1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/clojure/lang/MultiFn.java	Sat Aug 21 06:25:44 2010 -0400
     1.3 @@ -0,0 +1,314 @@
     1.4 +/**
     1.5 + *   Copyright (c) Rich Hickey. All rights reserved.
     1.6 + *   The use and distribution terms for this software are covered by the
     1.7 + *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
     1.8 + *   which can be found in the file epl-v10.html at the root of this distribution.
     1.9 + *   By using this software in any fashion, you are agreeing to be bound by
    1.10 + * 	 the terms of this license.
    1.11 + *   You must not remove this notice, or any other, from this software.
    1.12 + **/
    1.13 +
    1.14 +/* rich Sep 13, 2007 */
    1.15 +
    1.16 +package clojure.lang;
    1.17 +
    1.18 +import java.util.Map;
    1.19 +
    1.20 +public class MultiFn extends AFn{
    1.21 +final public IFn dispatchFn;
    1.22 +final public Object defaultDispatchVal;
    1.23 +final public IRef hierarchy;
    1.24 +final String name;
    1.25 +IPersistentMap methodTable;
    1.26 +IPersistentMap preferTable;
    1.27 +IPersistentMap methodCache;
    1.28 +Object cachedHierarchy;
    1.29 +
    1.30 +static final Var assoc = RT.var("clojure.core", "assoc");
    1.31 +static final Var dissoc = RT.var("clojure.core", "dissoc");
    1.32 +static final Var isa = RT.var("clojure.core", "isa?");
    1.33 +static final Var parents = RT.var("clojure.core", "parents");
    1.34 +
    1.35 +public MultiFn(String name, IFn dispatchFn, Object defaultDispatchVal, IRef hierarchy) throws Exception{
    1.36 +	this.name = name;
    1.37 +	this.dispatchFn = dispatchFn;
    1.38 +	this.defaultDispatchVal = defaultDispatchVal;
    1.39 +	this.methodTable = PersistentHashMap.EMPTY;
    1.40 +	this.methodCache = getMethodTable();
    1.41 +	this.preferTable = PersistentHashMap.EMPTY;
    1.42 +    this.hierarchy = hierarchy;
    1.43 +	cachedHierarchy = null;
    1.44 +}
    1.45 +
    1.46 +synchronized public MultiFn reset(){
    1.47 +	methodTable = methodCache = preferTable = PersistentHashMap.EMPTY;
    1.48 +	cachedHierarchy = null;
    1.49 +	return this;
    1.50 +}
    1.51 +
    1.52 +synchronized public MultiFn addMethod(Object dispatchVal, IFn method) throws Exception{
    1.53 +	methodTable = getMethodTable().assoc(dispatchVal, method);
    1.54 +	resetCache();
    1.55 +	return this;
    1.56 +}
    1.57 +
    1.58 +synchronized public MultiFn removeMethod(Object dispatchVal) throws Exception{
    1.59 +	methodTable = getMethodTable().without(dispatchVal);
    1.60 +	resetCache();
    1.61 +	return this;
    1.62 +}
    1.63 +
    1.64 +synchronized public MultiFn preferMethod(Object dispatchValX, Object dispatchValY) throws Exception{
    1.65 +	if(prefers(dispatchValY, dispatchValX))
    1.66 +		throw new IllegalStateException(
    1.67 +				String.format("Preference conflict in multimethod '%s': %s is already preferred to %s",
    1.68 +				              name, dispatchValY, dispatchValX));
    1.69 +	preferTable = getPreferTable().assoc(dispatchValX, RT.conj((IPersistentCollection) RT.get(getPreferTable(),
    1.70 +	                                                                                     dispatchValX,
    1.71 +	                                                                                     PersistentHashSet.EMPTY),
    1.72 +	                                                      dispatchValY));
    1.73 +	resetCache();
    1.74 +	return this;
    1.75 +}
    1.76 +
    1.77 +private boolean prefers(Object x, Object y) throws Exception{
    1.78 +	IPersistentSet xprefs = (IPersistentSet) getPreferTable().valAt(x);
    1.79 +	if(xprefs != null && xprefs.contains(y))
    1.80 +		return true;
    1.81 +	for(ISeq ps = RT.seq(parents.invoke(y)); ps != null; ps = ps.next())
    1.82 +		{
    1.83 +		if(prefers(x, ps.first()))
    1.84 +			return true;
    1.85 +		}
    1.86 +	for(ISeq ps = RT.seq(parents.invoke(x)); ps != null; ps = ps.next())
    1.87 +		{
    1.88 +		if(prefers(ps.first(), y))
    1.89 +			return true;
    1.90 +		}
    1.91 +	return false;
    1.92 +}
    1.93 +
    1.94 +private boolean isA(Object x, Object y) throws Exception{
    1.95 +    return RT.booleanCast(isa.invoke(hierarchy.deref(), x, y));
    1.96 +}
    1.97 +
    1.98 +private boolean dominates(Object x, Object y) throws Exception{
    1.99 +	return prefers(x, y) || isA(x, y);
   1.100 +}
   1.101 +
   1.102 +private IPersistentMap resetCache() throws Exception{
   1.103 +	methodCache = getMethodTable();
   1.104 +	cachedHierarchy = hierarchy.deref();
   1.105 +	return methodCache;
   1.106 +}
   1.107 +
   1.108 +synchronized public IFn getMethod(Object dispatchVal) throws Exception{
   1.109 +	if(cachedHierarchy != hierarchy.deref())
   1.110 +		resetCache();
   1.111 +	IFn targetFn = (IFn) methodCache.valAt(dispatchVal);
   1.112 +	if(targetFn != null)
   1.113 +		return targetFn;
   1.114 +	targetFn = findAndCacheBestMethod(dispatchVal);
   1.115 +	if(targetFn != null)
   1.116 +		return targetFn;
   1.117 +	targetFn = (IFn) getMethodTable().valAt(defaultDispatchVal);
   1.118 +	return targetFn;
   1.119 +}
   1.120 +
   1.121 +private IFn getFn(Object dispatchVal) throws Exception{
   1.122 +	IFn targetFn = getMethod(dispatchVal);
   1.123 +	if(targetFn == null)
   1.124 +		throw new IllegalArgumentException(String.format("No method in multimethod '%s' for dispatch value: %s",
   1.125 +		                                                 name, dispatchVal));
   1.126 +	return targetFn;
   1.127 +}
   1.128 +
   1.129 +private IFn findAndCacheBestMethod(Object dispatchVal) throws Exception{
   1.130 +	Map.Entry bestEntry = null;
   1.131 +	for(Object o : getMethodTable())
   1.132 +		{
   1.133 +		Map.Entry e = (Map.Entry) o;
   1.134 +		if(isA(dispatchVal, e.getKey()))
   1.135 +			{
   1.136 +			if(bestEntry == null || dominates(e.getKey(), bestEntry.getKey()))
   1.137 +				bestEntry = e;
   1.138 +			if(!dominates(bestEntry.getKey(), e.getKey()))
   1.139 +				throw new IllegalArgumentException(
   1.140 +						String.format(
   1.141 +								"Multiple methods in multimethod '%s' match dispatch value: %s -> %s and %s, and neither is preferred",
   1.142 +								name, dispatchVal, e.getKey(), bestEntry.getKey()));
   1.143 +			}
   1.144 +		}
   1.145 +	if(bestEntry == null)
   1.146 +		return null;
   1.147 +	//ensure basis has stayed stable throughout, else redo
   1.148 +	if(cachedHierarchy == hierarchy.deref())
   1.149 +		{
   1.150 +		//place in cache
   1.151 +		methodCache = methodCache.assoc(dispatchVal, bestEntry.getValue());
   1.152 +		return (IFn) bestEntry.getValue();
   1.153 +		}
   1.154 +	else
   1.155 +		{
   1.156 +		resetCache();
   1.157 +		return findAndCacheBestMethod(dispatchVal);
   1.158 +		}
   1.159 +}
   1.160 +
   1.161 +public Object invoke() throws Exception{
   1.162 +	return getFn(dispatchFn.invoke()).invoke();
   1.163 +}
   1.164 +
   1.165 +public Object invoke(Object arg1) throws Exception{
   1.166 +	return getFn(dispatchFn.invoke(arg1)).invoke(arg1);
   1.167 +}
   1.168 +
   1.169 +public Object invoke(Object arg1, Object arg2) throws Exception{
   1.170 +	return getFn(dispatchFn.invoke(arg1, arg2)).invoke(arg1, arg2);
   1.171 +}
   1.172 +
   1.173 +public Object invoke(Object arg1, Object arg2, Object arg3) throws Exception{
   1.174 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3)).invoke(arg1, arg2, arg3);
   1.175 +}
   1.176 +
   1.177 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4) throws Exception{
   1.178 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4)).invoke(arg1, arg2, arg3, arg4);
   1.179 +}
   1.180 +
   1.181 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5) throws Exception{
   1.182 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5)).invoke(arg1, arg2, arg3, arg4, arg5);
   1.183 +}
   1.184 +
   1.185 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6) throws Exception{
   1.186 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6)).invoke(arg1, arg2, arg3, arg4, arg5, arg6);
   1.187 +}
   1.188 +
   1.189 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7)
   1.190 +		throws Exception{
   1.191 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7))
   1.192 +			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7);
   1.193 +}
   1.194 +
   1.195 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.196 +                     Object arg8) throws Exception{
   1.197 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)).
   1.198 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
   1.199 +}
   1.200 +
   1.201 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.202 +                     Object arg8, Object arg9) throws Exception{
   1.203 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)).
   1.204 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9);
   1.205 +}
   1.206 +
   1.207 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.208 +                     Object arg8, Object arg9, Object arg10) throws Exception{
   1.209 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10)).
   1.210 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10);
   1.211 +}
   1.212 +
   1.213 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.214 +                     Object arg8, Object arg9, Object arg10, Object arg11) throws Exception{
   1.215 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11)).
   1.216 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11);
   1.217 +}
   1.218 +
   1.219 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.220 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12) throws Exception{
   1.221 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12)).
   1.222 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12);
   1.223 +}
   1.224 +
   1.225 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.226 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13) throws Exception{
   1.227 +	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13)).
   1.228 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13);
   1.229 +}
   1.230 +
   1.231 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.232 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14)
   1.233 +		throws Exception{
   1.234 +	return getFn(
   1.235 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14)).
   1.236 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14);
   1.237 +}
   1.238 +
   1.239 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.240 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.241 +                     Object arg15) throws Exception{
   1.242 +	return getFn(
   1.243 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.244 +			                  arg15))
   1.245 +			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14, arg15);
   1.246 +}
   1.247 +
   1.248 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.249 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.250 +                     Object arg15, Object arg16) throws Exception{
   1.251 +	return getFn(
   1.252 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.253 +			                  arg15, arg16))
   1.254 +			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.255 +			        arg15, arg16);
   1.256 +}
   1.257 +
   1.258 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.259 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.260 +                     Object arg15, Object arg16, Object arg17) throws Exception{
   1.261 +	return getFn(
   1.262 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.263 +			                  arg15, arg16, arg17))
   1.264 +			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.265 +			        arg15, arg16, arg17);
   1.266 +}
   1.267 +
   1.268 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.269 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.270 +                     Object arg15, Object arg16, Object arg17, Object arg18) throws Exception{
   1.271 +	return getFn(
   1.272 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.273 +			                  arg15, arg16, arg17, arg18)).
   1.274 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.275 +			       arg15, arg16, arg17, arg18);
   1.276 +}
   1.277 +
   1.278 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.279 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.280 +                     Object arg15, Object arg16, Object arg17, Object arg18, Object arg19) throws Exception{
   1.281 +	return getFn(
   1.282 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.283 +			                  arg15, arg16, arg17, arg18, arg19)).
   1.284 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.285 +			       arg15, arg16, arg17, arg18, arg19);
   1.286 +}
   1.287 +
   1.288 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.289 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.290 +                     Object arg15, Object arg16, Object arg17, Object arg18, Object arg19, Object arg20)
   1.291 +		throws Exception{
   1.292 +	return getFn(
   1.293 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.294 +			                  arg15, arg16, arg17, arg18, arg19, arg20)).
   1.295 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.296 +			       arg15, arg16, arg17, arg18, arg19, arg20);
   1.297 +}
   1.298 +
   1.299 +public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object arg5, Object arg6, Object arg7,
   1.300 +                     Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,
   1.301 +                     Object arg15, Object arg16, Object arg17, Object arg18, Object arg19, Object arg20, Object... args)
   1.302 +		throws Exception{
   1.303 +	return getFn(
   1.304 +			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.305 +			                  arg15, arg16, arg17, arg18, arg19, arg20, args)).
   1.306 +			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,
   1.307 +			       arg15, arg16, arg17, arg18, arg19, arg20, args);
   1.308 +}
   1.309 +
   1.310 +    public IPersistentMap getMethodTable() {
   1.311 +        return methodTable;
   1.312 +    }
   1.313 +
   1.314 +    public IPersistentMap getPreferTable() {
   1.315 +        return preferTable;
   1.316 +    }
   1.317 +}