# ReflectionHelper.java

    /*
    ** Module   : ReflectionHelper.java
    ** Abstract : utility methods to ease or replace use of J2SE reflection
    **
    ** Copyright (c) 2007-2017, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- --JPRM-- ----------------------------Description-----------------------------
    ** 001 GES 20070320   @32509 Created initial version. Includes methods
    **                           for signature matching and error display.
    ** 002 ECF 20150715          Replace StringBuffer with StringBuilder.
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero General Public License as
    ** published by the Free Software Foundation, either version 3 of the
    ** License, or (at your option) any later version.
    **
    ** This program 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 Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.util;

    import java.lang.reflect.*;

    /**
     * Utility methods to ease or replace use of J2SE reflection.
     */
    public final class ReflectionHelper
    {
       /**
        * Private constructor to prevent instances of this class from being
        * created.
        */
       private ReflectionHelper()
       {
       }

       /**
        * Compare signatures as described by two arrays of classes and report
        * if they are equivalent. This is useful because the J2SE 1.4.x
        * reflection services <code>Class.getConstructor()</code> and
        * <code>Class.getMethod()</code> don't check for assignability so
        * a signature based on child classes won't match a compatible signature
        * that uses super classes. The J2SE implementation uses a reference
        * comparison but this method uses <code>isAssignableFrom</code>.
        * <p>
        * A quick return occurs in any case where the number of parameters in
        * the signatures are different.
        *
        * @param    possible
        *           The candidate signature list.
        * @param    actual
        *           The signature being searched for.
        *
        * @return   <code>true</code> if the signatures are compatible.
        */
       public static boolean testSignature(Class[] possible, Class[] actual)
       {
          // if the signatures have a different number of elements, they
          // can't be compatible
          if (possible.length == actual.length)
          {
             // compare signatures
             for (int i = 0; i < possible.length; i++)
             {
                if (!possible[i].isAssignableFrom(actual[i]))
                {
                   // this constructor is not a match
                   return false;
                }
             }

             return true;
          }

          return false;
       }

       /**
        * Removes all text up to and including the last '.' in the given string
        * and returns the remaining text.  Some simple attempts are made to
        * detect if this is a J2SE signature string instead of a fully qualified
        * class or method name.  In such a case the entire text is returned.
        *
        * @param    full
        *           A fully qualified class or method name.
        *
        * @return   The simple name or the full text if no '.' qualifiers exist
        *           or if this is detected as a J2SE encoded signature string.
        */
       public static String simpleName(String full)
       {
          // try to detect if this is not a qualified class name but rather a
          // J2SE encoded signature
          if (full.indexOf(';') > 0 || full.indexOf('[') > 0)
             return full;

          // find the end of the fully qualified name
          int rest = full.lastIndexOf('.');

          return rest < 0 ? full : full.substring(rest + 1);
       }

       /**
        * Create a string representing the signature of the described method.
        * <p>
        * No modifiers are known so there will be no text like <code>public</code>
        * or <code>static</code> in the result.
        *
        * @param    name
        *           The method name, inserted verbetim into the result.
        * @param    parms
        *           The list of parameters.  If <code>null</code> or 0 length,
        *           then there are no parameters in the signature.
        * @param    returnType
        *           The type the method returns. Use <code>null</code> to indicate
        *           that the return type is unknown or irrelevent. Use
        *           <code>void.class</code> for a <code>void</code> return.
        *
        * @return   The signature string without any modifiers.
        */
       public static String toStringSignature(String  name,
                                              Class[] parms,
                                              Class   returnType)
       {
          StringBuilder sb = new StringBuilder();

          if (returnType != null)
          {
             sb.append(simpleName(returnType.getName())).append(" ");
          }

          sb.append(name).append("(");

          for (int i = 0; parms != null && i < parms.length; i++)
          {
             if (i > 0)
                sb.append(", ");

             sb.append(simpleName(parms[i].getName()));
          }

          sb.append(")");

          return sb.toString();
       }
    }