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.filters.util;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  
  import org.apache.bcel.classfile.ClassParser;
  import org.apache.bcel.classfile.ConstantValue;
  import org.apache.bcel.classfile.Field;
  
  // CheckStyle:HideUtilityClassConstructorCheck OFF - bc
  /**
   * Helper class that filters constants from a Java Class
   *
   */
  public final class JavaClassHelper {
      /**
       * Get the constants declared in a file as name=value
       *
       * @param bytes the class as a array of bytes
       * @return a StringBuffer contains the name=value pairs
       * @exception IOException if an error occurs
       */
      public static StringBuffer getConstants(final byte[] bytes)
          throws IOException {
          final StringBuffer sb = new StringBuffer();
          final ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
          final ClassParser parser = new ClassParser(bis, "");
          for (final Field field : parser.parse().getFields()) {
              if (field != null) {
                  final ConstantValue cv = field.getConstantValue();
                  if (cv != null) {
                      String cvs = cv.toString();
                      // Remove start and end quotes if field is a String
                      if (cvs.startsWith("\"") && cvs.endsWith("\"")) {
                          cvs = cvs.substring(1, cvs.length() - 1);
                      }
                      sb.append(String.format("%s=%s%n", field.getName(), cvs));
                  }
              }
          }
          return sb;
      }
  }
  