Examples of net.sf.saxon.value.Closure

net.sf.saxon.value.Closure

A Closure represents a value that has not yet been evaluated: the value is represented by an expression, together with saved values of all the context variables that the expression depends on.

This Closure is designed for use when the value is only read once. If the value is read more than once, a new iterator over the underlying expression is obtained each time: this may (for example in the case of a filter expression) involve significant re-calculation.

The expression may depend on local variables and on the context item; these values are held in the saved XPathContext object that is kept as part of the Closure, and they will always be read from that object. The expression may also depend on global variables; these are unchanging, so they can be read from the Bindery in the normal way. Expressions that depend on other contextual information, for example the values of position(), last(), current(), current-group(), should not be evaluated using this mechanism: they should always be evaluated eagerly. This means that the Closure does not need to keep a copy of these context variables.

     * @return the constructed Closure
     */


    public Value makeClosure(Expression expression, int ref, XPathContext context) throws XPathException {
        if (ref == 1) {
            return new Closure();
        } else {
            return new MemoClosure();
        }
    }

     * @return the constructed Closure
     */


    public Value makeClosure(Expression expression, int ref, XPathContext context) throws XPathException {
        if (ref == 1) {
            return new Closure();
        } else {
            return new MemoClosure();
        }
    }

Examples of net.sf.saxon.value.Closure

Related Classes of net.sf.saxon.value.Closure