object> set)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • RESULTS_SET

        public static final java.lang.String RESULTS_SET
        Name under which any set of results are stored in the state map. Used for aggregation.
        See Also:
        Constant Field Values

      • language

        protected final java.lang.String language

      • candidateAlias

        protected java.lang.String candidateAlias

      • candidates

        protected java.util.Collection<java.lang.Object> candidates
        Candidates objects to evaluate.

      • query

        protected Query query
        Underlying "string-based" query.

      • compilation

        protected QueryCompilation compilation
        Compilation of the underlying query, that we are evaluating.

      • parameterValues

        protected java.util.Map parameterValues
        Map of input parameter values, keyed by the parameter name.

      • state

        protected java.util.Map<java.lang.String,​java.lang.Object> state
        Map of state symbols for the query evaluation.

    • Constructor Detail

      • JavaQueryInMemoryEvaluator

        public JavaQueryInMemoryEvaluator​(java.lang.String language,
                                  Query query,
                                  QueryCompilation compilation,
                                  java.util.Map<java.lang.Object,​java.lang.Object> parameterValues,
                                  ClassLoaderResolver clr,
                                  java.util.Collection<java.lang.Object> candidates)
        Constructor for the evaluator of a query in the specified language.
        Parameters:
        language - Name of the language
        query - The underlying query
        compilation - Query compilation
        parameterValues - Input parameter values
        clr - ClassLoader resolver
        candidates - Candidate objects

    • Method Detail

      • evaluateSubquery

        protected abstract java.util.Collection<java.lang.Object> evaluateSubquery​(Query subquery,
                                                                           QueryCompilation compilation,
                                                                           java.util.Collection<java.lang.Object> candidates,
                                                                           java.lang.Object outerCandidate)
        Method to evaluate a subquery of the query being evaluated.
        Parameters:
        subquery - The subquery
        compilation - The subquery compilation
        candidates - The candidates for the subquery
        outerCandidate - The current outer candidate (for use when linking back to outer query)
        Returns:
        The result

      • execute

        public java.util.Collection<java.lang.Object> execute​(boolean applyFilter,
                                                      boolean applyOrdering,
                                                      boolean applyResult,
                                                      boolean applyResultClass,
                                                      boolean applyRange)
        Method to perform the evaluation, applying the query restrictions that are required.
        Parameters:
        applyFilter - Whether to apply any filter constraints on the results
        applyOrdering - Whether to apply any order constraints on the results
        applyResult - Whether to apply any result/grouping/having on the results
        applyResultClass - Whether to apply any resultClass constraint on the results
        applyRange - Whether to apply any range constraint on the results
        Returns:
        The results after evaluation.

      • handleFilter

        private java.util.List<java.lang.Object> handleFilter​(java.util.List<java.lang.Object> set)

      • evaluateBooleanExpression

        private java.lang.Boolean evaluateBooleanExpression​(Expression expr,
                                                    InMemoryExpressionEvaluator eval)
        Convenience method to evaluate the provided expression returning a boolean. Caters for variables in the provided expression, attempting to process all possible values for them.
        Parameters:
        expr - The expression
        eval - The evaluator
        Returns:
        The result

      • handleRange

        private java.util.List<java.lang.Object> handleRange​(java.util.List<java.lang.Object> set,
                                                     long fromIncl,
                                                     long toExcl)

      • sortByGrouping

        private java.util.List<java.lang.Object> sortByGrouping​(java.util.List<java.lang.Object> set)

      • ordering

        private java.util.List<java.lang.Object> ordering​(java.util.List<java.lang.Object> set)

      • handleAggregates

        private java.util.List<java.lang.Object> handleAggregates​(java.util.List<java.lang.Object> resultSet)
        Checks if there are aggregates and handle it.
        Parameters:
        resultSet - The resultSet containing all elements
        Returns:
        A list with aggregated elements

      • satisfiesHavingClause

        private boolean satisfiesHavingClause​(java.util.List set)
        Checks if the results set fulfils the having clause.
        Parameters:
        set - Set of results
        Returns:
        true if fulfilling having clause

      • handleResult

        private java.util.List<java.lang.Object> handleResult​(java.util.List<java.lang.Object> resultSet)
        Checks if there are aggregates and handles it.
        Parameters:
        resultSet - The resultSet containing all elements
        Returns:
        A list with aggregated elements

      • result

        private java.lang.Object[] result​(java.lang.Object obj)

      • result

        private java.lang.Object[] result​(java.util.List<java.lang.Object> set)

      • mapResultClass

        abstract java.util.Collection<java.lang.Object> mapResultClass​(java.util.Collection<java.lang.Object> resultSet)
        Constructs ResultClassMapper and calls its map function
        Parameters:
        resultSet - The resultSet containing the instances handled by setResult
        Returns:
        The resultSet containing instances of the Class defined by setResultClass