net.sf.saxon.om

Class NamePool

java.lang.Object

net.sf.saxon.om.NamePool

public final class NamePool
extends java.lang.Object

A NamePool holds a collection of expanded names, each containing a namespace URI, and a local name.

Each expanded name is allocated a unique 20-bit fingerprint. The fingerprint enables the URI and the local name to be determined. Some subsystems (notably the Tinytree) use the top 10 bits to represent the prefix, but the NamePool is no longer concerned with managing prefixes, and prefixes do not have global codes.

The NamePool has been redesigned in Saxon 9.7 to make use of two Java ConcurrentHashMaps, one from QNames to integers, one from integers to QNames. This gives better scaleability in terms of multithreaded concurrency and in terms of the capacity of the NamePool and retention of performance as the size of the vocabulary increases.

Fingerprints in the range 0 to 1023 are reserved for system use, and are allocated as constants mainly to names in the XSLT and XML Schema namespaces: constants representing these names are found in StandardNames.

The fingerprint -1 is reserved to mean "not known" or inapplicable.

Modified in 9.4 to remove namespace codes.

Modified in 9.7 to remove URI codes.

Modified in 9.8 to remove namecodes and all handling of prefixes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NamePool.NamePoolLimitException Unchecked Exception raised when some limit in the design of the name pool is exceeded

Field Summary

Fields

Modifier and Type	Field and Description
static int	FP_MASK FP_MASK is a mask used to obtain a fingerprint from a nameCode.
static int	USER_DEFINED_MASK

Constructor Summary

Constructors

Constructor and Description
NamePool() Create a NamePool

Method Summary

Modifier and Type	Method and Description
int	allocateClarkName(java.lang.String expandedName) Allocate a fingerprint given a Clark Name
int	allocateFingerprint(java.lang.String uri, java.lang.String local) Allocate a fingerprint from the pool, or a new Name if there is not a matching one there
java.lang.String	getClarkName(int nameCode) Get the Clark form of a name, given its name code or fingerprint
java.lang.String	getDisplayName(int nameCode) Get the display form of a name (the QName), given its name code or fingerprint
java.lang.String	getEQName(int nameCode) Get the EQName form of a name, given its name code or fingerprint
int	getFingerprint(java.lang.String uri, java.lang.String localName) Get a fingerprint for the name with a given uri and local name.
java.lang.String	getLocalName(int nameCode) Get the local part of a name, given its name code or fingerprint
StructuredQName	getStructuredQName(int fingerprint) Get a QName for a given fingerprint.
StructuredQName	getUnprefixedQName(int nameCode) Get a QName for a given namecode.
java.lang.String	getURI(int nameCode) Get the namespace-URI of a name, given its name code or fingerprint
static boolean	isPrefixed(int nameCode) Determine whether a given namecode has a non-empty prefix (and therefore, in the case of attributes, whether the name is in a non-null namespace
void	suggestPrefix(java.lang.String prefix, java.lang.String uri) Suggest a preferred prefix to be used with a given URI
java.lang.String	suggestPrefixForURI(java.lang.String uri) Suggest a prefix for a given URI.

Methods inherited from class java.lang.Object

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

Field Detail

FP_MASK

public static final int FP_MASK

FP_MASK is a mask used to obtain a fingerprint from a nameCode. Given a nameCode nc, the fingerprint is nc & NamePool.FP_MASK. (In practice, Saxon code often uses the literal constant 0xfffff, to extract the bottom 20 bits).

The difference between a fingerprint and a nameCode is that a nameCode contains information about the prefix of a name, the fingerprint depends only on the namespace URI and local name. Note that the "null" nameCode (-1) does not produce the "null" fingerprint (also -1) when this mask is applied.

See Also:

Constant Field Values

USER_DEFINED_MASK

public static final int USER_DEFINED_MASK

See Also:

Constant Field Values

Constructor Detail

NamePool

public NamePool()

Create a NamePool

Method Detail

suggestPrefix

public void suggestPrefix(java.lang.String prefix,
                          java.lang.String uri)

Suggest a preferred prefix to be used with a given URI

Parameters:

uri - the URI

prefix - the suggested prefix

getUnprefixedQName

public StructuredQName getUnprefixedQName(int nameCode)

Get a QName for a given namecode.

Parameters:

nameCode - a code identifying an expanded QName, e.g. of an element or attribute

Returns:

a qName containing the URI and local name corresponding to the supplied name code. The prefix will be set to an empty string.

getStructuredQName

public StructuredQName getStructuredQName(int fingerprint)

Get a QName for a given fingerprint.

Parameters:

fingerprint - a code identifying an expanded QName, e.g. of an element or attribute

Returns:

a qName containing the URI and local name corresponding to the supplied fingerprint. There will be no prefix

isPrefixed

public static boolean isPrefixed(int nameCode)

Determine whether a given namecode has a non-empty prefix (and therefore, in the case of attributes, whether the name is in a non-null namespace

Parameters:

nameCode - the name code to be tested

Returns:

true if the name has a non-empty prefix

suggestPrefixForURI

public java.lang.String suggestPrefixForURI(java.lang.String uri)

Suggest a prefix for a given URI. If there are several, it's undefined which one is returned. If there are no prefixes registered for this URI, return null.

Parameters:

uri - the namespace URI

Returns:

a prefix that has previously been associated with this URI, if available; otherwise null

allocateFingerprint

public int allocateFingerprint(java.lang.String uri,
                               java.lang.String local)

Allocate a fingerprint from the pool, or a new Name if there is not a matching one there

Parameters:

uri - the namespace URI. Use "" or null for the non-namespace.

local - the local part of the name

Returns:

an integer (the "fingerprint") identifying the name within the namepool. The fingerprint omits information about the prefix, and is the same as the nameCode for the same name with a prefix equal to "".

getURI

public java.lang.String getURI(int nameCode)

Get the namespace-URI of a name, given its name code or fingerprint

Parameters:

nameCode - the name code or fingerprint of a name

Returns:

the namespace URI corresponding to this name code. Returns "" for the no-namespace.

Throws:

java.lang.IllegalArgumentException - if the nameCode is not known to the NamePool.

getLocalName

public java.lang.String getLocalName(int nameCode)

Get the local part of a name, given its name code or fingerprint

Parameters:

nameCode - the integer name code or fingerprint of the name

Returns:

the local part of the name represented by this name code or fingerprint

getDisplayName

public java.lang.String getDisplayName(int nameCode)

Get the display form of a name (the QName), given its name code or fingerprint

Parameters:

nameCode - the integer name code or fingerprint of a name in the name pool

Returns:

the corresponding lexical QName (if a fingerprint was supplied, this will simply be the local name)

getClarkName

public java.lang.String getClarkName(int nameCode)

Get the Clark form of a name, given its name code or fingerprint

Parameters:

nameCode - the integer name code or fingerprint of a name in the name pool

Returns:

the local name if the name is in the null namespace, or "{uri}local" otherwise. The name is always interned.

getEQName

public java.lang.String getEQName(int nameCode)

Get the EQName form of a name, given its name code or fingerprint

Parameters:

nameCode - the integer name code or fingerprint of a name in the name pool

Returns:

the name in the form Q{}local for a name in no namespace, or Q{uri}local for a name in a namespace

allocateClarkName

public int allocateClarkName(java.lang.String expandedName)

Allocate a fingerprint given a Clark Name

Parameters:

expandedName - the name in Clark notation, that is "localname" or "{uri}localName"

Returns:

the fingerprint of the name, which need not previously exist in the name pool

getFingerprint

public int getFingerprint(java.lang.String uri,
                          java.lang.String localName)

Get a fingerprint for the name with a given uri and local name. These must be present in the NamePool. The fingerprint has the property that if two fingerprint are the same, the names are the same (ie. same local name and same URI).

Parameters:

uri - the namespace URI of the required QName

localName - the local part of the required QName

Returns:

the integer fingerprint, or -1 if this is not found in the name pool