Introduce an example of a custom message handler (#569)

Author: alxbilger

examples/MessageHandler.py

@@ -0,0 +1,99 @@
+import Sofa
+import Sofa.Helper
+
+RED = "\033[31m"
+ORANGE = "\033[38;5;214m"
+GREEN = "\033[32m"
+RESET = "\033[0m"
+
+
+class ExempleMessageHandler(Sofa.Helper.MessageHandler):
+    """A custom message handler that prints messages in the console and counts the number of errors, warnings and infos."""
+
+    def __init__(self):
+        super().__init__()
+        self.num_errors = 0
+        self.num_warnings = 0
+        self.num_infos = 0
+
+    def process(self, msg):
+        """Prints the message in the console and count the number of errors, warnings and infos."""
+        if msg["type"] == "Error":
+            self.print_error(msg["sender"], msg["message"])
+            self.num_errors += 1
+        elif msg["type"] == "Warning":
+            self.print_warning(msg["sender"], msg["message"])
+            self.num_warnings += 1
+        elif msg["type"] == "Info":
+            self.print_info(msg["sender"], msg["message"])
+            self.num_infos += 1
+        else:
+            print(f"{msg["type"]} {msg['message']}")
+
+    @staticmethod
+    def print_error(sender, message):
+        """Prints a string with [ERROR] in red"""
+        print(f"🚨{RED}[ERROR]{RESET} [👤{sender}] 📨{message}")
+
+    @staticmethod
+    def print_warning(sender, message):
+        """Prints a string with [WARNING] in orange"""
+        print(f"⚠️{ORANGE}[WARNING]{RESET} [👤{sender}] 📨{message}")
+
+    @staticmethod
+    def print_info(sender, message):
+        """Prints a string with [INFO] in green"""
+        print(f"ℹ️{GREEN}[INFO]{RESET} [👤{sender}] 📨{message}")
+
+
+with ExempleMessageHandler() as msg_handler:
+    def createScene(root):
+
+        root.addObject("RequiredPlugin", pluginName=[
+            'Sofa.Component.Constraint.Projective',
+            'Sofa.Component.Engine.Select',
+            'Sofa.Component.LinearSolver.Direct',
+            'Sofa.Component.Mass',
+            'Sofa.Component.ODESolver.Backward',
+            'Sofa.Component.SolidMechanics.FEM.Elastic',
+            'Sofa.Component.StateContainer',
+            'Sofa.Component.Topology.Container.Grid',
+            'Sofa.Component.Visual'
+        ])
+
+        root.addObject('VisualStyle', displayFlags="showBehaviorModels showForceFields")
+
+        root.addObject('DefaultAnimationLoop')
+        root.addObject('DefaultVisualManagerLoop')
+
+        root.addObject('EulerImplicitSolver', rayleighStiffness=0.1, rayleighMass=0.1, printLog=False)
+        root.addObject('SparseLDLSolver', template="CompressedRowSparseMatrixd")
+
+        root.addObject('MechanicalObject', name="DoFs")
+        root.addObject('MeshMatrixMass', name="mass", totalMass=320)
+        root.addObject('RegularGridTopology', name="grid",
+                       nx=4, ny=4, nz=20, xmin=-9, xmax=-6, ymin=0, ymax=3, zmin=0, zmax=19)
+        root.addObject('BoxROI', name="box", box=[-10, -1, -0.0001, -5, 4, 0.0001])
+        root.addObject('FixedProjectiveConstraint', indices="@box.indices")
+        root.addObject('HexahedronFEMForceField', name="FEM", youngModulus=4000, poissonRatio=0.3, method="large")
+
+        return root
+
+
+    def main():
+        root = Sofa.Core.Node("root")
+        createScene(root)
+        Sofa.Simulation.initRoot(root)
+
+        for iteration in range(10):
+            Sofa.Simulation.animate(root, root.dt.value)
+
+        print("Simulation is done.")
+
+        print(f"Number of errors: {msg_handler.num_errors}")
+        print(f"Number of warnings: {msg_handler.num_warnings}")
+        print(f"Number of infos: {msg_handler.num_infos}")
+
+
+    if __name__ == '__main__':
+        main()