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  */

    25 

    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

    35 

    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.

    39 

    40    You may not use this file except in compliance with either the Apache

    41    License or the BSD License.

    42 

    43    If you choose to use this file in compliance with the Apache License, the

    44    following notice applies to you:

    45 

    46        You may obtain a copy of the Apache License at

    47 

    48            http://www.apache.org/licenses/LICENSE-2.0

    49 

    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.

    55 

    56    If you choose to use this file in compliance with the BSD License, the

    57    following notice applies to you:

    58 

    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.

    70 

    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 */

    83 

    84 package jdk.internal.dynalink.beans;

    85 

    86 import java.lang.invoke.MethodHandles.Lookup;

    87 import java.util.Collections;

    88 import java.util.Set;

    89 import jdk.internal.dynalink.DynamicLinkerFactory;

    90 import jdk.internal.dynalink.StandardOperation;

    91 import jdk.internal.dynalink.linker.GuardedInvocation;

    92 import jdk.internal.dynalink.linker.GuardingDynamicLinker;

    93 import jdk.internal.dynalink.linker.LinkRequest;

    94 import jdk.internal.dynalink.linker.LinkerServices;

    95 import jdk.internal.dynalink.linker.TypeBasedGuardingDynamicLinker;

    96 

    97 /**

    98  * A linker for ordinary Java objects. Normally used as the ultimate fallback

    99  * linker by the {@link DynamicLinkerFactory} so it is given the chance to link

   100  * calls to all objects that no other linker recognized. Specifically, this

   101  * linker will:

   102  * <ul>

   103  * <li>expose all public methods of form {@code setXxx()}, {@code getXxx()},

   104  * and {@code isXxx()} as property setters and getters for

   105  * {@link StandardOperation#SET_PROPERTY} and {@link StandardOperation#GET_PROPERTY}

   106  * operations;</li>

   107  * <li>expose all public methods for invocation through

   108  * {@link StandardOperation#CALL_METHOD} operation;</li>

   109  * <li>expose all public methods for retrieval for

   110  * {@link StandardOperation#GET_METHOD} operation; the methods thus retrieved

   111  * can then be invoked using {@link StandardOperation#CALL}.</li>

   112  * <li>expose all public fields as properties, unless there are getters or

   113  * setters for the properties of the same name;</li>

   114  * <li>expose {@link StandardOperation#GET_LENGTH},

   115  * {@link StandardOperation#GET_ELEMENT} and {@link StandardOperation#SET_ELEMENT}

   116  * on native Java arrays, as well as {@link java.util.List} and

   117  * {@link java.util.Map} objects; ({@link StandardOperation#GET_LENGTH} works on

   118  * any {@link java.util.Collection});</li>

   119  * <li>expose a virtual property named {@code length} on Java arrays;</li>

   120  * <li>expose {@link StandardOperation#NEW} on instances of {@link StaticClass}

   121  * as calls to constructors, including those static class objects that represent

   122  * Java arrays (their constructors take a single {@code int} parameter

   123  * representing the length of the array to create);</li>

   124  * <li>expose static methods, fields, and properties of classes in a similar

   125  * manner to how instance method, fields, and properties are exposed, on

   126  * {@link StaticClass} objects.</li>

   127  * <li>expose a virtual property named {@code static} on instances of

   128  * {@link java.lang.Class} to access their {@link StaticClass}.</li>

   129  * </ul>

   130  * <p><strong>Overloaded method resolution</strong> is performed automatically

   131  * for property setters, methods, and constructors. Additionally, manual

   132  * overloaded method selection is supported by having a call site specify a name

   133  * for a method that contains an explicit signature, i.e.

   134  * {@code NamedMethod(GET_METHOD, "parseInt(String,int)")}. You can use

   135  * non-qualified class names in such signatures regardless of those classes'

   136  * packages, they will match any class with the same non-qualified name. You

   137  * only have to use a fully qualified class name in case non-qualified class

   138  * names would cause selection ambiguity (that is extremely rare). Overloaded

   139  * resolution for constructors is not automatic as there is no logical place to

   140  * attach that functionality to but if a language wishes to provide this

   141  * functionality, it can use {@link #getConstructorMethod(Class, String)} as a

   142  * useful building block for it.</p>

   143  * <p><strong>Variable argument invocation</strong> is handled for both methods

   144  * and constructors.</p>

   145  * <p><strong>Caller sensitive methods</strong> can be linked as long as they

   146  * are otherwise public and link requests have call site descriptors carrying

   147  * full-strength {@link Lookup} objects and not weakened lookups or the public

   148  * lookup.</p>

   149  * <p>The class also exposes various static methods for discovery of available

   150  * property and method names on classes and class instances, as well as access

   151  * to per-class linkers using the {@link #getLinkerForClass(Class)}

   152  * method.</p>

   153  */

   154 public class BeansLinker implements GuardingDynamicLinker {

   155     private static final ClassValue<TypeBasedGuardingDynamicLinker> linkers = new ClassValue<TypeBasedGuardingDynamicLinker>() {

   156         @Override

   157         protected TypeBasedGuardingDynamicLinker computeValue(final Class<?> clazz) {

   158             // If ClassValue.put() were public, we could just pre-populate with these known mappings...

   159             return

   160                 clazz == Class.class ? new ClassLinker() :

   161                 clazz == StaticClass.class ? new StaticClassLinker() :

   162                 DynamicMethod.class.isAssignableFrom(clazz) ? new DynamicMethodLinker() :

   163                 new BeanLinker(clazz);

   164         }

   165     };

   166 

   167     /**

   168      * Creates a new beans linker.

   169      */

   170     public BeansLinker() {

   171     }

   172 

   173     /**

   174      * Returns a bean linker for a particular single class. Useful when you need

   175      * to override or extend the behavior of linking for some classes in your

   176      * language runtime's linker, but still want to delegate to the default

   177      * behavior in some cases.

   178      * @param clazz the class

   179      * @return a bean linker for that class

   180      */

   181     public static TypeBasedGuardingDynamicLinker getLinkerForClass(final Class<?> clazz) {

   182         return linkers.get(clazz);

   183     }

   184 

   185     /**

   186      * Returns true if the object is a Java dynamic method (e.g., one

   187      * obtained through a {@code GET_METHOD} operation on a Java object or

   188      * {@link StaticClass} or through

   189      * {@link #getConstructorMethod(Class, String)}.

   190      *

   191      * @param obj the object we want to test for being a Java dynamic method.

   192      * @return true if it is a dynamic method, false otherwise.

   193      */

   194     public static boolean isDynamicMethod(final Object obj) {

   195         return obj instanceof DynamicMethod;

   196     }

   197 

   198     /**

   199      * Returns true if the object is a Java constructor (obtained through

   200      * {@link #getConstructorMethod(Class, String)}}.

   201      *

   202      * @param obj the object we want to test for being a Java constructor.

   203      * @return true if it is a constructor, false otherwise.

   204      */

   205     public static boolean isDynamicConstructor(final Object obj) {

   206         return obj instanceof DynamicMethod && ((DynamicMethod)obj).isConstructor();

   207     }

   208 

   209     /**

   210      * Return the dynamic method of constructor of the given class and the given

   211      * signature. This method is useful for exposing a functionality for

   212      * selecting an overloaded constructor based on an explicit signature, as

   213      * this functionality is not otherwise exposed by Dynalink as

   214      * {@link StaticClass} objects act as overloaded constructors without

   215      * explicit signature selection. Example usage would be:

   216      * {@code getConstructorMethod(java.awt.Color.class, "int, int, int")}.

   217      * @param clazz the class

   218      * @param signature full signature of the constructor. Note how you can use

   219      * names of primitive types, array names with normal Java notation (e.g.

   220      * {@code "int[]"}), and normally you can even use unqualified class names

   221      * (e.g. {@code "String, List"} instead of

   222      * {@code "java.lang.String, java.util.List"} as long as they don't cause

   223      * ambiguity in the specific parameter position.

   224      * @return dynamic method for the constructor or null if no constructor with

   225      * the specified signature exists.

   226      */

   227     public static Object getConstructorMethod(final Class<?> clazz, final String signature) {

   228         return StaticClassLinker.getConstructorMethod(clazz, signature);

   229     }

   230 

   231     /**

   232      * Returns a set of names of all readable instance properties of a class.

   233      * @param clazz the class

   234      * @return a set of names of all readable instance properties of a class.

   235      */

   236     public static Set<String> getReadableInstancePropertyNames(final Class<?> clazz) {

   237         final TypeBasedGuardingDynamicLinker linker = getLinkerForClass(clazz);

   238         if(linker instanceof BeanLinker) {

   239             return ((BeanLinker)linker).getReadablePropertyNames();

   240         }

   241         return Collections.emptySet();

   242     }

   243 

   244     /**

   245      * Returns a set of names of all writable instance properties of a class.

   246      * @param clazz the class

   247      * @return a set of names of all writable instance properties of a class.

   248      */

   249     public static Set<String> getWritableInstancePropertyNames(final Class<?> clazz) {

   250         final TypeBasedGuardingDynamicLinker linker = getLinkerForClass(clazz);

   251         if(linker instanceof BeanLinker) {

   252             return ((BeanLinker)linker).getWritablePropertyNames();

   253         }

   254         return Collections.emptySet();

   255     }

   256 

   257     /**

   258      * Returns a set of names of all instance methods of a class.

   259      * @param clazz the class

   260      * @return a set of names of all instance methods of a class.

   261      */

   262     public static Set<String> getInstanceMethodNames(final Class<?> clazz) {

   263         final TypeBasedGuardingDynamicLinker linker = getLinkerForClass(clazz);

   264         if(linker instanceof BeanLinker) {

   265             return ((BeanLinker)linker).getMethodNames();

   266         }

   267         return Collections.emptySet();

   268     }

   269 

   270     /**

   271      * Returns a set of names of all readable static properties of a class.

   272      * @param clazz the class

   273      * @return a set of names of all readable static properties of a class.

   274      */

   275     public static Set<String> getReadableStaticPropertyNames(final Class<?> clazz) {

   276         return StaticClassLinker.getReadableStaticPropertyNames(clazz);

   277     }

   278 

   279     /**

   280      * Returns a set of names of all writable static properties of a class.

   281      * @param clazz the class

   282      * @return a set of names of all writable static properties of a class.

   283      */

   284     public static Set<String> getWritableStaticPropertyNames(final Class<?> clazz) {

   285         return StaticClassLinker.getWritableStaticPropertyNames(clazz);

   286     }

   287 

   288     /**

   289      * Returns a set of names of all static methods of a class.

   290      * @param clazz the class

   291      * @return a set of names of all static methods of a class.

   292      */

   293     public static Set<String> getStaticMethodNames(final Class<?> clazz) {

   294         return StaticClassLinker.getStaticMethodNames(clazz);

   295     }

   296 

   297     @Override

   298     public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices)

   299             throws Exception {

   300         final Object receiver = request.getReceiver();

   301         if(receiver == null) {

   302             // Can't operate on null

   303             return null;

   304         }

   305         return getLinkerForClass(receiver.getClass()).getGuardedInvocation(request, linkerServices);

   306     }

   307 }