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.camel.component.language;
  
  import java.io.InputStream;
  
  import org.apache.camel.CamelExchangeException;
  import org.apache.camel.Exchange;
  import org.apache.camel.Expression;
  import org.apache.camel.support.DefaultProducer;
  import org.apache.camel.support.EndpointHelper;
  import org.apache.camel.support.ResourceHelper;
  import org.apache.camel.support.service.ServiceHelper;
  import org.apache.camel.util.IOHelper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Language producer.
   */
  public class LanguageProducer extends DefaultProducer {
  
      private static final Logger LOG = LoggerFactory.getLogger(LanguageProducer.class);
  
      private Class<?> resultType = Object.class;
  
      public LanguageProducer(LanguageEndpoint endpoint) {
          super(endpoint);
      }
  
      @Override
      public void process(Exchange exchange) throws Exception {
          String script = null;
  
          // is there a custom expression in the header?
          Expression exp = null;
          if (getEndpoint().isAllowTemplateFromHeader()) {
              exp = exchange.getIn().getHeader(LanguageConstants.LANGUAGE_SCRIPT, Expression.class);
              if (exp == null) {
                  script = exchange.getIn().getHeader(LanguageConstants.LANGUAGE_SCRIPT, String.class);
                  if (script != null) {
                      // the script may be a file: so resolve it before using
                      script = getEndpoint().resolveScript(script);
                      exp = getEndpoint().getLanguage().createExpression(script);
                      exp.init(getEndpoint().getCamelContext());
                  }
              }
          }
          // if not fallback to use expression from endpoint
          if (exp == null && getEndpoint().isCacheScript()) {
              exp = getEndpoint().getExpression();
          }
  
          // the script can be a resource from the endpoint,
          // or refer to a resource itself
          // or just be a plain string
          InputStream is = null;
  
          // fallback and use resource uri from endpoint
          if (exp == null) {
              script = getEndpoint().getScript();
  
              if (script == null && getEndpoint().getResourceUri() == null) {
                  // no script to execute
                  throw new CamelExchangeException("No script to evaluate", exchange);
              }
  
              if (script == null) {
                  is = getEndpoint().getResourceAsInputStream();
              } else if (ResourceHelper.hasScheme(script)) {
                  is = ResourceHelper.resolveMandatoryResourceAsInputStream(getEndpoint().getCamelContext(), script);
              } else if (EndpointHelper.isReferenceParameter(script)) {
                  String ref = "ref:" + script.substring(1);
                  is = ResourceHelper.resolveMandatoryResourceAsInputStream(getEndpoint().getCamelContext(), ref);
              }
  
              if (is != null && !getEndpoint().isBinary()) {
                  try {
                      script = getEndpoint().getCamelContext().getTypeConverter().convertTo(String.class, exchange, is);
                  } finally {
                      IOHelper.close(is);
                  }
              }
          }
  
          // if we have a text based script then use and evaluate it
          if (script != null) {
              // create the expression from the script
              Class<?> type = resultType != Object.class ? resultType : null;
              exp = getEndpoint().getLanguage().createExpression(script, new Object[] { type });
              exp.init(getEndpoint().getCamelContext());
              // expression was resolved from resource
              getEndpoint().setContentResolvedFromResource(true);
              // if we cache then set this as expression on endpoint so we don't re-create it again
              if (getEndpoint().isCacheScript()) {
                  getEndpoint().setExpression(exp);
              }
          }
  
          // the result is either the result of the expression or the input stream as-is because its binary content
          Object result;
          if (exp != null) {
              try {
                  result = exp.evaluate(exchange, resultType);
                  LOG.debug("Evaluated expression as: {} with: {}", result, exchange);
              } finally {
                  if (!getEndpoint().isCacheScript()) {
                      // some languages add themselves as a service which we then need to remove if we are not cached
                      ServiceHelper.stopService(exp);
                      getEndpoint().getCamelContext().removeService(exp);
                  }
              }
          } else {
              // use the result as-is
              result = is;
          }
  
          // set message body if transform is enabled
          if (getEndpoint().isTransform()) {
              exchange.getMessage().setBody(result);
          }
      }
  
      @Override
      public LanguageEndpoint getEndpoint() {
          return (LanguageEndpoint) super.getEndpoint();
      }
  
      @Override
      protected void doBuild() throws Exception {
          if (getEndpoint().getResultType() != null) {
              resultType = getEndpoint().getCamelContext()
                      .getClassResolver().resolveMandatoryClass(getEndpoint().getResultType());
          }
      }
  }
  