gnu.mapping

Class Symbol

java.lang.Object

gnu.mapping.Symbol

All Implemented Interfaces:

EnvironmentKey, java.io.Externalizable, java.io.Serializable, java.lang.Comparable

Direct Known Subclasses:

Keyword, SimpleSymbol, XName

public class Symbol
extends java.lang.Object
implements EnvironmentKey, java.lang.Comparable, java.io.Externalizable

A Symbol is a name, usually in a specific Namespace. A Symbol is stateless: Common Lisp-style "value", "function" and "property list" bindings are not part of the Symbol itself, but looked up in the current Environment. A Symbol may be viewed as an EnvironmentKey with a null property component.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static Symbol	FUNCTION Conventional value used as a property key for function bindings.
protected java.lang.String	name
static Symbol	PLIST Conventional value used as a Symbol name to access an Object's property list.

Constructor Summary

Constructors

Modifier	Constructor and Description
	Symbol()
protected	Symbol(java.lang.String name, Namespace ns) Create new Symbol in a given namespace.

Method Summary

Modifier and Type	Method and Description
int	compareTo(java.lang.Object o)
boolean	equals(java.lang.Object o) Just tests for identity.
static boolean	equals(Symbol sym1, Symbol sym2)
java.lang.Object	getKeyProperty()
Symbol	getKeySymbol()
java.lang.String	getLocalName() Synonym for getName - the "print name" of the symbol without Namespace.
java.lang.String	getLocalPart()
java.lang.String	getName()
Namespace	getNamespace()
java.lang.String	getNamespaceURI()
java.lang.String	getPrefix()
boolean	hasEmptyNamespace()
int	hashCode()
boolean	hasUnknownNamespace()
static Symbol	make(java.lang.Object namespace, java.lang.String name) Find or create a symbol in a specificed namespace.
static Symbol	make(java.lang.String uri, java.lang.String name, java.lang.String prefix) Find or create a symbol in a specificed namespace.
static Symbol	makeUninterned(java.lang.String name)
static Symbol	makeUninterned(java.lang.String name, Namespace namespace)
static Symbol	makeWithUnknownNamespace(java.lang.String local, java.lang.String prefix) Make a placeholder symbol with a known prefix and unknown namespace-uri.
boolean	matches(EnvironmentKey key)
boolean	matches(Symbol symbol, java.lang.Object property)
static Symbol	parse(java.lang.String symbol) Parse a String as a Symbol.
void	readExternal(java.io.ObjectInput in)
java.lang.Object	readResolve()
void	setNamespace(Namespace ns)
java.lang.String	toString()
java.lang.String	toString(char style) Convert a Symbol to a printable String.
static SimpleSymbol	valueOf(java.lang.String name)
static Symbol	valueOf(java.lang.String name, java.lang.Object spec)
static Symbol	valueOf(java.lang.String name, java.lang.String namespace, java.lang.String prefix)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

name

protected java.lang.String name

FUNCTION

public static final Symbol FUNCTION

Conventional value used as a property key for function bindings.

PLIST

public static final Symbol PLIST

Conventional value used as a Symbol name to access an Object's property list. A property list is a list with a even number of Pairs, containing alternating keys and values. They are used in Common Lisp and Emacs Lisp. Kawa (following XEmacs) allows arbitrary objects to have property lists, thus the PLIST as used as the name and the object as the property. (In the future we'll do somethingg clever so that get(SYMBOL, KEY) as the same as getf(get(PLIST, SYMBOL), KEY) - but much faster.)

Constructor Detail

Symbol

public Symbol()

Symbol

protected Symbol(java.lang.String name,
                 Namespace ns)

Create new Symbol in a given namespace. Does not enter the result in the namespace's symbol table.

Parameters:

name - an interned String

Method Detail

getKeySymbol

public final Symbol getKeySymbol()

Specified by:

getKeySymbol in interface EnvironmentKey

getKeyProperty

public final java.lang.Object getKeyProperty()

Specified by:

getKeyProperty in interface EnvironmentKey

matches

public boolean matches(EnvironmentKey key)

Specified by:

matches in interface EnvironmentKey

matches

public boolean matches(Symbol symbol,
                       java.lang.Object property)

Specified by:

matches in interface EnvironmentKey

getNamespaceURI

public final java.lang.String getNamespaceURI()

getLocalPart

public final java.lang.String getLocalPart()

getPrefix

public final java.lang.String getPrefix()

hasEmptyNamespace

public final boolean hasEmptyNamespace()

hasUnknownNamespace

public final boolean hasUnknownNamespace()

getLocalName

public final java.lang.String getLocalName()

Synonym for getName - the "print name" of the symbol without Namespace. Useful when thinking of a Symbol as an XML QName.

getName

public final java.lang.String getName()

make

public static Symbol make(java.lang.String uri,
                          java.lang.String name,
                          java.lang.String prefix)

Find or create a symbol in a specificed namespace.

Parameters:

uri - a namespace uri.

name - The "local name" or "print name" of the desired symbol.

prefix - namespace prefix, or ""

make

public static Symbol make(java.lang.Object namespace,
                          java.lang.String name)

Find or create a symbol in a specificed namespace.

Parameters:

namespace - can be an Namespace, or a namespace/environment name (resolved using Namespace.getInstance), or null (in which case an uninterned symbol is created).

name - The "local name" or "print name" of the desired symbol.

valueOf

public static SimpleSymbol valueOf(java.lang.String name)

valueOf

public static Symbol valueOf(java.lang.String name,
                             java.lang.Object spec)

valueOf

public static Symbol valueOf(java.lang.String name,
                             java.lang.String namespace,
                             java.lang.String prefix)

parse

public static Symbol parse(java.lang.String symbol)

Parse a String as a Symbol. Recognizes:

• "{namespace-uri}:local-name" - which creates a symbol with that namespace-uri and an empty prefix;
• "{namespace-uri}local-name" - which is the same as above
• "prefix{namespace-uri}:local-name" - which creates a symbok with that prefix and namespace-uri
• "prefix:local-name"- which creates a symbol with that prefix and an "unknown" namespace-uri, using makeWithUnknownNamespace(java.lang.String, java.lang.String);
• and plain "local-name" - which creates a symbol in Namespace.EmptyNamespace.

makeWithUnknownNamespace

public static Symbol makeWithUnknownNamespace(java.lang.String local,
                                              java.lang.String prefix)

Make a placeholder symbol with a known prefix and unknown namespace-uri. This is convenient for processing definition commands like "prefix:name=value" - such as on the Kawa command-line - where we don't yet know the namespace-uri. Code that later looks for a value should look both under the true namespace-uri and the prefix combined with Namespace.makeUnknownNamespace(String).

makeUninterned

public static Symbol makeUninterned(java.lang.String name)

makeUninterned

public static Symbol makeUninterned(java.lang.String name,
                                    Namespace namespace)

compareTo

public int compareTo(java.lang.Object o)

Specified by:

compareTo in interface java.lang.Comparable

equals

public static boolean equals(Symbol sym1,
                             Symbol sym2)

equals

public final boolean equals(java.lang.Object o)

Just tests for identity. Otherwise hashTables that have Symbols as keys will break.

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

getNamespace

public final Namespace getNamespace()

setNamespace

public final void setNamespace(Namespace ns)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toString

public java.lang.String toString(char style)

Convert a Symbol to a printable String.

Parameters:

style - if 'P' then print prefix if available (otherwise Uri), if 'U' then print Uri if available (otherwise prefix), if '+' then print both if available.

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Specified by:

writeExternal in interface java.io.Externalizable

Throws:

java.io.IOException

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

Throws:

java.io.IOException

java.lang.ClassNotFoundException

readResolve

public java.lang.Object readResolve()
                             throws java.io.ObjectStreamException

Throws:

java.io.ObjectStreamException