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/*
* RTReflClass.oj
*
* Oct 29, 1999 by Michiaki Tatsubori
*/
package examples.rtrefl;
import openjava.mop.*;
import openjava.ptree.*;
import openjava.syntax.*;
/**
* The class <code>RTReflClass</code> is a metaclass which
* provides hooks for runtime class metaobject.
* <p>
* All the fields in the class are hidden instead the readers and
* writers methods for fields are provided. Furthermore, accesses
* to fields of the class is to be replaced with these methods.
* Note that member accesses in its class body are not captured.
*/
public class RTReflClass instantiates Metaclass extends OJClass
{
protected static String RTMETAOBJ_FIELD = "mt";
protected static Expression METAFIELD_ACCESS
= new FieldAccess( RTMETAOBJ_FIELD );
protected static final String originalMethodName( String name ) {
return "org_" + name;
}
protected static final String fieldReaderName( String name ) {
return "read_" + name;
}
protected static final String fieldWriterName( String name ) {
return "write_" + name;
}
/** Overrides to translate definition */
public convenient void translateDefinition() throws MOPException {
addInterface( RTMetaLevel.class );
/* Gets all the declared fields and methods */
OJMethod[] methods = getDeclaredMethods();
OJField[] fields = getDeclaredFields();
OJField rtmobj_field
= new OJField( this, OJModifier.forModifier( OJModifier.PUBLIC ),
RTMetaObject.class, RTMETAOBJ_FIELD );
addField( rtmobj_field );
/* Generates trapping methods for each public method */
for (int i = 0; i < methods.length; ++i) {
OJModifier modif = methods[i].getModifiers();
if (modif.isPublic()) provideMethod( methods[i] );
}
/* Generates wrappers for each public field */
for (int i = 0; i < fields.length; ++i) {
OJModifier modif = fields[i].getModifiers();
if (modif.isPublic()) provideField( fields[i] );
}
}
private void provideMethod( OJMethod method ) throws MOPException {
System.err.println( "Providing a method : " + method.toString() );
OJMethod trapper = OJMethod.makePrototype( method );
method.setName( originalMethodName( method.getName() ) );
addMethod( trapper );
/* marshalling and trapping */
Expression trapexpr = generateTrappingMethodCall( trapper );
StatementList body = new StatementList();
OJClass retType = trapper.getReturnType();
if (retType == OJSystem.VOID) {
body.add( new ExpressionStatement( trapexpr ) );
} else {
Expression unwrapexpr = generateUnwrapping( retType, trapexpr );
body.add( new ReturnStatement( unwrapexpr ) );
}
trapper.setBody( body );
}
private static convenient MethodCall
generateTrappingMethodCall( OJMethod method ) throws MOPException {
ExpressionList params = method.getParameterVariables();
OJClass[] paramTypes = method.getParameterTypes();
/* wrapping arguments */
ExpressionList typeinfo_args = new ExpressionList();
ExpressionList args = new ExpressionList();
for (int i = 0; i < paramTypes.length; ++i) {
typeinfo_args.add( new ClassLiteral( paramTypes[i] ) );
args.add( generateWrapping( paramTypes[i], params.get( i ) ));
}
/* marshalling arguments */
Expression namearg
= Literal.makeLiteral( originalMethodName( method.getName() ) );
Expression mrsld_typearg = new ArrayAllocationExpression(
java.lang.Class.class, new ExpressionList( null ),
new ArrayInitializer( typeinfo_args )
);
Expression mrsld_arg = new ArrayAllocationExpression(
java.lang.Object.class, new ExpressionList( null ),
new ArrayInitializer( args )
);
ExpressionList metaargs
= new ExpressionList( namearg, mrsld_typearg, mrsld_arg );
return new MethodCall( METAFIELD_ACCESS, "trapMethodCall", metaargs );
}
private void provideField( OJField field ) throws MOPException {
System.err.println( "Providing a field : " + field.toString() );
generateReaderMethod( field );
generateWriterMethod( field );
}
/**
* int read_l() {
* return ((Integer) mt.trapFieldRead("l")).intValue();
* }
*/
private void generateReaderMethod( OJField field ) throws MOPException {
//Expression trapexpr = makeExpression(
// "mt.trapFieldRead(\"" + field.getName() + "\")"
//);
Expression metafld = new FieldAccess( RTMETAOBJ_FIELD );
ExpressionList args = new ExpressionList(
Literal.makeLiteral( field.getName() )
);
Expression trapexpr
= new MethodCall( METAFIELD_ACCESS, "trapFieldRead", args );
Expression unwrapping
= generateUnwrapping( field.getType(), trapexpr );
OJMethod reader = new OJMethod( this,
field.getModifiers(), field.getType(),
fieldReaderName( field.getName() ),
(OJClass[]) null, null,
new StatementList( new ReturnStatement( unwrapping ) )
);
addMethod( reader );
}
/**
* int write_l(int rvalue) {
* mt.trapFieldWrite("l", new Integer(rvalue));
* return rvalue;
* }
*/
private void generateWriterMethod( OJField field ) throws MOPException {
OJMethod writer = new OJMethod( this,
field.getModifiers(), field.getType(),
fieldWriterName( field.getName() ),
new OJClass[]{ field.getType() }, null, null
);
Expression param = writer.getParameterVariables().get( 0 );
//StatementList body = makeStatementList( writer.getEnvironment(),
// "mt.trapFieldWrite(\"" + field.getName() + "\");" +
// "return " + field.getName() + "=" + param + ";"
// );
ExpressionList args = new ExpressionList(
Literal.makeLiteral( field.getName() ),
generateWrapping( field.getType(), param )
);
Expression trapexpr
= new MethodCall( METAFIELD_ACCESS, "trapFieldWrite", args );
StatementList body = new StatementList(
new ExpressionStatement( trapexpr ),
new ReturnStatement( param )
);
writer.setBody( body );
addMethod( writer );
}
/** new Integer(expr) for expr */
private static Expression
generateWrapping(OJClass realType, Expression expr) {
if (! realType.isPrimitive()) return expr;
OJClass wrapperType = realType.primitiveWrapper();
return new AllocationExpression( wrapperType,
new ExpressionList( expr ) );
}
/** ((Integer) expr).intValue() for expr */
private static Expression
generateUnwrapping(OJClass realType, Expression expr) {
expr = new CastExpression( realType.primitiveWrapper(), expr );
if (! realType.isPrimitive()) return expr;
return new MethodCall( expr, realType.getName() + "Value", null );
}
/* overrides */
/** Allows references to private fields */
public OJField resolveException(NoSuchMemberException e, String name)
throws NoSuchMemberException
{
try {
return getDeclaredField( name );
} catch ( NoSuchMemberException e2 ) {}
return super.resolveException( e, name );
}
/** Overrides to expand fields to be read */
public Expression expandFieldRead(
Environment env,
FieldAccess expr )
{
if (expr.getName().equals( RTMETAOBJ_FIELD )) return expr;
Expression ref = expr.getReferenceExpr();
String name = fieldReaderName( expr.getName() );
Expression result;
if (ref != null) {
result = new MethodCall( ref, name, null );
} else {
result = new MethodCall( expr.getReferenceType(), name, null );
}
System.err.println( "Patch FR : " + expr + "\tto\t" + result );
return result;
}
/** Overrides to expand fields to be written */
public Expression expandFieldWrite(
Environment env,
AssignmentExpression expr )
{
FieldAccess fldac = (FieldAccess) expr.getLeft();
if (fldac.getName().equals( RTMETAOBJ_FIELD )) return expr;
ExpressionList args = new ExpressionList( expr.getRight() );
Expression ref = fldac.getReferenceExpr();
String name = fieldWriterName( fldac.getName() );
Expression result;
if (ref != null) {
result = new MethodCall( ref, name, args );
} else {
result = new MethodCall( fldac.getReferenceType(), name, args );
}
System.err.println( "Patch FW : " + expr + "\tto\t" + result );
return result;
}
}
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