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();
}
}