1 /*

     2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  *

     8  *   - Redistributions of source code must retain the above copyright

     9  *     notice, this list of conditions and the following disclaimer.

    10  *

    11  *   - Redistributions in binary form must reproduce the above copyright

    12  *     notice, this list of conditions and the following disclaimer in the

    13  *     documentation and/or other materials provided with the distribution.

    14  *

    15  *   - Neither the name of Oracle nor the names of its

    16  *     contributors may be used to endorse or promote products derived

    17  *     from this software without specific prior written permission.

    18  *

    19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    30  */

    31 

    32 import java.nio.DoubleBuffer;

    33 import jdk.nashorn.api.scripting.AbstractJSObject;

    34 

    35 /**

    36  * Simple class demonstrating pluggable script object

    37  * implementation. By implementing jdk.nashorn.api.scripting.JSObject

    38  * (or extending AbstractJSObject which implements it), you

    39  * can supply a friendly script object. Nashorn will call

    40  * 'magic' methods on such a class on 'obj.foo, obj.foo = 33,

    41  * obj.bar()' etc. from script.

    42  *

    43  * In this example, Java nio DoubleBuffer object is wrapped

    44  * as a friendly script object that provides indexed acces

    45  * to buffer content and also support array-like "length"

    46  * readonly property to retrieve buffer's capacity. This class

    47  * also demonstrates a function valued property called "buf".

    48  * On 'buf' method, we return the underlying nio buffer object

    49  * that is being wrapped.

    50  */

    51 public class BufferArray extends AbstractJSObject {

    52     // underlying nio buffer

    53     private final DoubleBuffer buf;

    54 

    55     /**

    56      * Constructor

    57      * @param size initial size

    58      */

    59     public BufferArray(final int size) {

    60         buf = DoubleBuffer.allocate(size);

    61     }

    62 

    63     /**

    64      * Constructur

    65      * @param buf {@link DoubleBuffer} to link to

    66      */

    67     public BufferArray(final DoubleBuffer buf) {

    68         this.buf = buf;

    69     }

    70 

    71     // called to check if indexed property exists

    72     @Override

    73     public boolean hasSlot(final int index) {

    74         return index > 0 && index < buf.capacity();

    75     }

    76 

    77     // get the value from that index

    78     @Override

    79     public Object getSlot(final int index) {

    80        return buf.get(index);

    81     }

    82 

    83     // set the value at that index

    84     @Override

    85     public void setSlot(final int index, final Object value) {

    86        buf.put(index, ((Number)value).doubleValue());

    87     }

    88 

    89     // do you have a property of that given name?

    90     @Override

    91     public boolean hasMember(final String name) {

    92        return "length".equals(name) || "buf".equals(name);

    93     }

    94 

    95     // get the value of that named property

    96     @Override

    97     public Object getMember(final String name) {

    98        switch (name) {

    99           case "length":

   100               return buf.capacity();

   101           case "buf":

   102               // return a 'function' value for this property

   103               return new AbstractJSObject() {

   104                   @Override

   105                   public Object call(final Object thiz, final Object... args) {

   106                       return BufferArray.this.buf;

   107                   }

   108 

   109                   // yes, I'm a function !

   110                   @Override

   111                   public boolean isFunction() {

   112                       return true;

   113                   }

   114               };

   115           default:

   116               break;

   117        }

   118        return null;

   119     }

   120 }