Example usage for javax.xml.xpath XPathExpression XPathExpression

Introduction

In this page you can find the example usage for javax.xml.xpath XPathExpression XPathExpression.

Prototype

XPathExpression

Source Link

Usage

From source file:org.callimachusproject.rdfa.test.RDFaGenerationTest.java

XPathExpression conjoinXPaths(Document fragment, String base) throws Exception {
    String path = "//*";
    final Element e = fragment.getDocumentElement();
    if (e == null)
        return null;
    final XPathIterator conjunction = new XPathIterator(e, base);
    if (conjunction.hasNext()) {
        path += "[";
        boolean first = true;
        while (conjunction.hasNext()) {
            if (!first)
                path += " and ";
            XPathExpression x = conjunction.next();
            String exp = x.toString();
            boolean positive = true;
            if (exp.startsWith("-")) {
                positive = false;//from   w w  w.j av  a2  s.  c  o m
                exp = exp.substring(1);
            }
            // remove the initial '/'
            exp = exp.substring(1);
            if (positive)
                path += exp;
            else
                path += "not(" + exp + ")";
            first = false;
        }
        path += "]";
    }
    XPath xpath = xPathFactory.newXPath();
    // add namespace prefix resolver to the xpath based on the current element
    xpath.setNamespaceContext(new AbstractNamespaceContext() {
        public String getNamespaceURI(String prefix) {
            // for the empty prefix lookup the default namespace
            if (prefix.isEmpty())
                return e.lookupNamespaceURI(null);
            for (int i = 0; i < conjunction.contexts.size(); i++) {
                NamespaceContext c = conjunction.contexts.get(i);
                String ns = c.getNamespaceURI(prefix);
                if (ns != null)
                    return ns;
            }
            return null;
        }
    });
    final String exp = path;
    final XPathExpression compiled = xpath.compile(path);
    if (verbose)
        System.out.println(exp);

    return new XPathExpression() {
        public String evaluate(Object source) throws XPathExpressionException {
            return compiled.evaluate(source);
        }

        public String evaluate(InputSource source) throws XPathExpressionException {
            return compiled.evaluate(source);
        }

        public Object evaluate(Object source, QName returnType) throws XPathExpressionException {
            return compiled.evaluate(source, returnType);
        }

        public Object evaluate(InputSource source, QName returnType) throws XPathExpressionException {
            return compiled.evaluate(source, returnType);
        }

        public String toString() {
            return exp;
        }
    };
}

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