first version of nonStarvingEntry. Also one test and its dump

dream/simulation/JSONInputs/NonStarvingEntry.json

+{
+    "_class": "Dream.Simulation",
+    "edges": {
+        "0": [
+            "NS1",
+            "M1",
+            {}
+        ],
+        "1": [
+            "M1",
+            "E1",
+            {}
+        ]
+    },
+    "general": {
+        "_class": "Dream.Configuration",
+        "confidenceLevel": "0.95",
+        "maxSimTime": "10",
+        "numberOfReplications": "1",
+        "trace": "No"
+    },
+    "nodes": {
+        "E1": {
+            "_class": "Dream.Exit",
+            "left": 0.5,
+            "name": "Stock",
+            "top": 0.10215053763440862
+        },
+        "M1": {
+            "_class": "Dream.Machine",
+            "failures": {
+                "failureDistribution": "No"
+            },
+            "left": 0.5,
+            "name": "Moulding",
+            "processingTime": {
+                "distributionType": "Fixed",
+                "mean": 1
+            },
+            "top": 0.5
+        },
+        "NS1": {
+            "_class": "Dream.NonStarvingEntry",
+            "entityData": {
+                "_class": "Dream.Part"
+            },
+            "left": 0.5,
+            "name": "Raw Material",
+            "top": 0.8978494623655914
+        }
+    }
+}
\ No newline at end of file

dream/simulation/NonStarvingEntry.py

+# ===========================================================================
+# Copyright 2013 University of Limerick
+#
+# This file is part of DREAM.
+#
+# DREAM is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# DREAM is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with DREAM.  If not, see <http://www.gnu.org/licenses/>.
+# ===========================================================================
+'''
+Created on 8 Nov 2012
+
+@author: George
+'''
+'''
+Models an intro element that is never starved. 
+In removeEntity, each time it falls below a specific level it creates new Entities
+'''
+
+import simpy
+from Queue import Queue
+# ===========================================================================
+#                            the Queue object
+# ===========================================================================
+class NonStarvingEntry(Queue):
+    family='Entry'
+    def __init__(self, id, name, capacity=float('inf'), entityData={'_class':'Dream.Part'}, threshold=2, 
+                 initialWIPLevel=2,**kw):
+        Queue.__init__(self, id=id,name=name, capacity=capacity)
+        self.threshold=int(threshold)
+        self.initialWIPLevel=int(initialWIPLevel)
+        self.entityData=dict(entityData)
+
+    def initialize(self):
+        Queue.initialize(self)
+        from Globals import G
+        import Globals
+        for i in range(self.initialWIPLevel):
+            self.createEntity()
+
+    def removeEntity(self, entity=None):
+        activeEntity=Queue.removeEntity(self, entity)                  #run the default method
+        activeObjectQueue=self.getActiveObjectQueue()
+        entityType=self.entityData.get('_class', None)
+        if len(activeObjectQueue)<self.threshold:
+            self.createEntity()
+        return activeEntity
+    
+    def createEntity(self):
+        from Globals import G
+        import Globals
+        entityType=self.entityData.get('_class', None)
+        assert entityType, 'the entity type of the non starving buffer could not be identified'
+        entityType=Globals.getClassFromName(entityType)
+        Eargs={'id':G.numberOfEntities,
+               'name':str(entityType)+str(G.numberOfEntities),
+               'currentStation':self
+               }
+        E=entityType(**Eargs)
+        Globals.setWIP([E])
+        G.numberOfEntities+=1
+        if not self.canDispose.triggered:
+            self.canDispose.succeed(self.env.now)
+    
\ No newline at end of file

dream/tests/dump/NonStarvingEntry.json.result

+{
+ "_class": "Dream.Simulation", 
+ "elementList": [
+  {
+   "_class": "Dream.Exit", 
+   "family": "Exit", 
+   "id": "E1", 
+   "results": {
+    "lifespan": 5.0, 
+    "takt_time": 1.0, 
+    "throughput": 9
+   }
+  }, 
+  {
+   "_class": "Dream.Machine", 
+   "family": "Server", 
+   "id": "M1", 
+   "results": {
+    "blockage_ratio": 0.0, 
+    "failure_ratio": 0.0, 
+    "waiting_ratio": 0.0, 
+    "working_ratio": 100.0
+   }
+  }, 
+  {
+   "_class": "Dream.NonStarvingEntry", 
+   "family": "Entry", 
+   "id": "NS1", 
+   "results": {}
+  }
+ ], 
+ "general": {
+  "_class": "Dream.Configuration"
+ }
+}
\ No newline at end of file