1 files changed, 169 insertions, 0 deletions
diff --git a/tutorial/examples/multimethod/MultimethodClass.java b/tutorial/examples/multimethod/MultimethodClass.java
new file mode 100644
index 0000000..4a81938
--- /dev/null
+++ b/tutorial/examples/multimethod/MultimethodClass.java
@@ -0,0 +1,169 @@
+/*
+ * MultimethodClass.oj
+ *
+ * comments here.
+ *
+ * @author   Michiaki Tatsubori
+ * @version  %VERSION% %DATE%
+ * @see      java.lang.Object
+ *
+ * COPYRIGHT 1999 by Michiaki Tatsubori, ALL RIGHTS RESERVED.
+ */
+package examples.multimethod;
+
+
+import java.util.*;
+import openjava.mop.*;
+import openjava.ptree.*;
+
+
+/**
+ * The class <code>MultimethodClass</code>
+ * <p>
+ * For example
+ * <pre>
+ * </pre>
+ * <p>
+ *
+ * @author   Michiaki Tatsubori
+ * @version  1.0
+ * @since    $Id: MultimethodClass.java,v 1.2 2003/02/19 02:55:01 tatsubori Exp $
+ * @see java.lang.Object
+ */
+public class MultimethodClass extends OJClass
+{
+    private static final String MULTIFORM = "multiform";
+    private static final String RUNTIME_EXCEPTION
+    = "examples.multimethod.NoAddaptableMethodException";
+
+    public void translateDefinition() throws MOPException {
+    Hashtable table = new Hashtable();
+    OJMethod[] m = getDeclaredMethods();
+
+    for (int i = 0; i < m.length; ++i) {
+        if (! m[i].getModifiers().has( MULTIFORM ))  continue;
+        ParameterSetTree set
+        = (ParameterSetTree) table.get( makeHashkey( m[i] ) );
+        if (set != null) {
+        set.add( m[i] );
+        } else {
+        set = new ParameterSetTree( m[i].getParameterTypes(), m[i] );
+        }
+        table.put( makeHashkey( m[i] ), set );
+    }
+
+    Enumeration ite = table.elements();
+    while (ite.hasMoreElements()) {
+        ParameterSetTree set = (ParameterSetTree) ite.nextElement();
+        modifyToBeGeneric( set );
+        System.out.println( set );
+    }
+    }
+
+    private void modifyToBeGeneric( ParameterSetTree set )
+    throws MOPException
+    {
+    if (! set.hasChildren())  return;
+
+    OJMethod method = set.getValue();
+    if (method == null)  addMethod( (method = genSelector( set )) );
+
+    StatementList result = new StatementList();
+    ParameterSetTree[] children = set.getChildren();
+    for (int i = 0; i < children.length; ++i) {
+        Expression cond
+        = makeCond( method, children[i].getParameterTypes() );
+        StatementList ifbody
+        = makeQualifiedCall( method, children[i].getParameterTypes() );
+        result.add( new IfStatement( cond, ifbody ) );
+        modifyToBeGeneric( children[i] );
+    }
+    result.addAll( method.getBody() );
+    method.addExceptionType( OJClass.forName( RUNTIME_EXCEPTION ) );
+    method.setBody( result );
+    }
+
+    /* generates a method only for testing params to invoke another */
+    private OJMethod genSelector( ParameterSetTree set )
+    throws MOPException
+    {
+    /* representer of other features such as throwing exceptions */
+    OJMethod rep = pickupOne( set );
+    return new OJMethod(
+        this, rep.getModifiers(), rep.getReturnType(), rep.getName(),
+        set.getParameterTypes(),  rep.getExceptionTypes(),
+        makeStatementList( "throw new " + RUNTIME_EXCEPTION + "();" )
+        );
+    }
+
+    private static Expression makeCond( OJMethod holder, OJClass[] ptypes )
+    throws MOPException
+    {
+    String[] params = holder.getParameters();
+    StringBuffer strbuf = new StringBuffer();
+    for (int i = 0; i < ptypes.length; ++i) {
+        if (i != 0)  strbuf.append( " && " );
+        strbuf.append( "(" );
+        strbuf.append( params[i] );
+        strbuf.append( " instanceof " );
+        strbuf.append( ptypes[i].getName() );
+        strbuf.append( ")" );
+    }
+    return makeExpression( holder.getEnvironment(), strbuf.toString() );
+    }
+
+    private static StatementList
+    makeQualifiedCall( OJMethod holder, OJClass[] ptypes )
+    throws MOPException
+    {
+    String[] params = holder.getParameters();
+    StringBuffer strbuf = new StringBuffer();
+    strbuf.append( "this." ).append( holder.getName() ).append( "( " );
+    for (int i = 0; i < ptypes.length; ++i) {
+        if (i != 0)  strbuf.append( ", " );
+        strbuf.append( "(" ).append( ptypes[i].getName() ).append( ") " );
+        strbuf.append( params[i] );
+    }
+    strbuf.append( " )" );
+    Expression mtdcall
+        = makeExpression( holder.getEnvironment(), strbuf.toString() );
+
+    StatementList result = new StatementList();
+    if (holder.getReturnType() == OJSystem.VOID) {
+        result.add( new ExpressionStatement( mtdcall ) );
+        result.add( new ReturnStatement() );
+    } else {
+        result.add( new ReturnStatement( mtdcall ) );
+    }
+    return result;
+    }
+
+    private static String makeHashkey( OJMethod method ) {
+        return method.getReturnType().getName() + "%" + method.getName() +
+        "%" + method.getParameterTypes().length;
+    }
+
+    private static OJMethod pickupOne( ParameterSetTree set ) {
+    while (set.getChildren().length != 0)  set = set.getChildren()[0];
+    return set.getValue();
+    }
+
+    /* syntax extension */
+
+    public static boolean isRegisteredModifier( String keyword ) {
+        return keyword.equals( MULTIFORM );
+    }
+
+    /* constructors */
+
+    public MultimethodClass( Environment outer_env, OJClass declarer,
+                 ClassDeclaration ptree )
+    {
+    super( outer_env, declarer, ptree );
+    }
+
+    public MultimethodClass( Class javaclass, MetaInfo minfo ) {
+        super( javaclass, minfo );
+    }
+
+}