content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.
   */
  package org.apache.hadoop.chukwa.hicc.rest;
  
  import java.lang.reflect.Type;
  
  import javax.servlet.ServletContext;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.ext.Provider;
  
  import org.apache.log4j.Logger;
  import org.apache.velocity.app.VelocityEngine;
  import org.apache.velocity.runtime.RuntimeConstants;
  
  import com.sun.jersey.core.spi.component.ComponentContext;
  import com.sun.jersey.core.spi.component.ComponentScope;
  import com.sun.jersey.spi.inject.Injectable;
  import com.sun.jersey.spi.inject.InjectableProvider;
  
  @Provider
  public class VelocityResolver implements InjectableProvider<Context, Type> {
    @Context
    private ServletContext servletContext;
  
    private VelocityEngine ve;
    private static Logger LOG = Logger.getLogger(VelocityResolver.class);
    public final static String LOGGER_NAME = VelocityResolver.class.getName();
    
    /**
     * Jersey configuration for setting up Velocity configuration.
     */
    @Override
    public Injectable<VelocityEngine> getInjectable(ComponentContext arg0,
        Context arg1, Type c) {
      if (c.equals(VelocityEngine.class)) {
        return new Injectable<VelocityEngine>() {
          public VelocityEngine getValue() {
            if (ve == null) {
              LOG.info("Ready to start velocity");
              ve = new VelocityEngine();
              ve.setProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS,
                      "org.apache.velocity.runtime.log.Log4JLogChute");
              ve.setProperty("runtime.log.logsystem.log4j.logger",
                  LOGGER_NAME);
              ve.setProperty(RuntimeConstants.RESOURCE_LOADER,
                  "webapp");
              ve.setProperty("webapp.resource.loader.class",
                      "org.apache.velocity.tools.view.WebappResourceLoader");
              ve.setProperty("webapp.resource.loader.path",
                  "/WEB-INF/vm/");
              ve.setApplicationAttribute(
                  "javax.servlet.ServletContext", servletContext);
              try {
                ve.init();
                LOG.info("Velocity is loaded");
              } catch (Exception e) {
                LOG.error("Error when initializing Velocity", e);
              }
            }
            return ve;
          }
        };
      }
      return null;
    }
  
    public ComponentScope getScope() {
      return ComponentScope.Singleton;
    }
  
  }
  