func NewTopology(id string, confFile string, seq sequence.Sequencer, volumeSizeLimit uint64, pulse int) (*Topology, error) {
t := &Topology{}
t.id = NodeId(id)
t.nodeType = "Topology"
t.NodeImpl.value = t
t.children = make(map[NodeId]Node)
t.collectionMap = util.NewConcurrentReadMap()
t.pulse = int64(pulse)
t.volumeSizeLimit = volumeSizeLimit
t.Sequence = seq
t.chanDeadDataNodes = make(chan *DataNode)
t.chanRecoveredDataNodes = make(chan *DataNode)
t.chanFullVolumes = make(chan storage.VolumeInfo)
err := t.loadConfiguration(confFile)
return t, err
}
func NewCollection(name string, volumeSizeLimit uint64) *Collection {
c := &Collection{Name: name, volumeSizeLimit: volumeSizeLimit}
c.storageType2VolumeLayout = util.NewConcurrentReadMap()
return c
}