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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package jdk.nashorn.internal.objects;

import static jdk.dynalink.StandardNamespace.METHOD;
import static jdk.dynalink.StandardNamespace.PROPERTY;
import static jdk.dynalink.StandardOperation.GET;
import static jdk.dynalink.StandardOperation.SET;
import static jdk.nashorn.internal.lookup.Lookup.MH;
import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Callable;
import jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.Operation;
import jdk.dynalink.beans.BeansLinker;
import jdk.dynalink.beans.StaticClass;
import jdk.dynalink.linker.GuardedInvocation;
import jdk.dynalink.linker.GuardingDynamicLinker;
import jdk.dynalink.linker.LinkRequest;
import jdk.dynalink.linker.support.SimpleLinkRequest;
import jdk.nashorn.api.scripting.ScriptObjectMirror;
import jdk.nashorn.internal.lookup.Lookup;
import jdk.nashorn.internal.objects.annotations.Attribute;
import jdk.nashorn.internal.objects.annotations.Constructor;
import jdk.nashorn.internal.objects.annotations.Function;
import jdk.nashorn.internal.objects.annotations.ScriptClass;
import jdk.nashorn.internal.objects.annotations.Where;
import jdk.nashorn.internal.runtime.AccessorProperty;
import jdk.nashorn.internal.runtime.ECMAException;
import jdk.nashorn.internal.runtime.JSType;
import jdk.nashorn.internal.runtime.Property;
import jdk.nashorn.internal.runtime.PropertyMap;
import jdk.nashorn.internal.runtime.ScriptObject;
import jdk.nashorn.internal.runtime.ScriptRuntime;
import jdk.nashorn.internal.runtime.arrays.ArrayData;
import jdk.nashorn.internal.runtime.arrays.ArrayIndex;
import jdk.nashorn.internal.runtime.linker.Bootstrap;
import jdk.nashorn.internal.runtime.linker.InvokeByName;
import jdk.nashorn.internal.runtime.linker.NashornBeansLinker;
import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;

ECMA 15.2 Object objects JavaScript Object constructor/prototype. Note: instances of this class are never created. This class is not even a subclass of ScriptObject. But, we use this class to generate prototype and constructor for "Object".
/** * ECMA 15.2 Object objects * * JavaScript Object constructor/prototype. Note: instances of this class are * never created. This class is not even a subclass of ScriptObject. But, we use * this class to generate prototype and constructor for "Object". * */
@ScriptClass("Object") public final class NativeObject {
Methodhandle to proto getter
/** Methodhandle to proto getter */
public static final MethodHandle GET__PROTO__ = findOwnMH("get__proto__", ScriptObject.class, Object.class);
Methodhandle to proto setter
/** Methodhandle to proto setter */
public static final MethodHandle SET__PROTO__ = findOwnMH("set__proto__", Object.class, Object.class, Object.class); private static final Object TO_STRING = new Object(); private static InvokeByName getTO_STRING() { return Global.instance().getInvokeByName(TO_STRING, new Callable<InvokeByName>() { @Override public InvokeByName call() { return new InvokeByName("toString", ScriptObject.class); } }); } private static final Operation GET_METHOD = GET.withNamespace(METHOD); private static final Operation GET_PROPERTY = GET.withNamespace(PROPERTY); private static final Operation SET_PROPERTY = SET.withNamespace(PROPERTY); @SuppressWarnings("unused") private static ScriptObject get__proto__(final Object self) { // See ES6 draft spec: B.2.2.1.1 get Object.prototype.__proto__ // Step 1 Let O be the result of calling ToObject passing the this. final ScriptObject sobj = Global.checkObject(Global.toObject(self)); return sobj.getProto(); } @SuppressWarnings("unused") private static Object set__proto__(final Object self, final Object proto) { // See ES6 draft spec: B.2.2.1.2 set Object.prototype.__proto__ // Step 1 Global.checkObjectCoercible(self); // Step 4 if (! (self instanceof ScriptObject)) { return UNDEFINED; } final ScriptObject sobj = (ScriptObject)self; // __proto__ assignment ignores non-nulls and non-objects // step 3: If Type(proto) is neither Object nor Null, then return undefined. if (proto == null || proto instanceof ScriptObject) { sobj.setPrototypeOf(proto); } return UNDEFINED; } private static final MethodType MIRROR_GETTER_TYPE = MethodType.methodType(Object.class, ScriptObjectMirror.class); private static final MethodType MIRROR_SETTER_TYPE = MethodType.methodType(Object.class, ScriptObjectMirror.class, Object.class); // initialized by nasgen @SuppressWarnings("unused") private static PropertyMap $nasgenmap$; private NativeObject() { // don't create me! throw new UnsupportedOperationException(); } private static ECMAException notAnObject(final Object obj) { return typeError("not.an.object", ScriptRuntime.safeToString(obj)); }
Nashorn extension: setIndexedPropertiesToExternalArrayData
Params:
  • self – self reference
  • obj – object whose index properties are backed by buffer
  • buf – external buffer - should be a nio ByteBuffer
Returns:the 'obj' object
/** * Nashorn extension: setIndexedPropertiesToExternalArrayData * * @param self self reference * @param obj object whose index properties are backed by buffer * @param buf external buffer - should be a nio ByteBuffer * @return the 'obj' object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject setIndexedPropertiesToExternalArrayData(final Object self, final Object obj, final Object buf) { Global.checkObject(obj); final ScriptObject sobj = (ScriptObject)obj; if (buf instanceof ByteBuffer) { sobj.setArray(ArrayData.allocate((ByteBuffer)buf)); } else { throw typeError("not.a.bytebuffer", "setIndexedPropertiesToExternalArrayData's buf argument"); } return sobj; }
ECMA 15.2.3.2 Object.getPrototypeOf ( O )
Params:
  • self – self reference
  • obj – object to get prototype from
Returns:the prototype of an object
/** * ECMA 15.2.3.2 Object.getPrototypeOf ( O ) * * @param self self reference * @param obj object to get prototype from * @return the prototype of an object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object getPrototypeOf(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).getProto(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).getProto(); } else { final JSType type = JSType.of(obj); if (type == JSType.OBJECT) { // host (Java) objects have null __proto__ return null; } // must be some JS primitive throw notAnObject(obj); } }
Nashorn extension: Object.setPrototypeOf ( O, proto ) Also found in ES6 draft specification.
Params:
  • self – self reference
  • obj – object to set prototype for
  • proto – prototype object to be used
Returns:object whose prototype is set
/** * Nashorn extension: Object.setPrototypeOf ( O, proto ) * Also found in ES6 draft specification. * * @param self self reference * @param obj object to set prototype for * @param proto prototype object to be used * @return object whose prototype is set */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object setPrototypeOf(final Object self, final Object obj, final Object proto) { if (obj instanceof ScriptObject) { ((ScriptObject)obj).setPrototypeOf(proto); return obj; } else if (obj instanceof ScriptObjectMirror) { ((ScriptObjectMirror)obj).setProto(proto); return obj; } throw notAnObject(obj); }
ECMA 15.2.3.3 Object.getOwnPropertyDescriptor ( O, P )
Params:
  • self – self reference
  • obj – object from which to get property descriptor for ToString(prop)
  • prop – property descriptor
Returns:property descriptor
/** * ECMA 15.2.3.3 Object.getOwnPropertyDescriptor ( O, P ) * * @param self self reference * @param obj object from which to get property descriptor for {@code ToString(prop)} * @param prop property descriptor * @return property descriptor */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object getOwnPropertyDescriptor(final Object self, final Object obj, final Object prop) { if (obj instanceof ScriptObject) { final String key = JSType.toString(prop); final ScriptObject sobj = (ScriptObject)obj; return sobj.getOwnPropertyDescriptor(key); } else if (obj instanceof ScriptObjectMirror) { final String key = JSType.toString(prop); final ScriptObjectMirror sobjMirror = (ScriptObjectMirror)obj; return sobjMirror.getOwnPropertyDescriptor(key); } else { throw notAnObject(obj); } }
ECMA 15.2.3.4 Object.getOwnPropertyNames ( O )
Params:
  • self – self reference
  • obj – object to query for property names
Returns:array of property names
/** * ECMA 15.2.3.4 Object.getOwnPropertyNames ( O ) * * @param self self reference * @param obj object to query for property names * @return array of property names */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject getOwnPropertyNames(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return new NativeArray(((ScriptObject)obj).getOwnKeys(true)); } else if (obj instanceof ScriptObjectMirror) { return new NativeArray(((ScriptObjectMirror)obj).getOwnKeys(true)); } else { throw notAnObject(obj); } }
ECMA 2 19.1.2.8 Object.getOwnPropertySymbols ( O )
Params:
  • self – self reference
  • obj – object to query for property names
Returns:array of property names
/** * ECMA 2 19.1.2.8 Object.getOwnPropertySymbols ( O ) * * @param self self reference * @param obj object to query for property names * @return array of property names */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject getOwnPropertySymbols(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return new NativeArray(((ScriptObject)obj).getOwnSymbols(true)); } else { // TODO: we don't support this on ScriptObjectMirror objects yet throw notAnObject(obj); } }
ECMA 15.2.3.5 Object.create ( O [, Properties] )
Params:
  • self – self reference
  • proto – prototype object
  • props – properties to define
Returns:object created
/** * ECMA 15.2.3.5 Object.create ( O [, Properties] ) * * @param self self reference * @param proto prototype object * @param props properties to define * @return object created */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject create(final Object self, final Object proto, final Object props) { if (proto != null) { Global.checkObject(proto); } // FIXME: should we create a proper object with correct number of // properties? final ScriptObject newObj = Global.newEmptyInstance(); newObj.setProto((ScriptObject)proto); if (props != UNDEFINED) { NativeObject.defineProperties(self, newObj, props); } return newObj; }
ECMA 15.2.3.6 Object.defineProperty ( O, P, Attributes )
Params:
  • self – self reference
  • obj – object in which to define a property
  • prop – property to define
  • attr – attributes for property descriptor
Returns:object
/** * ECMA 15.2.3.6 Object.defineProperty ( O, P, Attributes ) * * @param self self reference * @param obj object in which to define a property * @param prop property to define * @param attr attributes for property descriptor * @return object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject defineProperty(final Object self, final Object obj, final Object prop, final Object attr) { final ScriptObject sobj = Global.checkObject(obj); sobj.defineOwnProperty(JSType.toPropertyKey(prop), attr, true); return sobj; }
ECMA 5.2.3.7 Object.defineProperties ( O, Properties )
Params:
  • self – self reference
  • obj – object in which to define properties
  • props – properties
Returns:object
/** * ECMA 5.2.3.7 Object.defineProperties ( O, Properties ) * * @param self self reference * @param obj object in which to define properties * @param props properties * @return object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject defineProperties(final Object self, final Object obj, final Object props) { final ScriptObject sobj = Global.checkObject(obj); final Object propsObj = Global.toObject(props); if (propsObj instanceof ScriptObject) { final Object[] keys = ((ScriptObject)propsObj).getOwnKeys(false); for (final Object key : keys) { final String prop = JSType.toString(key); sobj.defineOwnProperty(prop, ((ScriptObject)propsObj).get(prop), true); } } return sobj; }
ECMA 15.2.3.8 Object.seal ( O )
Params:
  • self – self reference
  • obj – object to seal
Returns:sealed object
/** * ECMA 15.2.3.8 Object.seal ( O ) * * @param self self reference * @param obj object to seal * @return sealed object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object seal(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).seal(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).seal(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.9 Object.freeze ( O )
Params:
  • self – self reference
  • obj – object to freeze
Returns:frozen object
/** * ECMA 15.2.3.9 Object.freeze ( O ) * * @param self self reference * @param obj object to freeze * @return frozen object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object freeze(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).freeze(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).freeze(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.10 Object.preventExtensions ( O )
Params:
  • self – self reference
  • obj – object, for which to set the internal extensible property to false
Returns:object
/** * ECMA 15.2.3.10 Object.preventExtensions ( O ) * * @param self self reference * @param obj object, for which to set the internal extensible property to false * @return object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object preventExtensions(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).preventExtensions(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).preventExtensions(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.11 Object.isSealed ( O )
Params:
  • self – self reference
  • obj – check whether an object is sealed
Returns:true if sealed, false otherwise
/** * ECMA 15.2.3.11 Object.isSealed ( O ) * * @param self self reference * @param obj check whether an object is sealed * @return true if sealed, false otherwise */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static boolean isSealed(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).isSealed(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).isSealed(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.12 Object.isFrozen ( O )
Params:
  • self – self reference
  • obj – check whether an object
Returns:true if object is frozen, false otherwise
/** * ECMA 15.2.3.12 Object.isFrozen ( O ) * * @param self self reference * @param obj check whether an object * @return true if object is frozen, false otherwise */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static boolean isFrozen(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).isFrozen(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).isFrozen(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.13 Object.isExtensible ( O )
Params:
  • self – self reference
  • obj – check whether an object is extensible
Returns:true if object is extensible, false otherwise
/** * ECMA 15.2.3.13 Object.isExtensible ( O ) * * @param self self reference * @param obj check whether an object is extensible * @return true if object is extensible, false otherwise */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static boolean isExtensible(final Object self, final Object obj) { if (obj instanceof ScriptObject) { return ((ScriptObject)obj).isExtensible(); } else if (obj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)obj).isExtensible(); } else { throw notAnObject(obj); } }
ECMA 15.2.3.14 Object.keys ( O )
Params:
  • self – self reference
  • obj – object from which to extract keys
Returns:array of keys in object
/** * ECMA 15.2.3.14 Object.keys ( O ) * * @param self self reference * @param obj object from which to extract keys * @return array of keys in object */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static ScriptObject keys(final Object self, final Object obj) { if (obj instanceof ScriptObject) { final ScriptObject sobj = (ScriptObject)obj; return new NativeArray(sobj.getOwnKeys(false)); } else if (obj instanceof ScriptObjectMirror) { final ScriptObjectMirror sobjMirror = (ScriptObjectMirror)obj; return new NativeArray(sobjMirror.getOwnKeys(false)); } else { throw notAnObject(obj); } }
ECMA 15.2.2.1 , 15.2.1.1 new Object([value]) and Object([value]) Constructor
Params:
  • newObj – is the new object instantiated with the new operator
  • self – self reference
  • value – value of object to be instantiated
Returns:the new NativeObject
/** * ECMA 15.2.2.1 , 15.2.1.1 new Object([value]) and Object([value]) * * Constructor * * @param newObj is the new object instantiated with the new operator * @param self self reference * @param value value of object to be instantiated * @return the new NativeObject */
@Constructor public static Object construct(final boolean newObj, final Object self, final Object value) { final JSType type = JSType.ofNoFunction(value); // Object(null), Object(undefined), Object() are same as "new Object()" if (newObj || type == JSType.NULL || type == JSType.UNDEFINED) { switch (type) { case BOOLEAN: case NUMBER: case STRING: case SYMBOL: return Global.toObject(value); case OBJECT: return value; case NULL: case UNDEFINED: // fall through.. default: break; } return Global.newEmptyInstance(); } return Global.toObject(value); }
ECMA 15.2.4.2 Object.prototype.toString ( )
Params:
  • self – self reference
Returns:ToString of object
/** * ECMA 15.2.4.2 Object.prototype.toString ( ) * * @param self self reference * @return ToString of object */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static String toString(final Object self) { return ScriptRuntime.builtinObjectToString(self); }
ECMA 15.2.4.3 Object.prototype.toLocaleString ( )
Params:
  • self – self reference
Returns:localized ToString
/** * ECMA 15.2.4.3 Object.prototype.toLocaleString ( ) * * @param self self reference * @return localized ToString */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static Object toLocaleString(final Object self) { final Object obj = JSType.toScriptObject(self); if (obj instanceof ScriptObject) { final InvokeByName toStringInvoker = getTO_STRING(); final ScriptObject sobj = (ScriptObject)obj; try { final Object toString = toStringInvoker.getGetter().invokeExact(sobj); if (Bootstrap.isCallable(toString)) { return toStringInvoker.getInvoker().invokeExact(toString, sobj); } } catch (final RuntimeException | Error e) { throw e; } catch (final Throwable t) { throw new RuntimeException(t); } throw typeError("not.a.function", "toString"); } return ScriptRuntime.builtinObjectToString(self); }
ECMA 15.2.4.4 Object.prototype.valueOf ( )
Params:
  • self – self reference
Returns:value of object
/** * ECMA 15.2.4.4 Object.prototype.valueOf ( ) * * @param self self reference * @return value of object */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static Object valueOf(final Object self) { return Global.toObject(self); }
ECMA 15.2.4.5 Object.prototype.hasOwnProperty (V)
Params:
  • self – self reference
  • v – property to check for
Returns:true if property exists in object
/** * ECMA 15.2.4.5 Object.prototype.hasOwnProperty (V) * * @param self self reference * @param v property to check for * @return true if property exists in object */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static boolean hasOwnProperty(final Object self, final Object v) { // Convert ScriptObjects to primitive with String.class hint // but no need to convert other primitives to string. final Object key = JSType.toPrimitive(v, String.class); final Object obj = Global.toObject(self); return obj instanceof ScriptObject && ((ScriptObject)obj).hasOwnProperty(key); }
ECMA 15.2.4.6 Object.prototype.isPrototypeOf (V)
Params:
  • self – self reference
  • v – v prototype object to check against
Returns:true if object is prototype of v
/** * ECMA 15.2.4.6 Object.prototype.isPrototypeOf (V) * * @param self self reference * @param v v prototype object to check against * @return true if object is prototype of v */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static boolean isPrototypeOf(final Object self, final Object v) { if (!(v instanceof ScriptObject)) { return false; } final Object obj = Global.toObject(self); ScriptObject proto = (ScriptObject)v; do { proto = proto.getProto(); if (proto == obj) { return true; } } while (proto != null); return false; }
ECMA 15.2.4.7 Object.prototype.propertyIsEnumerable (V)
Params:
  • self – self reference
  • v – property to check if enumerable
Returns:true if property is enumerable
/** * ECMA 15.2.4.7 Object.prototype.propertyIsEnumerable (V) * * @param self self reference * @param v property to check if enumerable * @return true if property is enumerable */
@Function(attributes = Attribute.NOT_ENUMERABLE) public static boolean propertyIsEnumerable(final Object self, final Object v) { final String str = JSType.toString(v); final Object obj = Global.toObject(self); if (obj instanceof ScriptObject) { final ScriptObject sobj = (ScriptObject) obj; final Property property = sobj.getProperty(str); if (property != null) { return property.isEnumerable(); } else { return (sobj.getArray().has(ArrayIndex.getArrayIndex(v))); } } return false; }
Nashorn extension: Object.bindProperties Binds the source object's properties to the target object. Binding properties allows two-way read/write for the properties of the source object. Example:
var obj = { x: 34, y: 100 };
var foo = {}
// bind properties of "obj" to "foo" object
Object.bindProperties(foo, obj);
// now, we can access/write on 'foo' properties
print(foo.x); // prints obj.x which is 34
// update obj.x via foo.x
foo.x = "hello";
print(obj.x); // prints "hello" now
obj.x = 42;   // foo.x also becomes 42
print(foo.x); // prints 42

The source object bound can be a ScriptObject or a ScriptOjectMirror. null or undefined source object results in TypeError being thrown.

Example:
var obj = loadWithNewGlobal({
   name: "test",
   script: "obj = { x: 33, y: 'hello' }"
});
// bind 'obj's properties to global scope 'this'
Object.bindProperties(this, obj);
print(x);         // prints 33
print(y);         // prints "hello"
x = Math.PI;      // changes obj.x to Math.PI
print(obj.x);     // prints Math.PI
Limitations of property binding:
  • Only enumerable, immediate (not proto inherited) properties of the source object are bound.
  • If the target object already contains a property called "foo", the source's "foo" is skipped (not bound).
  • Properties added to the source object after binding to the target are not bound.
  • Property configuration changes on the source object (or on the target) is not propagated.
  • Delete of property on the target (or the source) is not propagated - only the property value is set to 'undefined' if the property happens to be a data property.

It is recommended that the bound properties be treated as non-configurable properties to avoid surprises.

Params:
  • self – self reference
  • target – the target object to which the source object's properties are bound
  • source – the source object whose properties are bound to the target
Returns:the target object after property binding
/** * Nashorn extension: Object.bindProperties * * Binds the source object's properties to the target object. Binding * properties allows two-way read/write for the properties of the source object. * * Example: * <pre> * var obj = { x: 34, y: 100 }; * var foo = {} * * // bind properties of "obj" to "foo" object * Object.bindProperties(foo, obj); * * // now, we can access/write on 'foo' properties * print(foo.x); // prints obj.x which is 34 * * // update obj.x via foo.x * foo.x = "hello"; * print(obj.x); // prints "hello" now * * obj.x = 42; // foo.x also becomes 42 * print(foo.x); // prints 42 * </pre> * <p> * The source object bound can be a ScriptObject or a ScriptOjectMirror. * null or undefined source object results in TypeError being thrown. * </p> * Example: * <pre> * var obj = loadWithNewGlobal({ * name: "test", * script: "obj = { x: 33, y: 'hello' }" * }); * * // bind 'obj's properties to global scope 'this' * Object.bindProperties(this, obj); * print(x); // prints 33 * print(y); // prints "hello" * x = Math.PI; // changes obj.x to Math.PI * print(obj.x); // prints Math.PI * </pre> * * Limitations of property binding: * <ul> * <li> Only enumerable, immediate (not proto inherited) properties of the source object are bound. * <li> If the target object already contains a property called "foo", the source's "foo" is skipped (not bound). * <li> Properties added to the source object after binding to the target are not bound. * <li> Property configuration changes on the source object (or on the target) is not propagated. * <li> Delete of property on the target (or the source) is not propagated - * only the property value is set to 'undefined' if the property happens to be a data property. * </ul> * <p> * It is recommended that the bound properties be treated as non-configurable * properties to avoid surprises. * </p> * * @param self self reference * @param target the target object to which the source object's properties are bound * @param source the source object whose properties are bound to the target * @return the target object after property binding */
@Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) public static Object bindProperties(final Object self, final Object target, final Object source) { // target object has to be a ScriptObject final ScriptObject targetObj = Global.checkObject(target); // check null or undefined source object Global.checkObjectCoercible(source); if (source instanceof ScriptObject) { final ScriptObject sourceObj = (ScriptObject)source; final PropertyMap sourceMap = sourceObj.getMap(); final Property[] properties = sourceMap.getProperties(); //replace the map and blow up everything to objects to work with dual fields :-( // filter non-enumerable properties final ArrayList<Property> propList = new ArrayList<>(); for (final Property prop : properties) { if (prop.isEnumerable()) { final Object value = sourceObj.get(prop.getKey()); prop.setType(Object.class); prop.setValue(sourceObj, sourceObj, value, false); propList.add(prop); } } if (!propList.isEmpty()) { targetObj.addBoundProperties(sourceObj, propList.toArray(new Property[0])); } } else if (source instanceof ScriptObjectMirror) { // get enumerable, immediate properties of mirror final ScriptObjectMirror mirror = (ScriptObjectMirror)source; final String[] keys = mirror.getOwnKeys(false); if (keys.length == 0) { // nothing to bind return target; } // make accessor properties using dynamic invoker getters and setters final AccessorProperty[] props = new AccessorProperty[keys.length]; for (int idx = 0; idx < keys.length; idx++) { props[idx] = createAccessorProperty(keys[idx]); } targetObj.addBoundProperties(source, props); } else if (source instanceof StaticClass) { final Class<?> clazz = ((StaticClass)source).getRepresentedClass(); Bootstrap.checkReflectionAccess(clazz, true); bindBeanProperties(targetObj, source, BeansLinker.getReadableStaticPropertyNames(clazz), BeansLinker.getWritableStaticPropertyNames(clazz), BeansLinker.getStaticMethodNames(clazz)); } else { final Class<?> clazz = source.getClass(); Bootstrap.checkReflectionAccess(clazz, false); bindBeanProperties(targetObj, source, BeansLinker.getReadableInstancePropertyNames(clazz), BeansLinker.getWritableInstancePropertyNames(clazz), BeansLinker.getInstanceMethodNames(clazz)); } return target; } private static AccessorProperty createAccessorProperty(final String name) { final MethodHandle getter = Bootstrap.createDynamicInvoker(name, NashornCallSiteDescriptor.GET_METHOD_PROPERTY, MIRROR_GETTER_TYPE); final MethodHandle setter = Bootstrap.createDynamicInvoker(name, NashornCallSiteDescriptor.SET_PROPERTY, MIRROR_SETTER_TYPE); return AccessorProperty.create(name, 0, getter, setter); }
Binds the source mirror object's properties to the target object. Binding properties allows two-way read/write for the properties of the source object. All inherited, enumerable properties are also bound. This method is used to to make 'with' statement work with ScriptObjectMirror as scope object.
Params:
  • target – the target object to which the source object's properties are bound
  • source – the source object whose properties are bound to the target
Returns:the target object after property binding
/** * Binds the source mirror object's properties to the target object. Binding * properties allows two-way read/write for the properties of the source object. * All inherited, enumerable properties are also bound. This method is used to * to make 'with' statement work with ScriptObjectMirror as scope object. * * @param target the target object to which the source object's properties are bound * @param source the source object whose properties are bound to the target * @return the target object after property binding */
public static Object bindAllProperties(final ScriptObject target, final ScriptObjectMirror source) { final Set<String> keys = source.keySet(); // make accessor properties using dynamic invoker getters and setters final AccessorProperty[] props = new AccessorProperty[keys.size()]; int idx = 0; for (final String name : keys) { props[idx] = createAccessorProperty(name); idx++; } target.addBoundProperties(source, props); return target; } private static void bindBeanProperties(final ScriptObject targetObj, final Object source, final Collection<String> readablePropertyNames, final Collection<String> writablePropertyNames, final Collection<String> methodNames) { final Set<String> propertyNames = new HashSet<>(readablePropertyNames); propertyNames.addAll(writablePropertyNames); final Class<?> clazz = source.getClass(); final MethodType getterType = MethodType.methodType(Object.class, clazz); final MethodType setterType = MethodType.methodType(Object.class, clazz, Object.class); final GuardingDynamicLinker linker = Bootstrap.getBeanLinkerForClass(clazz); final List<AccessorProperty> properties = new ArrayList<>(propertyNames.size() + methodNames.size()); for(final String methodName: methodNames) { final MethodHandle method; try { method = getBeanOperation(linker, GET_METHOD, methodName, getterType, source); } catch(final IllegalAccessError e) { // Presumably, this was a caller sensitive method. Ignore it and carry on. continue; } properties.add(AccessorProperty.create(methodName, Property.NOT_WRITABLE, getBoundBeanMethodGetter(source, method), Lookup.EMPTY_SETTER)); } for(final String propertyName: propertyNames) { MethodHandle getter; if(readablePropertyNames.contains(propertyName)) { try { getter = getBeanOperation(linker, GET_PROPERTY, propertyName, getterType, source); } catch(final IllegalAccessError e) { // Presumably, this was a caller sensitive method. Ignore it and carry on. getter = Lookup.EMPTY_GETTER; } } else { getter = Lookup.EMPTY_GETTER; } final boolean isWritable = writablePropertyNames.contains(propertyName); MethodHandle setter; if(isWritable) { try { setter = getBeanOperation(linker, SET_PROPERTY, propertyName, setterType, source); } catch(final IllegalAccessError e) { // Presumably, this was a caller sensitive method. Ignore it and carry on. setter = Lookup.EMPTY_SETTER; } } else { setter = Lookup.EMPTY_SETTER; } if(getter != Lookup.EMPTY_GETTER || setter != Lookup.EMPTY_SETTER) { properties.add(AccessorProperty.create(propertyName, isWritable ? 0 : Property.NOT_WRITABLE, getter, setter)); } } targetObj.addBoundProperties(source, properties.toArray(new AccessorProperty[0])); } private static MethodHandle getBoundBeanMethodGetter(final Object source, final MethodHandle methodGetter) { try { // NOTE: we're relying on the fact that StandardOperation.GET_METHOD return value is constant for any given method // name and object linked with BeansLinker. (Actually, an even stronger assumption is true: return value is // constant for any given method name and object's class.) return MethodHandles.dropArguments(MethodHandles.constant(Object.class, Bootstrap.bindCallable(methodGetter.invoke(source), source, null)), 0, Object.class); } catch(RuntimeException|Error e) { throw e; } catch(final Throwable t) { throw new RuntimeException(t); } } private static MethodHandle getBeanOperation(final GuardingDynamicLinker linker, final Operation operation, final String name, final MethodType methodType, final Object source) { final GuardedInvocation inv; try { inv = NashornBeansLinker.getGuardedInvocation(linker, createLinkRequest(operation.named(name), methodType, source), Bootstrap.getLinkerServices()); assert passesGuard(source, inv.getGuard()); } catch(RuntimeException|Error e) { throw e; } catch(final Throwable t) { throw new RuntimeException(t); } assert inv.getSwitchPoints() == null; // Linkers in Dynalink's beans package don't use switchpoints. // We discard the guard, as all method handles will be bound to a specific object. return inv.getInvocation(); } private static boolean passesGuard(final Object obj, final MethodHandle guard) throws Throwable { return guard == null || (boolean)guard.invoke(obj); } private static LinkRequest createLinkRequest(final Operation operation, final MethodType methodType, final Object source) { return new SimpleLinkRequest(new CallSiteDescriptor(MethodHandles.publicLookup(), operation, methodType), false, source); } private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { return MH.findStatic(MethodHandles.lookup(), NativeObject.class, name, MH.type(rtype, types)); } }