1 /*
2 * Copyright 2008-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.dyn;
27
28 import java.util.Arrays;
29 import java.util.Collections;
30 import java.util.HashMap;
31 import java.util.List;
32 import impl.java.dyn.*;
33 import impl.java.dyn.util.Signatures;
34 import static impl.java.dyn.MemberName.newIllegalArgumentException;
35
36 /**
37 * Run-time token used to match call sites with method handles.
38 * The structure is a return type accompanied by any number of parameter types.
39 * The types (primitive, void, and reference) are represented by Class objects.
40 * All instances of <code>MethodType</code> are immutable.
41 * Two instances are completely interchangeable if they compare equal.
42 * Equality depends exactly on the return and parameter types.
43 * <p>
44 * This type can be created only by factory methods, which manage interning.
45 *
46 * @author John Rose, JSR 292 EG
47 */
48 public final
49 class MethodType {
50 final Class<?> rtype;
51 final Class<?>[] ptypes;
52 MethodTypeForm form; // erased form, plus cached data about primitives
53 MethodType wrapAlt; // alternative wrapped/unwrapped version
54
55 private static final Access IMPL_TOKEN = Access.getToken();
56
57 private MethodType(Class<?> rtype, Class<?>[] ptypes) {
58 checkRtype(rtype);
59 checkPtypes(ptypes);
60 this.rtype = rtype;
61 this.ptypes = ptypes;
62 }
63
64 private void checkRtype(Class<?> rtype) {
65 rtype.equals(rtype); // null check
66 }
67 private void checkPtypes(Class<?>[] ptypes) {
68 for (Class<?> ptype : ptypes) {
69 ptype.equals(ptype); // null check
70 if (ptype == void.class)
71 throw newIllegalArgumentException("void parameter: "+this);
72 }
73 }
74
75 static final HashMap<MethodType,MethodType> internTable
76 = new HashMap<MethodType, MethodType>();
77
78 static final Class<?>[] NO_PTYPES = {};
79
80 /** Find or create an instance of the given method type.
81 * @param rtype the return type
82 * @param ptypes the parameter types
83 * @return the interned method type with the given parts
84 * @throws NullPointerException if rtype or any ptype is null
85 * @throws IllegalArgumentException if any of the ptypes is void
86 */
87 public static
88 MethodType make(Class<?> rtype, Class<?>[] ptypes) {
89 return makeImpl(rtype, ptypes, false);
90 }
91
92 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}. */
93 public static
94 MethodType make(Class<?> rtype, List<Class<?>> ptypes) {
95 return makeImpl(rtype, ptypes.toArray(NO_PTYPES), true);
96 }
97
98 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
99 * The leading parameter type is prepended to the remaining array.
100 */
101 public static
102 MethodType make(Class<?> rtype, Class<?> ptype0, Class<?>... ptypes) {
103 Class<?>[] ptypes1 = new Class<?>[1+ptypes.length];
104 ptypes1[0] = ptype0;
105 System.arraycopy(ptypes, 0, ptypes1, 1, ptypes.length);
106 return makeImpl(rtype, ptypes1, true);
107 }
108
109 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
110 * The resulting method has no parameter types.
111 */
112 public static
113 MethodType make(Class<?> rtype) {
114 return makeImpl(rtype, NO_PTYPES, true);
115 }
116
117 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
118 * The resulting method has the single given parameter type.
119 */
120 public static
121 MethodType make(Class<?> rtype, Class<?> ptype0) {
122 return makeImpl(rtype, new Class<?>[]{ ptype0 }, true);
123 }
124
125 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
126 * The resulting method has the same parameter types as {@code ptypes},
127 * and the specified return type.
128 */
129 public static
130 MethodType make(Class<?> rtype, MethodType ptypes) {
131 return makeImpl(rtype, ptypes.ptypes, true);
132 }
133
134 /**
135 * Sole factory method to find or create an interned method type.
136 * @param rtype desired return type
137 * @param ptypes desired parameter types
138 * @param trusted whether the ptypes can be used without cloning
139 * @return the unique method type of the desired structure
140 */
141 static
142 MethodType makeImpl(Class<?> rtype, Class<?>[] ptypes, boolean trusted) {
143 if (ptypes == null || ptypes.length == 0) {
144 ptypes = NO_PTYPES; trusted = true;
145 }
146 MethodType mt1 = new MethodType(rtype, ptypes);
147 MethodType mt0;
148 synchronized (internTable) {
149 mt0 = internTable.get(mt1);
150 if (mt0 != null)
151 return mt0;
152 }
153 if (!trusted)
154 // defensively copy the array passed in by the user
155 mt1 = new MethodType(rtype, ptypes.clone());
156 // promote the object to the Real Thing, and reprobe
157 mt1.form = MethodTypeForm.findForm(mt1);
158 if (mt1.form.erasedType == mt1)
159 MethodHandleImpl.init(IMPL_TOKEN, mt1);
160 synchronized (internTable) {
161 mt0 = internTable.get(mt1);
162 if (mt0 != null)
163 return mt0;
164 internTable.put(mt1, mt1);
165 }
166 return mt1;
167 }
168
169 private static final MethodType[] objectOnlyTypes = new MethodType[20];
170
171 /**
172 * Convenience method for {@link #make(java.lang.Class, java.lang.Class[], boolean)}.
173 * All parameters and the return type will be Object, except the final varargs parameter if any.
174 * @param objectArgCount number of parameters (excluding the varargs parameter if any)
175 * @param varargs whether there will be a varargs parameter
176 * @return a totally generic method type, given only its count of parameters and varargs
177 * @see #makeGeneric(int)
178 */
179 public static
180 MethodType makeGeneric(int objectArgCount, boolean varargs) {
181 MethodType mt;
182 int ivarargs = (!varargs ? 0 : 1);
183 int ootIndex = objectArgCount*2 + ivarargs;
184 if (ootIndex < objectOnlyTypes.length) {
185 mt = objectOnlyTypes[ootIndex];
186 if (mt != null) return mt;
187 }
188 Class<?>[] ptypes = new Class<?>[objectArgCount + ivarargs];
189 Arrays.fill(ptypes, Object.class);
190 if (ivarargs != 0) ptypes[objectArgCount] = Object[].class;
191 mt = makeImpl(Object.class, ptypes, true);
192 if (ootIndex < objectOnlyTypes.length) {
193 objectOnlyTypes[ootIndex] = mt; // cache it here also!
194 }
195 return mt;
196 }
197
198 /**
199 * All parameters and the return type will be Object.
200 * @param objectArgCount number of parameters
201 * @return a totally generic method type, given only its count of parameters
202 * @see #makeGeneric(int, boolean)
203 */
204 public static
205 MethodType makeGeneric(int objectArgCount) {
206 return makeGeneric(objectArgCount, false);
207 }
208
209 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[], boolean)}.
210 * @param num the index (zero-based) of the parameter type to change
211 * @param nptype a new parameter type to replace the old one with
212 * @return the same type, except with the selected parameter changed
213 */
214 public MethodType changeParameterType(int num, Class<?> nptype) {
215 if (parameterType(num) == nptype) return this;
216 Class<?>[] nptypes = ptypes.clone();
217 nptypes[num] = nptype;
218 return makeImpl(rtype, nptypes, true);
219 }
220
221 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[], boolean)}.
222 * @param num the position (zero-based) of the inserted parameter type
223 * @param nptype a new parameter type to insert into the parameter list
224 * @return the same type, except with the selected parameter inserted
225 */
226 public MethodType insertParameterType(int num, Class<?> nptype) {
227 int len = ptypes.length;
228 Class<?>[] nptypes = Arrays.copyOfRange(ptypes, 0, len+1);
229 System.arraycopy(nptypes, num, nptypes, num+1, len-num);
230 nptypes[num] = nptype;
231 return makeImpl(rtype, nptypes, true);
232 }
233
234 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[], boolean)}.
235 * @param num the index (zero-based) of the parameter type to remove
236 * @return the same type, except with the selected parameter removed
237 */
238 public MethodType deleteParameterType(int num) {
239 int len = ptypes.length;
240 Class<?>[] nptypes;
241 if (num == 0) {
242 nptypes = Arrays.copyOfRange(ptypes, 1, len);
243 } else {
244 nptypes = Arrays.copyOfRange(ptypes, 0, len-1);
245 System.arraycopy(ptypes, num+1, nptypes, num, (len-1)-num);
246 }
247 return makeImpl(rtype, nptypes, true);
248 }
249
250 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[], boolean)}.
251 * @param nrtype a return parameter type to replace the old one with
252 * @return the same type, except with the return type change
253 */
254 public MethodType changeReturnType(Class<?> nrtype) {
255 if (returnType() == nrtype) return this;
256 return makeImpl(nrtype, ptypes, true);
257 }
258
259 /** Convenience method.
260 * Report if this type contains a primitive argument or return value.
261 * @return true if any of the types are primitives
262 */
263 public boolean hasPrimitives() {
264 return form.primCounts != 0;
265 }
266
267 /** Convenience method.
268 * Report if this type contains a wrapper argument or return value.
269 * Wrappers are types which box primitive values, such as {@link Integer}.
270 * @return true if any of the types are wrappers
271 */
272 public boolean hasWrappers() {
273 return unwrap() != this;
274 }
275
276 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
277 * Erase all reference types to Object.
278 * @return a version of the original type with all reference types replaced
279 */
280 public MethodType erase() {
281 return form.erasedType;
282 }
283
284 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
285 * Erase all reference types to Object, and all primitive types to wrappers.
286 * @return a version of the original type with references erasedType and primitives wrapped
287 */
288 public MethodType eraseWrap() {
289 return form.wrappedType;
290 }
291
292 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
293 * Convert all types, both reference and primitive, to Object.
294 * @return a version of the original type with all types replaced
295 * @see #makeGeneric(int)
296 */
297 public MethodType generic() {
298 return form.wrappedType.erase();
299 }
300
301 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
302 * Convert all primitive types to their corresponding wrapper types.
303 * @return a version of the original type with all primitive types replaced
304 */
305 public MethodType wrap() {
306 return hasPrimitives() ? wrapWithPrims(this) : this;
307 }
308
309 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
310 * Convert all wrapper types to their corresponding primitive types.
311 * @return a version of the original type with all wrapper types replaced
312 */
313 public MethodType unwrap() {
314 MethodType noprims = !hasPrimitives() ? this : wrapWithPrims(this);
315 return unwrapWithNoPrims(noprims);
316 }
317
318 private static MethodType wrapWithPrims(MethodType pt) {
319 assert(pt.hasPrimitives());
320 MethodType wt = pt.wrapAlt;
321 if (wt == null) {
322 // fill in lazily
323 wt = MethodTypeForm.canonType(pt, MethodTypeForm.WRAP);
324 assert(wt != null);
325 pt.wrapAlt = wt;
326 }
327 return wt;
328 }
329
330 private static MethodType unwrapWithNoPrims(MethodType wt) {
331 assert(!wt.hasPrimitives());
332 MethodType uwt = wt.wrapAlt;
333 if (uwt == null) {
334 // fill in lazily
335 uwt = MethodTypeForm.canonType(wt, MethodTypeForm.UNWRAP);
336 if (uwt == null)
337 uwt = wt; // type has no wrappers or prims at all
338 wt.wrapAlt = uwt;
339 }
340 return uwt;
341 }
342
343 /** @param num the index (zero-based) of the desired parameter type
344 * @return the selected parameter type
345 */
346 public Class<?> parameterType(int num) {
347 return ptypes[num];
348 }
349 /** @return the number of parameter types */
350 public int parameterCount() {
351 return ptypes.length;
352 }
353 /** @return the return type */
354 public Class<?> returnType() {
355 return rtype;
356 }
357
358 /**
359 * Convenience method to present the arguments as a list.
360 * @return the parameter types (as an immutable list)
361 */
362 public List<Class<?>> parameterList() {
363 return Collections.unmodifiableList(Arrays.asList(ptypes));
364 }
365
366 /**
367 * Convenience method to present the arguments as an array.
368 * @return the parameter types (as a fresh copy if necessary)
369 */
370 public Class<?>[] parameterArray() {
371 return ptypes.clone();
372 }
373
374 /**
375 * Compares the specified object with this type for equality.
376 * That is, it returns <tt>true</tt> if and only if the specified object
377 * is also a method type with exactly the same parameters and return type.
378 * @param x object to compare
379 * @see Object#equals(Object)
380 */
381 @Override
382 public boolean equals(Object x) {
383 return this == x || x instanceof MethodType && equals((MethodType)x);
384 }
385
386 private boolean equals(MethodType that) {
387 return this.rtype == that.rtype
388 && Arrays.equals(this.ptypes, that.ptypes);
389 }
390
391 /**
392 * Returns the hash code value for this method type.
393 * It is defined to be the same as the hashcode of a List
394 * whose elements are the return type followed by the
395 * parameter types.
396 * @return the hash code value for this method type
397 * @see Object#hashCode()
398 * @see #equals(Object)
399 * @see List#hashCode()
400 */
401 @Override
402 public int hashCode() {
403 int hashCode = 31 + rtype.hashCode();
404 for (Class<?> ptype : ptypes)
405 hashCode = 31*hashCode + ptype.hashCode();
406 return hashCode;
407 }
408
409 /**
410 * The string representation of a method type is a
411 * parenthesis enclosed, comma separated list of type names,
412 * followed immediately by the return type.
413 * <p>
414 * If a type name is array, it the base type followed
415 * by [], rather than the Class.getName of the array type.
416 */
417 @Override
418 public String toString() {
419 StringBuilder sb = new StringBuilder();
420 sb.append("(");
421 for (int i = 0; i < ptypes.length; i++) {
422 if (i > 0) sb.append(",");
423 }
424 sb.append(")");
425 putName(sb, rtype);
426 return sb.toString();
427 }
428
429 static void putName(StringBuilder sb, Class<?> cls) {
430 int brackets = 0;
431 while (cls.isArray()) {
432 cls = cls.getComponentType();
433 brackets++;
434 }
435 String n = cls.getName();
436 /*
437 if (n.startsWith("java.lang.")) {
438 String nb = n.substring("java.lang.".length());
439 if (nb.indexOf('.') < 0) n = nb;
440 } else if (n.indexOf('.') < 0) {
441 n = "."+n; // anonymous package
442 }
443 */
444 sb.append(n);
445 while (brackets > 0) {
446 sb.append("[]");
447 brackets--;
448 }
449 }
450
451 /// Queries which have to do with the bytecode architecture
452
453 /** The number of JVM stack slots required to invoke a method
454 * of this type. Note that (for historic reasons) the JVM requires
455 * a second stack slot to pass long and double arguments.
456 * So this method returns {@link #parameterCount()} plus the
457 * number of long and double parameters (if any).
458 * @return the number of JVM stack slots for this type's parameters
459 */
460 public int parameterSlotCount() {
461 return form.parameterSlotCount();
462 }
463
464 /** The JVM stack slot which carries the given parameter.
465 * The last parameter ({@link #parameterCount()}-1) is carried in the
466 * the most shallowly stacked argument slot, which is numbered as slot zero.
467 * The first parameter is carried in the most deeply stacked argument slot,
468 * which is {@link #parameterSlotCount()} minus the number of slots used
469 * by that parameter.
470 * <p>
471 * As a useful edge case, {@code parameterSlot(-1)} returns
472 * {@link #parameterSlotCount()}. No other negative values are accepted.
473 * <p>
474 * In general, the number returned is the number of arguments <em>after</em>
475 * the given parameter, <em>plus</em> the number of long or double arguments
476 * after the argument for the given parameter.
477 * @param num the index (zero-based) of the desired parameter type
478 * @return the index of the (shallowest) JVM stack slot transmitting the
479 * given parameter
480 */
481 public int parameterSlot(int num) {
482 return form.parameterToArgSlot(num);
483 }
484
485 /** The number of JVM stack slots required to receive a return value
486 * from a method of this type.
487 * If the {@link #returnType() return type} is void, it will be zero,
488 * else if the return type is long or double, it will be two, else one.
489 * @return the number of JVM stack slots (0, 1, or 2) for this type's return value
490 */
491 public int returnSlotCount() {
492 return form.returnSlotCount();
493 }
494
495 /** Convenience method for {@link #make(java.lang.Class, java.lang.Class[])}.
496 * Find or create an instance (interned) of the given method type.
497 * Any class or interface name embedded in the signature string
498 * will be resolved by calling {@link ClassLoader#loadClass(java.lang.String)}
499 * on the given loader (or if it is null, on the system class loader).
500 * <p>
501 * Note that it is possible to build method types which cannot be
502 * constructed by this method, because their component types are
503 * not all reachable from a common class loader.
504 * @param bytecodeSignature a bytecode-level signature string "(T...)T"
505 * @param loader the class loader in which to look up the types
506 * @return a method type matching the bytecode-level signature
507 * @throws IllegalArgumentException if the string is not well-formed
508 * @throws TypeNotPresentException if a named type cannot be found
509 */
510 public static MethodType fromBytecodeString(String bytecodeSignature, ClassLoader loader)
511 throws IllegalArgumentException, TypeNotPresentException
512 {
513 List<Class<?>> types = Signatures.parseMethod(bytecodeSignature, loader);
514 Class<?> rtype = types.remove(types.size() - 1);
515 Class<?>[] ptypes = types.toArray(NO_PTYPES);
516 return makeImpl(rtype, ptypes, true);
517 }
518
519 /**
520 * Create a bytecode signature representation of the type.
521 * Note that this is not a strict inverse of
522 * {@link #fromBytecodeString(java.lang.String, java.lang.ClassLoader)},
523 * because the latter requires a suitable class loader argument.
524 * @return the bytecode signature representation
525 */
526 public String toBytecodeString() {
527 return Signatures.unparse(this);
528 }
529 }