DM_attribute_handling.py

## @package python.demo.DM_attribute_handling
# 
#   managing attributes using addinfo layouts and views
#   (script works in python 2 and 3)
# 
from __future__ import print_function  # print function syntax as in python 3
import sys
 
from opals import pyDM  
 
typeNames = {
    pyDM.ColumnType.bool_: "bit(boolean)",
    pyDM.ColumnType.int8: "int8",
    pyDM.ColumnType.uint8: "uint8",
    pyDM.ColumnType.int16: "int16",
    pyDM.ColumnType.uint16: "uint16",
    pyDM.ColumnType.int32: "int32",
    pyDM.ColumnType.uint32: "uint32",
    pyDM.ColumnType.int64: "int64",
    pyDM.ColumnType.float_: "float",
    pyDM.ColumnType.double_: "double",
    pyDM.ColumnType.string: "string",
    pyDM.ColumnType.cstr: "cstr"
    }
 
 
def output_layout(layout):
    for i in range(layout.columns()):
        print("\t" + layout.name(i) + " (type = " + typeNames[layout.type(i)] + ")")
 
 
def DM_attribute_handling(filename):
    # create a point without attributes
    pt1 = pyDM.Point()
    assert pt1.hasInfo() == False  # point has no attributes (addinfo object)
 
    # =================================================================================================================
    # now create layouts for the addinfo object
    f = pyDM.AddInfoLayoutFactory()
    f.addColumn(pyDM.ColumnSemantic.Amplitude)  # pre-defined attribute "Amplitude"
    f.addColumn(pyDM.ColumnSemantic.EchoWidth)  # pre-defined attribute "EchoWidth"
    f.addColumn(pyDM.ColumnType.uint32, "_testAttr")  # user-defined attribute "_testAttr" (type unsigned int)
    layout1 = f.getLayout()
 
    f.addColumn(pyDM.ColumnType.uint32, "_testAttr")  # user-defined attribute "_testAttr" (type unsigned int)
    layout2 = f.getLayout()
 
    print("Layout 1:")
    output_layout(layout1)
 
    print("Layout 2:")
    output_layout(layout2)
 
    # create a point with 3 attribut columns
    pt2 = pyDM.Point(layout1)
    assert pt2.hasInfo() == True  # point has an attributes
    assert pt2.info().columns() == 3  # point has 3 attribute columns
 
    # cloning a point DOES NOT clone the attribute (AddInfo) object!
    pt3 = pt2.clone()
    assert pt2.info().isNull(0) == True and pt3.info().isNull(0) == True  # attribute 0 (Amplitude) is not set yet
    assert pt2.getAddInfo() == pt3.getAddInfo()  # attribute object is the same for pt2 and pt3
 
    pt2.info().set(0, 10.23)  # setting attribute value
    amp = pt3.info().get(0)
    assert pt2.info().get(0) == pt3.info().get(
        0)  # since both point use the same AddInfo object the attribute has to be same
 
    # to create a separate attribute object for each point, it is necessary clone it explicitly
    pt4 = pt2.clone()
    pt4.setAddInfo(pt2.info().clone())  # clone the attribute object
    assert pt2.getAddInfo() != pt4.getAddInfo()  # p2 and p4 have different attribute objects
 
    pt2.info().set(0, 5.92)  # change attribute 0 of p2
    assert abs(pt2.info().get(0) - 5.92) < 1e-5 and abs(pt4.info().get(0) - 10.23) < 1e-5
 
    # =================================================================================================================
    # using views only the attributes of interest are visible
    # since we want to access "_testAttr" only, we can apply a view (layout2)
    assert pt2.info().isView() == False
    pt2.setAddInfoView(layout2, True)
 
    assert pt2.info().isView() == True
    assert layout2.columns() == 1 and pt2.info().columns() == 1
 
    pt2.info().set(0, 15)  # set _testAttr to 15
 
    # since pt2 and pt3 point to the same attribute object the view is also applied to pt3
    assert pt3.info().columns() == 1 and pt3.info().get(0) == 15
 
    # the view can be removed as well
    pt2.restoreAddInfoFullLayout()
    assert pt2.info().isView() == False and pt2.info().columns() == 3
 
    value = pt3.info().get(2)  # in the real layout "_testAttr" is at index 2
    assert value == 15
 
    # it is also possible to create a cloned view object, which still points to the same data object, but a new
    # attribute object is created. this allows to create multiple views on the same attribute data object
    pt3.cloneAddInfoView(layout2, True)
 
    assert pt2.getAddInfo() != pt3.getAddInfo()
    pt3.info().set(0, 35)
    value = pt2.info().get(2)
    assert pt2.info().get(2) == 35 and pt3.info().get(0) == 35
 
    # =================================================================================================================
    # simplified way to access attributes within an ODM by
    # list of given attribute names
    attributs = ["Amplitude", "EchoWidth", "_testAttr"]
 
    # open the odm / pyDM.Datamanager.load parameters: filename(string), readOnly(bool) threadSafety(bool)
    dm = pyDM.Datamanager.load(filename, True, False)
 
    # if the dm wasn't opened successfully exit function
    if not dm:
        print("Unable to open ODM '" + filename + "'")
        return
 
    print("Create layout based on ODM '" + filename + "'")
    for attr in attributs:
        type, inDM = f.addColumn(dm, attr, True, pyDM.ColumnType.uint32)
        if inDM:
            print("\t" + attr + " exists in ODM (type = " + typeNames[type] + ")")
        else:
            print("\t" + attr + " does NOT exist in ODM (type = " + typeNames[type] + ")")
    layout3 = f.getLayout()
 
    print("layout3 :")
    output_layout(layout3)
 
 
if len(sys.argv) == 1:
    print("ODM parameter missing")
    sys.exit(-1)
 
DM_attribute_handling(sys.argv[1])