Package org.apache.sis.internal.util

Class DefinitionURI

java.lang.Object

org.apache.sis.internal.util.DefinitionURI

public final class DefinitionURI
extends Object

Utility methods for parsing OGC's URI (URN or URL) in the "urn:ogc:def" namespace.

For example, all the following URIs are for the same object:

• "EPSG:4326" (older format)
• "EPSG::4326" (often seen for similarity with URN below)
• "urn:ogc:def:crs:EPSG::4326" (version number is omitted)
• "urn:ogc:def:crs:EPSG:8.2:4326" (explicit version number, here 8.2)
• "urn:x-ogc:def:crs:EPSG::4326" (prior registration of "ogc" to IANA)
• "http://www.opengis.net/def/crs/EPSG/0/4326"
• "http://www.opengis.net/gml/srs/epsg.xml#4326"

This class does not attempt to decode URL characters. For example, a URL for "m/s" may be encoded as below, in which case the value in the code field will be "m%2Fs" instead of "m/s".

• http://www.opengis.net/def/uom/SI/0/m%2Fs

Parts of URN

URN begins with "urn:ogc:def:" (formerly "urn:x-ogc:def:") followed by:

• an object type
• an authority
• an optional version number (often omitted)
• the code
• an arbitrary number of parameters

The object type can be one of the following name. Mapping between those names and GeoAPI interfaces is provided by the NameMeaning class.

Recognized object types in URN

Object type	Meaning
axis	Coordinate system axe definition
axisDirection	Axis direction code definition
coordinateOperation	Coordinate operation definition
crs	Coordinate reference system definition
cs	Coordinate system definition
datum	Datum definition
dataType	Data type definition
derivedCRSType	Derived CRS type code definition
documentType	Document type definition
ellipsoid	Ellipsoid definition
featureType	Feature type definition
group	Operation parameter group definition
meaning	Parameter meaning definition
meridian	Prime meridian definition
method	Operation method definition
nil	Explanations for missing information
parameter	Operation parameter definition
phenomenon	Observable property definition
pixelInCell	Pixel in cell code definition
rangeMeaning	Range meaning code definition
referenceSystem	Value reference system definition
uom	Unit of measure definition
verticalDatumType	Vertical datum type code definition

Some example of authorities are:

Authority examples

Authority	Purpose
"OGC"	Objects defined by the Open Geospatial Consortium.
"EPSG"	Referencing objects defined in the EPSG database.
"EDCS"	Environmental Data Coding Specification.
"SI"	International System of Units.
"UCUM"	Unified Code for Units of Measure.

Combined URNs

This implementation does not handle combined URNs. An example of combined URN would be "urn:ogc:def:crs,crs:EPSG:6.3:27700,crs:EPSG:6.3:5701".

Since:

0.4

Version:

1.3

Author:

Martin Desruisseaux (Geomatys)

See Also:

• NameMeaning
• Definition identifier URNs in OGC namespace
• OGC Naming Authority

Field Summary

Fields

Modifier and Type	Field	Description
String	authority	The authority part of a URI, or null if none (empty).
String	code	The code part of a URI, or null if none (empty).
static final char	COMPONENT_SEPARATOR	The separator between components in a URN.
DefinitionURI[]	components	If the URI contains sub-components, those sub-components.
static final String	DOMAIN	The domain of URLs in the OGC namespace.
boolean	isGML	true if the URI is a "http://www.opengis.net/gml/…" URL.
boolean	isHTTP	true if the URI is a "http://www.opengis.net/…" URL, or false if the URI is a "urn:ogc:def:…" URN.
static final String	NO_VERSION	A version number to be considered as if no version were provided.
String[]	parameters	The parameters, or null if none.
static final String	PREFIX	The "urn:ogc:def" prefix used in all URN supported by this class.
static final char	SEPARATOR	The path separator in URN.
String	type	The type part of a URI, or null if none (empty).
String	version	The version part of a URI, or null if none (empty).

Method Summary

Modifier and Type	Method	Description
static String	codeOf(String type, String authority, CharSequence uri)	Returns the code part of the given URI, provided that it matches the given object type and authority.
static DefinitionURI	parse(String uri)	Attempts to parse the given URI, which may either a URN or URL.
static boolean	regionMatches(String part, String urn, int lower, int upper)	Returns true if a sub-region of urn matches the given part, ignoring case, leading and trailing whitespaces.
String	toString()	Returns a string representation of this URI.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

PREFIX

public static final String PREFIX

The "urn:ogc:def" prefix used in all URN supported by this class.

See Also:

• Constant Field Values

SEPARATOR

public static final char SEPARATOR

The path separator in URN.

See Also:

• Constant Field Values

COMPONENT_SEPARATOR

public static final char COMPONENT_SEPARATOR

The separator between components in a URN.

Example: in "urn:ogc:def:crs,crs:EPSG:9.1:27700,crs:EPSG:9.1:5701", the components are "crs:EPSG:9.1:27700" and "crs:EPSG:9.1:5701".

See Also:

• Constant Field Values

DOMAIN

public static final String DOMAIN

The domain of URLs in the OGC namespace.

See Also:

• Constant Field Values

NO_VERSION

public static final String NO_VERSION

A version number to be considered as if no version were provided. This value is part of OGC specification (not a SIS-specific hack).

See Also:

• Constant Field Values

isHTTP

public boolean isHTTP

true if the URI is a "http://www.opengis.net/…" URL, or false if the URI is a "urn:ogc:def:…" URN.

isGML

public boolean isGML

true if the URI is a "http://www.opengis.net/gml/…" URL. A value of true should imply that isHTTP is also true.

type

public String type

The type part of a URI, or null if none (empty). Note that the set of valid types in OGC namespace is restricted. See class javadoc for more information.

Example: In the "urn:ogc:def:crs:EPSG:8.2:4326" URN, this is "crs".

See Also:

• NameMeaning.toObjectType(Class)

authority

public String authority

The authority part of a URI, or null if none (empty). Note that the set of valid authorities in OGC namespace is restricted. See class javadoc for more information.

Example: In the "urn:ogc:def:crs:EPSG:8.2:4326" URN, this is "EPSG".

version

public String version

The version part of a URI, or null if none (empty). This field is null if the version in the parsed string was "0".

Example: In the "urn:ogc:def:crs:EPSG:8.2:4326" URN, this is "8.2".

code

public String code

The code part of a URI, or null if none (empty).

Example: In the "urn:ogc:def:crs:EPSG:8.2:4326" URN, this is "4326".

parameters

public String[] parameters

The parameters, or null if none.

Example: In the "urn:ogc:def:crs:OGC:1.3:AUTO42003:1:-100:45" URN, this is {"1", "-100", "45"}}.

components

public DefinitionURI[] components

If the URI contains sub-components, those sub-components. Otherwise null.

URN example: if the URI is "urn:ogc:def:crs,crs:EPSG:9.1:27700,crs:EPSG:9.1:5701", then this DefinitionURI will contain the "urn:ogc:def:crs" header with two components:

1. "urn:ogc:def:crs:EPSG:9.1:27700"
2. "urn:ogc:def:crs:EPSG:9.1:5701"

HTTP example: if the URI is "http://www.opengis.net/def/crs-compound?1=(…)/crs/EPSG/9.1/27700&2=(…)/crs/EPSG/9.1/5701", then this DefinitionURI will contain the "http://www.opengis.net/def/crs-compound" header with two components:

1. "http://http://www.opengis.net/def/crs/EPSG/9.1/27700"
2. "http://http://www.opengis.net/def/crs/EPSG/9.1/5701"

Note that this array may contain null elements if we failed to parse the corresponding component.

Method Details

parse

public static DefinitionURI parse(String uri)

Attempts to parse the given URI, which may either a URN or URL. If this method does not recognize the given URI, then it returns null. If the given URI is incomplete, then the code value will be null.

Parameters:

uri - the URI to parse.

Returns:

the parse result, or null if the given URI is not recognized.

regionMatches

public static boolean regionMatches(String part,
 String urn,
 int lower,
 int upper)

Returns true if a sub-region of urn matches the given part, ignoring case, leading and trailing whitespaces.

Parameters:

part - the expected part ("urn", "ogc", "def", etc.)

urn - the URN for which to test a subregion.

lower - index of the first character in urn to compare, after skipping whitespaces.

upper - index after the last character in urn to compare, ignoring whitespaces.

Returns:

true if the given sub-region of urn match the given part.

codeOf

public static String codeOf(String type,
 String authority,
 CharSequence uri)

Returns the code part of the given URI, provided that it matches the given object type and authority. This method is useful when:

• the URI is expected to have a specific object type and authority;
• the version number is considered irrelevant;
• the code is expected to have no parameters.

This method accepts the following URI representations:

• The given authority followed by the code (e.g. "EPSG:4326").
• The URN form (e.g. "urn:ogc:def:crs:EPSG::4326"), ignoring version number. This method accepts also the former "x-ogc" in place of "ogc".
• The HTTP form (e.g. "http://www.opengis.net/def/crs/EPSG/0/4326").
• The GML form (e.g. "http://www.opengis.net/gml/srs/epsg.xml#4326").

Parameters:

type - the expected object type (e.g. "crs") in lower cases. See class javadoc for a list of types.

authority - the expected authority, typically "EPSG". See class javadoc for a list of authorities.

uri - the URI to parse.

Returns:

the code part of the given URI, or null if the codespace does not match the given type and authority, the code is empty, or the code is followed by parameters.

toString

public String toString()

Returns a string representation of this URI. If the URI were originally a GML's URL, then this method formats the URI in the "http://www.opengis.net/gml/srs/" namespace. Otherwise the URI were originally a URL, then this method formats the URI in the "http://www.opengis.net/" namespace. Otherwise this method formats the URI as a URN.

Overrides:

toString in class Object

Returns:

the string representation of this URI.