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Marathon » org » python » core » PyReflectedConstructor.java
// Copyright (c) Corporation for National Research Initiatives
package org.python.core;

import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;
import java.lang.InstantiationException;


public class PyReflectedConstructor extends PyReflectedFunction
{
    
    public PyReflectedConstructor(String name) {
        super(name);
        __name__ = name;
        argslist = new ReflectedArgs[1];
        nargs = 0;
    }

    public PyReflectedConstructor(Constructor c) {
        this(c.getDeclaringClass().getName());
        addConstructor(c);
    }

    private ReflectedArgs makeArgs(Constructor m) {
        return new ReflectedArgs(m, m.getParameterTypes(),
                                 m.getDeclaringClass(), true);
    }

    public void addConstructor(Constructor m) {
        int mods = m.getModifiers();
        // Only add public methods unless we're overriding
        if (!Modifier.isPublic(mods) && !JavaAccessibility.accessIsMutable())
            return;
        addArgs(makeArgs(m));
    }

    // xxx temporary solution, type ctr will go through __new__ ...
    PyObject make(PyObject[] args,String[] keywords) {
        ReflectedArgs[] argsl = argslist;
                
        ReflectedCallData callData = new ReflectedCallData();
        Object method=null;
        boolean consumes_keywords = false;
        int n = nargs;
        int nkeywords = keywords.length;
        PyObject[] allArgs = null;
        
        // Check for a matching constructor to call
        if (n > 0) { // PyArgsKeywordsCall signature, if present, is the first 
            if (argsl[0].matches(null, args, keywords, callData)) {
                method = argsl[0].data;
                consumes_keywords = argsl[0].flags == ReflectedArgs.PyArgsKeywordsCall;
            } else {
                allArgs = args;
                int i = 1;
                if (nkeywords > 0) {
                    args = new PyObject[allArgs.length-nkeywords];
                    System.arraycopy(allArgs, 0, args, 0, args.length);
                    i = 0;
                }
                for (; i < n; i++) {
                    ReflectedArgs rargs = argsl[i];
                        if (rargs
                            .matches(null, args, Py.NoKeywords, callData)) {
                        method = rargs.data; break; }
                }
            }
        }

        // Throw an error if no valid set of arguments
        if (method == null) {
            throwError(callData.errArg, args.length, true /*xxx?*/,false);
        }

        // Do the actual constructor call
        PyObject obj = null;
        Constructor ctor = (Constructor)method;
        try {
            obj = (PyObject)ctor.newInstance(callData.getArgsArray());
        }
        catch (Throwable t) {
            throw Py.JavaError(t);
        }
        
        if (!consumes_keywords) {
            int offset = args.length;
            for (int i=0; i<nkeywords; i++) {
                obj.__setattr__(keywords[i], allArgs[i+offset]);
            }            
        }
    
        return obj;
    }

    public PyObject __call__(PyObject self, PyObject[] args,
                             String[] keywords)
    {
        ReflectedArgs[] argsl = argslist;

        if (self == null || !(self instanceof PyInstance)) {
            throw Py.TypeError("invalid self argument to constructor");
        }

        PyInstance iself = (PyInstance)self;
        Class javaClass = iself.instclass.proxyClass;
        //Class[] javaClasses = iself.__class__.proxyClasses;
        //int myIndex = -1;
        boolean proxyConstructor=false;
        Class declaringClass = argsl[0].declaringClass;

        // If this is the constructor for a proxy class or not...
        if (PyProxy.class.isAssignableFrom(declaringClass)) {
//             if (self instanceof PyJavaInstance) {
//                 throw Py.TypeError(
//                     "invalid self argument to proxy constructor");
//             }
        }
        else {
            if (!(iself instanceof PyJavaInstance)) {
                // Get proxy constructor and call it
                if (declaringClass.isAssignableFrom(javaClass)) {
                    proxyConstructor = true;
                } else {
                    throw Py.TypeError("invalid self argument");
                }

                PyJavaClass jc = PyJavaClass.lookup(javaClass); // xxx
                jc.initConstructors();
                return jc.__init__.__call__(iself, args, keywords);
            }
        }


        if (declaringClass.isAssignableFrom(javaClass)) {
            proxyConstructor = true;
        } else {
            throw Py.TypeError("self invalid - must implement: "+
                               declaringClass.getName());
        }

        if (iself.javaProxy != null) {
            Class sup = iself.instclass.proxyClass;
            if (PyProxy.class.isAssignableFrom(sup))
                sup = sup.getSuperclass();
            throw Py.TypeError("instance already instantiated for "+
                               sup.getName());
        }

        ReflectedCallData callData = new ReflectedCallData();
        Object method=null;

        // Remove keyword args
        int nkeywords = keywords.length;
        PyObject[] allArgs = args;
        if (nkeywords > 0) {
            args = new PyObject[allArgs.length-nkeywords];
            System.arraycopy(allArgs, 0, args, 0, args.length);
        }

        // Check for a matching constructor to call
        int n = nargs;
        for (int i=0; i<n; i++) {
            ReflectedArgs rargs = argsl[i];
            if (rargs.matches(null, args, Py.NoKeywords, callData)) {
                method = rargs.data;
                break;
            }
        }

        // Throw an error if no valid set of arguments
        if (method == null) {
            throwError(callData.errArg, args.length, self != null, false);
        }

        // Do the actual constructor call
        Object jself = null;
        ThreadState ts = Py.getThreadState();
        try {
            ts.pushInitializingProxy(iself);
            Constructor ctor = (Constructor)method;
            try {
                jself = ctor.newInstance(callData.getArgsArray());
            }
            catch (InvocationTargetException e) {
                if (e.getTargetException() instanceof InstantiationException){
                    Class sup = iself.instclass.proxyClass.getSuperclass();
                    String msg = "Constructor failed for Java superclass";
                    if (sup != null)
                        msg += " " + sup.getName();
                    throw Py.TypeError(msg);
                }
                else throw Py.JavaError(e);
            }
            catch (Throwable t) {
                throw Py.JavaError(t);
            }
        }
        finally {
            ts.popInitializingProxy();
        }

        iself.javaProxy = jself;

        // Do setattr's for keyword args
        int offset = args.length;
        for (int i=0; i<nkeywords; i++) {
            iself.__setattr__(keywords[i], allArgs[i+offset]);
        }
        return Py.None;
    }

    public PyObject __call__(PyObject[] args, String[] keywords) {
        if (args.length < 1) {
            throw Py.TypeError("constructor requires self argument");
        }
        PyObject[] newArgs = new PyObject[args.length-1];
        System.arraycopy(args, 1, newArgs, 0, newArgs.length);

        return __call__(args[0], newArgs, keywords);
    }

    public String toString() {
        //printArgs();
        return "<java constructor "+__name__+" "+Py.idstr(this)+">";
    }
}
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