Class BooleanExpressionPattern

    • Constructor Detail

      • BooleanExpressionPattern

        public BooleanExpressionPattern​(Expression expression)
        Create a BooleanExpressionPattern
        Parameters:
        expression - the expression to be evaluated (the expression in the predicate)
    • Method Detail

      • operands

        public java.lang.Iterable<Operand> operands()
        Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()

        If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

        Overrides:
        operands in class Expression
        Returns:
        an iterator containing the sub-expressions of this expression
      • getUType

        public UType getUType()
        Get a UType indicating which kinds of items this Pattern can match.
        Specified by:
        getUType in class Pattern
        Returns:
        a UType indicating all the primitive types of item that the pattern can match.
      • allocateSlots

        public int allocateSlots​(SlotManager slotManager,
                                 int nextFree)
        Allocate slots to any variables used within the pattern
        Overrides:
        allocateSlots in class Pattern
        Parameters:
        slotManager - holds details of the allocated slots
        nextFree - the next slot that is free to be allocated @return the next slot that is free to be allocated
        Returns:
        the next slot that is free to be allocated
      • typeCheck

        public Pattern typeCheck​(ExpressionVisitor visitor,
                                 ContextItemStaticInfo contextItemType)
                          throws XPathException
        Type-check the pattern.
        Overrides:
        typeCheck in class Pattern
        Parameters:
        visitor - the expression visitor
        contextItemType - the type of the context item at the point where the pattern is defined. Set to null if it is known that the context item is undefined.
        Returns:
        the optimised Pattern
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • optimize

        public Pattern optimize​(ExpressionVisitor visitor,
                                ContextItemStaticInfo contextInfo)
                         throws XPathException
        Description copied from class: Pattern
        Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

        This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

        Overrides:
        optimize in class Pattern
        Parameters:
        visitor - an expression visitor
        contextInfo - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
        Returns:
        the original expression, rewritten if appropriate to optimize execution
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • isMotionless

        public boolean isMotionless()
        Description copied from class: Pattern
        Test whether a pattern is motionless, that is, whether it can be evaluated against a node without repositioning the input stream. This is a necessary condition for patterns used as the match pattern of a streamed template rule.
        Overrides:
        isMotionless in class Pattern
        Returns:
        true if the pattern is motionless, that is, if it can be evaluated against a streamed node without changing the position in the streamed input file
      • matches

        public boolean matches​(Item item,
                               XPathContext context)
        Determine whether this Pattern matches the given item. This is the main external interface for matching patterns: it sets current() to the node being tested
        Specified by:
        matches in class Pattern
        Parameters:
        item - The item to be tested against the Pattern
        context - The context in which the match is to take place. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key().
        Returns:
        true if the item matches the Pattern, false otherwise
      • getItemType

        public ItemType getItemType()
        Get an Itemtype that all the items matching this pattern must satisfy
        Specified by:
        getItemType in class Pattern
        Returns:
        an ItemType, as specific as possible, which all the matching items satisfy
      • getFingerprint

        public int getFingerprint()
        Determine the name fingerprint of nodes to which this pattern applies. Used for optimisation.
        Overrides:
        getFingerprint in class Pattern
        Returns:
        A fingerprint that the nodes must match, or -1 if it can match multiple fingerprints
      • reconstruct

        public java.lang.String reconstruct()
        Display the pattern for diagnostics
        Overrides:
        reconstruct in class Pattern
      • equals

        public boolean equals​(java.lang.Object other)
        Determine whether this pattern is the same as another pattern
        Overrides:
        equals in class Expression
        Parameters:
        other - the other object
        Returns:
        true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.
      • computeHashCode

        protected int computeHashCode()
        Hashcode supporting equals()
        Overrides:
        computeHashCode in class Expression
        Returns:
        a computed hash code
      • copy

        public Pattern copy​(RebindingMap rebindings)
        Copy a pattern. This makes a deep copy.
        Specified by:
        copy in class Pattern
        Parameters:
        rebindings - variables that need to be re-bound
        Returns:
        the copy of the original pattern
      • export

        public void export​(ExpressionPresenter presenter)
                    throws XPathException
        Description copied from class: Expression
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        export in interface ExportAgent
        Specified by:
        export in class Pattern
        Parameters:
        presenter - the expression presenter used to display the structure
        Throws:
        XPathException - if the export fails, for example if an expression is found that won't work in the target environment.