Fixes #120 - clone of JaxenComplied instance.

Now it does a Copy-Constructor clone instead of changing final instance fields.

Author: rolfl

core/src/java/org/jdom2/xpath/jaxen/JaxenCompiled.java

@@ -156,6 +156,16 @@ public JaxenCompiled(String expression, Filter<T> filter,
 		xPath.setVariableContext(this);
 	}
 
+	/**
+	 * Make a copy-constructor available to the clone() method.
+	 * This is simpler than trying to do a deep clone anyway.
+	 * 
+	 * @param toclone The JaxenCompiled instance to clone
+	 */
+	private JaxenCompiled(JaxenCompiled<T> toclone) {
+		this(toclone.getExpression(), toclone.getFilter(), toclone.getVariables(), toclone.getNamespaces());
+	}
+
 	@Override
 	public String translateNamespacePrefixToUri(String prefix) {
 		return getNamespace(prefix).getURI();
@@ -201,5 +211,14 @@ protected Object evaluateRawFirst(Object context) {
 					"Unable to evaluate expression. See cause", e);
 		}
 	}
+	
+	@Override
+	public JaxenCompiled<T> clone() {
+		// Use a copy-constructor instead of a deep clone.
+		// we have a couple of final variables on this class that we cannot share
+		// between instances, and the Jaxen xpath variable is pretty complicated to reconstruct
+		// anyway. Easier to just reconstruct it.
+		return new JaxenCompiled<T>(this);
+	}
 
 }

core/src/java/org/jdom2/xpath/util/AbstractXPathCompiled.java

@@ -88,6 +88,21 @@ public int compare(Namespace ns1, Namespace ns2) {
 
 	private static final NamespaceComparator NSSORT = new NamespaceComparator();
 
+	/**
+	 * Utility method to find a Namespace that has a given URI, and return the prefix.
+	 * @param uri the URI to search for
+	 * @param nsa the array of namespaces to search through
+	 * @return the prefix of the namespace
+	 */
+	private static final String getPrefixForURI(final String uri, final Namespace[] nsa) {
+		for (final Namespace ns : nsa) {
+			if (ns.getURI().equals(uri)) {
+				return ns.getPrefix();
+			}
+		}
+		throw new IllegalStateException("No namespace defined with URI " + uri);
+	}
+	
 	private final Map<String, Namespace> xnamespaces = new HashMap<String, Namespace>();
 	// Not final to support cloning.
 	private Map<String, Map<String, Object>> xvariables = new HashMap<String, Map<String, Object>>();
@@ -309,6 +324,28 @@ public Object setVariable(String qname, Object value) {
 		return setVariable(qname, Namespace.NO_NAMESPACE, value);
 	}
 
+	/**
+	 * utility method that allows descendant classes to access the variables
+	 * that were set on this expression, in a format that can be used in a constructor (qname/value).
+	 * @return the variables set on this instance.
+	 */
+	protected Map<String,Object> getVariables() {
+		HashMap<String,Object> vars = new HashMap<String, Object>();
+		Namespace[] nsa = getNamespaces();
+		for (Map.Entry<String, Map<String,Object>> ue : xvariables.entrySet()) {
+			final String uri = ue.getKey();
+			final String pfx = getPrefixForURI(uri, nsa);
+			for (Map.Entry<String, Object> ve : ue.getValue().entrySet()) {
+				if ("".equals(pfx)) {
+					vars.put(ve.getKey(), ve.getValue());
+				} else {
+					vars.put(pfx + ":" + ve.getKey(), ve.getValue());
+				}
+			}
+		}
+		return vars;
+	}
+
 	@Override
 	public final Filter<T> getFilter() {
 		return xfilter;

test/src/java/org/jdom2/test/cases/xpath/AbstractTestXPathCompiled.java

@@ -752,6 +752,42 @@ public void testClone() {
 
 	}
 
+	@Test
+	public void testCloneVariables() {
+		List<Element> lst = null;
+		HashMap<String,Object> vars = new HashMap<String,Object>();
+		vars.put("vns:vname", "1");
+		Namespace vns = Namespace.getNamespace("vns", "http://jdom.org/xpath_variable_namespace");
+		XPathExpression<Element> xpathhc = XPathFactory.instance().compile(
+				"/main/child[1]", Filters.element());
+		lst = xpathhc.evaluate(doc);
+		assertTrue(1 == lst.size());
+		assertTrue(child1emt == lst.get(0));
+		
+		XPathExpression<Element> xpath = XPathFactory.instance().compile(
+				"/main/child[position() = $vns:vname]", Filters.element(), vars, vns);
+		lst = xpath.evaluate(doc);
+		assertTrue(1 == lst.size());
+		assertTrue(child1emt == lst.get(0));
+		xpath.setVariable("vns:vname", "2");
+		assertTrue("2" == xpath.getVariable("vname", vns));
+		lst = xpath.evaluate(doc);
+		assertTrue(1 == lst.size());
+		assertTrue(child2emt == lst.get(0));
+		
+		XPathExpression<Element> cloned = xpath.clone();
+		lst = cloned.evaluate(doc);
+		assertTrue(1 == lst.size());
+		assertTrue(child2emt == lst.get(0));
+		
+		cloned.setVariable("vns:vname", "1");
+		assertTrue("2" == xpath.getVariable("vname", vns));
+		assertTrue("1" == cloned.getVariable("vname", vns));
+		lst = cloned.evaluate(doc);
+		assertTrue(1 == lst.size());
+		assertTrue(child1emt == lst.get(0));
+	}
+	
 	@Test
 	public void testSelectDocumentDoc() {
 		checkXPath("/", doc, mainvalue, doc);