1 /*

     2  * Copyright (c) 2015, 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 2015 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;

    85 

    86 import java.util.Objects;

    87 

    88 /**

    89  * Operation that associates a name with another operation. Typically used with

    90  * operations that normally take a name or an index to bind them to a fixed

    91  * name. E.g. {@code new NamedOperation(StandardOperation.GET_PROPERTY, "color")}

    92  * will be a named operation for getting the property named "color" on the

    93  * object it is applied to, and

    94  * {@code new NamedOperation(StandardOperation.GET_ELEMENT, 3)} will be a named

    95  * operation for getting the element at index 3 from the collection it is

    96  * applied to. In these cases, the expected signature of the call site for the

    97  * operation will change to no longer include the name parameter. Specifically,

    98  * the documentation for all {@link StandardOperation} members describes how

    99  * they are affected by being incorporated into a named operation.

   100  */

   101 public final class NamedOperation implements Operation {

   102     private final Operation baseOperation;

   103     private final Object name;

   104 

   105     /**

   106      * Creates a new named operation.

   107      * @param baseOperation the base operation that is associated with a name.

   108      * @param name the name associated with the base operation. Note that the

   109      * name is not necessarily a string, but can be an arbitrary object. As the

   110      * name is used for addressing, it can be an {@link Integer} when meant

   111      * to be used as an index into an array or list etc.

   112      * @throws NullPointerException if either {@code baseOperation} or

   113      * {@code name} is null.

   114      * @throws IllegalArgumentException if {@code baseOperation} is itself a

   115      * {@code NamedOperation}.

   116      */

   117     public NamedOperation(final Operation baseOperation, final Object name) {

   118         if (baseOperation instanceof NamedOperation) {

   119             throw new IllegalArgumentException("baseOperation is a named operation");

   120         }

   121         this.baseOperation = Objects.requireNonNull(baseOperation, "baseOperation is null");

   122         this.name = Objects.requireNonNull(name, "name is null");

   123     }

   124 

   125     /**

   126      * Returns the base operation of this named operation.

   127      * @return the base operation of this named operation.

   128      */

   129     public Operation getBaseOperation() {

   130         return baseOperation;

   131     }

   132 

   133     /**

   134      * Returns the name of this named operation.

   135      * @return the name of this named operation.

   136      */

   137     public Object getName() {

   138         return name;

   139     }

   140 

   141     /**

   142      * Compares this named operation to another object. Returns true if the

   143      * other object is also a named operation, and both their base operations

   144      * and name are equal.

   145      */

   146     @Override

   147     public boolean equals(final Object obj) {

   148         if (obj instanceof NamedOperation) {

   149             final NamedOperation other = (NamedOperation)obj;

   150             return baseOperation.equals(other.baseOperation) && name.equals(other.name);

   151         }

   152         return false;

   153     }

   154 

   155     /**

   156      * Returns the hash code of this named operation. It is defined to be equal

   157      * to {@code baseOperation.hashCode() + 31 * name.hashCode()}.

   158      */

   159     @Override

   160     public int hashCode() {

   161         return baseOperation.hashCode() + 31 * name.hashCode();

   162     }

   163 

   164     /**

   165      * Returns the string representation of this named operation. It is defined

   166      * to be equal to {@code baseOperation.toString() + ":" + name.toString()}.

   167      */

   168     @Override

   169     public String toString() {

   170         return baseOperation.toString() + ":" + name.toString();

   171     }

   172 

   173     /**

   174      * If the passed operation is a named operation, returns its

   175      * {@link #getBaseOperation()}, otherwise returns the operation as is.

   176      * @param op the operation

   177      * @return the base operation of the passed operation.

   178      */

   179     public static Operation getBaseOperation(final Operation op) {

   180         return op instanceof NamedOperation ? ((NamedOperation)op).baseOperation : op;

   181     }

   182 

   183     /**

   184      * If the passed operation is a named operation, returns its

   185      * {@link #getName()}, otherwise returns null. Note that a named operation

   186      * object can never have a null name, therefore returning null is indicative

   187      * that the passed operation is not, in fact, a named operation.

   188      * @param op the operation

   189      * @return the name in the passed operation, or null if it is not a named

   190      * operation.

   191      */

   192     public static Object getName(final Operation op) {

   193         return op instanceof NamedOperation ? ((NamedOperation)op).name : null;

   194     }

   195 }