Mercurial > lasercutter

view src/clojure/lang/MultiFn.java @ 10:ef7dbbd6452c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
added clojure source goodness
author Robert McIntyre <rlm@mit.edu>
date Sat, 21 Aug 2010 06:25:44 -0400
parents
children
line wrap: on
line source
     1 /**



     2  *   Copyright (c) Rich Hickey. All rights reserved.



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



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



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



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



     7  * 	 the terms of this license.



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



     9  **/



    10 



    11 /* rich Sep 13, 2007 */



    12 



    13 package clojure.lang;



    14 



    15 import java.util.Map;



    16 



    17 public class MultiFn extends AFn{



    18 final public IFn dispatchFn;



    19 final public Object defaultDispatchVal;



    20 final public IRef hierarchy;



    21 final String name;



    22 IPersistentMap methodTable;



    23 IPersistentMap preferTable;



    24 IPersistentMap methodCache;



    25 Object cachedHierarchy;



    26 



    27 static final Var assoc = RT.var("clojure.core", "assoc");



    28 static final Var dissoc = RT.var("clojure.core", "dissoc");



    29 static final Var isa = RT.var("clojure.core", "isa?");



    30 static final Var parents = RT.var("clojure.core", "parents");



    31 



    32 public MultiFn(String name, IFn dispatchFn, Object defaultDispatchVal, IRef hierarchy) throws Exception{



    33 	this.name = name;



    34 	this.dispatchFn = dispatchFn;



    35 	this.defaultDispatchVal = defaultDispatchVal;



    36 	this.methodTable = PersistentHashMap.EMPTY;



    37 	this.methodCache = getMethodTable();



    38 	this.preferTable = PersistentHashMap.EMPTY;



    39     this.hierarchy = hierarchy;



    40 	cachedHierarchy = null;



    41 }



    42 



    43 synchronized public MultiFn reset(){



    44 	methodTable = methodCache = preferTable = PersistentHashMap.EMPTY;



    45 	cachedHierarchy = null;



    46 	return this;



    47 }



    48 



    49 synchronized public MultiFn addMethod(Object dispatchVal, IFn method) throws Exception{



    50 	methodTable = getMethodTable().assoc(dispatchVal, method);



    51 	resetCache();



    52 	return this;



    53 }



    54 



    55 synchronized public MultiFn removeMethod(Object dispatchVal) throws Exception{



    56 	methodTable = getMethodTable().without(dispatchVal);



    57 	resetCache();



    58 	return this;



    59 }



    60 



    61 synchronized public MultiFn preferMethod(Object dispatchValX, Object dispatchValY) throws Exception{



    62 	if(prefers(dispatchValY, dispatchValX))



    63 		throw new IllegalStateException(



    64 				String.format("Preference conflict in multimethod '%s': %s is already preferred to %s",



    65 				              name, dispatchValY, dispatchValX));



    66 	preferTable = getPreferTable().assoc(dispatchValX, RT.conj((IPersistentCollection) RT.get(getPreferTable(),



    67 	                                                                                     dispatchValX,



    68 	                                                                                     PersistentHashSet.EMPTY),



    69 	                                                      dispatchValY));



    70 	resetCache();



    71 	return this;



    72 }



    73 



    74 private boolean prefers(Object x, Object y) throws Exception{



    75 	IPersistentSet xprefs = (IPersistentSet) getPreferTable().valAt(x);



    76 	if(xprefs != null && xprefs.contains(y))



    77 		return true;



    78 	for(ISeq ps = RT.seq(parents.invoke(y)); ps != null; ps = ps.next())



    79 		{



    80 		if(prefers(x, ps.first()))



    81 			return true;



    82 		}



    83 	for(ISeq ps = RT.seq(parents.invoke(x)); ps != null; ps = ps.next())



    84 		{



    85 		if(prefers(ps.first(), y))



    86 			return true;



    87 		}



    88 	return false;



    89 }



    90 



    91 private boolean isA(Object x, Object y) throws Exception{



    92     return RT.booleanCast(isa.invoke(hierarchy.deref(), x, y));



    93 }



    94 



    95 private boolean dominates(Object x, Object y) throws Exception{



    96 	return prefers(x, y) || isA(x, y);



    97 }



    98 



    99 private IPersistentMap resetCache() throws Exception{



   100 	methodCache = getMethodTable();



   101 	cachedHierarchy = hierarchy.deref();



   102 	return methodCache;



   103 }



   104 



   105 synchronized public IFn getMethod(Object dispatchVal) throws Exception{



   106 	if(cachedHierarchy != hierarchy.deref())



   107 		resetCache();



   108 	IFn targetFn = (IFn) methodCache.valAt(dispatchVal);



   109 	if(targetFn != null)



   110 		return targetFn;



   111 	targetFn = findAndCacheBestMethod(dispatchVal);



   112 	if(targetFn != null)



   113 		return targetFn;



   114 	targetFn = (IFn) getMethodTable().valAt(defaultDispatchVal);



   115 	return targetFn;



   116 }



   117 



   118 private IFn getFn(Object dispatchVal) throws Exception{



   119 	IFn targetFn = getMethod(dispatchVal);



   120 	if(targetFn == null)



   121 		throw new IllegalArgumentException(String.format("No method in multimethod '%s' for dispatch value: %s",



   122 		                                                 name, dispatchVal));



   123 	return targetFn;



   124 }



   125 



   126 private IFn findAndCacheBestMethod(Object dispatchVal) throws Exception{



   127 	Map.Entry bestEntry = null;



   128 	for(Object o : getMethodTable())



   129 		{



   130 		Map.Entry e = (Map.Entry) o;



   131 		if(isA(dispatchVal, e.getKey()))



   132 			{



   133 			if(bestEntry == null || dominates(e.getKey(), bestEntry.getKey()))



   134 				bestEntry = e;



   135 			if(!dominates(bestEntry.getKey(), e.getKey()))



   136 				throw new IllegalArgumentException(



   137 						String.format(



   138 								"Multiple methods in multimethod '%s' match dispatch value: %s -> %s and %s, and neither is preferred",



   139 								name, dispatchVal, e.getKey(), bestEntry.getKey()));



   140 			}



   141 		}



   142 	if(bestEntry == null)



   143 		return null;



   144 	//ensure basis has stayed stable throughout, else redo



   145 	if(cachedHierarchy == hierarchy.deref())



   146 		{



   147 		//place in cache



   148 		methodCache = methodCache.assoc(dispatchVal, bestEntry.getValue());



   149 		return (IFn) bestEntry.getValue();



   150 		}



   151 	else



   152 		{



   153 		resetCache();



   154 		return findAndCacheBestMethod(dispatchVal);



   155 		}



   156 }



   157 



   158 public Object invoke() throws Exception{



   159 	return getFn(dispatchFn.invoke()).invoke();



   160 }



   161 



   162 public Object invoke(Object arg1) throws Exception{



   163 	return getFn(dispatchFn.invoke(arg1)).invoke(arg1);



   164 }



   165 



   166 public Object invoke(Object arg1, Object arg2) throws Exception{



   167 	return getFn(dispatchFn.invoke(arg1, arg2)).invoke(arg1, arg2);



   168 }



   169 



   170 public Object invoke(Object arg1, Object arg2, Object arg3) throws Exception{



   171 	return getFn(dispatchFn.invoke(arg1, arg2, arg3)).invoke(arg1, arg2, arg3);



   172 }



   173 



   174 public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4) throws Exception{



   175 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4)).invoke(arg1, arg2, arg3, arg4);



   176 }



   177 



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



   179 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5)).invoke(arg1, arg2, arg3, arg4, arg5);



   180 }



   181 



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



   183 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6)).invoke(arg1, arg2, arg3, arg4, arg5, arg6);



   184 }



   185 



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



   187 		throws Exception{



   188 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7))



   189 			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7);



   190 }



   191 



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



   193                      Object arg8) throws Exception{



   194 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)).



   195 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);



   196 }



   197 



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



   199                      Object arg8, Object arg9) throws Exception{



   200 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)).



   201 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9);



   202 }



   203 



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



   205                      Object arg8, Object arg9, Object arg10) throws Exception{



   206 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10)).



   207 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10);



   208 }



   209 



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



   211                      Object arg8, Object arg9, Object arg10, Object arg11) throws Exception{



   212 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11)).



   213 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11);



   214 }



   215 



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



   217                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12) throws Exception{



   218 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12)).



   219 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12);



   220 }



   221 



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



   223                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13) throws Exception{



   224 	return getFn(dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13)).



   225 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13);



   226 }



   227 



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



   229                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14)



   230 		throws Exception{



   231 	return getFn(



   232 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14)).



   233 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14);



   234 }



   235 



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



   237                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   238                      Object arg15) throws Exception{



   239 	return getFn(



   240 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   241 			                  arg15))



   242 			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14, arg15);



   243 }



   244 



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



   246                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   247                      Object arg15, Object arg16) throws Exception{



   248 	return getFn(



   249 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   250 			                  arg15, arg16))



   251 			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   252 			        arg15, arg16);



   253 }



   254 



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



   256                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   257                      Object arg15, Object arg16, Object arg17) throws Exception{



   258 	return getFn(



   259 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   260 			                  arg15, arg16, arg17))



   261 			.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   262 			        arg15, arg16, arg17);



   263 }



   264 



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



   266                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   267                      Object arg15, Object arg16, Object arg17, Object arg18) throws Exception{



   268 	return getFn(



   269 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   270 			                  arg15, arg16, arg17, arg18)).



   271 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   272 			       arg15, arg16, arg17, arg18);



   273 }



   274 



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



   276                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   277                      Object arg15, Object arg16, Object arg17, Object arg18, Object arg19) throws Exception{



   278 	return getFn(



   279 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   280 			                  arg15, arg16, arg17, arg18, arg19)).



   281 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   282 			       arg15, arg16, arg17, arg18, arg19);



   283 }



   284 



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



   286                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   287                      Object arg15, Object arg16, Object arg17, Object arg18, Object arg19, Object arg20)



   288 		throws Exception{



   289 	return getFn(



   290 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   291 			                  arg15, arg16, arg17, arg18, arg19, arg20)).



   292 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   293 			       arg15, arg16, arg17, arg18, arg19, arg20);



   294 }



   295 



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



   297                      Object arg8, Object arg9, Object arg10, Object arg11, Object arg12, Object arg13, Object arg14,



   298                      Object arg15, Object arg16, Object arg17, Object arg18, Object arg19, Object arg20, Object... args)



   299 		throws Exception{



   300 	return getFn(



   301 			dispatchFn.invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   302 			                  arg15, arg16, arg17, arg18, arg19, arg20, args)).



   303 			invoke(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13, arg14,



   304 			       arg15, arg16, arg17, arg18, arg19, arg20, args);



   305 }



   306 



   307     public IPersistentMap getMethodTable() {



   308         return methodTable;



   309     }



   310 



   311     public IPersistentMap getPreferTable() {



   312         return preferTable;



   313     }



   314 }