1 # Copyright (c) 2004-2006 The Regents of The University of Michigan
4 # Redistribution and use in source and binary forms, with or without
5 # modification, are permitted provided that the following conditions are
6 # met: redistributions of source code must retain the above copyright
7 # notice, this list of conditions and the following disclaimer;
8 # redistributions in binary form must reproduce the above copyright
9 # notice, this list of conditions and the following disclaimer in the
10 # documentation and/or other materials provided with the distribution;
11 # neither the name of the copyright holders nor the names of its
12 # contributors may be used to endorse or promote products derived from
13 # this software without specific prior written permission.
15 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 # Authors: Steve Reinhardt
30 #############################
32 # Utility classes & methods
34 #############################
36 class Singleton(type):
37 def __call__(cls
, *args
, **kwargs
):
38 if hasattr(cls
, '_instance'):
41 cls
._instance
= super(Singleton
, cls
).__call
__(*args
, **kwargs
)
44 # Apply method to object.
45 # applyMethod(obj, 'meth', <args>) is equivalent to obj.meth(<args>)
46 def applyMethod(obj
, meth
, *args
, **kwargs
):
47 return getattr(obj
, meth
)(*args
, **kwargs
)
49 # If the first argument is an (non-sequence) object, apply the named
50 # method with the given arguments. If the first argument is a
51 # sequence, apply the method to each element of the sequence (a la
53 def applyOrMap(objOrSeq
, meth
, *args
, **kwargs
):
54 if not isinstance(objOrSeq
, (list, tuple)):
55 return applyMethod(objOrSeq
, meth
, *args
, **kwargs
)
57 return [applyMethod(o
, meth
, *args
, **kwargs
) for o
in objOrSeq
]