AToMPM/mt/ptcal/pytcore/rules/ndarule.py

'''This file is part of AToMPM - A Tool for Multi-Paradigm Modelling
Copyright 2011 by the AToMPM team and licensed under the LGPL
See COPYING.lesser and README.md in the root of this project for full details'''

from ..tcore.composer import Composer
from ..tcore.matcher import Matcher
from ..tcore.iterator import Iterator
from ..tcore.rewriter import Rewriter
from ..tcore.resolver import Resolver


class NDARule(Composer):
    '''
        Applies the transformation on one match.
    '''
    def __init__(self, LHS, RHS, rng, sendAndApplyDeltaFunc,ignore_resolver=False, external_matches_only=False,
                 custom_resolution=lambda packet: False):
        '''
            Applies the transformation on one match.
            @param LHS: The pre-condition pattern (LHS + NACs).
            @param RHS: The post-condition pattern (RHS).
            @param ignore_resolver: Specifies whether or not a resolver is needed.
            @param external_matches_only: Resolve conflicts ignoring the matches found in this ARule.
            @param custom_resolution: Override the default resolution function.
        '''
        super(NDARule, self).__init__()
        self.ignore_resolver = ignore_resolver
        self.M = Matcher(condition=LHS)
        self.I = Iterator(max_iterations=1, rng=rng)
        self.W = Rewriter(condition=RHS,sendAndApplyDeltaFunc=sendAndApplyDeltaFunc)
        self.R = Resolver(external_matches_only=external_matches_only,
                          custom_resolution=custom_resolution)
    
    def packet_in(self, packet):
        self.exception = None
        self.is_success = False
        # Match
        packet = self.M.packet_in(packet)
        if not self.M.is_success:
            self.exception = self.M.exception
            return packet
        # Choose the only match
        packet = self.I.packet_in(packet)
        if not self.I.is_success:
            self.exception = self.I.exception
            return packet
        # Rewrite
        packet = self.W.packet_in(packet)
        if not self.W.is_success:
            self.exception = self.W.exception
            return packet
        # Output success packet
        self.is_success = True
        return packet