content: package act.view;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  
  import act.Act;
  import act.ActResponse;
  import act.app.ActionContext;
  import act.mail.MailerContext;
  import org.osgl.http.H;
  import org.osgl.util.Charsets;
  
  import java.nio.charset.Charset;
  import java.util.Map;
  
  /**
   * Base class for {@link Template} implementations
   */
  public abstract class TemplateBase implements Template {
  
      private static final Charset UTF8 = Charsets.UTF_8;
  
      @Override
      public void merge(ActionContext context) {
          Map<String, Object> renderArgs = context.renderArgs();
          if (!context.isByPassImplicitTemplateVariable()) {
              exposeImplicitVariables(renderArgs, context);
          }
          beforeRender(context);
          ActResponse resp = context.resp();
          merge(renderArgs, resp);
          //resp.commit();
      }
  
      @Override
      public String render(ActionContext context) {
          Map<String, Object> renderArgs = context.renderArgs();
          exposeImplicitVariables(renderArgs, context);
          beforeRender(context);
          return render(renderArgs);
      }
  
      @Override
      public String render(MailerContext context) {
          Map<String, Object> renderArgs = context.renderArgs();
          exposeImplicitVariables(renderArgs, context);
          beforeRender(context);
          return render(renderArgs);
      }
  
      @Override
      public boolean supportCache() {
          return true;
      }
  
      /**
       * Sub class can implement this method to inject logic that needs to be done
       * before rendering happening
       *
       * @param context
       */
      protected void beforeRender(ActionContext context) {}
  
      /**
       * Sub class can implement this method to inject logic that needs to be done
       * before rendering happening
       *
       * @param context
       */
      protected void beforeRender(MailerContext context) {}
  
      protected void merge(Map<String, Object> renderArgs, H.Response response) {
          String result = render(renderArgs);
          response.writeContent(result);
      }
  
      protected abstract String render(Map<String, Object> renderArgs);
  
      private void exposeImplicitVariables(Map<String, Object> renderArgs, ActionContext context) {
          for (ActionViewVarDef var : Act.viewManager().implicitActionViewVariables()) {
              Object val = var.eval(context);
              if (null != val) {
                  renderArgs.put(var.name(), val);
              }
          }
      }
  
  
      private void exposeImplicitVariables(Map<String, Object> renderArgs, MailerContext context) {
          for (MailerViewVarDef var : Act.viewManager().implicitMailerViewVariables()) {
              Object val = var.eval(context);
              if (null != val) {
                  renderArgs.put(var.name(), val);
              }
          }
      }
  }
  