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 jdk.nashorn.api.scripting.AbstractJSObject;

    33 import java.nio.DoubleBuffer;

    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     public BufferArray(int size) {

    56         buf = DoubleBuffer.allocate(size);

    57     }

    58 

    59     public BufferArray(DoubleBuffer buf) {

    60         this.buf = buf;

    61     }

    62 

    63     // called to check if indexed property exists

    64     @Override

    65     public boolean hasSlot(int index) {

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

    67     }

    68 

    69     // get the value from that index

    70     @Override

    71     public Object getSlot(int index) {

    72        return buf.get(index);

    73     }

    74 

    75     // set the value at that index

    76     @Override

    77     public void setSlot(int index, Object value) {

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

    79     }

    80 

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

    82     @Override

    83     public boolean hasMember(String name) {

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

    85     }

    86 

    87     // get the value of that named property

    88     @Override

    89     public Object getMember(String name) {

    90        switch (name) {

    91           case "length":

    92               return buf.capacity();

    93           case "buf":

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

    95               return new AbstractJSObject() {

    96                   @Override

    97                   public Object call(Object thiz, Object... args) {

    98                       return BufferArray.this.buf;

    99                   }

   100 

   101                   // yes, I'm a function !

   102                   @Override

   103                   public boolean isFunction() {

   104                       return true;

   105                   }

   106               };

   107        }

   108        return null;

   109     }

   110 }