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 package jdk.nashorn.internal.runtime.linker;
  27 
  28 import java.util.Arrays;
  29 import jdk.nashorn.internal.runtime.ScriptRuntime;
  30 
  31 /**
  32  * Represents a Nashorn callable bound to a receiver and optionally arguments. Note that objects of this class
  33  * are just the tuples of a callable and a bound this and arguments, without any behavior. All the behavior is
  34  * defined in the {@code BoundCallableLinker}.
  35  */
  36 public final class BoundCallable {
  37     private final Object callable;
  38     private final Object boundThis;
  39     private final Object[] boundArgs;
  40 
  41     BoundCallable(final Object callable, final Object boundThis, final Object[] boundArgs) {
  42         this.callable = callable;
  43         this.boundThis = boundThis;
  44         this.boundArgs = isEmptyArray(boundArgs) ? ScriptRuntime.EMPTY_ARRAY : boundArgs.clone();
  45     }
  46 
  47     private BoundCallable(final BoundCallable original, final Object[] extraBoundArgs) {
  48         this.callable = original.callable;
  49         this.boundThis = original.boundThis;
  50         this.boundArgs = original.concatenateBoundArgs(extraBoundArgs);
  51     }
  52 
  53     Object getCallable() {
  54         return callable;
  55     }
  56 
  57     Object getBoundThis() {
  58         return boundThis;
  59     }
  60 
  61     Object[] getBoundArgs() {
  62         return boundArgs;
  63     }
  64 
  65     BoundCallable bind(final Object[] extraBoundArgs) {
  66         if (isEmptyArray(extraBoundArgs)) {
  67             return this;
  68         }
  69         return new BoundCallable(this, extraBoundArgs);
  70     }
  71 
  72     private Object[] concatenateBoundArgs(final Object[] extraBoundArgs) {
  73         if (boundArgs.length == 0) {
  74             return extraBoundArgs.clone();
  75         }
  76         final int origBoundArgsLen = boundArgs.length;
  77         final int extraBoundArgsLen = extraBoundArgs.length;
  78         final Object[] newBoundArgs = new Object[origBoundArgsLen + extraBoundArgsLen];
  79         System.arraycopy(boundArgs, 0, newBoundArgs, 0, origBoundArgsLen);
  80         System.arraycopy(extraBoundArgs, 0, newBoundArgs, origBoundArgsLen, extraBoundArgsLen);
  81         return newBoundArgs;
  82     }
  83 
  84     private static boolean isEmptyArray(final Object[] a) {
  85         return a == null || a.length == 0;
  86     }
  87 
  88     @Override
  89     public String toString() {
  90         final StringBuilder b = new StringBuilder(callable.toString()).append(" on ").append(boundThis);
  91         if (boundArgs.length != 0) {
  92             b.append(" with ").append(Arrays.toString(boundArgs));
  93         }
  94         return b.toString();
  95     }
  96 }