Thu, 24 May 2018 16:39:31 +0800
Merge
1 /*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
26 /*
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file, and Oracle licenses the original version of this file under the BSD
31 * license:
32 */
33 /*
34 Copyright 2009-2013 Attila Szegedi
36 Licensed under both the Apache License, Version 2.0 (the "Apache License")
37 and the BSD License (the "BSD License"), with licensee being free to
38 choose either of the two at their discretion.
40 You may not use this file except in compliance with either the Apache
41 License or the BSD License.
43 If you choose to use this file in compliance with the Apache License, the
44 following notice applies to you:
46 You may obtain a copy of the Apache License at
48 http://www.apache.org/licenses/LICENSE-2.0
50 Unless required by applicable law or agreed to in writing, software
51 distributed under the License is distributed on an "AS IS" BASIS,
52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
53 implied. See the License for the specific language governing
54 permissions and limitations under the License.
56 If you choose to use this file in compliance with the BSD License, the
57 following notice applies to you:
59 Redistribution and use in source and binary forms, with or without
60 modification, are permitted provided that the following conditions are
61 met:
62 * Redistributions of source code must retain the above copyright
63 notice, this list of conditions and the following disclaimer.
64 * Redistributions in binary form must reproduce the above copyright
65 notice, this list of conditions and the following disclaimer in the
66 documentation and/or other materials provided with the distribution.
67 * Neither the name of the copyright holder nor the names of
68 contributors may be used to endorse or promote products derived from
69 this software without specific prior written permission.
71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
82 */
84 package jdk.internal.dynalink.beans;
86 import java.lang.invoke.MethodHandle;
87 import java.lang.invoke.MethodHandles;
88 import java.lang.invoke.MethodType;
89 import java.text.Collator;
90 import java.util.ArrayList;
91 import java.util.Collections;
92 import java.util.Iterator;
93 import java.util.LinkedList;
94 import java.util.List;
95 import jdk.internal.dynalink.CallSiteDescriptor;
96 import jdk.internal.dynalink.beans.ApplicableOverloadedMethods.ApplicabilityTest;
97 import jdk.internal.dynalink.linker.LinkerServices;
98 import jdk.internal.dynalink.support.TypeUtilities;
100 /**
101 * Represents a group of {@link SingleDynamicMethod} objects that represents all overloads of a particular name (or all
102 * constructors) for a particular class. Correctly handles overload resolution, variable arity methods, and caller
103 * sensitive methods within the overloads.
104 *
105 * @author Attila Szegedi
106 */
107 class OverloadedDynamicMethod extends DynamicMethod {
108 /**
109 * Holds a list of all methods.
110 */
111 private final LinkedList<SingleDynamicMethod> methods;
112 private final ClassLoader classLoader;
114 /**
115 * Creates a new overloaded dynamic method.
116 *
117 * @param clazz the class this method belongs to
118 * @param name the name of the method
119 */
120 OverloadedDynamicMethod(final Class<?> clazz, final String name) {
121 this(new LinkedList<SingleDynamicMethod>(), clazz.getClassLoader(), getClassAndMethodName(clazz, name));
122 }
124 private OverloadedDynamicMethod(final LinkedList<SingleDynamicMethod> methods, final ClassLoader classLoader, final String name) {
125 super(name);
126 this.methods = methods;
127 this.classLoader = classLoader;
128 }
130 @Override
131 SingleDynamicMethod getMethodForExactParamTypes(final String paramTypes) {
132 final LinkedList<SingleDynamicMethod> matchingMethods = new LinkedList<>();
133 for(final SingleDynamicMethod method: methods) {
134 final SingleDynamicMethod matchingMethod = method.getMethodForExactParamTypes(paramTypes);
135 if(matchingMethod != null) {
136 matchingMethods.add(matchingMethod);
137 }
138 }
139 switch(matchingMethods.size()) {
140 case 0: {
141 return null;
142 }
143 case 1: {
144 return matchingMethods.getFirst();
145 }
146 default: {
147 throw new BootstrapMethodError("Can't choose among " + matchingMethods + " for argument types "
148 + paramTypes + " for method " + getName());
149 }
150 }
151 }
153 @Override
154 public MethodHandle getInvocation(final CallSiteDescriptor callSiteDescriptor, final LinkerServices linkerServices) {
155 final MethodType callSiteType = callSiteDescriptor.getMethodType();
156 // First, find all methods applicable to the call site by subtyping (JLS 15.12.2.2)
157 final ApplicableOverloadedMethods subtypingApplicables = getApplicables(callSiteType,
158 ApplicableOverloadedMethods.APPLICABLE_BY_SUBTYPING);
159 // Next, find all methods applicable by method invocation conversion to the call site (JLS 15.12.2.3).
160 final ApplicableOverloadedMethods methodInvocationApplicables = getApplicables(callSiteType,
161 ApplicableOverloadedMethods.APPLICABLE_BY_METHOD_INVOCATION_CONVERSION);
162 // Finally, find all methods applicable by variable arity invocation. (JLS 15.12.2.4).
163 final ApplicableOverloadedMethods variableArityApplicables = getApplicables(callSiteType,
164 ApplicableOverloadedMethods.APPLICABLE_BY_VARIABLE_ARITY);
166 // Find the methods that are maximally specific based on the call site signature
167 List<SingleDynamicMethod> maximallySpecifics = subtypingApplicables.findMaximallySpecificMethods();
168 if(maximallySpecifics.isEmpty()) {
169 maximallySpecifics = methodInvocationApplicables.findMaximallySpecificMethods();
170 if(maximallySpecifics.isEmpty()) {
171 maximallySpecifics = variableArityApplicables.findMaximallySpecificMethods();
172 }
173 }
175 // Now, get a list of the rest of the methods; those that are *not* applicable to the call site signature based
176 // on JLS rules. As paradoxical as that might sound, we have to consider these for dynamic invocation, as they
177 // might match more concrete types passed in invocations. That's why we provisionally call them "invokables".
178 // This is typical for very generic signatures at call sites. Typical example: call site specifies
179 // (Object, Object), and we have a method whose parameter types are (String, int). None of the JLS applicability
180 // rules will trigger, but we must consider the method, as it can be the right match for a concrete invocation.
181 @SuppressWarnings({ "unchecked", "rawtypes" })
182 final List<SingleDynamicMethod> invokables = (List)methods.clone();
183 invokables.removeAll(subtypingApplicables.getMethods());
184 invokables.removeAll(methodInvocationApplicables.getMethods());
185 invokables.removeAll(variableArityApplicables.getMethods());
186 for(final Iterator<SingleDynamicMethod> it = invokables.iterator(); it.hasNext();) {
187 final SingleDynamicMethod m = it.next();
188 if(!isApplicableDynamically(linkerServices, callSiteType, m)) {
189 it.remove();
190 }
191 }
193 // If no additional methods can apply at invocation time, and there's more than one maximally specific method
194 // based on call site signature, that is a link-time ambiguity. In a static scenario, javac would report an
195 // ambiguity error.
196 if(invokables.isEmpty() && maximallySpecifics.size() > 1) {
197 throw new BootstrapMethodError("Can't choose among " + maximallySpecifics + " for argument types "
198 + callSiteType);
199 }
201 // Merge them all.
202 invokables.addAll(maximallySpecifics);
203 switch(invokables.size()) {
204 case 0: {
205 // No overloads can ever match the call site type
206 return null;
207 }
208 case 1: {
209 // Very lucky, we ended up with a single candidate method handle based on the call site signature; we
210 // can link it very simply by delegating to the SingleDynamicMethod.
211 return invokables.iterator().next().getInvocation(callSiteDescriptor, linkerServices);
212 }
213 default: {
214 // We have more than one candidate. We have no choice but to link to a method that resolves overloads on
215 // every invocation (alternatively, we could opportunistically link the one method that resolves for the
216 // current arguments, but we'd need to install a fairly complex guard for that and when it'd fail, we'd
217 // go back all the way to candidate selection. Note that we're resolving any potential caller sensitive
218 // methods here to their handles, as the OverloadedMethod instance is specific to a call site, so it
219 // has an already determined Lookup.
220 final List<MethodHandle> methodHandles = new ArrayList<>(invokables.size());
221 final MethodHandles.Lookup lookup = callSiteDescriptor.getLookup();
222 for(final SingleDynamicMethod method: invokables) {
223 methodHandles.add(method.getTarget(lookup));
224 }
225 return new OverloadedMethod(methodHandles, this, callSiteType, linkerServices).getInvoker();
226 }
227 }
229 }
231 @Override
232 public boolean contains(final SingleDynamicMethod m) {
233 for(final SingleDynamicMethod method: methods) {
234 if(method.contains(m)) {
235 return true;
236 }
237 }
238 return false;
239 }
241 @Override
242 public boolean isConstructor() {
243 assert !methods.isEmpty();
244 return methods.getFirst().isConstructor();
245 }
247 @Override
248 public String toString() {
249 // First gather the names and sort them. This makes it consistent and easier to read.
250 final List<String> names = new ArrayList<>(methods.size());
251 int len = 0;
252 for (final SingleDynamicMethod m: methods) {
253 final String name = m.getName();
254 len += name.length();
255 names.add(name);
256 }
257 // Case insensitive sorting, so e.g. "Object" doesn't come before "boolean".
258 final Collator collator = Collator.getInstance();
259 collator.setStrength(Collator.SECONDARY);
260 Collections.sort(names, collator);
262 final String className = getClass().getName();
263 // Class name length + length of signatures + 2 chars/per signature for indentation and newline +
264 // 3 for brackets and initial newline
265 final int totalLength = className.length() + len + 2 * names.size() + 3;
266 final StringBuilder b = new StringBuilder(totalLength);
267 b.append('[').append(className).append('\n');
268 for(final String name: names) {
269 b.append(' ').append(name).append('\n');
270 }
271 b.append(']');
272 assert b.length() == totalLength;
273 return b.toString();
274 };
276 ClassLoader getClassLoader() {
277 return classLoader;
278 }
280 private static boolean isApplicableDynamically(final LinkerServices linkerServices, final MethodType callSiteType,
281 final SingleDynamicMethod m) {
282 final MethodType methodType = m.getMethodType();
283 final boolean varArgs = m.isVarArgs();
284 final int fixedArgLen = methodType.parameterCount() - (varArgs ? 1 : 0);
285 final int callSiteArgLen = callSiteType.parameterCount();
287 // Arity checks
288 if(varArgs) {
289 if(callSiteArgLen < fixedArgLen) {
290 return false;
291 }
292 } else if(callSiteArgLen != fixedArgLen) {
293 return false;
294 }
296 // Fixed arguments type checks, starting from 1, as receiver type doesn't participate
297 for(int i = 1; i < fixedArgLen; ++i) {
298 if(!isApplicableDynamically(linkerServices, callSiteType.parameterType(i), methodType.parameterType(i))) {
299 return false;
300 }
301 }
302 if(!varArgs) {
303 // Not vararg; both arity and types matched.
304 return true;
305 }
307 final Class<?> varArgArrayType = methodType.parameterType(fixedArgLen);
308 final Class<?> varArgType = varArgArrayType.getComponentType();
310 if(fixedArgLen == callSiteArgLen - 1) {
311 // Exactly one vararg; check both array type matching and array component type matching.
312 final Class<?> callSiteArgType = callSiteType.parameterType(fixedArgLen);
313 return isApplicableDynamically(linkerServices, callSiteArgType, varArgArrayType)
314 || isApplicableDynamically(linkerServices, callSiteArgType, varArgType);
315 }
317 // Either zero, or more than one vararg; check if all actual vararg types match the vararg array component type.
318 for(int i = fixedArgLen; i < callSiteArgLen; ++i) {
319 if(!isApplicableDynamically(linkerServices, callSiteType.parameterType(i), varArgType)) {
320 return false;
321 }
322 }
324 return true;
325 }
327 private static boolean isApplicableDynamically(final LinkerServices linkerServices, final Class<?> callSiteType,
328 final Class<?> methodType) {
329 return TypeUtilities.isPotentiallyConvertible(callSiteType, methodType)
330 || linkerServices.canConvert(callSiteType, methodType);
331 }
333 private ApplicableOverloadedMethods getApplicables(final MethodType callSiteType, final ApplicabilityTest test) {
334 return new ApplicableOverloadedMethods(methods, callSiteType, test);
335 }
337 /**
338 * Add a method to this overloaded method's set.
339 *
340 * @param method a method to add
341 */
342 public void addMethod(final SingleDynamicMethod method) {
343 assert constructorFlagConsistent(method);
344 methods.add(method);
345 }
347 private boolean constructorFlagConsistent(final SingleDynamicMethod method) {
348 return methods.isEmpty()? true : (methods.getFirst().isConstructor() == method.isConstructor());
349 }
350 }