--- a/flys-artifacts/ChangeLog	Wed Jul 20 14:01:38 2011 +0000
+++ b/flys-artifacts/ChangeLog	Wed Jul 20 14:59:25 2011 +0000
@@ -1,3 +1,37 @@
+2011-07-20  Sascha L. Teichmann <sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/flys/artifacts/services/meta/App.java:
+	  Check if builder was created properly before using it.
+
+	* src/main/java/de/intevation/flys/artifacts/services/meta/StackFrames.java:
+	  Implements now variable provider for XPath expressions.
+	
+	* src/main/java/de/intevation/flys/artifacts/services/meta/Builder.java:
+	  Added new choose/when/otherwise construct similiar to XSLT
+
+	      <dc:choose>
+	         <dc:when test="$river = 'Mosel'">
+	             <dc:text>Es ist die Mosel.</dc:text>
+	         </dc:when>
+	         <dc:when test="$river = 'Saar'">
+	             <dc:text>Es ist die Saar.</dc:text>
+	         </dc:when>
+	         <dc:otherwise>
+	            <dc:text>Es ist weder Mosel noch Saar.</dc:text>
+	         </dc:otherwise>
+	      </dc:choose>
+
+	  A 'choose' block can contain a list of 'when's and an optional
+	  'otherwise'. For each 'when' the test attribute is evaluated
+	  as an XPath expression on an empty document. The result of
+	  the evaluation is taken as a boolean value. If its value is
+	  true the control flow is continued inside the corresponding
+	  'when' and the other choose elements are not tested.
+	  If the value is values the testing continues with the next
+	  'when'. If no 'test' expression is evaluated to true, the
+	  control flow continues inside the 'otherwise'. If no 'otherwise'
+	  is given nothing happens at all.
+
 2011-07-20  Ingo Weinzierl <ingo@intevation.de>
 
 	* doc/conf/conf.xml: Added a config section for floodmaps. Currently, the

--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/App.java	Wed Jul 20 14:01:38 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/App.java	Wed Jul 20 14:59:25 2011 +0000
@@ -58,6 +58,12 @@
 
         final Document result = XMLUtils.newDocument();
         final Builder builder = dc.getBuilder();
+
+        if (builder == null) {
+            System.err.println("No builder created");
+            return;
+        }
+
         final Map<String, Object> parameters = getParameters();
 
         Session session = SessionFactoryProvider

--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/Builder.java	Wed Jul 20 14:01:38 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/Builder.java	Wed Jul 20 14:59:25 2011 +0000
@@ -12,6 +12,11 @@
 import org.w3c.dom.Node;
 import org.w3c.dom.Element;
 
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathFactory;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathConstants;
+
 import java.sql.SQLException;
 import java.sql.Connection;
 
@@ -26,6 +31,14 @@
     public static final String DC_NAMESPACE_URI =
         "http://www.intevation.org/2011/Datacage";
 
+    private static final Document EVAL_DOCUMENT =
+        XMLUtils.newDocument();
+
+    private static final XPathFactory XPATH_FACTORY =
+        XPathFactory.newInstance();
+
+
+
     protected Document template;
 
     public class BuildHelper
@@ -169,6 +182,61 @@
             element.setAttribute(name, value);
         }
 
+        protected void choose(Node parent, Element current)
+        throws SQLException
+        {
+            Node branch = null;
+
+            NodeList children = current.getChildNodes();
+            for (int i = 0, N = children.getLength(); i < N; ++i) {
+                Node child = children.item(i);
+                String ns = child.getNamespaceURI();
+                if (ns == null
+                || !ns.equals(DC_NAMESPACE_URI)
+                || child.getNodeType() != Node.ELEMENT_NODE
+                ) {
+                    continue;
+                }
+                String name = child.getLocalName();
+                if ("when".equals(name)) {
+                    Element when = (Element)child;
+                    String test = when.getAttribute("test");
+                    if (test.length() == 0) {
+                        log.warn("no 'test' attribute found for when");
+                        continue;
+                    }
+
+                    try {
+                        XPath xpath = XPATH_FACTORY.newXPath();
+                        xpath.setXPathVariableResolver(frames);
+                        Object result = xpath.evaluate(
+                            test, EVAL_DOCUMENT, XPathConstants.BOOLEAN);
+
+                        if (result instanceof Boolean
+                        && ((Boolean)result).booleanValue()) {
+                            branch = child;
+                            break;
+                        }
+                    }
+                    catch (XPathExpressionException xfce) {
+                        log.error(xfce);
+                    }
+                    continue;
+                }
+                else if ("otherwise".equals(name)) {
+                    branch = child;
+                    // No break here.
+                }
+            }
+
+            if (branch != null) {
+                NodeList subs = branch.getChildNodes();
+                for (int i = 0, N = subs.getLength(); i < N; ++i) {
+                    build(parent, subs.item(i));
+                }
+            }
+        }
+
         protected void convert(Node parent, Element current) {
 
             String variable = expand(current.getAttribute("var"));
@@ -208,6 +276,9 @@
                     if ("context".equals(localName)) {
                         context(parent, (Element)current);
                     }
+                    else if ("choose".equals(localName)) {
+                        choose(parent, (Element)current);
+                    }
                     else if ("attribute".equals(localName)) {
                         attribute(parent, (Element)current);
                     }

--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/StackFrames.java	Wed Jul 20 14:01:38 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/services/meta/StackFrames.java	Wed Jul 20 14:59:25 2011 +0000
@@ -5,7 +5,12 @@
 import java.util.HashMap;
 import java.util.ArrayList;
 
+import javax.xml.xpath.XPathVariableResolver;
+
+import javax.xml.namespace.QName;
+
 public class StackFrames
+implements   XPathVariableResolver
 {
     protected List<Map<String, Object>> frames;
 
@@ -66,5 +71,10 @@
 
         return def;
     }
+
+    @Override
+    public Object resolveVariable(QName variableName) {
+        return get(variableName.getLocalPart());
+    }
 }
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