package com.atlassian.plugin.web.model;
   
   import com.atlassian.plugin.PluginAccessor;
   import com.atlassian.plugin.web.renderer.RendererException;
   import com.google.common.base.Preconditions;
   import org.apache.commons.lang3.StringEscapeUtils;
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
  import java.io.IOException;
  import java.io.StringWriter;
  import java.io.Writer;
  import java.util.Map;
  
  /**
   * This class is used for web panel declaration that do not have a custom
   * <code>class</code> attribute in their descriptor, but do have a
   * <code>location</code> attribute in their resource child element, which
   * points to a template file on the (plugin's) classpath.
   *
   * @see com.atlassian.plugin.web.descriptors.DefaultWebPanelModuleDescriptor
   * @since 2.5.0
   */
  public class ResourceTemplateWebPanel extends AbstractWebPanel {
      private static final Logger logger = LoggerFactory.getLogger(ResourceTemplateWebPanel.class.getName());
      private String resourceFilename;
  
      public ResourceTemplateWebPanel(PluginAccessor pluginAccessor) {
          super(pluginAccessor);
      }
  
      /**
       * Specifies the name of the template file that is to be rendered.
       * This file will be loaded from the (plugin's) classpath.
       *
       * @param resourceFilename the name of the template file that is to be rendered.
       *                         May not be null.
       */
      public void setResourceFilename(String resourceFilename) {
          this.resourceFilename = Preconditions.checkNotNull(resourceFilename, "resourceFilename");
      }
  
      public void writeHtml(Writer writer, Map<String, Object> context) throws IOException {
          try {
              getRenderer().render(resourceFilename, plugin, context, writer);
          } catch (RendererException e) {
              final String message = String.format("Error rendering WebPanel (%s): %s", resourceFilename, e.getMessage());
              logger.warn(message, e);
              writer.write(StringEscapeUtils.escapeHtml4(message));
          }
      }
  
      public String getHtml(final Map<String, Object> context) {
          try {
              final StringWriter sink = new StringWriter();
              writeHtml(sink, context);
              return sink.toString();
          } catch (IOException e) {
              // Something went very wrong: we couldn't write to a StringWriter!
              throw new RuntimeException(e);
          }
      }
  }