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
   *
   *      https://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.tools.ant.types.resources;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.reflect.Field;
  import java.nio.charset.StandardCharsets;
  
  /**
   * A resource that is a java constant.
   * This lets you extract values off the classpath and use them elsewhere
   * @since Ant 1.7
   */
  public class JavaConstantResource extends AbstractClasspathResource {
  
      /**
       * open the input stream from a specific classloader
       *
       * @param cl the classloader to use. Will be null if the system classloader is used
       * @return an open input stream for the resource
       * @throws IOException if an error occurs.
       */
      @Override
      protected InputStream openInputStream(ClassLoader cl) throws IOException {
          String constant = getName();
          if (constant == null) {
              throw new IOException("Attribute 'name' must be set.");
          }
          int index = constant.lastIndexOf('.');
          if (index < 0) {
              throw new IOException("No class name in " + constant);
          }
          String classname = constant.substring(0, index);
          String fieldname = constant.substring(index + 1);
          try {
              Class<?> clazz =
                  cl != null
                  ? Class.forName(classname, true, cl)
                  : Class.forName(classname);
              Field field = clazz.getField(fieldname);
              String value = field.get(null).toString();
              return new ByteArrayInputStream(value.getBytes(StandardCharsets.UTF_8));
          } catch (ClassNotFoundException e) {
              throw new IOException("Class not found:" + classname);
          } catch (NoSuchFieldException e) {
              throw new IOException(
                  "Field not found:" + fieldname + " in " + classname);
          } catch (IllegalAccessException e) {
              throw new IOException("Illegal access to :" + fieldname + " in " + classname);
          } catch (NullPointerException npe) {
              throw new IOException("Not a static field: " + fieldname + " in " + classname);
          }
      }
  
  }
  