/**
* Copyright 2005-2014 Restlet
*
* The contents of this file are subject to the terms of one of the following
* open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
* select the license that you prefer but you may not use this file except in
* compliance with one of these Licenses.
*
* You can obtain a copy of the Apache 2.0 license at
* http://www.opensource.org/licenses/apache-2.0
*
* You can obtain a copy of the EPL 1.0 license at
* http://www.opensource.org/licenses/eclipse-1.0
*
* See the Licenses for the specific language governing permissions and
* limitations under the Licenses.
*
* Alternatively, you can obtain a royalty free commercial license with less
* limitations, transferable or non-transferable, directly at
* http://restlet.com/products/restlet-framework
*
* Restlet is a registered trademark of Restlet S.A.S.
*/
package org.restlet.ext.velocity;
import java.io.IOException;
import java.io.Writer;
import java.util.Date;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.runtime.RuntimeSingleton;
import org.restlet.Context;
import org.restlet.Request;
import org.restlet.Response;
import org.restlet.data.CharacterSet;
import org.restlet.data.MediaType;
import org.restlet.representation.Representation;
import org.restlet.representation.WriterRepresentation;
import org.restlet.util.Resolver;
/**
* Velocity template representation. Useful for dynamic string-based
* representations.
*
* @see <a href="http://velocity.apache.org/">Velocity home page</a>
* @author Jerome Louvel
*/
public class TemplateRepresentation extends WriterRepresentation {
/**
* Velocity context based on a Resolver.
*
* @see Resolver
*/
private class ResolverContext implements
org.apache.velocity.context.Context {
/** The inner resolver instance. */
private final Resolver<? extends Object> resolver;
/**
* Constructor.
*
* @param resolver
* The resolver.
*/
public ResolverContext(Resolver<? extends Object> resolver) {
super();
this.resolver = resolver;
}
/**
* Indicates whether the specified key is in the context.
*
* @param key
* The key to look for.
* @Return True if the key is in the context, false otherwise.
*/
public boolean containsKey(Object key) {
return this.resolver.resolve((String) key) != null;
}
/**
* Gets the value corresponding to the provided key from the context.
*
* @Param key The name of the desired value.
* @Return The value corresponding to the provided key.
*/
public Object get(String key) {
return this.resolver.resolve(key);
}
/**
* Returns null since a resolver does not know by advance the whole
* values.
*
* @Return null.
*/
public Object[] getKeys() {
return null;
}
/**
* Returns null since a resolver as a data model cannot be updated.
*
* @param key
* The name to key the provided value with.
* @param value
* The corresponding value.
* @return null.
*/
public Object put(String key, Object value) {
return null;
}
/**
* Does nothing since resolver as a data model cannot be updated.
*
* @param value
* The name of the value to remove.
* @return null.
*/
public Object remove(Object value) {
return null;
}
}
/** The template's data model. */
private volatile org.apache.velocity.context.Context context;
/** The Velocity engine. */
private volatile VelocityEngine engine;
/** The template. */
private volatile Template template;
/** The template name. */
private volatile String templateName;
/**
* Constructor based on a Velocity 'encoded' representation.
*
* @param templateRepresentation
* The representation to 'decode'.
* @param dataModel
* The Velocity template's data model.
* @param mediaType
* The representation's media type.
* @throws IOException
* @throws ParseErrorException
* @throws ResourceNotFoundException
*/
public TemplateRepresentation(Representation templateRepresentation,
Map<String, Object> dataModel, MediaType mediaType)
throws ResourceNotFoundException, ParseErrorException, IOException {
super(mediaType);
setDataModel(dataModel);
this.engine = null;
this.template = new Template();
CharacterSet charSet = (templateRepresentation.getCharacterSet() != null) ? templateRepresentation
.getCharacterSet() : CharacterSet.DEFAULT;
this.template.setEncoding(charSet.getName());
if (templateRepresentation.getModificationDate() != null) {
this.template.setLastModified(templateRepresentation
.getModificationDate().getTime());
}
this.template.setName("org.restlet.resource.representation");
this.template.setRuntimeServices(RuntimeSingleton.getRuntimeServices());
this.template.setResourceLoader(new RepresentationResourceLoader(
templateRepresentation));
this.template.process();
this.templateName = null;
}
/**
* Constructor based on a Velocity 'encoded' representation.
*
* @param templateRepresentation
* The representation to 'decode'.
* @param mediaType
* The representation's media type.
* @throws IOException
* @throws ParseErrorException
* @throws ResourceNotFoundException
*/
public TemplateRepresentation(Representation templateRepresentation,
MediaType mediaType) throws ResourceNotFoundException,
ParseErrorException, IOException {
super(mediaType);
this.engine = null;
this.template = new Template();
CharacterSet charSet = (templateRepresentation.getCharacterSet() != null) ? templateRepresentation
.getCharacterSet() : CharacterSet.DEFAULT;
this.template.setEncoding(charSet.getName());
this.template.setLastModified((templateRepresentation
.getModificationDate() == null) ? new Date().getTime()
: templateRepresentation.getModificationDate().getTime());
this.template.setName("org.restlet.resource.representation");
this.template.setRuntimeServices(RuntimeSingleton.getRuntimeServices());
this.template.setResourceLoader(new RepresentationResourceLoader(
templateRepresentation));
this.template.process();
this.templateName = null;
}
/**
* Constructor.
*
* @param templateName
* The Velocity template's name. The actual template is retrieved
* using the Velocity configuration.
* @param dataModel
* The Velocity template's data model.
* @param mediaType
* The representation's media type.
*/
public TemplateRepresentation(String templateName,
Map<String, Object> dataModel, MediaType mediaType) {
super(mediaType);
try {
setDataModel(dataModel);
this.engine = new VelocityEngine();
this.template = null;
this.templateName = templateName;
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Constructor.
*
* @param templateName
* The Velocity template's name. The full path is resolved by the
* configuration.
* @param mediaType
* The representation's media type.
*/
public TemplateRepresentation(String templateName, MediaType mediaType) {
this(templateName, new ConcurrentHashMap<String, Object>(), mediaType);
}
/**
* Constructor.
*
* @param template
* The Velocity template.
* @param dataModel
* The Velocity template's data model.
* @param mediaType
* The representation's media type.
*/
public TemplateRepresentation(Template template,
Map<String, Object> dataModel, MediaType mediaType) {
super(mediaType);
setDataModel(dataModel);
this.engine = null;
this.template = template;
this.templateName = null;
}
/**
* Constructor.
*
* @param template
* The Velocity template.
* @param mediaType
* The representation's media type.
*/
public TemplateRepresentation(Template template, MediaType mediaType) {
super(mediaType);
this.engine = null;
this.template = template;
this.templateName = null;
}
/**
* Returns the Velocity context.
*
* @return The Velocity context.
*/
private org.apache.velocity.context.Context getContext() {
return this.context;
}
/**
* Returns the Velocity engine.
*
* @return The Velocity engine.
*/
public VelocityEngine getEngine() {
return this.engine;
}
/**
* Returns the Velocity template.
*
* @return The Velocity template.
*/
public Template getTemplate() {
if (this.template == null) {
if (this.templateName != null) {
try {
getEngine().init();
this.template = getEngine().getTemplate(this.templateName);
} catch (Exception e) {
final Context context = Context.getCurrent();
if (context != null) {
context.getLogger().log(Level.WARNING,
"Unable to get template", e);
}
}
}
}
return this.template;
}
/**
* Sets the Velocity context.
*
* @param context
* The Velocity context
*/
private void setContext(org.apache.velocity.context.Context context) {
this.context = context;
}
/**
* Sets the template's data model.
*
* @param dataModel
* The template's data model.
*/
public void setDataModel(Map<String, Object> dataModel) {
setContext(new VelocityContext(dataModel));
}
/**
* Sets the template's data model from a request/response pair. This default
* implementation uses a Resolver.
*
* @see Resolver
* @see Resolver#createResolver(Request, Response)
*
* @param request
* The request where data are located.
* @param response
* The response where data are located.
*/
public void setDataModel(Request request, Response response) {
setContext(new ResolverContext(Resolver.createResolver(request,
response)));
}
/**
* Sets the template's data model from a resolver.
*
* @param resolver
* The resolver.
*/
public void setDataModel(Resolver<Object> resolver) {
setContext(new ResolverContext(resolver));
}
/**
* Writes the datum as a stream of characters.
*
* @param writer
* The writer to use when writing.
*/
@Override
public void write(Writer writer) throws IOException {
try {
// Load the template
// Process the template
getTemplate().merge(getContext(), writer);
} catch (Exception e) {
final Context context = Context.getCurrent();
if (context != null) {
context.getLogger().log(Level.WARNING,
"Unable to process the template", e);
}
e.printStackTrace();
throw new IOException("Template processing error. "
+ e.getMessage());
}
}
}