XML metadata extraction with sample.

Added tests into build.

This is now ready for testing, comments and suggestions.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@6056 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/content/metadata/AbstractMappingMetadataExtracter.java

@@ -93,7 +93,6 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
     
     private MetadataExtracterRegistry registry;
     private MimetypeService mimetypeService;
-    private long extractionTime;
     private boolean initialized;
     
     private Set<String> supportedMimetypes;
@@ -101,12 +100,23 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
     private Map<String, Set<QName>> mapping;
     private boolean inheritDefaultMapping;
 
+    /**
+     * Default constructor.  If this is called, then {@link #isSupported(String)} should
+     * be implemented.  This is useful when the list of supported mimetypes is not known
+     * when the instance is constructed.  Alternatively, once the set becomes known, call
+     * {@link #setSupportedMimetypes(Collection)}.
+     *
+     * @see #isSupported(String)
+     * @see #setSupportedMimetypes(Collection)
+     */
     protected AbstractMappingMetadataExtracter()
     {
         this(Collections.<String>emptySet());
     }
 
     /**
+     * Constructor that can be used when the list of supported mimetypes is known up front.
+     * 
      * @param supportedMimetypes    the set of mimetypes supported by default
      */
     protected AbstractMappingMetadataExtracter(Set<String> supportedMimetypes)
@@ -179,13 +189,29 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
     }
 
     /**
-     * @param overwritePolicy   the policy to apply when there are existing system properties
+     * Set the policy to use when existing values are encountered.  Depending on how the extracer
+     * is called, this may not be relevant, i.e an empty map of existing properties may be passed
+     * in by the client code, which may follow its own overwrite strategy.
+     * 
+     * @param overwritePolicy       the policy to apply when there are existing system properties
      */
     public void setOverwritePolicy(OverwritePolicy overwritePolicy)
     {
         this.overwritePolicy = overwritePolicy;
     }
 
+    /**
+     * Set the policy to use when existing values are encountered.  Depending on how the extracer
+     * is called, this may not be relevant, i.e an empty map of existing properties may be passed
+     * in by the client code, which may follow its own overwrite strategy.
+     * 
+     * @param overwritePolicyStr    the policy to apply when there are existing system properties
+     */
+    public void setOverwritePolicy(String overwritePolicyStr)
+    {
+        this.overwritePolicy = OverwritePolicy.valueOf(overwritePolicyStr);
+    }
+
     /**
      * Set if the property mappings augment or override the mapping generically provided by the
      * extracter implementation.  The default is <tt>false</tt>, i.e. any mapping set completely
@@ -410,10 +436,6 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
         {
             registry.register(this);
         }
-        else
-        {
-            logger.warn("No registry provided.  Not registering: " + this);
-        }
     }
     
     /**
@@ -466,7 +488,7 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
     /** {@inheritDoc} */
     public long getExtractionTime()
     {
-        return extractionTime;
+        return 1000L;
     }
 
     /**
@@ -510,7 +532,7 @@ abstract public class AbstractMappingMetadataExtracter implements MetadataExtrac
     /**
      * {@inheritDoc}
      */
-    public final Map<QName, Serializable> extract(
+    public Map<QName, Serializable> extract(
             ContentReader reader,
             OverwritePolicy overwritePolicy,
             Map<QName, Serializable> destination,

source/java/org/alfresco/repo/content/metadata/MetadataExtracter.java

@@ -222,6 +222,8 @@ public interface MetadataExtracter extends ContentWorker
      * reliant transformers will be used for a specific extraction.
      * 
      * @return Returns the approximate number of milliseconds per transformation
+     * 
+     * @deprecated          Generally not useful or used.  Extraction is normally specifically configured.
      */
     public long getExtractionTime();
 

source/java/org/alfresco/repo/content/metadata/MetadataExtracterRegistry.java

@@ -145,7 +145,6 @@ public class MetadataExtracterRegistry
      */
     private MetadataExtracter findBestExtracter(String sourceMimetype)
     {
-        long bestTime = Long.MAX_VALUE;
         logger.debug("Finding best extracter for " + sourceMimetype);
 
         MetadataExtracter bestExtracter = null;
@@ -157,12 +156,7 @@ public class MetadataExtracterRegistry
                 // extraction not achievable
                 continue;
             }
-            long time = ext.getExtractionTime();
-            if (time < bestTime)
-            {
-                bestExtracter = ext;
-                bestTime = time;
-            }
+            bestExtracter = ext;
         }
         return bestExtracter;
     }

source/java/org/alfresco/repo/content/metadata/xml/XmlMetadataExtracter.java

@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2005-2007 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.repo.content.metadata.xml;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.alfresco.repo.content.selector.ContentWorkerSelector;
+import org.alfresco.repo.content.MimetypeMap;
+import org.alfresco.repo.content.metadata.AbstractMappingMetadataExtracter;
+import org.alfresco.repo.content.metadata.MetadataExtracter;
+import org.alfresco.service.cmr.repository.ContentReader;
+import org.alfresco.service.namespace.QName;
+import org.alfresco.util.PropertyCheck;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * A metadata extractor that selects an appropiate workder for the extraction.
+ * <p>
+ * The {@linkplain #setSelectors(List) selectors} are used to find an extracter most
+ * appropriate of a given XML document.  The chosen extracter is then asked to extract
+ * the values, passing through the {@linkplain MetadataExtracter.OverwritePolicy overwrite policy}
+ * as {@linkplain #setOverwritePolicy(String)} on this instance.  The overwrite policy of the
+ * embedded extracters is not relevant unless they are used separately in another context.
+ * 
+ * @see ContentWorkerSelector
+ * @see MetadataExtracter
+ * 
+ * @since 2.1
+ * @author Derek Hulley
+ */
+public class XmlMetadataExtracter extends AbstractMappingMetadataExtracter
+{
+    public static String[] SUPPORTED_MIMETYPES = new String[] {MimetypeMap.MIMETYPE_XML};
+    
+    private static Log logger = LogFactory.getLog(XPathMetadataExtracter.class);
+    
+    private List<ContentWorkerSelector<MetadataExtracter>> selectors;
+
+    /**
+     * Default constructor
+     */
+    public XmlMetadataExtracter()
+    {
+        super(new HashSet<String>(Arrays.asList(SUPPORTED_MIMETYPES)));
+    }
+
+    /**
+     * Sets the list of metadata selectors to use to find the extracter to use, given
+     * some content.  The evaluations are done in the order that they occur in the
+     * list.
+     * 
+     * @param selectors     A list of selectors
+     */
+    public void setSelectors(List<ContentWorkerSelector<MetadataExtracter>> selectors)
+    {
+        this.selectors = selectors;
+    }
+
+    @Override
+    protected void init()
+    {
+        PropertyCheck.mandatory(this, "selectors", selectors);
+        // Get the base class to set up its mappings
+        super.init();
+    }
+
+    /**
+     * It is not possible to have any default mappings, but something has to be returned.
+     * 
+     * @return              Returns an empty map
+     */
+    @Override
+    protected Map<String, Set<QName>> getDefaultMapping()
+    {
+        return Collections.emptyMap();
+    }
+
+    /**
+     * Selects and extracter to perform the work and redirects to it.
+     */
+    @Override
+    public Map<QName, Serializable> extract(
+            ContentReader reader,
+            OverwritePolicy overwritePolicy,
+            Map<QName, Serializable> destination,
+            Map<String, Set<QName>> mapping)
+    {
+        MetadataExtracter extracter = null;
+        // Select a worker
+        for (ContentWorkerSelector<MetadataExtracter> selector : selectors)
+        {
+            ContentReader spawnedReader = reader.getReader();
+            try
+            {
+                extracter = selector.getWorker(spawnedReader);
+            }
+            finally
+            {
+                if (reader.isChannelOpen())
+                {
+                    logger.error("Content reader not closed by MetadataExtractor selector: \n" +
+                            "   reader:   " + reader + "\n" +
+                            "   selector: " + selector);
+                }
+            }
+            // Just take the first successful one
+            if (extracter != null)
+            {
+                if (logger.isDebugEnabled())
+                {
+                    logger.debug("\n" +
+                            "Found metadata extracter to process XML document: \n" +
+                            "   Selector: " + selector + "\n" +
+                            "   Document: " + reader);
+                }
+                break;
+            }
+        }
+        Map<QName, Serializable> modifiedProperties = null;
+        // Did we find anything?
+        if (extracter == null)
+        {
+            // There will be no properties extracted
+            modifiedProperties = Collections.emptyMap();
+        }
+        else
+        {
+            // An extractor was selected
+            try
+            {
+                modifiedProperties = extracter.extract(reader, overwritePolicy, destination, mapping);
+            }
+            finally
+            {
+                if (reader.isChannelOpen())
+                {
+                    logger.error("Content reader not closed by MetadataExtractor: \n" +
+                            "   Reader:   " + reader + "\n" +
+                            "   extracter: " + extracter);
+                }
+            }
+        }
+        // Done
+        if (logger.isDebugEnabled())
+        {
+            logger.debug("\n" +
+                    "XML metadata extractor redirected: \n" +
+                    "   Reader:    " + reader + "\n" +
+                    "   Extracter: " + extracter + "\n" +
+                    "   Extracted: " + modifiedProperties);
+        }
+        return modifiedProperties;
+    }
+
+    /**
+     * This is not required as the 
+     */
+    protected Map<String, Serializable> extractRaw(ContentReader reader) throws Throwable
+    {
+        throw new UnsupportedOperationException();
+    }
+}

source/java/org/alfresco/repo/content/metadata/xml/XmlMetadataExtracterTest.java

@@ -31,10 +31,27 @@ import java.net.URL;
 import junit.framework.TestCase;
 
 import org.alfresco.model.ContentModel;
+import org.alfresco.repo.action.ActionImpl;
+import org.alfresco.repo.action.executer.ActionExecuter;
+import org.alfresco.repo.action.executer.SetPropertyValueActionExecuter;
 import org.alfresco.repo.content.MimetypeMap;
 import org.alfresco.repo.content.filestore.FileContentReader;
+import org.alfresco.repo.content.metadata.MetadataExtracter;
+import org.alfresco.repo.content.selector.RootElementNameContentWorkerSelector;
+import org.alfresco.repo.content.selector.XPathContentWorkerSelector;
 import org.alfresco.repo.content.transform.AbstractContentTransformerTest;
+import org.alfresco.repo.security.authentication.AuthenticationComponent;
+import org.alfresco.service.ServiceRegistry;
+import org.alfresco.service.cmr.action.Action;
 import org.alfresco.service.cmr.repository.ContentReader;
+import org.alfresco.service.cmr.repository.ContentService;
+import org.alfresco.service.cmr.repository.ContentWriter;
+import org.alfresco.service.cmr.repository.NodeRef;
+import org.alfresco.service.cmr.repository.NodeService;
+import org.alfresco.service.cmr.repository.StoreRef;
+import org.alfresco.service.namespace.NamespaceService;
+import org.alfresco.service.namespace.QName;
+import org.alfresco.util.GUID;
 import org.alfresco.util.PropertyMap;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
@@ -54,8 +71,13 @@ public class XmlMetadataExtracterTest extends TestCase
     private static final String CTX_LOCATION = "classpath:xml-metadata/xml-metadata-test-context.xml";
     private static final ApplicationContext ctx = new ClassPathXmlApplicationContext(CTX_LOCATION);
     
-    private XPathMetadataExtracter alfrescoModelMetadataExtractor;
-    private XPathMetadataExtracter eclipseProjectMetadataExtractor;
+    private ServiceRegistry serviceRegistry;
+    private AuthenticationComponent authenticationComponent;
+    private XPathMetadataExtracter alfrescoModelMetadataExtracter;
+    private XPathMetadataExtracter eclipseProjectMetadataExtracter;
+    private RootElementNameContentWorkerSelector<MetadataExtracter> rootElementNameMetadataExtracterSelector;
+    private XPathContentWorkerSelector<MetadataExtracter> xpathMetadataExtracterSelector;
+    private XmlMetadataExtracter xmlMetadataExtracter;
 
     /**
      * Get a reader for a file that should be on the classpath.
@@ -78,16 +100,30 @@ public class XmlMetadataExtracterTest extends TestCase
     }
     
     @Override
+    @SuppressWarnings("unchecked")
     public void setUp() throws Exception
     {
-        alfrescoModelMetadataExtractor = (XPathMetadataExtracter) ctx.getBean("extracter.xml.AlfrescoModelMetadataExtracter");
-        eclipseProjectMetadataExtractor = (XPathMetadataExtracter) ctx.getBean("extracter.xml.EclipseProjectMetadataExtracter");
+        serviceRegistry = (ServiceRegistry) ctx.getBean(ServiceRegistry.SERVICE_REGISTRY);
+        authenticationComponent = (AuthenticationComponent) ctx.getBean("authenticationComponent");
+        alfrescoModelMetadataExtracter = (XPathMetadataExtracter) ctx.getBean("extracter.xml.AlfrescoModelMetadataExtracter");
+        eclipseProjectMetadataExtracter = (XPathMetadataExtracter) ctx.getBean("extracter.xml.EclipseProjectMetadataExtracter");
+        rootElementNameMetadataExtracterSelector = (RootElementNameContentWorkerSelector<MetadataExtracter>) ctx.getBean("extracter.xml.selector.RootElementSelector");
+        xpathMetadataExtracterSelector = (XPathContentWorkerSelector<MetadataExtracter>) ctx.getBean("extracter.xml.selector.XPathSelector");
+        xmlMetadataExtracter = (XmlMetadataExtracter) ctx.getBean("extracter.xml.XMLMetadataExtracter");
+        
+        authenticationComponent.setSystemUserAsCurrentUser();
+    }
+    
+    @Override
+    public void tearDown() throws Exception
+    {
+        try { authenticationComponent.clearCurrentSecurityContext(); } catch (Throwable e) {}
     }
 
     public void testSetUp()
     {
-        assertNotNull(alfrescoModelMetadataExtractor);
-        assertNotNull(eclipseProjectMetadataExtractor);
+        assertNotNull(alfrescoModelMetadataExtracter);
+        assertNotNull(eclipseProjectMetadataExtracter);
     }
     
     public void testExtractAlfresocModel() throws Exception
@@ -98,7 +134,7 @@ public class XmlMetadataExtracterTest extends TestCase
         
         // Pass it to the extracter
         PropertyMap checkProperties = new PropertyMap();
-        alfrescoModelMetadataExtractor.extract(reader, checkProperties);
+        alfrescoModelMetadataExtracter.extract(reader, checkProperties);
         
         // Check the values
         assertEquals("Gavin Cornwell", checkProperties.get(ContentModel.PROP_AUTHOR));
@@ -114,10 +150,128 @@ public class XmlMetadataExtracterTest extends TestCase
         
         // Pass it to the extracter
         PropertyMap checkProperties = new PropertyMap();
-        eclipseProjectMetadataExtractor.extract(reader, checkProperties);
+        eclipseProjectMetadataExtracter.extract(reader, checkProperties);
         
         // Check the values
         assertEquals("Repository", checkProperties.get(ContentModel.PROP_TITLE));
         assertEquals("JavaCC Nature", checkProperties.get(ContentModel.PROP_DESCRIPTION));
     }
+    
+    public void testRootElementNameSelector() throws Exception
+    {
+        // Load the example files
+        ContentReader alfrescoModelReader = getReader(FILE_ALFRESCO_MODEL);
+        assertTrue(alfrescoModelReader.exists());
+        ContentReader eclipseProjectReader = getReader(FILE_ECLIPSE_PROJECT);
+        assertTrue(eclipseProjectReader.exists());
+        
+        // Check with an alfresco model document
+        MetadataExtracter alfrescoModelExtracter = rootElementNameMetadataExtracterSelector.getWorker(alfrescoModelReader);
+        assertNotNull("Failed to select correct extracter", alfrescoModelExtracter);
+        assertTrue("Incorrect extracter instance selected", alfrescoModelMetadataExtracter == alfrescoModelExtracter);
+        assertFalse("Read channel not closed", alfrescoModelReader.isChannelOpen());
+        
+        // Check with an eclipse project document
+        MetadataExtracter eclipseProjectExtracter = rootElementNameMetadataExtracterSelector.getWorker(eclipseProjectReader);
+        assertNotNull("Failed to select correct extracter", eclipseProjectExtracter);
+        assertTrue("Incorrect extracter instance selected", eclipseProjectMetadataExtracter == eclipseProjectExtracter);
+        assertFalse("Read channel not closed", eclipseProjectReader.isChannelOpen());
+    }
+    
+    public void testXpathSelector() throws Exception
+    {
+        // Load the example files
+        ContentReader alfrescoModelReader = getReader(FILE_ALFRESCO_MODEL);
+        assertTrue(alfrescoModelReader.exists());
+        ContentReader eclipseProjectReader = getReader(FILE_ECLIPSE_PROJECT);
+        assertTrue(eclipseProjectReader.exists());
+        
+        // Check with an alfresco model document
+        MetadataExtracter alfrescoModelExtracter = xpathMetadataExtracterSelector.getWorker(alfrescoModelReader);
+        assertNotNull("Failed to select correct extracter", alfrescoModelExtracter);
+        assertTrue("Incorrect extracter instance selected", alfrescoModelMetadataExtracter == alfrescoModelExtracter);
+        assertFalse("Read channel not closed", alfrescoModelReader.isChannelOpen());
+        
+        // Check with an eclipse project document
+        MetadataExtracter eclipseProjectExtracter = xpathMetadataExtracterSelector.getWorker(eclipseProjectReader);
+        assertNotNull("Failed to select correct extracter", eclipseProjectExtracter);
+        assertTrue("Incorrect extracter instance selected", eclipseProjectMetadataExtracter == eclipseProjectExtracter);
+        assertFalse("Read channel not closed", eclipseProjectReader.isChannelOpen());
+    }
+    
+    public void testXmlMetadataExtracter() throws Exception
+    {
+        // Load the example files
+        ContentReader alfrescoModelReader = getReader(FILE_ALFRESCO_MODEL);
+        assertTrue(alfrescoModelReader.exists());
+        ContentReader eclipseProjectReader = getReader(FILE_ECLIPSE_PROJECT);
+        assertTrue(eclipseProjectReader.exists());
+        
+        // Pass the Alfresco Model xml to the extractor
+        PropertyMap checkAlfrescoModelProperties = new PropertyMap();
+        xmlMetadataExtracter.extract(alfrescoModelReader, checkAlfrescoModelProperties);
+        // Check the values
+        assertEquals("Gavin Cornwell", checkAlfrescoModelProperties.get(ContentModel.PROP_AUTHOR));
+        assertEquals("fm:forummodel", checkAlfrescoModelProperties.get(ContentModel.PROP_TITLE));
+        assertEquals("Forum Model", checkAlfrescoModelProperties.get(ContentModel.PROP_DESCRIPTION));
+
+        // Pass the Eclipse Project xml to the extractor
+        PropertyMap checkEclipseProjectProperties = new PropertyMap();
+        xmlMetadataExtracter.extract(eclipseProjectReader, checkEclipseProjectProperties);
+        // Check the values
+        assertEquals("Repository", checkEclipseProjectProperties.get(ContentModel.PROP_TITLE));
+        assertEquals("JavaCC Nature", checkEclipseProjectProperties.get(ContentModel.PROP_DESCRIPTION));
+    }
+    
+    /**
+     * Tests metadata extraction using an action with an EAGER MetadataExtracter for XML.
+     */
+    public void testLifecycleOfXmlMetadataExtraction() throws Exception
+    {
+        NodeService nodeService = serviceRegistry.getNodeService();
+        ContentService contentService = serviceRegistry.getContentService();
+        ActionExecuter executer = (ActionExecuter) ctx.getBean("extract-metadata");
+        Action action = new ActionImpl(null, GUID.generate(), SetPropertyValueActionExecuter.NAME, null);
+        
+        StoreRef storeRef = new StoreRef("test", getName());
+        NodeRef rootNodeRef = null;
+        if (nodeService.exists(storeRef))
+        {
+            rootNodeRef = nodeService.getRootNode(storeRef);
+        }
+        else
+        {
+            nodeService.createStore("test", getName());
+            rootNodeRef = nodeService.getRootNode(storeRef);
+        }
+        
+        // Set up some properties
+        PropertyMap properties = new PropertyMap();
+        properties.put(ContentModel.PROP_TITLE, "My title");
+        properties.put(ContentModel.PROP_DESCRIPTION, "My description");
+        
+        NodeRef contentNodeRef = nodeService.createNode(
+                rootNodeRef,
+                ContentModel.ASSOC_CHILDREN,
+                QName.createQName(NamespaceService.CONTENT_MODEL_1_0_URI, getName()),
+                ContentModel.TYPE_CONTENT,
+                properties).getChildRef();
+        // Add some content
+        ContentReader alfrescoModelReader = getReader(FILE_ALFRESCO_MODEL);
+        assertTrue(alfrescoModelReader.exists());
+        ContentWriter writer = contentService.getWriter(contentNodeRef, ContentModel.PROP_CONTENT, true);
+        writer.setEncoding("UTF-8");
+        writer.setMimetype(MimetypeMap.MIMETYPE_XML);
+        writer.putContent(alfrescoModelReader);
+        
+        // Execute the action
+        executer.execute(action, contentNodeRef);
+        
+        // Check the node's properties.  The EAGER overwrite policy should have replaced the required
+        // properties.
+        String checkTitle = (String) nodeService.getProperty(contentNodeRef, ContentModel.PROP_TITLE);
+        String checkDescription = (String) nodeService.getProperty(contentNodeRef, ContentModel.PROP_DESCRIPTION);
+        assertEquals("fm:forummodel", checkTitle);
+        assertEquals("Forum Model", checkDescription);
+    }
 }

source/java/org/alfresco/repo/content/selector/ContentWorkerSelector.java

@@ -22,8 +22,9 @@
  * the FLOSS exception, and it is also available here: 
  * http://www.alfresco.com/legal/licensing"
  */
-package org.alfresco.repo.content;
+package org.alfresco.repo.content.selector;
 
+import org.alfresco.repo.content.ContentWorker;
 import org.alfresco.service.cmr.repository.ContentIOException;
 import org.alfresco.service.cmr.repository.ContentReader;
 

source/java/org/alfresco/repo/content/selector/RootElementNameContentWorkerSelector.java

@@ -22,7 +22,7 @@
  * the FLOSS exception, and it is also available here: 
  * http://www.alfresco.com/legal/licensing"
  */
-package org.alfresco.repo.content.metadata.xml;
+package org.alfresco.repo.content.selector;
 
 import java.io.InputStream;
 import java.util.Collections;
@@ -33,11 +33,11 @@ import java.util.Set;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;
 
-import org.alfresco.repo.content.ContentWorkerSelector;
+import org.alfresco.repo.content.ContentWorker;
 import org.alfresco.repo.content.MimetypeMap;
-import org.alfresco.repo.content.metadata.MetadataExtracter;
 import org.alfresco.service.cmr.repository.ContentIOException;
 import org.alfresco.service.cmr.repository.ContentReader;
+import org.alfresco.util.PropertyCheck;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.xml.sax.Attributes;
@@ -48,33 +48,38 @@ import org.xml.sax.helpers.DefaultHandler;
  * A selector that looks at the root node of an XML document to determine which worker to provide.
  * There are many ways to identify XML documents and this is probably the simplest.  Alternate
  * implementations might execute a series of xpath statements or look for specific namespace
- * declarations in the document.  The net result is the same, i.e. given an XML document, an
- * extracter is provided to the caller.
- * <p>
- * In this selector, there is no guarantee that the different extracters will generate the same
- * (or even nearly the same) metadata.  It is up to the configurer to ensure that if it is a
- * requirement, but otherwise each extracter is responsible for its own mappings.  Mostly, though,
- * a root node match will imply a structure that has the necessary metadata.
+ * declarations in the document.  The net result is the same, i.e. given an XML document, a
+ * worker is provided to the caller.
  * 
  * @since 2.1
  * @author Derek Hulley
  */
-public class RootElementNameMetadataExtracterSelector
+public class RootElementNameContentWorkerSelector<W extends ContentWorker>
         extends DefaultHandler
-        implements ContentWorkerSelector<MetadataExtracter>
+        implements ContentWorkerSelector<ContentWorker>
 {
-    private static Log logger = LogFactory.getLog(RootElementNameMetadataExtracterSelector.class);
+    private static Log logger = LogFactory.getLog(RootElementNameContentWorkerSelector.class);
     
     private SAXParserFactory saxParserFactory;
     private Set<String> supportedMimetypes;
-    private Map<String, MetadataExtracter> extractersByRootElementName;
+    private Map<String, W> workersByRootElementName;
     
-    public RootElementNameMetadataExtracterSelector()
+    public RootElementNameContentWorkerSelector()
     {
         saxParserFactory = SAXParserFactory.newInstance();
         supportedMimetypes = new HashSet<String>();
         supportedMimetypes.add(MimetypeMap.MIMETYPE_XML);
-        extractersByRootElementName = Collections.emptyMap();
+        workersByRootElementName = Collections.emptyMap();
+    }
+
+    @Override
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder(50);
+        sb.append("RootElementNameContentWorkerSelector")
+          .append("[ workers=").append(workersByRootElementName)
+          .append("]");
+        return sb.toString();
     }
 
     /**
@@ -89,26 +94,35 @@ public class RootElementNameMetadataExtracterSelector
     }
 
     /**
-     * Set the extractors to use.
+     * Set the workers to choose from.
      * 
-     * @param extracters            a map of {@linkplain MetadataExtracter} instances
+     * @param workers               a map of {@linkplain ContentWorker} instances
      *                              keyed by root element name
      */
-    public void setExtracters(Map<String, MetadataExtracter> extracters)
+    public void setWorkers(Map<String, W> workers)
     {
-        this.extractersByRootElementName = extracters;
+        this.workersByRootElementName = workers;
     }
 
     /**
-     * Performs a match of the root element name to find the correct extracter.
+     * Checks the configuration.
      */
-    public MetadataExtracter getWorker(ContentReader reader)
+    public void init()
+    {
+        PropertyCheck.mandatory(this, "workers", workersByRootElementName);
+        PropertyCheck.mandatory(this, "supportedMimetypes", supportedMimetypes);
+    }
+    
+    /**
+     * Performs a match of the root element name to find the correct content worker.
+     */
+    public W getWorker(ContentReader reader)
     {
         if (!supportedMimetypes.contains(reader.getMimetype()))
         {
             return null;
         }
-        MetadataExtracter extracter = null;
+        W worker = null;
         InputStream is = null;
         String rootElementName = null;
         try
@@ -121,11 +135,15 @@ public class RootElementNameMetadataExtracterSelector
         catch (RootElementFoundException e)
         {
             rootElementName = e.getElementName();
-            extracter = extractersByRootElementName.get(rootElementName);
+            worker = workersByRootElementName.get(rootElementName);
         }
         catch (Throwable e)
         {
-            throw new ContentIOException("Failed to extract root element from XML document", e);
+            throw new ContentIOException("\n" +
+                    "Failed to extract root element from XML document: \n" +
+                    "   Reader:   " + reader + "\n" +
+                    "   Selector: " + this,
+                    e);
         }
         finally
         {
@@ -138,18 +156,18 @@ public class RootElementNameMetadataExtracterSelector
         if (logger.isDebugEnabled())
         {
             logger.debug("\n" +
-                    "Chosen metadata extracter for reader: \n" +
+                    "Chosen content worker for reader: \n" +
                     "   Reader:       " + reader + "\n" +
                     "   Root Element: " + rootElementName + "\n" +
-                    "   Extracter:    " + extracter);
+                    "   Worker:       " + worker);
         }
-        return extracter;
+        return worker;
     }
 
     @Override
     public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException
     {
-        throw new RootElementFoundException(localName);
+        throw new RootElementFoundException(qName);
     }
 
     /**

source/java/org/alfresco/repo/content/selector/XPathContentWorkerSelector.java

@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2005-2007 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.repo.content.selector;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+import org.alfresco.error.AlfrescoRuntimeException;
+import org.alfresco.repo.content.ContentWorker;
+import org.alfresco.repo.content.MimetypeMap;
+import org.alfresco.service.cmr.repository.ContentIOException;
+import org.alfresco.service.cmr.repository.ContentReader;
+import org.alfresco.util.PropertyCheck;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.w3c.dom.Document;
+
+/**
+ * A selector that executes a set of XPath statements against the XML document to determine
+ * which content worker to provide.  The XPath rules are simple, i.e. if an XML node is
+ * found by the XPath statement, then it is considered to be a hit and the corresponding
+ * worker is returned.
+ * <p>
+ * Currently, the only namespaces supported are those contained in the XML documents being
+ * tested.
+ * 
+ * @since 2.1
+ * @author Derek Hulley
+ */
+public class XPathContentWorkerSelector<W extends ContentWorker> implements ContentWorkerSelector
+{
+    private static Log logger = LogFactory.getLog(XPathContentWorkerSelector.class);
+    
+    private DocumentBuilder documentBuilder;
+    private XPathFactory xpathFactory;
+    private Set<String> supportedMimetypes;
+    private Map<String, W> workersByXPath;
+    
+    public XPathContentWorkerSelector()
+    {
+        try
+        {
+            documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
+            xpathFactory = XPathFactory.newInstance();
+        }
+        catch (Throwable e)
+        {
+            throw new AlfrescoRuntimeException("Failed to initialize XPathContentWorkerSelector", e);
+        }
+        supportedMimetypes = new HashSet<String>();
+        supportedMimetypes.add(MimetypeMap.MIMETYPE_XML);
+    }
+
+    @Override
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder(50);
+        sb.append("XPathContentWorkerSelector")
+          .append("[ workers=").append(workersByXPath)
+          .append("]");
+        return sb.toString();
+    }
+
+    /**
+     * Optionally set the mimetypes supported.  They must be XML formats that the chosen
+     * parser will be able to handle.
+     * 
+     * @param supportedMimetypes        the list of mimetypes.  The default is <b>text/xml</b>.
+     */
+    public void setSupportedMimetypes(Set<String> supportedMimetypes)
+    {
+        this.supportedMimetypes = supportedMimetypes;
+    }
+
+    /**
+     * Set the workers to use.  All the XPath statements provided must be compatible with
+     * a return value of type {@linkplain XPathConstants#NODE NODE}.
+     * 
+     * @param workers            a map of {@linkplain ContentWorker} instances
+     *                           keyed by XPath statements
+     */
+    public void setWorkers(Map<String, W> workers)
+    {
+        this.workersByXPath = workers;
+    }
+
+    /**
+     * Checks the configuration.
+     */
+    public void init()
+    {
+        PropertyCheck.mandatory(this, "workers", workersByXPath);
+        PropertyCheck.mandatory(this, "supportedMimetypes", supportedMimetypes);
+    }
+    
+    /**
+     * Execute the XPath statements, in order, against the document.  Any statements that fail
+     * to run will be ignored.
+     */
+    public W getWorker(ContentReader reader)
+    {
+        if (!supportedMimetypes.contains(reader.getMimetype()))
+        {
+            return null;
+        }
+        W worker = null;
+        InputStream is = null;
+        String xpath = null;
+        try
+        {
+            is = reader.getContentInputStream();
+            Document doc = documentBuilder.parse(is);
+            // Execute the statements
+            worker = processDocument(doc);
+        }
+        catch (Throwable e)
+        {
+            throw new ContentIOException("\n" +
+                    "Failed to XPaths against XML document: \n" +
+                    "   Reader:   " + reader + "\n" +
+                    "   Selector: " + this,
+                    e);
+        }
+        finally
+        {
+            if (is != null)
+            {
+                try { is.close(); } catch (IOException e) {}
+            }
+        }
+        // Done
+        if (logger.isDebugEnabled())
+        {
+            logger.debug("\n" +
+                    "Chosen content worker for reader: \n" +
+                    "   Reader:       " + reader + "\n" +
+                    "   XPath:        " + xpath + "\n" +
+                    "   Worker:    " + worker);
+        }
+        return worker;
+    }
+    
+    /**
+     * Check the given document against the list of XPath statements provided.
+     * 
+     * @param document          the XML document
+     * @return                  Returns a content worker that was matched or <tt>null</tt>
+     */
+    private W processDocument(Document doc)
+    {
+        for (Map.Entry<String, W> entry : workersByXPath.entrySet())
+        {
+            try
+            {
+                String xpath = entry.getKey();
+                W worker = entry.getValue();
+                // Execute the statement
+                Object ret = xpathFactory.newXPath().evaluate(xpath, doc, XPathConstants.NODE);
+                if (ret != null)
+                {
+                    // We found one
+                    return worker;
+                }
+            }
+            catch (XPathExpressionException e)
+            {
+                // We accept this and move on
+            }
+        }
+        // Nothing found
+        return null;
+    }
+}

source/test-resources/xml-metadata/xml-metadata-test-context.xml

@@ -47,4 +47,59 @@
       </property>
    </bean>
    
+   <!-- A selector that checks root element names -->
+   <bean
+         id="extracter.xml.selector.RootElementSelector"
+         class="org.alfresco.repo.content.selector.RootElementNameContentWorkerSelector"
+         init-method="init">
+      <property name="workers">
+         <map>
+            <entry key="BOGUS_ROOT_ELEMENT">
+               <null />
+            </entry>
+            <entry key="model">
+               <ref bean="extracter.xml.AlfrescoModelMetadataExtracter" />
+            </entry>
+            <entry key="projectDescription">
+               <ref bean="extracter.xml.EclipseProjectMetadataExtracter" />
+            </entry>
+         </map>
+      </property>
+   </bean>
+   
+   <!-- A selector that executes XPath statements -->
+   <bean
+         id="extracter.xml.selector.XPathSelector"
+         class="org.alfresco.repo.content.selector.XPathContentWorkerSelector"
+         init-method="init">
+      <property name="workers">
+         <map>
+            <entry key="/my:test">
+               <null />
+            </entry>
+            <entry key="/model[@name='fm:forummodel']">
+               <ref bean="extracter.xml.AlfrescoModelMetadataExtracter" />
+            </entry>
+            <entry key="/projectDescription">
+               <ref bean="extracter.xml.EclipseProjectMetadataExtracter" />
+            </entry>
+         </map>
+      </property>
+   </bean>
+   
+   <!-- The wrapper XML metadata extracter -->
+   <bean
+         id="extracter.xml.XMLMetadataExtracter"
+         class="org.alfresco.repo.content.metadata.xml.XmlMetadataExtracter"
+         parent="baseMetadataExtracter">
+      <property name="overwritePolicy">
+         <value>EAGER</value>
+      </property>
+      <property name="selectors">
+         <list>
+            <ref bean="extracter.xml.selector.XPathSelector" />
+         </list>
+      </property>
+   </bean>
+   
 </beans>