Power Tip: Common Attribute Groups

The DDMS specification identifies several groups of attributes which always tend to be used together: ISM security attributes (such as classification), ISM notice attributes, XLink attributes, GML SRS attributes, and attributes used as part of the Extensible Layer.

ExtensibleAttributes are discussed in the Power Tip on The Extensible Layer.

ISM Security Attributes

ISM security attributes are defined in the Intelligence Community's "XML Data Encoding Specification for Information Security Marking Metadata" document (DES) and implemented in the SecurityAttributes class. This class encapsulates the ISM attributes which can decorate various DDMS components, such as ddms:resource or ddms:security. The constructor which builds the attributes from a XOM element will simply load these attributes from the element itself. The constructor which builds the attributes from raw data is defined as: 

public SecurityAttributes(String classification, List<String> ownerProducers, Map<String,String> otherAttributes)

Figure 1. SecurityAttributes constructor

Because the classification and ownerProducers are the most commonly referenced attributes, they are explicit parameters. Any other attribute can be added in the String-based map called otherAttributes. Here is an example which creates Confidential markings and puts them on a ddms:title element:

List<String> ownerProducers = Util.getXsListAsList("AUS USA");
Map<String, String> otherAttributes = new HashMap<String, String>();
otherAttributes.put("SCIcontrols", "SI");
otherAttributes.put("SARIdentifier", "SAR-USA");
SecurityAttributes security = new SecurityAttributes("C", ownerProducers, otherAttributes);
Title title = new Title("My Confidential Notes", security);
System.out.println(title.toXML());

Figure 2. Code to generate SecurityAttributes

Note: The actual values assigned to each attribute in Figure 2 are for example's sake only, and might be illogical in real-world metadata.

<ddms:title xmlns:ddms="http://metadata.dod.mil/mdr/ns/DDMS/3.0/" xmlns:ISM="urn:us:gov:ic:ism" 
   ISM:classification="C" ISM:ownerProducer="AUS USA" ISM:SCIcontrols="SI"
   ISM:SARIdentifier="SAR-USA">
   My Confidential Notes
</ddms:title>

Figure 3. The resultant XML element with security attributes

If an attribute in the otherAttributes map does not have one of the expected ISM attribute names, it is ignored. In addition, the parameter versions of classification and ownerProducer always take precedence if you try to override them with otherAttributes: 

List<String> ownerProducers = Util.getXsListAsList("AUS USA");
Map<String, String> otherAttributes = new HashMap<String, String>();
// The next line will be ignored, because there is no ISM attribute with this name.
otherAttributes.put("favoriteColor", "blue");
// The next line will be ignored, because the "classification" parameter takes precedence.
otherAttributes.put("classification", "U");
// The next line will be ignored, because the "ownerProducers" parameter takes precedence.
otherAttributes.put("ownerProducer", "FRA"); 
SecurityAttributes security = new SecurityAttributes("C", ownerProducers, otherAttributes);
Title title = new Title("My Confidential Notes", security);
System.out.println(title.toXML());

Figure 4. Code to generate SecurityAttributes

<ddms:title xmlns:ddms="http://metadata.dod.mil/mdr/ns/DDMS/3.0/" xmlns:ISM="urn:us:gov:ic:ism" 
   ISM:classification="C" ISM:ownerProducer="AUS USA">
   My Confidential Notes
</ddms:title>

Figure 5. The resultant XML element with security attributes

The DES also defines many logical constraints on these attributes, but DDMSence does not validate these rules today. A set of Schematron files is bundled with ISM.XML V5, and V9 (which are used by DDMS 3.1 and 4.1, respectively), and sample code for using DDMSence with these files can be found in the Schematron Validation Power Tip.

The values assigned to some attributes must come from the Controlled Vocabulary Enumerations (CVEs) defined by the Intelligence Community. The enumerations used by DDMSence are taken from Public Release versions of ISM.XML, so DDMSence will not be able to recognize enumeration values from higher classification levels. This restriction will be addressed in a future release.

ISM Notice Attributes

NoticeAttributes are only applicable in DDMS 4.0.1 and 4.1, and follow the same patterns used by the SecurityAttributes. The ISM:noticeType attribute is validated against a CVE when present.

// Assume that a list of noticeTexts, and the security attributes were previously created.
NoticeAttributes noticeAttributes = new NoticeAttributes("POC", "This is a reason.", "2011-09-15", null, Boolean.TRUE);
Notice notice = new Notice(noticeTexts, securityAttributes, noticeAttributes);
System.out.println(notice.toXML());

Figure 6. Code to generate NoticeAttributes

<ISM:Notice ISM:noticeType="POC" ISM:noticeReason="This is a reason." ISM:noticeDate="2011-09-15" ISM:externalNotice="true"
   ISM:classification="U" ISM:ownerProducer="USA">
   [...]
</ISM:Notice>

Figure 7. The resultant XML element with notice attributes

XLink Attributes

XLinkAttributes support the various components which provide external link attributes. An XLinkAttributes instance can function as 3 different types of XLink attribute groups: locator, simple, and resource, based on the value of the xlink:type attribute, or the constructor used to build the instance.

// Constructor for attributes with type="locator", used with ddms:link
public XLinkAttributes(String href, String role, String title, String label);

// Constructor for attributes with type="resource", used with ddms:revisionRecall
public XLinkAttributes(String role, String title, String label);

// Constructor for attributes with type="simple", used with ddms:taskID
public XLinkAttributes(String href, String role, String title, String arcrole, String show, String actuate);

Figure 8. Constructors to generate XLinkAttributes for various purposes

GML SRS Attributes

Spatial Reference System (SRS) attributes are defined in the GML specification and implemented as an SRSAttributes class. They can be applied to the various GML and TSPI shapes inside of a ddms:boundingGeometry element.

Here is an example which creates SRS attributes on a gml:pos element in DDMS 4.1:

List<String> axisLabels = Util.getXsListAsList("X Y");
List<String> uomLabels = Util.getXsListAsList("Meter Meter");
SRSAttributes srsAttributes = new SRSAttributes("http://metadata.dod.mil/mdr/ns/GSIP/crs/WGS84E_2D",
   new Integer(10), axisLabels, uomLabels);
List<Double> coordinates = new ArrayList<Double>();
coordinates.add(new Double(32.1));
coordinates.add(new Double(40.1));
Position position = new Position(coordinates, srsAttributes);
System.out.println(position.toXML());

Figure 9. Code to generate SRSAttributes in DDMS 4.1

<gml:pos srsName="http://metadata.dod.mil/mdr/ns/GSIP/crs/WGS84E_2D" srsDimension="10" 
   axisLabels="X Y" uomLabels="Meter Meter">32.1 40.1</gml:pos>

Figure 10. The resultant XML element with SRS attributes

Please note that the SRSAttributes do not belong in any XML namespace.

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