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ImageAttrHandler.h
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1//# ImageAttrHandler.h: Abstract base class for an image attributes handler
2//# Copyright (C) 2012
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have received a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//# $Id$
27
28#ifndef IMAGES_IMAGEATTRHANDLER_H
29#define IMAGES_IMAGEATTRHANDLER_H
30
31
32//# Includes
33#include <casacore/casa/aips.h>
34#include <casacore/images/Images/ImageAttrGroup.h>
35#include <casacore/casa/Containers/ValueHolder.h>
36#include <casacore/casa/Arrays/Vector.h>
37
38namespace casacore {
39
40// <summary>
41// Abstract base class for an image attributes handler.
42// </summary>
43
44// <use visibility=export>
45
46// <reviewed reviewer="" date="" tests="tPagedmage.cc" demos="dPagedImage.cc">
47// </reviewed>
48
49// <prerequisite>
50// <li> <linkto class=ImageInterface>ImageInterface</linkto>
51// </prerequisite>
52
53// <etymology>
54// This class makes it possible to store extra attributes with an image to
55// describe atrbitrary meta information.
56// </etymology>
57
58// <synopsis>
59// For LOFAR it was needed to store extra meta information and to be able to
60// convert it from casacore table format to HDF5 format and vice-versa.
61// Furthermore, it must be possible to access the information in a way that
62// arbitrary info can be stored and retrieved.
63//
64// An ImageAttrHandler object handles those attributes in an image. Specific
65// handler classes exist for images stored in casacore and in HDF5 format.
66// The attributes are divided into group which are handled by ImageAttrGroup.
67// A group (e.g. LOFAR_SOURCES) maps to a subtable in casacore format and a
68// group in HDF5 format.
69// </synopsis>
70
71// <example>
72// This example shows how to get attributes from an image.
73// <srcblock>
74// // Open the image (done as read/write when having write access).
75// PagedImage<Float> myimage ("image.name");
76// // Get access to the attibute handler.
77// ImageAttrHandler& attrHandler = myimage.attrHandler();
78// // Get the names of all attribute groups.
79// Vector<String> groupNames = attrHandler.groupNames();
80// // Create a new group and define an attribute defining Freq in Hz.
81// ImageAttrGroup& newGroup = attrHandler.createGroup ("NEW_GROUP");
82// newGroup.putAttr ("Freq", ValueHolder(Vector<Double>(1, 1e7)),
83// Vector<String>(1,"Hz"));
84// </srcblock>
85// </example>
86//
87// <motivation>
88// LOFAR needed functionality to store arbitrary attributes.
89// </motivation>
90
92{
93public:
94 // Default constructor.
97
99
100 // Flush the attibrutes if needed.
101 // The default implementation does nothing.
102 virtual void flush();
103
104 // Test if the given attribute group is present.
105 // The default implementation returns False.
106 virtual Bool hasGroup (const String& name);
107
108 // Get all attribute group names.
109 // The default implementation returns an empty vector.
110 virtual Vector<String> groupNames() const;
111
112 // Get access to a group.
113 // The default implementation throws an exception.
114 virtual ImageAttrGroup& openGroup (const String& groupName);
115
116 // Create an attribute group with the given name.
117 // The default implementation throws an exception.
118 virtual ImageAttrGroup& createGroup (const String& groupName);
119
120 // Close the group with the given name.
121 // The default implementation does nothing.
122 virtual void closeGroup (const String& groupName);
123};
124
125} //# NAMESPACE CASACORE - END
126
127#endif
virtual ImageAttrGroup & createGroup(const String &groupName)
Create an attribute group with the given name.
virtual Vector< String > groupNames() const
Get all attribute group names.
virtual ImageAttrGroup & openGroup(const String &groupName)
Get access to a group.
ImageAttrHandler()
Default constructor.
virtual void closeGroup(const String &groupName)
Close the group with the given name.
virtual Bool hasGroup(const String &name)
Test if the given attribute group is present.
virtual void flush()
Flush the attibrutes if needed.
String: the storage and methods of handling collections of characters.
Definition String.h:225
this file contains all the compiler specific defines
Definition mainpage.dox:28
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:42