Package gnu.mapping

Class Symbol

java.lang.Object
gnu.mapping.Symbol
All Implemented Interfaces:
EnvironmentKey, Externalizable, Serializable, Comparable
Direct Known Subclasses:
Keyword, SimpleSymbol, XName
public class Symbol extends Object implements EnvironmentKey, Comparable, 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:

  • Field Details

    • name

      protected 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 Details

    • Symbol

      public Symbol()

    • Symbol

      protected Symbol(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 Details

    • getKeySymbol

      public final Symbol getKeySymbol()
      Specified by:
      getKeySymbol in interface EnvironmentKey

    • getKeyProperty

      public final 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, Object property)
      Specified by:
      matches in interface EnvironmentKey

    • getNamespaceURI

      public final String getNamespaceURI()

    • getLocalPart

      public final String getLocalPart()

    • getPrefix

      public final String getPrefix()

    • hasEmptyNamespace

      public final boolean hasEmptyNamespace()

    • hasUnknownNamespace

      public final boolean hasUnknownNamespace()

    • getLocalName

      public final 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 String getName()

    • make

      public static Symbol make(String uri, String name, 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(Object namespace, 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(String name)

    • valueOf

      public static Symbol valueOf(String name, Object spec)

    • valueOf

      public static Symbol valueOf(String name, String namespace, String prefix)

    • parse

      public static Symbol parse(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(String local, 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(String name)

    • makeUninterned

      public static Symbol makeUninterned(String name, Namespace namespace)

    • compareTo

      public int compareTo(Object o)
      Specified by:
      compareTo in interface Comparable

    • equals

      public static boolean equals(Symbol sym1, Symbol sym2)

    • equals

      public final boolean equals(Object o)
      Just tests for identity. Otherwise hashTables that have Symbols as keys will break.
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • getNamespace

      public final Namespace getNamespace()

    • setNamespace

      public final void setNamespace(Namespace ns)

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • toString

      public 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(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Throws:
      IOException

    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Throws:
      IOException
      ClassNotFoundException

    • readResolve

      public Object readResolve() throws ObjectStreamException
      Throws:
      ObjectStreamException