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 }