Class to address issue of MSV being shaded making it hard/impossible … (

#106)

Fix #103: add Class to address issue of MSV being shaded making it hard/impossible for other applications that need more complex XMLValidationSchema creation.

src/main/java/com/ctc/wstx/msv/W3CMultiSchemaFactory.java

@@ -0,0 +1,152 @@
+/* Woodstox XML processor
+ *
+ * Copyright (c) 2004- Tatu Saloranta, tatu.saloranta@iki.fi
+ *
+ * Licensed under the License specified in the file LICENSE which is
+ * included with the source code.
+ * You may not use this file except in compliance with the License.
+ *
+ * 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 com.ctc.wstx.msv;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+
+import javax.xml.parsers.SAXParserFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.transform.Source;
+import javax.xml.transform.dom.DOMSource;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+
+import org.xml.sax.Locator;
+
+import com.ctc.wstx.msv.W3CSchema;
+import com.sun.msv.grammar.ExpressionPool;
+import com.sun.msv.grammar.xmlschema.XMLSchemaGrammar;
+import com.sun.msv.grammar.xmlschema.XMLSchemaSchema;
+import com.sun.msv.reader.GrammarReaderController;
+import com.sun.msv.reader.State;
+import com.sun.msv.reader.xmlschema.EmbeddedSchema;
+import com.sun.msv.reader.xmlschema.MultiSchemaReader;
+import com.sun.msv.reader.xmlschema.SchemaState;
+import com.sun.msv.reader.xmlschema.WSDLGrammarReaderController;
+import com.sun.msv.reader.xmlschema.XMLSchemaReader;
+
+import org.codehaus.stax2.validation.XMLValidationSchema;
+
+/**
+ * This is a StAX2 schema factory that can parse and create schema instances
+ * for creating validators that validate documents to check their validity
+ * against specific W3C Schema instances. It requires
+ * Sun Multi-Schema Validator
+ * (http://www.sun.com/software/xml/developers/multischema/)
+ * to work, and acts as a quite thin wrapper layer, similar to
+ * how matching RelaxNG validator works
+ */
+public class W3CMultiSchemaFactory {
+
+    private MultiSchemaReader multiSchemaReader;
+    private SAXParserFactory parserFactory;
+    private RecursiveAllowedXMLSchemaReader xmlSchemaReader;
+
+    public W3CMultiSchemaFactory() {
+    }
+
+    static class RecursiveAllowedXMLSchemaReader extends XMLSchemaReader {
+        Set<String> sysIds = new TreeSet<String>();
+        RecursiveAllowedXMLSchemaReader(GrammarReaderController controller, SAXParserFactory parserFactory) {
+            super(controller, parserFactory, new StateFactory() {
+                public State schemaHead(String expectedNamespace) {
+                    return new SchemaState(expectedNamespace) {
+                        private XMLSchemaSchema old;
+                        protected void endSelf() {
+                            super.endSelf();
+                            RecursiveAllowedXMLSchemaReader r = (RecursiveAllowedXMLSchemaReader)reader;
+                            r.currentSchema = old;
+                        }
+                        protected void onTargetNamespaceResolved(String targetNs, boolean ignoreContents) {
+
+                            RecursiveAllowedXMLSchemaReader r = (RecursiveAllowedXMLSchemaReader)reader;
+                            // sets new XMLSchemaGrammar object.
+                            old = r.currentSchema;
+                            r.currentSchema = r.getOrCreateSchema(targetNs);
+                            if (ignoreContents) {
+                                return;
+                            }
+                            if (!r.isSchemaDefined(r.currentSchema)) {
+                                r.markSchemaAsDefined(r.currentSchema);
+                            }
+                        }
+                    };
+                }
+            }, new ExpressionPool());
+        }
+
+        public void setLocator(Locator locator) {
+            if (locator == null && getLocator() != null && getLocator().getSystemId() != null) {
+                sysIds.add(getLocator().getSystemId());
+            }
+            super.setLocator(locator);
+        }
+        public void switchSource(Source source, State newState) {
+            String url = source.getSystemId();
+            if (url != null && sysIds.contains(url)) {
+                return;
+            }
+            super.switchSource(source, newState);
+        }
+
+    }
+
+    /**
+     * Creates an XMLValidateSchema that can be used to validate XML instances against any of the schemas
+     * defined in the Map of schemaSources.
+     * 
+     * Map of schemas is namespace -> Source
+     */
+    public XMLValidationSchema createSchema(String baseURI,
+                                            Map<String, Source> schemaSources) throws XMLStreamException {
+
+        Map<String, EmbeddedSchema> embeddedSources = new HashMap<String, EmbeddedSchema>();
+        for (Map.Entry<String, Source> source : schemaSources.entrySet()) {
+            if (source.getValue() instanceof DOMSource) {
+                Node nd = ((DOMSource)source.getValue()).getNode();
+                Element el = null;
+                if (nd instanceof Element) {
+                    el = (Element)nd;
+                } else if (nd instanceof Document) {
+                    el = ((Document)nd).getDocumentElement();
+                }
+                embeddedSources.put(source.getKey(), new EmbeddedSchema(source.getValue().getSystemId(), el));
+            }
+        }
+
+        parserFactory = SAXParserFactory.newInstance();
+        parserFactory.setNamespaceAware(true); 
+
+        WSDLGrammarReaderController ctrl = new WSDLGrammarReaderController(null, baseURI, embeddedSources);
+        xmlSchemaReader = new RecursiveAllowedXMLSchemaReader(ctrl, parserFactory);
+        multiSchemaReader = new MultiSchemaReader(xmlSchemaReader);
+        for (Source source : schemaSources.values()) {
+            multiSchemaReader.parse(source);
+        }
+
+        XMLSchemaGrammar grammar = multiSchemaReader.getResult();
+        if (grammar == null) {
+            throw new XMLStreamException("Failed to load schemas");
+        }
+        return new W3CSchema(grammar);
+    }
+
+}