The Android Open Source Project | cf31fe9 | 2008-10-21 07:00:00 -0700 | [diff] [blame] | 1 | # Protocol Buffers - Google's data interchange format |
| 2 | # Copyright 2008 Google Inc. All rights reserved. |
| 3 | # http://code.google.com/p/protobuf/ |
| 4 | # |
| 5 | # Redistribution and use in source and binary forms, with or without |
| 6 | # modification, are permitted provided that the following conditions are |
| 7 | # met: |
| 8 | # |
| 9 | # * Redistributions of source code must retain the above copyright |
| 10 | # notice, this list of conditions and the following disclaimer. |
| 11 | # * Redistributions in binary form must reproduce the above |
| 12 | # copyright notice, this list of conditions and the following disclaimer |
| 13 | # in the documentation and/or other materials provided with the |
| 14 | # distribution. |
| 15 | # * Neither the name of Google Inc. nor the names of its |
| 16 | # contributors may be used to endorse or promote products derived from |
| 17 | # this software without specific prior written permission. |
| 18 | # |
| 19 | # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 20 | # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 21 | # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 22 | # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 23 | # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 24 | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 25 | # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 26 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 27 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 28 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 29 | # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 | |
| 31 | """Defines a listener interface for observing certain |
| 32 | state transitions on Message objects. |
| 33 | |
| 34 | Also defines a null implementation of this interface. |
| 35 | """ |
| 36 | |
| 37 | __author__ = 'robinson@google.com (Will Robinson)' |
| 38 | |
| 39 | |
| 40 | class MessageListener(object): |
| 41 | |
| 42 | """Listens for transitions to nonempty and for invalidations of cached |
| 43 | byte sizes. Meant to be registered via Message._SetListener(). |
| 44 | """ |
| 45 | |
| 46 | def TransitionToNonempty(self): |
| 47 | """Called the *first* time that this message becomes nonempty. |
| 48 | Implementations are free (but not required) to call this method multiple |
| 49 | times after the message has become nonempty. |
| 50 | """ |
| 51 | raise NotImplementedError |
| 52 | |
| 53 | def ByteSizeDirty(self): |
| 54 | """Called *every* time the cached byte size value |
| 55 | for this object is invalidated (transitions from being |
| 56 | "clean" to "dirty"). |
| 57 | """ |
| 58 | raise NotImplementedError |
| 59 | |
| 60 | |
| 61 | class NullMessageListener(object): |
| 62 | |
| 63 | """No-op MessageListener implementation.""" |
| 64 | |
| 65 | def TransitionToNonempty(self): |
| 66 | pass |
| 67 | |
| 68 | def ByteSizeDirty(self): |
| 69 | pass |