Package com.saxonica.xqj

Class SaxonXQPreparedExpression

  • All Implemented Interfaces:
    XQDynamicContext, XQPreparedExpression
    public class SaxonXQPreparedExpression
extends SaxonXQDynamicContext
implements XQPreparedExpression
    Saxon implementation of the XQJ interface XQPreparedExpression. This represents a compiled XQuery expression, together with the dynamic context for its evaluation. Note that this means the object should not be used in more than one thread concurrently.

    Note that an expression is scrollable or not depending on the scrollability property of the XQConnection that was used to compile this expression (at the time it was compiled). If the expression is scrollable then its results are delivered in an XQSequence that supports scrolling backwards as well as forwards.

    For full Javadoc details, see the XQJ interface specification.

    • Method Detail

      • cancel

        public void cancel()
            throws XQException
        Description copied from interface: XQPreparedExpression
        Attempts to cancel the execution if both the XQuery engine and XQJ driver support aborting the execution of an XQPreparedExpression. This method can be used by one thread to cancel an XQPreparedExpression, that is being executed in another thread. If cancellation is not supported or the attempt to cancel the execution was not successful, the method returns without any error. If the cancellation is successful, an XQException is thrown, to indicate that it has been aborted, by executeQuery, executeCommand or any method accessing the XQResultSequence returned by executeQuery. If applicable, any open XQResultSequence and XQResultItem objects will also be implicitly closed in this case.
        Specified by:
        cancel in interface XQPreparedExpression
        Throws:
        XQException - if the prepared expression is in a closed state

      • executeQuery

        public XQResultSequence executeQuery()
                              throws XQException
        Description copied from interface: XQPreparedExpression
        Executes the prepared query expression. Calling this method implicitly closes any previous result sequence obtained from this expression.
        Specified by:
        executeQuery in interface XQPreparedExpression
        Returns:
        the xquery sequence object containing the result of the query execution
        Throws:
        XQException - if (1) there are errors when executing the prepared expression, (2) the prepared expression is in a closed state, or (3) the query execution is cancelled

      • getAllExternalVariables

        public javax.xml.namespace.QName[] getAllExternalVariables()
                                                    throws XQException
        Description copied from interface: XQPreparedExpression
        Retrieves all the external variables defined in the prolog of the prepared expression.
        Specified by:
        getAllExternalVariables in interface XQPreparedExpression
        Returns:
        an array of QName objects for all the external variables defined in the prolog of a prepared expression. Empty array if there are no external variables present.
        Throws:
        XQException - if the prepared expression is in a closed state

      • getAllUnboundExternalVariables

        public javax.xml.namespace.QName[] getAllUnboundExternalVariables()
                                                           throws XQException
        Description copied from interface: XQPreparedExpression
        Retrieves the names of all unbound external variables.
        Specified by:
        getAllUnboundExternalVariables in interface XQPreparedExpression
        Returns:
        the QName for all the external variables defined in the prolog of a prepared expression that are yet to be bound with a value. If there are no such variables an empty array is returned
        Throws:
        XQException - if the prepared expression is in a closed state

      • getStaticContext

        public XQStaticContext getStaticContext()
                                 throws XQException
        Description copied from interface: XQPreparedExpression
        Gets an XQStaticContext representing the values for all expression properties. Note that these properties cannot be changed; in order to change, a new XQPreparedExpression needs to be created.
        Specified by:
        getStaticContext in interface XQPreparedExpression
        Returns:
        an XQStaticContext representing the values for all expression properties
        Throws:
        XQException - if the expression is in a closed state

      • getStaticResultType

        public XQSequenceType getStaticResultType()
                                   throws XQException
        Description copied from interface: XQPreparedExpression
        Gets the static type information of the result sequence. If an implementation does not do static typing of the query, then this method must return an XQSequenceType object corresponding to the XQuery sequence type item()*.
        Specified by:
        getStaticResultType in interface XQPreparedExpression
        Returns:
        XQSequenceType containing the static result information.
        Throws:
        XQException - if the prepared expression is in a closed state

      • getStaticVariableType

        public XQSequenceType getStaticVariableType​(javax.xml.namespace.QName name)
                                     throws XQException
        Description copied from interface: XQPreparedExpression
        Retrieves the static type of a given external variable.
        Specified by:
        getStaticVariableType in interface XQPreparedExpression
        Parameters:
        name - the name of the external variable
        Returns:
        the static type information of the variable as defined in the prolog of the prepared expression
        Throws:
        XQException - if (1) the variable does not exist in the static context of the expression, or (2) the sequence is in a closed state, or (3) the name parameter is null