content: /*
   * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package openjdk.tools.jdeprscan.scan;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Represents a method's signature, that is, its parameter types
   * and its return type.
   */
  public class MethodSig {
      final List<String> parameters;
      final String returnType;
  
      /**
       * Parses the method descriptor and returns a MethodSig instance.
       *
       * @param desc the descriptor to parse
       * @return the new MethodSig instance
       */
      public static MethodSig fromDesc(String desc) {
          return parse(desc, 0, desc.length());
      }
  
      /**
       * Returns this method's return type.
       *
       * @return the return type
       */
      public String getReturnType() {
          return returnType;
      }
  
      /**
       * Returns a list of parameters of this method.
       *
       * @return the parameter list
       */
      public List<String> getParameters() {
          return parameters;
      }
  
      /**
       * Returns a string describing this method.
       *
       * @return the string description
       */
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder();
          sb.append("parameters");
          if (parameters.isEmpty()) {
              sb.append(" none");
          } else {
              int i = 0;
              for (String p : parameters) {
                  sb.append(String.format(" %d=%s", i++, p));
              }
          }
          sb.append(String.format(" return %s", returnType));
          return sb.toString();
      }
  
      private MethodSig(List<String> parameters, String returnType) {
          this.parameters = Collections.unmodifiableList(parameters);
          this.returnType = returnType;
      }
  
      private static IllegalArgumentException ex(String desc, int pos) {
          return new IllegalArgumentException(String.format(
              "illegal descriptor \"%s\" at position %d", desc, pos));
      }
  
      private static MethodSig parse(String desc, int start, int end)
              throws IllegalArgumentException {
          int p = start;
          int dims = 0;
          boolean inReturnType = false;
          String returnType = null;
          List<String> parameters = new ArrayList<>();
  
          while (p < end) {
              String type;
              char ch;
              switch (ch = desc.charAt(p)) {
                  case '(':
                      p++;
                      continue;
  
                  case ')':
                      p++;
                      inReturnType = true;
                      continue;
  
                  case '[':
                      p++;
                      dims++;
                      continue;
  
                  case 'B': // byte
                  case 'C': // char
                  case 'D': // double
                  case 'F': // float
                  case 'I': // int
                  case 'J': // long
                  case 'S': // short
                  case 'Z': // boolean
                  case 'V': // void
                      type = Character.toString(ch);
                      p++;
                      break;
  
                  case 'L':
                      int sep = desc.indexOf(';', p);
                      if (sep == -1 || sep >= end)
                          throw ex(desc, p);
                      type = desc.substring(p, ++sep);
                      p = sep;
                      break;
  
                  default:
                      throw ex(desc, p);
              }
  
              StringBuilder sb = new StringBuilder();
              for ( ; dims > 0; dims-- )
                  sb.append("[");
              sb.append(type);
              if (inReturnType) {
                  returnType = sb.toString();
              } else {
                  parameters.add(sb.toString());
              }
          }
  
          if (returnType == null) {
              throw ex(desc, end);
          }
  
          return new MethodSig(parameters, returnType);
      }
  }
  