diff options
Diffstat (limited to 'tutorial/FreeArgs.html')
| -rw-r--r-- | tutorial/FreeArgs.html | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/tutorial/FreeArgs.html b/tutorial/FreeArgs.html new file mode 100644 index 0000000..43c9cb9 --- /dev/null +++ b/tutorial/FreeArgs.html @@ -0,0 +1,171 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<html> + + +<head> +<title>OpenJava : Tutorial</title> +<meta http-equiv="Keywords" content="java, openjava, reflection"> +</head> + + +<body bgcolor="white" + text="#000000" link="#007fff" vlink="#006fdf" alink="#ff0000"> + + +<!----------------------------------------------------------------------> + + +<center> + +<h1><font color="Blue">OpenJava Tutorial</font></h1> + +</center> + + +<!----------------------------------------------------------------------> +<hr width="100%"> +<!----------------------------------------------------------------------> + + +<h2>6. <font color="blue">Callee-side Translation</font></h2> + + +<p>In this section, an example of simple translation at <i>caller-side</i> +is described. + +<h3>6.1. What the base-level program should look like</h3> + +<p>Most of example programs given in the text are ready to be executed by +the OpenJava system and are similar in form to: + + +<br><blockquote><pre><font color=darkblue> +import java.util.*; +public class <font color=black>StringCollection</font> <b>instantiates <font color=black>FreeArgsClass</font></b> +{ + <font color=black>Vector</font> contents = new <font color=black>Vector</font>(); + public <b>generous</b> <font color=black>void</font> addAll( <font color=black>String[]</font> args ) { + for (<font color=black>int</font> i = 0; i < args.length; ++i) contents.addElement( args[i] ); + } +} +</font></pre></blockquote> + +<br><blockquote><pre><font color=darkblue> +public class <font color=black>Test</font> +{ + void test() { + <font color=black>StringCollection</font> strs = new <font color=black>StringCollection</font>(); + strs.addAll( <b>"one", "two", "three"</b> ); + } +} +</font></pre></blockquote> + + +<h3>6.2. What the base-level program should be translated</h3> + +<p>Like following: +<br><blockquote><pre><font color=darkblue> +public class <font color=black>Test</font> +{ + void test() { + <font color=black>StringCollection</font> strs = new <font color=black>StringCollection</font>(); + strs.addAll( <b>new <font color=black>String</font>[]{ "one", "two", "three" }</b> ); + } +} +</font></pre></blockquote> + + +<h3>6.3. Write a meta-level program</h3> + +<br><blockquote><pre><font color=darkblue> +import openjava.mop.*; +import openjava.ptree.*; +import openjava.syntax.*; + +public class FreeArgsClass instantiates Metaclass extends OJClass +{ + private static final String GENEROUS = "generous"; + /** Translates definition */ + + public void translateDefinition() throws MOPException { + OJMethod[] methods = getDeclaredMethods(); + for (int i = 0; i < methods.length; ++i) { + if (! methods[i].getModifiers().has( GENEROUS )) continue; + System.err.println( methods[i] ); + OJClass[] paramtypes = methods[i].getParameterTypes(); + if (paramtypes.length != 1 || ! paramtypes[0].isArray()) { + System.err.println( "illegal parameter, ignored." ); + continue; + } + putMetaInfo( methods[i].getName(), paramtypes[0].getName() ); + } + } + + public OJMethod resolveException( NoSuchMemberException e, + String name, OJClass[] params ) + throws NoSuchMemberException + { + try { + String argtypename = getMetaInfo( name ); + if (argtypename != null) { + OJClass paramtype = OJClass.forName( argtypename ); + return getMethod( name, new OJClass[]{ paramtype }, this ); + } + } catch ( OJClassNotFoundException e2 ) { + System.err.println( e2 ); + } + return super.resolveException( e, name, params ); + } + + /** Translates allocation parts */ + public Expression expandMethodCall( Environment env, MethodCall expr ) { + String argtypename = getMetaInfo( expr.getName() ); + if (argtypename == null) return expr; + OJClass comptype; + try { + comptype = OJClass.forName( argtypename ).getComponentType(); + } catch ( OJClassNotFoundException e ) { + System.err.println( e ); + return expr; + } + ExpressionList dim = new ExpressionList( null ); + ArrayInitializer ainit = new ArrayInitializer( expr.getArguments() ); + ArrayAllocationExpression carrier + = new ArrayAllocationExpression( comptype, dim, ainit ); + expr.setArguments( new ExpressionList( carrier ) ); + return expr; + } + + public static boolean isRegisteredModifier( String keyword ) { + if (keyword.equals( GENEROUS )) return true; + return false; + } +</font></pre></blockquote> + + +<!----------------------------------------------------------------------> +<hr width="100%"> +<!----------------------------------------------------------------------> + + +<center> + +Please send any message to : +<address> +mich@acm.org +</address><BR> + +</center> + + +<font size=1>Copyright (C) 1999 by Michaki Tatsubori.</font><br> +<font size=1>Java(TM) is a trademark of Sun Microsystems, Inc.</font> + + +<!----------------------------------------------------------------------> + + +</body> + + +</html> |