/* TypeSignature.java -- Class used to compute type signatures Copyright (C) 1998 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath 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 for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ package gnu.java.lang.reflect; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Member; import java.lang.reflect.Method; /** This class provides static methods that can be used to compute type-signatures of <code>Class</code>s or <code>Member</code>s. More specific methods are also provided for computing the type-signature of <code>Constructor</code>s and <code>Method</code>s. Methods are also provided to go in the reverse direction. */ public class TypeSignature { /** Returns a <code>String</code> representing the type-encoding of CLAZZ. Type-encodings are computed as follows: <pre> boolean -> "Z" byte -> "B" char -> "C" double -> "D" float -> "F" int -> "I" long -> "J" short -> "S" void -> "V" arrays -> "[" + type-encoding of component type object -> "L" + fully qualified class name with "."'s replaced by "/"'s + ";"</pre> */ public static String getEncodingOfClass( Class clazz ) { if( clazz.isPrimitive() ) { if( clazz == Boolean.TYPE ) return "Z"; if( clazz == Byte.TYPE ) return "B"; if( clazz == Character.TYPE ) return "C"; if( clazz == Double.TYPE ) return "D"; if( clazz == Float.TYPE ) return "F"; if( clazz == Integer.TYPE ) return "I"; if( clazz == Long.TYPE ) return "J"; if( clazz == Short.TYPE ) return "S"; if( clazz == Void.TYPE ) return "V"; else throw new RuntimeException( "Unknown primitive class " + clazz ); } else if( clazz.isArray() ) { return '[' + getEncodingOfClass( clazz.getComponentType() ); } else { String classname = clazz.getName(); int name_len = classname.length(); char[] buf = new char[ name_len + 2 ]; buf[0] = 'L'; classname.getChars( 0, name_len, buf, 1 ); int i; for( i=1; i <= name_len; i++ ) { if( buf[i] == '.' ) buf[i] = '/'; } buf[i] = ';'; return new String( buf ); } } /** This function is the inverse of <code>getEncodingOfClass</code>. @see getEncodingOfClass @exception ClassNotFoundException If class encoded as type_code cannot be located. */ public static Class getClassForEncoding( String type_code ) throws ClassNotFoundException { if( type_code.equals( "B" ) ) return Byte.TYPE; if( type_code.equals( "C" ) ) return Character.TYPE; if( type_code.equals( "D" ) ) return Double.TYPE; if( type_code.equals( "F" ) ) return Float.TYPE; if( type_code.equals( "I" ) ) return Integer.TYPE; if( type_code.equals( "J" ) ) return Long.TYPE; if( type_code.equals( "S" ) ) return Short.TYPE; if( type_code.equals( "Z" ) ) return Boolean.TYPE; if( type_code.charAt( 0 ) == 'L' ) { return Class.forName( type_code.substring( 1, type_code.length() - 1 ).replace( '/', '.' )); } if( type_code.charAt( 0 ) == '[' ) { int last_bracket = type_code.lastIndexOf( '[' ); String brackets = type_code.substring( 0, last_bracket + 1 ); String component = type_code.substring( last_bracket + 1 ); // ??? This is what the Classpath implementation did, but I don't // think that it's correct. The JLS says that Class.forName takes the // classname of an array element in fully qualified form, whereas this // code is tring to strip off the punctuation. // if( component.charAt( 0 ) == 'L' ) // component = // component.substring( 1, component.length() - 1 ).replace('/', '.'); if( component.charAt( 0 ) == 'L' ) component = component.replace('/', '.'); return Class.forName( brackets + component ); } else throw new ClassNotFoundException( "Type code cannot be parsed as a valid class name" ); } /** Returns a <code>String</code> representing the type-encoding of M. The type-encoding of a method is: "(" + type-encodings of parameter types + ")" + type-encoding of return type */ public static String getEncodingOfMethod( Method m ) { String returnEncoding = getEncodingOfClass( m.getReturnType() ); Class[] paramTypes = m.getParameterTypes(); String[] paramEncodings = new String[ paramTypes.length ]; String paramEncoding; int size = 2; // make room for parens for( int i=0; i < paramTypes.length; i++ ) { paramEncoding = getEncodingOfClass( paramTypes[i] ); size += paramEncoding.length(); paramEncodings[i] = paramEncoding; } size += returnEncoding.length(); StringBuffer buf = new StringBuffer( size ); buf.append( '(' ); for( int i=0; i < paramTypes.length; i++ ) { buf.append( paramEncodings[i] ); } buf.append( ')' ); buf.append( returnEncoding ); return buf.toString(); } /** Returns a <code>String</code> representing the type-encoding of C. The type-encoding of a method is: "(" + type-encodings of parameter types + ")V" */ public static String getEncodingOfConstructor( Constructor c ) { Class[] paramTypes = c.getParameterTypes(); String[] paramEncodings = new String[ paramTypes.length ]; String paramEncoding; int size = 3; // make room for parens and V for return type for( int i=0; i < paramTypes.length; i++ ) { paramEncoding = getEncodingOfClass( paramTypes[i] ); size += paramEncoding.length(); paramEncodings[i] = paramEncoding; } StringBuffer buf = new StringBuffer( size ); buf.append( '(' ); for( int i=0; i < paramTypes.length; i++ ) { buf.append( paramEncodings[i] ); } buf.append( ")V" ); return buf.toString(); } /** Returns a <code>String</code> representing the type-encoding of MEM. <code>Constructor</code>s are handled by <code>getEncodingOfConstructor</code>. <code>Method</code>s are handled by <code>getEncodingOfMethod</code>. <code>Field</code>s are handled by returning the encoding of the type of the <code>Field</code>. */ public static String getEncodingOfMember( Member mem ) { if( mem instanceof Constructor ) return getEncodingOfConstructor( (Constructor)mem ); if( mem instanceof Method ) return getEncodingOfMethod( (Method)mem ); else // Field return getEncodingOfClass( ((Field)mem).getType() ); } }