SCM-Manager/scm-webapp/src/main/java/sonia/scm/api/rest/TemplateEngineViewable.java

/**
 * Copyright (c) 2010, Sebastian Sdorra
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of SCM-Manager; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://bitbucket.org/sdorra/scm-manager
 *
 */


package sonia.scm.api.rest;

//~--- non-JDK imports --------------------------------------------------------

import com.google.inject.Inject;

import sonia.scm.template.Template;
import sonia.scm.template.TemplateEngine;
import sonia.scm.template.TemplateEngineFactory;

//~--- JDK imports ------------------------------------------------------------

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;

import javax.ws.rs.ext.Provider;
import sonia.scm.template.Viewable;

/**
 *
 * @author Sebastian Sdorra
 */
@Provider
public class TemplateEngineViewable implements MessageBodyWriter<Viewable>
{
  
  private final TemplateEngineFactory templateEngineFactory;

  @Inject
  public TemplateEngineViewable(TemplateEngineFactory templateEngineFactory)
  {
    this.templateEngineFactory = templateEngineFactory;
  }


  @Override
  public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
    return type.isAssignableFrom(Viewable.class);
  }

  @Override
  public long getSize(Viewable viewable, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
    return -1;
  }

  @Override
  public void writeTo(Viewable viewable, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
    String path = viewable.getPath();
    
    TemplateEngine engine = templateEngineFactory.getEngineByExtension(path);

    if (engine == null)
    {
      throw new IOException("could not find template engine for ".concat(path));
    }

    Template template = engine.getTemplate(path);

    if (template == null)
    {
      throw new IOException("could not find template for ".concat(path));
    }

    PrintWriter writer = new PrintWriter(entityStream);

    template.execute(writer, viewable.getContext());
    writer.flush();
  }
}