[nit.git] / src / metrics / mendel_metrics.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2014 Alexandre Terrasa <alexandre@moz-code.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# The mndel model helps to understand class hierarchies
#
# It provides metrics to extract interesting classes:
#
# * Large classes that have a lot of local mproperties
# * Budding classes that provide more mproperties than their superclasses
# * Blooming classes that are both large and budding
#
# Also, this model helps to understand inheritance behviours between classes.
# It provide metrics to categorize classes as:
#
# * pure overriders that contain only redefinitions
# * overriders that contain more definitions than introductions
# * pure extenders that contain only introductions
# * extenders that contain more introduction than redefinitions
#
# Finally, this model can characterize overriding behaviors
#
# * pure specializers that always call to super in its redefinitions
# * specializers that have more redefinitions that call super than not calling it
# * pure replacers that never call to super in its redefinitions
# * replacers that have less redefinitions that call super than not calling it
#
# For more details see
#  Mendel: A Model, Metrics and Rules to Understan Class Hierarchies
#  S. Denier and Y. Gueheneuc
#  in Proceedings of the 16th IEEE International Conference on Program Comprehension (OCPC'08)
module mendel_metrics

import metrics_base
import mclasses_metrics
import modelize

redef class ToolContext
        # Compute MENDEL metrics.
        #
        # See `mendel_metrics` module documentation.
        var mendel_metrics_phase: Phase = new MendelMetricsPhase(self, null)
end

private class MendelMetricsPhase
        super Phase
        redef fun process_mainmodule(mainmodule, given_mmodules)
        do
                if not toolcontext.opt_mendel.value and not toolcontext.opt_all.value then return
                var csv = toolcontext.opt_csv.value
                var out = "{toolcontext.opt_dir.value or else "metrics"}/mendel"
                out.mkdir

                print toolcontext.format_h1("\n# Mendel metrics")

                var vis = protected_visibility
                var model = toolcontext.modelbuilder.model

                var mclasses = new HashSet[MClass]
                for mclass in model.mclasses do
                        if mclass.visibility < vis then continue
                        if mclass.is_interface then continue
                        mclasses.add(mclass)
                end

                var cnblp = new CNBLP(mainmodule, vis)
                var cnvi = new CNVI(mainmodule)
                var cnvs = new CNVS(mainmodule)

                var metrics = new MetricSet
                metrics.register(cnblp, cnvi, cnvs)
                metrics.collect(mclasses)
                if csv then metrics.to_csv.save("{out}/mendel.csv")

                var threshold = cnblp.threshold
                print toolcontext.format_h4("\tlarge mclasses (threshold: {threshold})")
                for mclass in cnblp.sort do
                        var val = cnblp.values[mclass]
                        if val.to_f < threshold then break
                        print toolcontext.format_p("\t   {mclass.name}: {val}")
                end

                threshold = cnvi.threshold
                print toolcontext.format_h4("\tbudding mclasses (threshold: {threshold})")
                for mclass in cnvi.sort do
                        var val = cnvi.values[mclass]
                        if val.to_f < threshold then break
                        print toolcontext.format_p("\t   {mclass.name}: {val}")
                end

                threshold = cnvs.threshold
                print toolcontext.format_h4("\tblooming mclasses (threshold: {threshold})")
                for mclass in cnvs.sort do
                        var val = cnvs.values[mclass]
                        if val.to_f < threshold then break
                        print toolcontext.format_p("\t   {mclass.name}: {val}")
                end

                if csv then
                        var csvh = new CsvDocument
                        csvh.format = new CsvFormat('"', ';', "\n")
                        csvh.header = ["povr", "ovr", "pext", "ext", "pspe", "spe", "prep", "rep", "eq"]
                        for mclass in mclasses do
                                var povr = mclass.is_pure_overrider(vis).object_id
                                var ovr = mclass.is_overrider(vis).object_id
                                var pext = mclass.is_pure_extender(vis).object_id
                                var ext = mclass.is_extender(vis).object_id
                                var pspe = mclass.is_pure_specializer(vis).object_id
                                var spe = mclass.is_pure_specializer(vis).object_id
                                var prep = mclass.is_pure_replacer(vis).object_id
                                var rep = mclass.is_replacer(vis).object_id
                                var eq = mclass.is_equal(vis).object_id
                                csvh.add_record(povr, ovr, pext, ext, pspe, spe, prep, rep, eq)
                        end
                        csvh.save("{out}/inheritance_behaviour.csv")
                end
        end
end

# Class Branch Mean Size
# cbms(class) = |TotS(class)| / (DIT(class) + 1)
class CBMS
        super MClassMetric
        super FloatMetric
        redef fun name do return "cbms"
        redef fun desc do return "branch mean size, mean number of introduction available among ancestors"

        # Mainmodule used to compute class hierarchy.
        var mainmodule: MModule

        redef fun collect(mclasses) do
                for mclass in mclasses do
                        var totc = mclass.collect_accessible_mproperties(protected_visibility).length
                        var ditc = mclass.in_hierarchy(mainmodule).depth
                        values[mclass] = totc.to_f / (ditc + 1).to_f
                end
        end
end

# Class Novelty Index
# cnvi = |LocS(class)| / cbms(parents(class))
class CNVI
        super MClassMetric
        super FloatMetric
        redef fun name do return "cnvi"
        redef fun desc do return "class novelty index, contribution of the class to its branch in term of introductions"

        # Mainmodule used to compute class hierarchy.
        var mainmodule: MModule

        redef fun collect(mclasses) do
                var cbms = new CBMS(mainmodule)
                for mclass in mclasses do
                        # compute branch mean size
                        var parents = mclass.in_hierarchy(mainmodule).direct_greaters
                        if parents.length > 0 then
                                cbms.clear
                                cbms.collect(new HashSet[MClass].from(parents))
                                # compute class novelty index
                                var locc = mclass.collect_accessible_mproperties(protected_visibility).length
                                values[mclass] = locc.to_f / cbms.avg
                        else
                                values[mclass] = 0.0
                        end
                end
        end
end

# Class Novelty Score
# cnvs = |LocS(class)| x nvi
class CNVS
        super MClassMetric
        super FloatMetric
        redef fun name do return "cnvs"
        redef fun desc do return "class novelty score, importance of the contribution of the class to its branch"

        # Mainmodule used to compute class hierarchy.
        var mainmodule: MModule

        redef fun collect(mclasses) do
                var cnvi = new CNVI(mainmodule)
                cnvi.collect(mclasses)
                for mclass in mclasses do
                        var locc = mclass.collect_local_mproperties(protected_visibility).length
                        values[mclass] = cnvi.values[mclass] * locc.to_f
                end
        end
end

redef class MClass
        # the set of redefition that call to super
        fun extended_mproperties(min_visibility: MVisibility): Set[MProperty] do
                var set = new HashSet[MProperty]
                for mclassdef in mclassdefs do
                        for mpropdef in mclassdef.mpropdefs do
                                if mpropdef.mproperty.visibility < min_visibility then continue
                                if not mpropdef.has_supercall then continue
                                if mpropdef.mproperty.intro_mclassdef.mclass != self then set.add(mpropdef.mproperty)
                        end
                end
                return set
        end

        # the set of redefition that do not call to super
        fun overriden_mproperties(min_visibility: MVisibility): Set[MProperty] do
                var set = new HashSet[MProperty]
                for mclassdef in mclassdefs do
                        for mpropdef in mclassdef.mpropdefs do
                                if mpropdef.mproperty.visibility < min_visibility then continue
                                if mpropdef.has_supercall then continue
                                if mpropdef.mproperty.intro_mclassdef.mclass != self then set.add(mpropdef.mproperty)
                        end
                end
                return set
        end

        # pure overriders contain only redefinitions
        private fun is_pure_overrider(min_visibility: MVisibility): Bool do
                var news = collect_intro_mproperties(min_visibility).length
                var locs = collect_local_mproperties(min_visibility).length
                if news == 0 and locs > 0 then return true
                return false
        end

        # overriders contain more definitions than introductions
        private fun is_overrider(min_visibility: MVisibility): Bool do
                var rdfs = collect_redef_mproperties(min_visibility).length
                var news = collect_intro_mproperties(min_visibility).length
                var locs = collect_local_mproperties(min_visibility).length
                if rdfs >= news and locs > 0 then return true
                return false
        end

        # pure extenders contain only introductions
        private fun is_pure_extender(min_visibility: MVisibility): Bool do
                var rdfs = collect_redef_mproperties(min_visibility).length
                var locs = collect_local_mproperties(min_visibility).length
                if rdfs == 0 and locs > 0 then return true
                return false
        end

        # extenders contain more introduction than redefinitions
        private fun is_extender(min_visibility: MVisibility): Bool do
                var rdfs = collect_redef_mproperties(min_visibility).length
                var news = collect_intro_mproperties(min_visibility).length
                var locs = collect_local_mproperties(min_visibility).length
                if news > rdfs and locs > 0 then return true
                return false
        end

        # pure specializers always call to super in its redefinitions
        private fun is_pure_specializer(min_visibility: MVisibility): Bool do
                var ovrs = overriden_mproperties(min_visibility).length
                var rdfs = collect_redef_mproperties(min_visibility).length
                if ovrs == 0 and rdfs > 0 then return true
                return false
        end

        # specializers have more redefinitions that call super than not calling it
        private fun is_specializer(min_visibility: MVisibility): Bool do
                var spcs = extended_mproperties(min_visibility).length
                var ovrs = overriden_mproperties(min_visibility).length
                var rdfs = collect_redef_mproperties(min_visibility).length
                if spcs > ovrs and rdfs > 0 then return true
                return false
        end

        # pure replacers never call to super in its redefinitions
        private fun is_pure_replacer(min_visibility: MVisibility): Bool do
                var spcs = extended_mproperties(min_visibility).length
                var rdfs = collect_redef_mproperties(min_visibility).length
                if spcs == 0 and rdfs > 0 then return true
                return false
        end

        # replacers have less redefinitions that call super than not calling it
        private fun is_replacer(min_visibility: MVisibility): Bool do
                var spcs = extended_mproperties(min_visibility).length
                var ovrs = overriden_mproperties(min_visibility).length
                var rdfs = collect_redef_mproperties(min_visibility).length
                if ovrs > spcs and rdfs > 0 then return true
                return false
        end

        # equals contain as redifinition than introduction
        private fun is_equal(min_visibility: MVisibility): Bool do
                var spcs = extended_mproperties(min_visibility).length
                var ovrs = overriden_mproperties(min_visibility).length
                var rdfs = collect_redef_mproperties(min_visibility).length
                if spcs == ovrs and rdfs > 0 then return true
                return false
        end
end