Rename policy-builder to builder as the module to host Tuscany model builders

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@819676 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 250 insertions, 0 deletions

diff --git a/java/sca/modules/builder/src/main/java/org/apache/tuscany/sca/policy/builder/impl/PolicyAttachmentBuilderImpl.java b/java/sca/modules/builder/src/main/java/org/apache/tuscany/sca/policy/builder/impl/PolicyAttachmentBuilderImpl.java
new file mode 100644
index 0000000000..98d93d8186
--- /dev/null
+++ b/java/sca/modules/builder/src/main/java/org/apache/tuscany/sca/policy/builder/impl/PolicyAttachmentBuilderImpl.java
@@ -0,0 +1,233 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.tuscany.sca.policy.builder.impl;
+
+import static javax.xml.XMLConstants.DEFAULT_NS_PREFIX;
+import static javax.xml.XMLConstants.XMLNS_ATTRIBUTE;
+import static javax.xml.XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
+
+import java.io.StringWriter;
+import java.util.Set;
+import java.util.StringTokenizer;
+
+import javax.xml.namespace.QName;
+import javax.xml.stream.XMLStreamReader;
+import javax.xml.stream.XMLStreamWriter;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathExpression;
+
+import org.apache.tuscany.sca.assembly.Component;
+import org.apache.tuscany.sca.assembly.Composite;
+import org.apache.tuscany.sca.assembly.Implementation;
+import org.apache.tuscany.sca.assembly.builder.CompositeBuilder;
+import org.apache.tuscany.sca.assembly.builder.CompositeBuilderException;
+import org.apache.tuscany.sca.common.xml.dom.DOMHelper;
+import org.apache.tuscany.sca.common.xml.stax.StAXHelper;
+import org.apache.tuscany.sca.contribution.processor.StAXArtifactProcessor;
+import org.apache.tuscany.sca.contribution.processor.StAXArtifactProcessorExtensionPoint;
+import org.apache.tuscany.sca.core.ExtensionPointRegistry;
+import org.apache.tuscany.sca.definitions.Definitions;
+import org.apache.tuscany.sca.monitor.Monitor;
+import org.apache.tuscany.sca.policy.PolicySet;
+import org.w3c.dom.Attr;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * A builder that attaches policy sets to the domain composite using the xpath defined by
+ * the attachTo attribute. It first creates a DOM model for the composite so that the xpath
+ * expression can be evaluated. For the nodes selected by the xpath, add the policySets attribute
+ * to the subject element. Then reload the patched DOM into a Composite model again.  
+ *
+ * @version $Rev$ $Date$
+ */
+public class PolicyAttachmentBuilderImpl implements CompositeBuilder {
+    private StAXHelper staxHelper;
+    private DOMHelper domHelper;
+    private StAXArtifactProcessor<Composite> processor;
+
+    public PolicyAttachmentBuilderImpl(ExtensionPointRegistry registry) {
+        domHelper = DOMHelper.getInstance(registry);
+        staxHelper = StAXHelper.getInstance(registry);
+        StAXArtifactProcessorExtensionPoint processors =
+            registry.getExtensionPoint(StAXArtifactProcessorExtensionPoint.class);
+        processor = processors.getProcessor(Composite.class);
+    }
+
+    public String getID() {
+        return "org.apache.tuscany.sca.policy.builder.PolicyAttachmentBuilder";
+    }
+
+    public Composite build(Composite composite, Definitions definitions, Monitor monitor) throws CompositeBuilderException {
+        try {
+            Composite patched = applyXPath(composite, definitions, monitor);
+            return patched;
+        } catch (Exception e) {
+            throw new CompositeBuilderException(e);
+        }
+    }
+
+    /**
+     * Apply the attachTo XPath against the composite model
+     * @param composite The orginal composite
+     * @param definitions SCA definitions that contain the policy sets
+     * @param monitor The monitor
+     * @return A reloaded composite
+     * @throws Exception
+     */
+    private Composite applyXPath(Composite composite, Definitions definitions, Monitor monitor) throws Exception {
+        // Recursively apply the xpath against the composites referenced by <implementation.composite>
+        for (Component component : composite.getComponents()) {
+            Implementation impl = component.getImplementation();
+            if (impl instanceof Composite) {
+                Composite patched = applyXPath((Composite)impl, definitions, monitor);
+                if (patched != impl) {
+                    component.setImplementation(patched);
+                }
+            }
+        }
+        // First write the composite into a DOM document so that we can apply the xpath
+        StringWriter sw = new StringWriter();
+        XMLStreamWriter writer = staxHelper.createXMLStreamWriter(sw);
+        // Write the composite into a DOM document
+        processor.write(composite, writer);
+        writer.close();
+
+        Document document = domHelper.load(sw.toString());
+
+        boolean changed = false;
+        for (PolicySet ps : definitions.getPolicySets()) {
+            // First calculate the applicable nodes
+            Set<Node> applicableNodes = null;
+            /*
+            XPathExpression appliesTo = ps.getAppliesToXPathExpression();
+            if (appliesTo != null) {
+                applicableNodes = new HashSet<Node>();
+                NodeList nodes = (NodeList)appliesTo.evaluate(document, XPathConstants.NODESET);
+                for (int i = 0; i < nodes.getLength(); i++) {
+                    applicableNodes.add(nodes.item(i));
+                }
+            }
+            */
+            XPathExpression exp = ps.getAttachToXPathExpression();
+            if (exp != null) {
+                NodeList nodes = (NodeList)exp.evaluate(document, XPathConstants.NODESET);
+                for (int i = 0; i < nodes.getLength(); i++) {
+                    Node node = nodes.item(i);
+                    if (applicableNodes == null || applicableNodes.contains(node)) {
+                        // The node can be a component, service, reference or binding
+                        if (attach(node, ps) && !changed) {
+                            changed = true;
+                        }
+                    }
+                }
+            }
+        }
+
+        if (changed) {
+            XMLStreamReader reader = staxHelper.createXMLStreamReader(document);
+            reader.nextTag();
+            Composite patchedComposite = (Composite)processor.read(reader);
+            return patchedComposite;
+        } else {
+            return composite;
+        }
+    }
+
+    /**
+     * Attach the policySet to the given DOM node 
+     * @param node The DOM node (should be an element)
+     * @param policySet The policy set to be attached
+     * @return true if the element is changed, false if the element already contains the same policy set
+     * and no change is made
+     */
+    private boolean attach(Node node, PolicySet policySet) {
+        Element element = (Element)node;
+        Document document = element.getOwnerDocument();
+
+        QName qname = policySet.getName();
+        String prefix = DOMHelper.getPrefix(element, qname.getNamespaceURI());
+        if (prefix == null) {
+            // Find the a non-conflicting prefix
+            int i = 0;
+            while (true) {
+                prefix = "ns" + i;
+                String ns = DOMHelper.getNamespaceURI(element, prefix);
+                if (ns == null) {
+                    break;
+                }
+            }
+            // Declare the namespace
+            Attr nsAttr = document.createAttributeNS(XMLNS_ATTRIBUTE_NS_URI, XMLNS_ATTRIBUTE + ":" + prefix);
+            nsAttr.setValue(qname.getNamespaceURI());
+            element.setAttributeNodeNS(nsAttr);
+        }
+        // Form the value as a qualified name
+        String qvalue = null;
+        if (DEFAULT_NS_PREFIX.equals(prefix)) {
+            qvalue = qname.getLocalPart();
+        } else {
+            qvalue = prefix + ":" + qname.getLocalPart();
+        }
+
+        // Check if the attribute exists
+        Attr attr = element.getAttributeNode("policySets");
+        if (attr == null) {
+            // Create the policySets attr
+            attr = document.createAttributeNS(null, "policySets");
+            attr.setValue(qvalue);
+            element.setAttributeNodeNS(attr);
+            return true;
+        } else {
+            // Append to the existing value
+            boolean duplicate = false;
+            String value = attr.getValue();
+            StringTokenizer tokenizer = new StringTokenizer(value);
+            while (tokenizer.hasMoreTokens()) {
+                String ps = tokenizer.nextToken();
+                int index = ps.indexOf(':');
+                String ns = null;
+                String localName = null;
+                if (index == -1) {
+                    ns = DOMHelper.getNamespaceURI(element, DEFAULT_NS_PREFIX);
+                    localName = ps;
+                } else {
+                    ns = DOMHelper.getNamespaceURI(element, ps.substring(0, index));
+                    localName = ps.substring(index + 1);
+                }
+                QName psName = new QName(ns, localName);
+                if (qname.equals(psName)) {
+                    duplicate = true;
+                    break;
+                }
+            }
+            if (!duplicate) {
+                // REVIEW: [rfeng] How to comply to POL40012?
+                value = value + " " + qvalue;
+                attr.setValue(value.trim());
+                return true;
+            }
+            return false;
+        }
+    }
+
+}
diff --git a/java/sca/modules/builder/src/main/resources/META-INF/services/org.apache.tuscany.sca.assembly.builder.CompositeBuilder b/java/sca/modules/builder/src/main/resources/META-INF/services/org.apache.tuscany.sca.assembly.builder.CompositeBuilder
new file mode 100644
index 0000000000..5de5512c82
--- /dev/null
+++ b/java/sca/modules/builder/src/main/resources/META-INF/services/org.apache.tuscany.sca.assembly.builder.CompositeBuilder
@@ -0,0 +1,17 @@
+# Licensed to the Apache Software Foundation (ASF) under one

+# or more contributor license agreements.  See the NOTICE file

+# distributed with this work for additional information

+# regarding copyright ownership.  The ASF licenses this file

+# to you under the Apache License, Version 2.0 (the

+# "License"); you may not use this file except in compliance

+# with the License.  You may obtain a copy of the License at

+# 

+#   http://www.apache.org/licenses/LICENSE-2.0

+# 

+# Unless required by applicable law or agreed to in writing,

+# software distributed under the License is distributed on an

+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

+# KIND, either express or implied.  See the License for the

+# specific language governing permissions and limitations

+# under the License. 

+org.apache.tuscany.sca.builder.impl.ModelBuilderImpl;id=org.apache.tuscany.sca.assembly.builder.CompositeBuilder