Module org.eclipse.persistence.jpa.jpql
Package org.eclipse.persistence.jpa.jpql.parser

Class JPQLExpression

java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.JPQLExpression
All Implemented Interfaces:
Expression
public final class JPQLExpression extends AbstractExpression
A JPQLExpression is the root of the parsed tree representation of a JPQL query. The query is parsed based on what was registered in the JPQLGrammar's ExpressionRegistry.

A JPQL statement may be either a SELECT statement, an UPDATE statement, or a DELETE FROM statement.

It is possible to parse a portion of a JPQL query. The ID of the JPQLQueryBNF is used to parse that portion and getQueryStatement() then returns only the parsed tree representation of that JPQL fragment.

Since:
2.3
Version:
2.5

  • Constructor Details

    • JPQLExpression

      public JPQLExpression(CharSequence query, JPQLGrammar jpqlGrammar)
      Creates a new JPQLExpression, which is the root of the JPQL parsed tree.
      Parameters:
      query - The string representation of the JPQL query to parse
      jpqlGrammar - The JPQL grammar that defines how to parse a JPQL query

    • JPQLExpression

      public JPQLExpression(CharSequence query, JPQLGrammar jpqlGrammar, boolean tolerant)
      Creates a new JPQLExpression, which is the root of the JPQL parsed tree.
      Parameters:
      query - The string representation of the JPQL query to parse
      jpqlGrammar - The JPQL grammar that defines how to parse a JPQL query
      tolerant - Determines if the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries

    • JPQLExpression

      public JPQLExpression(CharSequence jpqlFragment, JPQLGrammar jpqlGrammar, String queryBNFId, boolean tolerant)
      Creates a new JPQLExpression that will parse the given fragment of a JPQL query. This means getQueryStatement() will not return a query statement (select, delete or update) but only the parsed tree representation of the fragment if the query BNF can pare it. If the fragment of the JPQL query could not be parsed using the given JPQLQueryBNF, then getUnknownEndingStatement() will contain the non-parsable fragment.
      Parameters:
      jpqlFragment - A fragment of a JPQL query, which is a portion of a complete JPQL query
      jpqlGrammar - The JPQL grammar that defines how to parse a JPQL query
      queryBNFId - The unique identifier of the JPQLQueryBNF
      tolerant - Determines if the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries
      Since:
      2.4

  • Method Details

    • accept

      public void accept(ExpressionVisitor visitor)
      Description copied from interface: Expression
      Visits this Expression by the given visitor.
      Parameters:
      visitor - The ExpressionVisitor to visit this object

    • acceptChildren

      public void acceptChildren(ExpressionVisitor visitor)
      Description copied from interface: Expression
      Visits the children of this Expression. This method can be used to optimize traversing the children since a new list is not created every time Expression.children() is called.

      This does not traverse the Expression sub-hierarchy, use a subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.

      Parameters:
      visitor - The visitor to visit the children of this object.

    • addChildrenTo

      protected void addChildrenTo(Collection<Expression> children)
      Description copied from class: AbstractExpression
      Adds the children of this AbstractExpression to the given collection.
      Overrides:
      addChildrenTo in class AbstractExpression
      Parameters:
      children - The collection used to store the children

    • addOrderedChildrenTo

      protected void addOrderedChildrenTo(List<Expression> children)
      Description copied from class: AbstractExpression
      Adds the children of this AbstractExpression to the given list.
      Overrides:
      addOrderedChildrenTo in class AbstractExpression
      Parameters:
      children - The list used to store the string representation of this AbstractExpression

    • buildPosition

      public QueryPosition buildPosition(String actualQuery, int position)
      Creates a map of the position of the cursor within each Expression of the parsed tree.
      Parameters:
      actualQuery - The actual query is a string representation of the query that may contain extra whitespace
      position - The position of the cursor in the actual query, which is used to retrieve the deepest Expression. The position will be adjusted to fit into the beautified version of the query
      Returns:
      A new QueryPosition

    • getExpression

      public Expression getExpression(String actualQuery, int position)
      Returns the deepest Expression for the given position.
      Parameters:
      actualQuery - The actual query is the text version of the query that may contain extra whitespace and different formatting than the trim down version generated by the parsed tree
      position - The position in the actual query used to retrieve the Expression
      Returns:
      The Expression located at the given position in the given query

    • getGrammar

      public JPQLGrammar getGrammar()
      Description copied from interface: Expression
      Returns the JPQLGrammar that defines how the JPQL query was parsed.
      Specified by:
      getGrammar in interface Expression
      Overrides:
      getGrammar in class AbstractExpression
      Returns:
      The JPQLGrammar that was used to parse this Expression

    • getJPAVersion

      public JPAVersion getJPAVersion()
      Description copied from class: AbstractExpression
      Returns the version of the Java Persistence to support.
      Overrides:
      getJPAVersion in class AbstractExpression
      Returns:
      The JPA version supported by the grammar
      See Also:

    • getQueryBNF

      public JPQLQueryBNF getQueryBNF()
      Description copied from interface: Expression
      Returns the BNF of this Expression.
      Returns:
      The JPQLQueryBNF, which represents the grammar of this Expression

    • getQueryStatement

      public Expression getQueryStatement()
      Returns the Expression representing the query, which is either a SELECT, a DELETE or an UPDATE clause.
      Returns:
      The expression representing the Java Persistence query

    • getUnknownEndingStatement

      public Expression getUnknownEndingStatement()
      Returns the Expression that may contain a portion of the query that could not be parsed, this happens when the query is either incomplete or malformed.
      Returns:
      The expression used when the ending of the query is unknown or malformed

    • hasQueryStatement

      public boolean hasQueryStatement()
      Determines whether a query was parsed. The query may be incomplete but it started with one of the three clauses (SELECT, DELETE FROM, or UPDATE).
      Returns:
      true the query was parsed; false otherwise

    • hasUnknownEndingStatement

      public boolean hasUnknownEndingStatement()
      Determines whether the query that got parsed had some malformed or unknown information.
      Returns:
      true if the query could not be parsed correctly because it is either incomplete or malformed

    • isTolerant

      protected boolean isTolerant()
      Description copied from class: AbstractExpression
      Determines if the parser is in tolerant mode or is in fast mode. When the tolerant is turned on, it means the parser will attempt to parse incomplete or invalid queries.
      Overrides:
      isTolerant in class AbstractExpression
      Returns:
      true if the parsing system should parse invalid or incomplete queries; false when the query is well-formed and valid

    • parse

      protected void parse(WordParser wordParser, boolean tolerant)
      Description copied from class: AbstractExpression
      Parses the query by starting at the current position, which is part of the given WordParser.
      Specified by:
      parse in class AbstractExpression
      Parameters:
      wordParser - The text to parse based on the current position of the cursor
      tolerant - Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries

    • toParsedText

      protected void toParsedText(StringBuilder writer, boolean actual)
      Description copied from class: AbstractExpression
      Generates a string representation of this Expression, including its children, if it has any.
      Specified by:
      toParsedText in class AbstractExpression
      Parameters:
      writer - The buffer used to append this Expression's string representation
      actual - Determines whether the string representation should represent what was parsed, i.e. include any "virtual" whitespace (such as ending whitespace) and the actual case of the JPQL identifiers