Hello, I have made a few changes to the VelocityGenerator that I thought
others might be interested in. The patch uses the new Velocity 1.2
VelocityEngine instead of the Velocity 1.1 Singleton. The change allowed
me to code a custom Velocity ResourceLoader that uses the Cocoon
SourceResolver interface. This means that we can now place our Velocity
templates anywhere we like instead of the hard-coded /templates directory.
It also allows us to take advantage of any custom protocols such as
cocoon: and context:.
I also added the ability to configure the VelocityEngine via properties
set in the sitemap. This allows the changing of Velocity parameters such
as the input.encoding/output.encoding, template caching, etc. I will
volunteer to submit a patch to the velocity-generator.xml xdocs if the
patch is deemed worthy of a commit.
Included in the patch file is an updated hello-page.vm and sitemap.xconf.
The patch was created at the xml-cocoon2 module level using 'cvs diff -u
...'.
In order for the patch to compile, the velocity-1.1.jar needs to be
replaced with the current velocity-1.2-rc2.jar available at
http://jakarta.apache.org/builds/jakarta-velocity/release/v1.2/
Regards,
--mike
Index: webapp/templates/hello-page.vm
===================================================================
RCS file: /home/cvspublic/xml-cocoon2/webapp/templates/hello-page.vm,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 hello-page.vm
--- webapp/templates/hello-page.vm 2001/05/09 20:50:09 1.1.1.1
+++ webapp/templates/hello-page.vm 2001/10/31 21:15:45
@@ -1,3 +1,6 @@
+<?xml version="1.0"?>
+#set($name = $parameters.getParameter("name", ""))
+#set($project = $parameters.getParameter("project", ""))
<page>
<title>Hello</title>
<content>
Index: src/org/apache/cocoon/generation/VelocityGenerator.java
===================================================================
RCS file:
/home/cvspublic/xml-cocoon2/src/org/apache/cocoon/generation/VelocityGenerator.java,v
retrieving revision 1.10
diff -u -r1.10 VelocityGenerator.java
--- src/org/apache/cocoon/generation/VelocityGenerator.java 2001/10/30 15:20:46
1.10
+++ src/org/apache/cocoon/generation/VelocityGenerator.java 2001/10/31 21:15:46
@@ -8,87 +8,568 @@
package org.apache.cocoon.generation;
import org.apache.avalon.excalibur.pool.Recyclable;
+import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.component.ComponentException;
+import org.apache.avalon.framework.configuration.Configurable;
+import org.apache.avalon.framework.configuration.Configuration;
+import org.apache.avalon.framework.configuration.ConfigurationException;
+import org.apache.avalon.framework.context.Context;
+import org.apache.avalon.framework.context.ContextException;
+import org.apache.avalon.framework.context.DefaultContext;
+import org.apache.avalon.framework.parameters.Parameters;
+import org.apache.avalon.framework.parameters.ParameterException;
+import org.apache.log.Logger;
+import org.apache.cocoon.Constants;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.ResourceNotFoundException;
import org.apache.cocoon.components.parser.Parser;
+import org.apache.cocoon.environment.Source;
+import org.apache.cocoon.environment.SourceResolver;
+import org.apache.commons.collections.ExtendedProperties;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
+import org.apache.velocity.app.VelocityEngine;
+import org.apache.velocity.runtime.log.LogSystem;
+import org.apache.velocity.runtime.RuntimeServices;
+import org.apache.velocity.runtime.resource.loader.ResourceLoader;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
+import java.io.InputStream;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
/**
+ * <p>Cocoon {@link Generator} that produces dynamic XML SAX events
+ * from a Velocity template file.</p>
+ *
+ * <h2>Sitemap Configuration</h2>
+ *
+ * <p>
+ * Attributes:
+ * <dl>
+ * <dt>usecache (optional; default: 'false')</dt>
+ * <dd>set to 'true' to enable template caching on the 'cocoon'
+ * resource loader</dd>
+ *
+ * <dt>checkInterval (optional; default: '0')</dt>
+ * <dd>This is the number of seconds between modification checks when
+ * caching is turned on. When this is an integer > 0, this represents
+ * the number of seconds between checks to see if the template was
+ * modified. If the template has been modified since last check, then
+ * it is reloaded and reparsed. Otherwise nothing is done. When <= 0,
+ * no modification checks will take place, and assuming that the
+ * property cache (above) is true, once a template is loaded and
+ * parsed the first time it is used, it will not be checked or
+ * reloaded after that until the application or servlet engine is
+ * restarted.</dd>
+ * </dl>
+ * </p>
+ *
+ * <p>
+ * Child Elements:
+ *
+ * <dl>
+ * <dt><property key="propertyKey" value="propertyValue"/> (optional;
+0..n)</dt>
+ * <dd>An additional property to pass along to the Velocity template
+ * engine during initialization</dd>
+ *
+ * <dt><resource-loader name="loaderName" class="javaClassName" > (optional;
+0..n; children: property*)</dt>
+ * <dd>The default configuration uses the 'cocoon' resource loader
+ * which resolves resources via the Cocoon SourceResolver. Additional
+ * resource loaders can be added with this configuration
+ * element. Configuration properties for the resource loader can be
+ * specified by adding a child property element of the resource-loader
+ * element. The prefix '<name>.resource.loader.' is
+ * automatically added to the property name.</dd>
+ *
+ * <dt><export-object key="objectMapKey" name="velocityContextName"/>
+(optional; 0..n)</dt>
+ * <dd>Export the object specified by <em>key</em> from the Cocoon
+ * object map to the Velocity context of the template. The object can
+ * be accessed from the template as <em>name</em>. Be careful to use a
+ * valid VTL variable name.</dd>
+ * </dl>
+ * </p>
+ *
+ * <p>
+ * Default Java objects exported to the Velocity context:
+ *
+ * <dl>
+ * <dt>request (org.apache.cocoon.environment.Request)</dt>
+ * <dd>The Cocoon current request</dd>
+ *
+ * <dt>template (java.lang.String)</dt>
+ * <dd>The path of the template file currently being evaluated</dd>
+ *
+ * <dt>response (org.apache.cocoon.environment.Response)</dt>
+ * <dd>The Cocoon response associated with the current request</dd>
+ *
+ * <dt>context (org.apache.cocoon.environment.Context)</dt>
+ * <dd>The Cocoon context associated with the current request</dd>
+ *
+ * <dt>parameters (org.apache.avalon.framework.parameters.Parameters)</dt>
+ * <dd>Any parameters passed to the generator in the pipeline</dd>
+ * </dl>
+ * </p>
+ *
+ * <p> Additional Java objects can be exported from the Cocoon object
+ * map to the Velocity context by adding one or more <export-object
+ * key="objectMapKey" name="velocityContextName"/> child elements
+ * to the generator configuration in the sitemap.</p>
+ *
* @author <a href="mailto:[EMAIL PROTECTED]";>Davanum Srinivas</a>
+ * @author <a href="mailto:[EMAIL PROTECTED]";>Michael McKibben</a>
* @version CVS $Revision: 1.10 $ $Date: 2001/10/30 15:20:46 $
*/
-public class VelocityGenerator extends ServletGenerator implements Recyclable {
+public class VelocityGenerator extends ComposerGenerator
+ implements Initializable, Configurable, Recyclable, LogSystem
+{
- /** Flag for checking initialization */
- private static boolean initVelocity = false;
+ /**
+ * Velocity {@link org.apache.velocity.runtime.resource.loader.ResourceLoader}
+ * implementation to load template resources using Cocoon's
+ *{@link SourceResolver}. This class is created by the Velocity
+ * framework via the ResourceLoaderFactory.
+ *
+ * @see org.apache.velocity.runtime.resource.loader.ResourceLoader
+ */
+ public static class TemplateLoader extends
+org.apache.velocity.runtime.resource.loader.ResourceLoader
+ {
+ private Context resolverContext;
+
+ /**
+ * Initialize this resource loader. The 'context' property is
+ * required and must be of type {@link Context}. The context
+ * is used to pass the Cocoon SourceResolver for the current
+ * pipeline.
+ *
+ * @param config the properties to configure this resource.
+ * @throws IllegalArgumentException thrown if the required
+ * 'context' property is not set.
+ * @throws ClassCastException if the 'context' property is not
+ * of type {@link Context}.
+ * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#init
+ */
+ public void init(ExtendedProperties config)
+ {
+ this.resolverContext = (Context)config.get("context");
+ if (this.resolverContext == null)
+ {
+ throw new IllegalArgumentException("Runtime Cocoon resolver context
+not specified in resource loader configuration.");
+ }
+ }
+
+ /**
+ * @param systemId the path to the resource
+ * @see
+org.apache.velocity.runtime.resource.loader.ResourceLoader#getResourceStream
+ */
+ public InputStream getResourceStream(String systemId) throws
+org.apache.velocity.exception.ResourceNotFoundException
+ {
+ try
+ {
+ return resolveSource(systemId).getInputStream();
+ }
+ catch (org.apache.velocity.exception.ResourceNotFoundException ex)
+ {
+ throw ex;
+ }
+ catch (Exception ex)
+ {
+ throw new
+org.apache.velocity.exception.ResourceNotFoundException("Unable to resolve source: "
++ ex);
+ }
+ }
+
+ /**
+ * @see
+org.apache.velocity.runtime.resource.loader.ResourceLoader#isSourceModified
+ */
+ public boolean isSourceModified(org.apache.velocity.runtime.resource.Resource
+resource)
+ {
+ long lastModified = 0;
+ try
+ {
+ lastModified = resolveSource(resource.getName()).getLastModified();
+ }
+ catch (Exception ex)
+ {
+ super.rsvc.warn("Unable to determine last modified for resource: " +
+resource.getName() + ": " + ex);
+ }
+
+ return lastModified > 0? lastModified != resource.getLastModified() :
+true;
+ }
+
+ /**
+ * @see
+org.apache.velocity.runtime.resource.loader.ResourceLoader#getLastModified
+ */
+ public long getLastModified(org.apache.velocity.runtime.resource.Resource
+resource)
+ {
+ long lastModified = 0;
+ try
+ {
+ lastModified = resolveSource(resource.getName()).getLastModified();
+ }
+ catch (Exception ex)
+ {
+ super.rsvc.warn("Unable to determine last modified for resource: " +
+resource.getName() + ": " + ex);
+ }
+
+ return lastModified;
+ }
+
+ /**
+ * Store all the Source objects we lookup via the SourceResolver so that they
+can be properly
+ * recycled later.
+ *
+ * @param systemId the path to the resource
+ */
+ private Source resolveSource(String systemId) throws
+org.apache.velocity.exception.ResourceNotFoundException
+ {
+ Map sourceCache;
+ try
+ {
+ sourceCache =
+(Map)this.resolverContext.get(CONTEXT_SOURCE_CACHE_KEY);
+ }
+ catch (ContextException ignore)
+ {
+ throw new
+org.apache.velocity.exception.ResourceNotFoundException("Runtime Cocoon source cache
+not specified in resource loader resolver context.");
+ }
+
+ Source source = (Source)sourceCache.get(systemId);
+ if (source == null)
+ {
+ try
+ {
+ SourceResolver resolver =
+(SourceResolver)this.resolverContext.get(CONTEXT_RESOLVER_KEY);
+ source = resolver.resolve(systemId);
+ }
+ catch (ContextException ex)
+ {
+ throw new
+org.apache.velocity.exception.ResourceNotFoundException("No Cocoon source resolver
+associated with current request.");
+ }
+ catch (Exception ex)
+ {
+ throw new
+org.apache.velocity.exception.ResourceNotFoundException("Unable to resolve source: "
++ ex);
+ }
+ }
+ sourceCache.put(systemId, source);
+ return source;
+ }
+ }
+
/**
- * Generate XML data using Velocity template.
+ * Holder object for controlling Cocoon objects exported to the
+ * Velocity Context
*/
- public void generate()
- throws IOException, SAXException, ProcessingException {
- Parser parser = null;
- try
- {
- parser = (Parser)(this.manager.lookup(Parser.ROLE));
- getLogger().debug("Processing File :" + super.source);
+ private static class ObjectExport
+ {
+ public String key;
+ public String name;
+ }
+
+ /**
+ * Key to lookup the {@link SourceResolver} from the context of
+ * the resource loader
+ */
+ final private static String CONTEXT_RESOLVER_KEY = "resolver";
- /* first, we init the runtime engine. Defaults are fine. */
- if(initVelocity == false)
- {
- initVelocity = true;
-
- String templatePath =
super.context.getResource("/templates").toExternalForm();
- if (templatePath.startsWith("file:") == true) {
- templatePath = templatePath.substring(5);
+ /**
+ * Key to lookup the source cache {@link Map} from the context of
+ * the resource loader
+ */
+ final private static String CONTEXT_SOURCE_CACHE_KEY = "source-cache";
+
+ private List objectExports;
+ private VelocityEngine tmplEngine;
+ private DefaultContext resolverContext;
+ private VelocityContext velocityContext;
+ private boolean activeFlag;
+
+ /**
+ * Read any additional objects to export to the Velocity context
+ * from the configuration.
+ *
+ * @param configuration the class configurations.
+ * @see org.apache.avalon.framework.configuration.Configurable#configure
+ */
+ public void configure(Configuration configuration) throws ConfigurationException
+ {
+ this.resolverContext = new DefaultContext();
+ this.objectExports = new ArrayList();
+ this.tmplEngine = new VelocityEngine();
+ this.tmplEngine.setProperty(Velocity.RUNTIME_LOG_LOGSYSTEM, this);
+
+ // First set up our default 'cocoon' resource loader
+ //
+ this.tmplEngine.setProperty("cocoon.resource.loader.class",
+TemplateLoader.class.getName());
+ this.tmplEngine.setProperty("cocoon.resource.loader.cache",
+configuration.getAttribute("usecache", "false"));
+
+this.tmplEngine.setProperty("cocoon.resource.loader.modificationCheckInterval",
+configuration.getAttribute("checkInterval", "0"));
+ this.tmplEngine.setProperty("cocoon.resource.loader.context",
+this.resolverContext);
+
+ // Read in any additional properties to pass to the VelocityEngine during
+initialization
+ //
+ Configuration[] properties = configuration.getChildren("property");
+ for (int i=0; i < properties.length; ++i)
+ {
+ Configuration c = properties[i];
+ String name = c.getAttribute("name");
+
+ // disallow setting of certain properties
+ //
+ if (name.startsWith("runtime.log")
+ || name.indexOf(".resource.loader.") != -1)
+ {
+ if (getLogger().isInfoEnabled())
+ {
+ getLogger().info("ignoring disallowed property '" + name + "'.");
}
- getLogger().debug("Templates Directory:" + templatePath);
+ continue;
+ }
+ this.tmplEngine.setProperty(name, c.getAttribute("value"));
+ }
- Velocity.setProperty(Velocity.FILE_RESOURCE_LOADER_PATH,
templatePath);
- Velocity.init();
+ // now read in any additional Velocity resource loaders
+ //
+ List resourceLoaders = new ArrayList();
+ Configuration[] loaders = configuration.getChildren("resource-loader");
+ for (int i=0; i < loaders.length; ++i)
+ {
+ Configuration loader = loaders[i];
+ String name = loader.getAttribute("name");
+ if (name.equals("cocoon"))
+ {
+ if (getLogger().isInfoEnabled())
+ {
+ getLogger().info("'cocoon' resource loader already defined.");
+ }
+ continue;
+ }
+ resourceLoaders.add(name);
+ String prefix = name + ".resource.loader.";
+ String type = loader.getAttribute("class");
+ this.tmplEngine.setProperty(prefix + "class", type);
+ Configuration [] loaderProperties = loader.getChildren("property");
+ for (int j=0; i < loaderProperties.length; ++j)
+ {
+ Configuration c = loaderProperties[j];
+ String propName = c.getAttribute("name");
+ this.tmplEngine.setProperty(prefix + propName,
+c.getAttribute("value"));
+ }
+ }
+
+ // Velocity expects resource loaders as CSV list
+ //
+ StringBuffer buffer = new StringBuffer("cocoon");
+ for (Iterator it = resourceLoaders.iterator(); it.hasNext(); )
+ {
+ buffer.append(',');
+ buffer.append((String)it.next());
+ }
+ tmplEngine.setProperty(Velocity.RESOURCE_LOADER, buffer.toString());
+
+ // read in additional objects to export from the object map
+ //
+ Configuration[] exports = configuration.getChildren("export-object");
+ for (int i=0; i < exports.length; ++i)
+ {
+ Configuration c = exports[i];
+ ObjectExport export = new ObjectExport();
+ export.key = c.getAttribute("key");
+ export.name = c.getAttribute("name");
+ this.objectExports.add(export);
+ }
+ }
+
+ /**
+ * @see org.apache.avalon.framework.activity.Initializable#initialize
+ */
+ public void initialize() throws Exception
+ {
+ this.tmplEngine.init();
+ }
+
+ /**
+ * @see org.apache.cocoon.sitemap.SitemapModelComponent#setup
+ */
+ public void setup(SourceResolver resolver, Map objectModel, String src,
+Parameters params) throws ProcessingException,SAXException,IOException
+ {
+ if (activeFlag)
+ {
+ throw new IllegalStateException("setup called on recyclable sitemap
+component before properly recycling previous state");
+ }
+
+ super.setup(resolver, objectModel, src, params);
+
+ // pass along the SourceResolver to the Velocity resource loader
+ //
+ this.resolverContext.put(CONTEXT_RESOLVER_KEY, resolver);
+ this.resolverContext.put(CONTEXT_SOURCE_CACHE_KEY, new HashMap());
+
+ // Initialize the Velocity context
+ //
+ this.velocityContext = new VelocityContext();
+ this.velocityContext.put("template", src);
+ this.velocityContext.put("request",
+objectModel.get(Constants.REQUEST_OBJECT));
+ this.velocityContext.put("response",
+objectModel.get(Constants.RESPONSE_OBJECT));
+ this.velocityContext.put("context",
+objectModel.get(Constants.CONTEXT_OBJECT));
+ this.velocityContext.put("parameters", params);
+
+ // Export any additional objects to the Velocity context
+ //
+ for (Iterator it = this.objectExports.iterator(); it.hasNext();)
+ {
+ ObjectExport export = (ObjectExport)it.next();
+ Object object = objectModel.get(export.key);
+ if (object != null)
+ {
+ this.velocityContext.put(export.name, object);
+ if (getLogger().isDebugEnabled())
+ {
+ getLogger().debug("exporting object under key '" + export.key +
+"' to velocity context with name '" + export.name + "'.");
+ }
+ }
+ else if (getLogger().isInfoEnabled())
+ {
+ getLogger().info("unable to export object under key '" +
+export.key + "' to velocity context.");
+ }
+ }
+
+ this.activeFlag = true;
+ }
+
+ /**
+ * Free up the VelocityContext associated with the pipeline, and
+ * release any Source objects resolved by the resource loader.
+ *
+ * @see org.apache.avalon.excalibur.pool.Recyclable#recycle
+ */
+ public void recycle()
+ {
+ this.activeFlag = false;
+
+ // recycle all the Source objects resolved/used by our resource loader
+ //
+ try
+ {
+ Map sourceCache =
+(Map)this.resolverContext.get(CONTEXT_SOURCE_CACHE_KEY);
+ for (Iterator it = sourceCache.values().iterator(); it.hasNext();)
+ {
+ ((Source)it.next()).recycle();
}
+ }
+ catch (ContextException ignore)
+ {
+ }
+
+ this.velocityContext = null;
+ super.recycle();
+ }
- /* lets make a Context and put data into it */
- VelocityContext context = new VelocityContext();
+ /**
+ * Generate XML data using Velocity template.
+ *
+ * @see org.apache.cocoon.generation.Generator#generate
+ */
+ public void generate()
+ throws IOException, SAXException, ProcessingException
+ {
+ // Guard against calling generate before setup.
+ //
+ if (!activeFlag)
+ {
+ throw new IllegalStateException("generate called on sitemap component
+before setup.");
+ }
- context.put("name", "Velocity Generator");
- context.put("project", "Cocoon2");
- context.put("request", this.request);
- context.put("response", this.response);
- context.put("context", this.context);
+ Parser parser = null;
+ try
+ {
+ parser = (Parser)(this.manager.lookup(Parser.ROLE));
+ if (getLogger().isDebugEnabled())
+ {
+ getLogger().debug("Processing File: " + super.source);
+ }
/* lets render a template */
StringWriter w = new StringWriter();
- Velocity.mergeTemplate(super.source, context, w );
+ this.tmplEngine.mergeTemplate(super.source, velocityContext, w);
InputSource xmlInput =
- new InputSource(new StringReader(w.toString()));
+ new InputSource(new StringReader(w.toString()));
parser.setConsumer(this.xmlConsumer);
parser.parse(xmlInput);
- } catch (IOException e){
+ }
+ catch (IOException e)
+ {
getLogger().warn("VelocityGenerator.generate()", e);
throw new ResourceNotFoundException("Could not get Resource for
VelocityGenerator", e);
- } catch (SAXException e){
+ }
+ catch (SAXException e)
+ {
getLogger().error("VelocityGenerator.generate()", e);
- throw(e);
- } catch (ComponentException e){
+ throw e;
+ }
+ catch (ComponentException e)
+ {
getLogger().error("Could not get parser", e);
- throw new ProcessingException("Exception in
VelocityGenerator.generate()",e);
- } catch (ProcessingException e){
+ throw new ProcessingException("Exception in
+VelocityGenerator.generate()", e);
+ }
+ catch (ProcessingException e)
+ {
throw e;
- } catch (Exception e){
+ }
+ catch (Exception e)
+ {
getLogger().error("Could not get parser", e);
- throw new ProcessingException("Exception in
VelocityGenerator.generate()",e);
- } finally {
- if (parser != null) this.manager.release(parser);
+ throw new ProcessingException("Exception in
+VelocityGenerator.generate()", e);
+ }
+ finally
+ {
+ if (parser != null)
+ {
+ this.manager.release(parser);
+ }
+ }
+ }
+
+ /**
+ * This implementation does nothing.
+ *
+ * @see org.apache.velocity.runtime.log.LogSystem#init
+ */
+ public void init(RuntimeServices rs) throws Exception
+ {
+ }
+
+ /**
+ * Pass along Velocity log messages to our configured logger.
+ *
+ * @see org.apache.velocity.runtime.log.LogSystem#logVelocityMessage
+ */
+ public void logVelocityMessage(int level, String message)
+ {
+ Logger logger = getLogger();
+ switch (level)
+ {
+ case LogSystem.WARN_ID:
+ logger.warn(message);
+ break;
+ case LogSystem.INFO_ID:
+ logger.info(message);
+ break;
+ case LogSystem.DEBUG_ID:
+ logger.debug(message);
+ break;
+ case LogSystem.ERROR_ID:
+ logger.error(message);
+ break;
+ default:
+ logger.info(message);
+ break;
}
}
}
Index: webapp/sitemap.xmap
===================================================================
RCS file: /home/cvspublic/xml-cocoon2/webapp/sitemap.xmap,v
retrieving revision 1.60
diff -u -r1.60 sitemap.xmap
--- webapp/sitemap.xmap 2001/10/29 21:55:39 1.60
+++ webapp/sitemap.xmap 2001/10/31 21:15:46
@@ -446,7 +446,10 @@
</map:match>
<map:match pattern="templates/*">
- <map:generate type="velocity" src="{1}"/>
+ <map:generate type="velocity" src="templates/{1}">
+ <map:parameter name="name" value="Velocity"/>
+ <map:parameter name="project" value="Cocoon"/>
+ </map:generate>
<map:transform src="stylesheets/page/simple-page2html.xsl"/>
<map:serialize type="html"/>
</map:match>
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