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Java > Open Source Codes > org > python > core > PyMethod


1 // Copyright (c) Corporation for National Research Initiatives
2 package org.python.core;
3
4 /**
5  * A python method.
6  */
7
8 public class PyMethod extends PyObject
9 {
10     public PyObject im_self;
11     public PyObject im_func;
12     public PyObject im_class;
13     public String JavaDoc __name__;
14     public PyObject __doc__;
15
16     public PyMethod(PyObject self, PyObject f, PyObject wherefound) {
17         im_func = f;
18         im_self = self;
19         im_class = wherefound;
20     }
21
22     public PyMethod(PyObject self, PyFunction f, PyObject wherefound) {
23         this(self, (PyObject)f, wherefound);
24         __name__ = f.__name__;
25         __doc__ = f.__doc__;
26     }
27
28     public PyMethod(PyObject self, PyReflectedFunction f, PyObject wherefound)
29     {
30         this(self, (PyObject)f, wherefound);
31         __name__ = f.__name__;
32         __doc__ = f.__doc__;
33     }
34
35     private static final String JavaDoc[] __members__ = {
36         "im_self", "im_func", "im_class",
37         "__doc__", "__name__", "__dict__",
38     };
39
40     // TBD: this should be unnecessary
41 public PyObject __dir__() {
42         PyString members[] = new PyString[__members__.length];
43         for (int i = 0; i < __members__.length; i++)
44             members[i] = new PyString(__members__[i]);
45         PyList ret = new PyList(members);
46         PyObject k = im_func.__getattr__("__dict__").invoke("keys");
47         ret.extend(k);
48         return ret;
49     }
50
51     private void throwReadonly(String JavaDoc name) {
52         for (int i = 0; i < __members__.length; i++)
53             if (__members__[i] == name)
54                 throw Py.TypeError("readonly attribute");
55         throw Py.AttributeError(name);
56     }
57
58     public PyObject __findattr__(String JavaDoc name) {
59         PyObject ret = super.__findattr__(name);
60         if (ret != null)
61             return ret;
62         return im_func.__findattr__(name);
63     }
64
65     public void __delattr__(String JavaDoc name) {
66         im_func.__delattr__(name);
67     }
68
69     public PyObject _doget(PyObject container) {
70         return _doget(container, null);
71     }
72
73     public PyObject _doget(PyObject container, PyObject wherefound) {
74         /* Only if classes are compatible */
75         if (container == null)
76             return this;
77         if (__builtin__.issubclass(container.fastGetClass(), im_class))
78              if (im_func instanceof PyFunction)
79                  return new PyMethod(container, (PyFunction)im_func,
80                                      im_class);
81              else if (im_func instanceof PyReflectedFunction)
82                  return new PyMethod(container, (PyReflectedFunction)im_func,
83                                      im_class);
84              else
85                  return new PyMethod(container, im_func, im_class);
86         return this;
87     }
88
89
90     public PyObject __call__(PyObject[] args, String JavaDoc[] keywords) {
91         if (im_self != null)
92             // bound method
93 return im_func.__call__(im_self, args, keywords);
94         // unbound method.
95 boolean badcall = false;
96         if (im_class == null)
97             // TBD: An example of this is running any function defined in
98 // the os module. If you "import os", you'll find it's a
99 // jclass object instead of a module object. Still unclear
100 // whether that's wrong, but it's definitely not easily fixed
101 // right now. Running, e.g. os.getcwd() creates an unbound
102 // method with im_class == null. For backwards compatibility,
103 // let this pass the call test
104 ;
105         else if (args.length < 1)
106             badcall = true;
107         else // xxx can be faster?
108 // first argument must be an instance who's class is im_class
109 // or a subclass of im_class
110 badcall = ! __builtin__.issubclass(args[0].fastGetClass(),im_class);
111         if (badcall) {
112             String JavaDoc got ="nothing";
113             if (args.length>=1)
114                 got = class_name(args[0].fastGetClass())+" instance";
115             throw Py.TypeError("unbound method " + __name__ + "() must be " +
116                                "called with "+class_name(im_class)+ " instance as first argument"+
117                                " (got "+got+" instead)");
118         }
119         else
120             return im_func.__call__(args, keywords);
121     }
122
123     public int __cmp__(PyObject other) {
124         if (other instanceof PyMethod) {
125             PyMethod mother = (PyMethod)other;
126             if (im_self != mother.im_self)
127                 return System.identityHashCode(im_self) <
128                        System.identityHashCode(mother.im_self) ? -1 : 1;
129             if (im_func != mother.im_func)
130                 return System.identityHashCode(im_func) <
131                        System.identityHashCode(mother.im_func) ? -1 : 1;
132             return 0;
133         }
134         return -2;
135     }
136
137     public String JavaDoc safeRepr() throws PyIgnoreMethodTag {
138         return "'method' object";
139     }
140     
141     private String JavaDoc class_name(PyObject cls) {
142         if (cls instanceof PyClass)
143            return ((PyClass)cls).__name__;
144         if (cls instanceof PyType)
145             return ((PyType)cls).fastGetName();
146         return "?";
147     }
148
149     public String JavaDoc toString() {
150         String JavaDoc classname = "?";
151         if (im_class != null)
152             classname = class_name(im_class);
153         if (im_self == null)
154             // this is an unbound method
155 return "<unbound method " + classname + "." + __name__ + ">";
156         else
157             return "<method " + classname + "." +
158                 __name__ + " of " + class_name(im_self.fastGetClass()) +
159                 " instance " + Py.idstr(im_self) + ">";
160     }
161 }
162
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