1 files changed, 129 insertions, 0 deletions
diff --git a/Monitoring/MonitoringService/DataProcessing/Prefix.py b/Monitoring/MonitoringService/DataProcessing/Prefix.py
new file mode 100644
index 0000000..5e4e1d3
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+++ b/Monitoring/MonitoringService/DataProcessing/Prefix.py
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+'''
+Created on Feb 27, 2012
+
+@author: steger
+'''
+from DataProcessing.DataError import PrefixError
+
+class PrefixManager(object):
+    '''
+    @summary: acts a unit prefix container
+    @ivar prefixes: the container of the known prefixes
+    @type prefixes: dict(str: L{Prefix})
+    @ivar duplicatesymbols: the set of prefixes, which map to the same symbol
+    @type duplicatesymbols: set(str)
+    '''
+    class Prefix(object):
+        '''
+        @summary: represents a unit prefix and the scaling information
+        @ivar reference: a uniq prefix identifier
+        @ivar symbol: a short representation of the prefix
+        @type symbol: str
+        @ivar base: the base of the scaling factor
+        @type base: int
+        @ivar exponent: the exponent of the scaling factor
+        @type exponent: int
+        @ivar scale: the scaling factor, which is base ** exponent
+        @type scale: float
+        '''
+        def __init__(self, reference, symbol, base, exponent):
+            '''
+            @summary: constructor
+            @param reference: the reference to the unit prefix
+            @type reference: str
+            @param symbol: a short form of the unit prefix
+            @type symbol: str
+            @param base: the base of the unit prefix, typically 2 or 10
+            @type base: int
+            @param exponent: the exponent of the unit prefix
+            @type exponent: int
+            '''
+            scale = base ** exponent
+            self._data = (reference, symbol, base, exponent, scale)
+        def __str__(self):
+            return self.symbol
+        @property
+        def reference(self):
+            return self._data[0]
+        @property
+        def symbol(self):
+            return self._data[1]
+        @property
+        def base(self):
+            return self._data[2]
+        @property
+        def exponent(self):
+            return self._data[3]
+        @property
+        def scale(self):
+            return self._data[4]
+
+    def __init__(self):
+        '''
+        @summary: constructor
+        '''
+        self.prefixes = {}
+        self.duplicatesymbols = set()
+
+    def __contains__(self, item):
+        '''
+        @summary: check the existence of a unit prefix
+        @param item: a prefix or a prefix symbol
+        @type item: L{Prefix} or str
+        @return: True if the prefix is known by the L{PrefixManager}
+        @rtype: bool
+        @raise L{PrefixError}: Wrong item type
+        '''
+        if isinstance(item, self.Prefix):
+            return item in self.prefixes.values()
+        elif isinstance(item, str):
+            for prefix in self.prefixes.values():
+                if prefix.symbol == item:
+                    return True
+            return False
+        else:
+            raise PrefixError("Wrong item type %s" % item)
+    
+    def __len__(self):
+        '''
+        @summary: the number of prefixes known by the L{PrefixManager}
+        @return: the number of prefixes known by the L{PrefixManager}
+        @rtype: int
+        '''
+        return len(self.prefixes)
+    
+    def newPrefix(self, reference, symbol, base, exponent):
+        '''
+        @summary: generate a new unit prefix
+        @param reference: the reference to the unit prefix
+        @type reference: str
+        @param symbol: a short form of the unit prefix
+        @type symbol: str
+        @param base: the base of the unit prefix, typically 2 or 10
+        @type base: int
+        @param exponent: the exponent of the unit prefix
+        @type exponent: int
+        @return: the new unit prefix
+        @rtype: L{Prefix}
+        @raise L{PrefixError}: Prefix with reference exists
+        '''
+        if self.prefixes.has_key(reference): 
+            raise PrefixError("Prefix with reference %s already exists" % reference)
+        if PrefixManager.__contains__(self, symbol):
+            self.duplicatesymbols.add(symbol)
+        prefix = self.Prefix(reference, symbol, base, exponent)
+        self.prefixes[reference] = prefix
+        return prefix
+
+    def __getitem__(self, reference):
+        '''
+        @summary: look up the prefix in the L{PrefixManager} based on its reference
+        @param reference: the reference to the unit prefix
+        @type reference: str
+        @return: the unit prefix found
+        @rtype: L{Prefix}
+        @raise L{PrefixError}: Prefix with reference not found
+        '''
+        if self.prefixes.has_key(reference):
+            return self.prefixes[reference]
+        raise PrefixError("Prefix with reference %s not found" % reference)