lvalue.java

来自「jpda例子文件」· Java 代码 · 共 1,049 行 · 第 1/3 页

    static LValue make(VirtualMachine vm, double val) {
        return new LValueConstant(vm.mirrorOf(val));
    }

    static LValue make(VirtualMachine vm, String val) throws ParseException {
        return new LValueConstant(vm.mirrorOf(val));
    }

    static LValue makeBoolean(VirtualMachine vm, Token token) {
        return make(vm, token.image.charAt(0) == 't');
    }

    static LValue makeCharacter(VirtualMachine vm, Token token) {
        return make(vm, token.image.charAt(1));
    }

    static LValue makeFloat(VirtualMachine vm, Token token) {
        return make(vm, Float.valueOf(token.image).floatValue());
    }

    static LValue makeDouble(VirtualMachine vm, Token token) {
        return make(vm, Double.valueOf(token.image).doubleValue());
    }

    static LValue makeInteger(VirtualMachine vm, Token token) {
        return make(vm, Integer.parseInt(token.image));
    }

    static LValue makeShort(VirtualMachine vm, Token token) {
        return make(vm, Short.parseShort(token.image));
    }

    static LValue makeLong(VirtualMachine vm, Token token) {
        return make(vm, Long.parseLong(token.image));
    }

    static LValue makeByte(VirtualMachine vm, Token token) {
        return make(vm, Byte.parseByte(token.image));
    }

    static LValue makeString(VirtualMachine vm, 
                             Token token) throws ParseException {
        int len = token.image.length();
        return make(vm, token.image.substring(1,len-1));
    }

    static LValue makeNull(VirtualMachine vm, 
                           Token token) throws ParseException {
        return new LValueConstant(null);
    }

    static LValue makeThisObject(VirtualMachine vm, 
                                 ExpressionParser.GetFrame frameGetter, 
                                 Token token) throws ParseException {
        if (frameGetter == null) {
            throw new ParseException("No current thread");
        } else {
            try {
                StackFrame frame = frameGetter.get();
                ObjectReference thisObject = frame.thisObject();
                
		if (thisObject==null) {
       			throw new ParseException(
                            "No 'this'.  In native or static method");
		} else {
			return new LValueConstant(thisObject);
                }
            } catch (IncompatibleThreadStateException exc) {
                throw new ParseException("Thread not suspended");
            }
        }
    }

    static LValue makeNewObject(VirtualMachine vm, 
                                 ExpressionParser.GetFrame frameGetter, 
                                String className, List arguments) throws ParseException {
        List classes = vm.classesByName(className);
        if (classes.size() == 0) {
            throw new ParseException("No class named: " + className);
        }

        if (classes.size() > 1) {
            throw new ParseException("More than one class named: " +
                                     className);
        }
        ReferenceType refType = (ReferenceType)classes.get(0);


        if (!(refType instanceof ClassType)) {
            throw new ParseException("Cannot create instance of interface " +
                                     className);
        }

        ClassType classType = (ClassType)refType;
        List methods = new ArrayList(classType.methods()); // writable
        Iterator iter = methods.iterator();
        while (iter.hasNext()) {
            Method method = (Method)iter.next();
            if (!method.isConstructor()) {
                iter.remove();
            }
        }
        Method constructor = LValue.resolveOverload(methods, arguments);

        ObjectReference newObject;
        try {
            ThreadReference thread = frameGetter.get().thread();
            newObject = classType.newInstance(thread, constructor, arguments, 0);
        } catch (InvocationException ie) {
            throw new ParseException("Exception in " + className + " constructor: " + 
                                     ie.exception().referenceType().name());
        } catch (IncompatibleThreadStateException exc) {
            throw new ParseException("Thread not suspended");
        } catch (Exception e) {
            /*
             * TO DO: Better error handling
             */
            throw new ParseException("Unable to create " + className + " instance");
        }
	return new LValueConstant(newObject);
    }

    private static LValue nFields(LValue lval, 
                                  StringTokenizer izer,
                                  ThreadReference thread) 
                                          throws ParseException {
        if (!izer.hasMoreTokens()) {
            return lval;
        } else {
            return nFields(lval.memberLValue(izer.nextToken(), thread), izer, thread);
        }                    
    }

    static LValue makeName(VirtualMachine vm, 
                           ExpressionParser.GetFrame frameGetter, 
                           String name) throws ParseException {
        StringTokenizer izer = new StringTokenizer(name, ".");
        String first = izer.nextToken();
        // check local variables
        if (frameGetter != null) {
            try {
                StackFrame frame = frameGetter.get();
                ThreadReference thread = frame.thread();
                LocalVariable var;
                try {
                    var = frame.visibleVariableByName(first);
                } catch (AbsentInformationException e) {
                    var = null;
                }
                if (var != null) {
                    return nFields(new LValueLocal(frame, var), izer, thread);
                } else {
                    ObjectReference thisObject = frame.thisObject();
                    if (thisObject != null) {
                        // check if it is a field of 'this'
                        LValue thisLValue = new LValueConstant(thisObject);
                        LValue fv;
                        try {
                            fv = thisLValue.memberLValue(first, thread);
                        } catch (ParseException exc) {
                            fv = null;
                        }
                        if (fv != null) {
                            return nFields(fv, izer, thread);
                        }
                    }
                }
                // check for class name
                while (izer.hasMoreTokens()) {
                    List classes = vm.classesByName(first);
                    if (classes.size() > 0) {
                        if (classes.size() > 1) {
                            throw new ParseException("More than one class named: " +
                                                     first);
                        } else {
                            ReferenceType refType = (ReferenceType)classes.get(0);
                            LValue lval = new LValueStaticMember(refType, 
                                                            izer.nextToken(), thread);
                            return nFields(lval, izer, thread);
                        }
                    }
                    first = first + '.' + izer.nextToken();
                }
            } catch (IncompatibleThreadStateException exc) {
                throw new ParseException("Thread not suspended");
            }
        }
        throw new ParseException("Name unknown: " + name);
    }

    static String stringValue(LValue lval, ExpressionParser.GetFrame frameGetter
                              ) throws ParseException {
        Value val = lval.getMassagedValue(frameGetter);
        if (val == null) {
            return "null";
        }
        if (val instanceof StringReference) {
            return ((StringReference)val).value();
        }
        return val.toString();  // is this correct in all cases?
    }

    static LValue booleanOperation(VirtualMachine vm, Token token, 
                            LValue rightL, 
                            LValue leftL) throws ParseException {
        String op = token.image;
        Value right = rightL.interiorGetValue();
        Value left = leftL.interiorGetValue();
        if ( !(right instanceof PrimitiveValue) || 
             !(left instanceof PrimitiveValue) ) {
            if (op.equals("==")) {
                return make(vm, right.equals(left));
            } else if (op.equals("!=")) {
                return make(vm, !right.equals(left));
            } else {
                throw new ParseException("Operands or '" + op + 
                                     "' must be primitive");
            }
        }
        // can compare any numeric doubles
        double rr = ((PrimitiveValue)right).doubleValue();
        double ll = ((PrimitiveValue)left).doubleValue();
        boolean res;
        if (op.equals("<")) {
            res = rr < ll;
        } else if (op.equals(">")) {
            res = rr > ll;
        } else if (op.equals("<=")) {
            res = rr <= ll;
        } else if (op.equals(">=")) {
            res = rr >= ll;
        } else if (op.equals("==")) {
            res = rr == ll;
        } else if (op.equals("!=")) {
            res = rr != ll;
        } else {
            throw new ParseException("Unknown operation: " + op);
        }
        return make(vm, res);
    }                                

    static LValue operation(VirtualMachine vm, Token token, 
                            LValue rightL, LValue leftL,
                            ExpressionParser.GetFrame frameGetter
                            ) throws ParseException {
        String op = token.image;
        Value right = rightL.interiorGetValue();
        Value left = leftL.interiorGetValue();
        if ((right instanceof StringReference) ||
                              (left instanceof StringReference)) {
            if (op.equals("+")) {
                // If one is an ObjectRef, we will need to invoke
                // toString on it, so we need the thread. 
                return make(vm, stringValue(rightL, frameGetter) +
                            stringValue(leftL, frameGetter));
            }
        }
        if ((right instanceof ObjectReference) ||
                              (left instanceof ObjectReference)) {
            if (op.equals("==")) {
                return make(vm, right.equals(left));
            } else if (op.equals("!=")) {
                return make(vm, !right.equals(left));
            } else {
                throw new ParseException("Invalid operation '" +
                                         op + "' on an Object");
            }
        }
        if ((right instanceof BooleanValue) ||
                              (left instanceof BooleanValue)) {
            throw new ParseException("Invalid operation '" +
                                     op + "' on a Boolean");
        }
        // from here on, we know it is a integer kind of type
        PrimitiveValue primRight = (PrimitiveValue)right;
        PrimitiveValue primLeft = (PrimitiveValue)left;
        if ((primRight instanceof DoubleValue) ||
                              (primLeft instanceof DoubleValue)) {
            double rr = primRight.doubleValue();
            double ll = primLeft.doubleValue();
            double res;
            if (op.equals("+")) {
                res = rr + ll;
            } else if (op.equals("-")) {
                res = rr - ll;
            } else if (op.equals("*")) {
                res = rr * ll;
            } else if (op.equals("/")) {
                res = rr / ll;
            } else {
                throw new ParseException("Unknown operation: " + op);
            }
            return make(vm, res);
        }
        if ((primRight instanceof FloatValue) ||
                              (primLeft instanceof FloatValue)) {
            float rr = primRight.floatValue();
            float ll = primLeft.floatValue();
            float res;
            if (op.equals("+")) {
                res = rr + ll;
            } else if (op.equals("-")) {
                res = rr - ll;
            } else if (op.equals("*")) {
                res = rr * ll;
            } else if (op.equals("/")) {
                res = rr / ll;
            } else {
                throw new ParseException("Unknown operation: " + op);
            }
            return make(vm, res);
        }
        if ((primRight instanceof LongValue) ||
                              (primLeft instanceof LongValue)) {
            long rr = primRight.longValue();
            long ll = primLeft.longValue();
            long res;
            if (op.equals("+")) {
                res = rr + ll;
            } else if (op.equals("-")) {
                res = rr - ll;
            } else if (op.equals("*")) {
                res = rr * ll;
            } else if (op.equals("/")) {
                res = rr / ll;
            } else {
                throw new ParseException("Unknown operation: " + op);
            }
            return make(vm, res);
        } else {
            int rr = primRight.intValue();
            int ll = primLeft.intValue();
            int res;
            if (op.equals("+")) {
                res = rr + ll;
            } else if (op.equals("-")) {
                res = rr - ll;
            } else if (op.equals("*")) {
                res = rr * ll;
            } else if (op.equals("/")) {
                res = rr / ll;
            } else {
                throw new ParseException("Unknown operation: " + op);
            }
            return make(vm, res);
        }
    }   
}