clojure/src/jvm/clojure/lang/Keyword.java at master · clojure/clojure · GitHub

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/**

* The use and distribution terms for this software are covered by the

* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

* which can be found in the file epl-v10.html at the root of this distribution.

* By using this software in any fashion, you are agreeing to be bound by

* the terms of this license.

* You must not remove this notice, or any other, from this software.

**/

/* rich Mar 29, 2006 10:39:05 AM */

package clojure.lang;

import java.io.ObjectStreamException;

import java.io.Serializable;

import java.lang.ref.Reference;

import java.lang.ref.WeakReference;

import java.util.concurrent.ConcurrentHashMap;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.SoftReference;

public class Keyword implements IFn, Comparable, Named, Serializable, IHashEq {

private static final long serialVersionUID = -2105088845257724163L;

private static ConcurrentHashMap<Symbol, Reference<Keyword>> table = new ConcurrentHashMap();

static final ReferenceQueue rq = new ReferenceQueue();

public final Symbol sym;

final int hasheq;

transient String _str;

public static Keyword intern(Symbol sym){

Keyword k = null;

Reference<Keyword> existingRef = table.get(sym);

if(existingRef == null)

{

Util.clearCache(rq, table);

if(sym.meta() != null)

sym = (Symbol) sym.withMeta(null);

k = new Keyword(sym);

existingRef = table.putIfAbsent(sym, new WeakReference<Keyword>(k, rq));

}

if(existingRef == null)

return k;

Keyword existingk = existingRef.get();

if(existingk != null)

return existingk;

//entry died in the interim, do over

table.remove(sym, existingRef);

return intern(sym);

}

public static Keyword intern(String ns, String name){

return intern(Symbol.intern(ns, name));

}

public static Keyword intern(String nsname){

return intern(Symbol.intern(nsname));

}

private Keyword(Symbol sym){

this.sym = sym;

hasheq = sym.hasheq() + 0x9e3779b9;

}

public static Keyword find(Symbol sym){

Reference<Keyword> ref = table.get(sym);

if (ref != null)

return ref.get();

else

return null;

}

public static Keyword find(String ns, String name){

return find(Symbol.intern(ns, name));

}

public static Keyword find(String nsname){

return find(Symbol.intern(nsname));

}

public final int hashCode(){

return sym.hashCode() + 0x9e3779b9;

}

public int hasheq() {

return hasheq;

}

public String toString(){

if(_str == null)

_str = (":" + sym);

return _str;

}

/**

* @deprecated CLJ-2350: This function is no longer called, but has not been

* removed to maintain the public interface.

public Object throwArity(){

throw new IllegalArgumentException("Wrong number of args passed to keyword: "

+ toString());

}

Object throwArity(int n) {

throw new ArityException(n, toString());

}

public Object call() {

return throwArity(0);

}

public void run(){

throw new UnsupportedOperationException();

}

public Object invoke() {

return throwArity(0);

}

public int compareTo(Object o){

return sym.compareTo(((Keyword) o).sym);

}

public String getNamespace(){

return sym.getNamespace();

}

public String getName(){

return sym.getName();

}

private Object readResolve() throws ObjectStreamException{

return intern(sym);

}

/**

* Indexer implements IFn for attr access

* @param obj - must be IPersistentMap

* @return the value at the key or nil if not found

final public Object invoke(Object obj) {

if(obj instanceof ILookup)

return ((ILookup)obj).valAt(this);

return RT.get(obj, this);

}

final public Object invoke(Object obj, Object notFound) {

if(obj instanceof ILookup)

return ((ILookup)obj).valAt(this,notFound);

return RT.get(obj, this, notFound);

}

public Object invoke(Object arg1, Object arg2, Object arg3) {

return throwArity(3);

}

public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4) {

return throwArity(4);

}

public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5) {

return throwArity(5);

}

public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6) {

return throwArity(6);

}

public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7)

{

return throwArity(7);

}