ojluni/src/main/java/com/sun/script/javascript/JSAdapter.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
  * 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.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package com.sun.script.javascript;

 import sun.org.mozilla.javascript.internal.*;
 import java.util.*;

 /**
  * JSAdapter is java.lang.reflect.Proxy equivalent for JavaScript. JSAdapter
  * calls specially named JavaScript methods on an adaptee object when property
  * access is attempted on it.
  *
  * Example:
  *
  *    var y = {
  *                __get__    : function (name) { ... }
  *                __has__    : function (name) { ... }
  *                __put__    : function (name, value) {...}
  *                __delete__ : function (name) { ... }
  *                __getIds__ : function () { ... }
  *            };
  *
  *    var x = new JSAdapter(y);
  *
  *    x.i;                        // calls y.__get__
  *    i in x;                     // calls y.__has__
  *    x.p = 10;                   // calls y.__put__
  *    delete x.p;                 // calls y.__delete__
  *    for (i in x) { print(i); }  // calls y.__getIds__
  *
  * If a special JavaScript method is not found in the adaptee, then JSAdapter
  * forwards the property access to the adaptee itself.
  *
  * JavaScript caller of adapter object is isolated from the fact that
  * the property access/mutation/deletion are really calls to
  * JavaScript methods on adaptee.  Use cases include 'smart'
  * properties, property access tracing/debugging, encaptulation with
  * easy client access - in short JavaScript becomes more "Self" like.
  *
  * Note that Rhino already supports special properties like __proto__
  * (to set, get prototype), __parent__ (to set, get parent scope). We
  * follow the same double underscore nameing convention here. Similarly
  * the name JSAdapter is derived from JavaAdapter -- which is a facility
  * to extend, implement Java classes/interfaces by JavaScript.
  *
  * @author A. Sundararajan
  * @since 1.6
  */
 public final class JSAdapter implements Scriptable, Function {
     private JSAdapter(Scriptable obj) {
         setAdaptee(obj);
     }

     // initializer to setup JSAdapter prototype in the given scope
     public static void init(Context cx, Scriptable scope, boolean sealed)
     throws RhinoException {
         JSAdapter obj = new JSAdapter(cx.newObject(scope));
         obj.setParentScope(scope);
         obj.setPrototype(getFunctionPrototype(scope));
         obj.isPrototype = true;
         ScriptableObject.defineProperty(scope, "JSAdapter",  obj,
                 ScriptableObject.DONTENUM);
     }

     public String getClassName() {
         return "JSAdapter";
     }

     public Object get(String name, Scriptable start) {
         Function func = getAdapteeFunction(GET_PROP);
         if (func != null) {
             return call(func, new Object[] { name });
         } else {
             start = getAdaptee();
             return start.get(name, start);
         }
     }

     public Object get(int index, Scriptable start) {
         Function func = getAdapteeFunction(GET_PROP);
         if (func != null) {
             return call(func, new Object[] { new Integer(index) });
         } else {
             start = getAdaptee();
             return start.get(index, start);
         }
     }

     public boolean has(String name, Scriptable start) {
         Function func = getAdapteeFunction(HAS_PROP);
         if (func != null) {
             Object res = call(func, new Object[] { name });
             return Context.toBoolean(res);
         } else {
             start = getAdaptee();
             return start.has(name, start);
         }
     }

     public boolean has(int index, Scriptable start) {
         Function func = getAdapteeFunction(HAS_PROP);
         if (func != null) {
             Object res = call(func, new Object[] { new Integer(index) });
             return Context.toBoolean(res);
         } else {
             start = getAdaptee();
             return start.has(index, start);
         }
     }

     public void put(String name, Scriptable start, Object value) {
         if (start == this) {
             Function func = getAdapteeFunction(PUT_PROP);
             if (func != null) {
                 call(func, new Object[] { name, value });
             } else {
                 start = getAdaptee();
                 start.put(name, start, value);
             }
         } else {
             start.put(name, start, value);
         }
     }

     public void put(int index, Scriptable start, Object value) {
         if (start == this) {
             Function func = getAdapteeFunction(PUT_PROP);
             if( func != null) {
                 call(func, new Object[] { new Integer(index), value });
             } else {
                 start = getAdaptee();
                 start.put(index, start, value);
             }
         } else {
             start.put(index, start, value);
         }
     }

     public void delete(String name) {
         Function func = getAdapteeFunction(DEL_PROP);
         if (func != null) {
             call(func, new Object[] { name });
         } else {
             getAdaptee().delete(name);
         }
     }

     public void delete(int index) {
         Function func = getAdapteeFunction(DEL_PROP);
         if (func != null) {
             call(func, new Object[] { new Integer(index) });
         } else {
             getAdaptee().delete(index);
         }
     }

     public Scriptable getPrototype() {
         return prototype;
     }

     public void setPrototype(Scriptable prototype) {
         this.prototype = prototype;
     }

     public Scriptable getParentScope() {
         return parent;
     }

     public void setParentScope(Scriptable parent) {
         this.parent = parent;
     }

     public Object[] getIds() {
         Function func = getAdapteeFunction(GET_PROPIDS);
         if (func != null) {
             Object val = call(func, new Object[0]);
             // in most cases, adaptee would return native JS array
             if (val instanceof NativeArray) {
                 NativeArray array = (NativeArray) val;
                 Object[] res = new Object[(int)array.getLength()];
                 for (int index = 0; index < res.length; index++) {
                     res[index] = mapToId(array.get(index, array));
                 }
                 return res;
             } else if (val instanceof NativeJavaArray) {
                 // may be attempt wrapped Java array
                 Object tmp = ((NativeJavaArray)val).unwrap();
                 Object[] res;
                 if (tmp.getClass() == Object[].class) {
                     Object[]  array = (Object[]) tmp;
                     res = new Object[array.length];
                     for (int index = 0; index < array.length; index++) {
                         res[index] = mapToId(array[index]);
                     }
                 } else {
                     // just return an empty array
                     res = Context.emptyArgs;
                 }
                 return res;
             } else {
                 // some other return type, just return empty array
                 return Context.emptyArgs;
             }
         } else {
             return getAdaptee().getIds();
         }
     }

     public boolean hasInstance(Scriptable scriptable) {
         if (scriptable instanceof JSAdapter) {
             return true;
         } else {
             Scriptable proto = scriptable.getPrototype();
             while (proto != null) {
                 if (proto.equals(this)) return true;
                 proto = proto.getPrototype();
             }
             return false;
         }
     }

     public Object getDefaultValue(Class hint) {
         return getAdaptee().getDefaultValue(hint);
     }

     public Object call(Context cx, Scriptable scope, Scriptable thisObj,
             Object[] args)
             throws RhinoException {
         if (isPrototype) {
             return construct(cx, scope, args);
         } else {
             Scriptable tmp = getAdaptee();
             if (tmp instanceof Function) {
                 return ((Function)tmp).call(cx, scope, tmp, args);
             } else {
                 throw Context.reportRuntimeError("TypeError: not a function");
             }
         }
     }

     public Scriptable construct(Context cx, Scriptable scope, Object[] args)
     throws RhinoException {
         if (isPrototype) {
             Scriptable topLevel = ScriptableObject.getTopLevelScope(scope);
             JSAdapter newObj;
             if (args.length > 0) {
                 newObj = new JSAdapter(Context.toObject(args[0], topLevel));
             } else {
                 throw Context.reportRuntimeError("JSAdapter requires adaptee");
             }
             return newObj;
         } else {
             Scriptable tmp = getAdaptee();
             if (tmp instanceof Function) {
                 return ((Function)tmp).construct(cx, scope, args);
             } else {
                 throw Context.reportRuntimeError("TypeError: not a constructor");
             }
         }
     }

     public Scriptable getAdaptee() {
         return adaptee;
     }

     public void setAdaptee(Scriptable adaptee) {
         if (adaptee == null) {
             throw new NullPointerException("adaptee can not be null");
         }
         this.adaptee = adaptee;
     }

     //-- internals only below this point

     // map a property id. Property id can only be an Integer or String
     private Object mapToId(Object tmp) {
         if (tmp instanceof Double) {
             return new Integer(((Double)tmp).intValue());
         } else {
             return Context.toString(tmp);
         }
     }

     private static Scriptable getFunctionPrototype(Scriptable scope) {
         return ScriptableObject.getFunctionPrototype(scope);
     }

     private Function getAdapteeFunction(String name) {
         Object o = ScriptableObject.getProperty(getAdaptee(), name);
         return (o instanceof Function)? (Function)o : null;
     }

     private Object call(Function func, Object[] args) {
         Context cx = Context.getCurrentContext();
         Scriptable thisObj = getAdaptee();
         Scriptable scope = func.getParentScope();
         try {
             return func.call(cx, scope, thisObj, args);
         } catch (RhinoException re) {
             throw Context.reportRuntimeError(re.getMessage());
         }
     }

     private Scriptable prototype;
     private Scriptable parent;
     private Scriptable adaptee;
     private boolean isPrototype;

     // names of adaptee JavaScript functions
     private static final String GET_PROP = "__get__";
     private static final String HAS_PROP = "__has__";
     private static final String PUT_PROP = "__put__";
     private static final String DEL_PROP = "__delete__";
     private static final String GET_PROPIDS = "__getIds__";
 }
	/*
	* Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
	* 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.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.script.javascript;

	import sun.org.mozilla.javascript.internal.*;
	import java.util.*;

	/**
	* JSAdapter is java.lang.reflect.Proxy equivalent for JavaScript. JSAdapter
	* calls specially named JavaScript methods on an adaptee object when property
	* access is attempted on it.
	*
	* Example:
	*
	* var y = {
	* __get__ : function (name) { ... }
	* __has__ : function (name) { ... }
	* __put__ : function (name, value) {...}
	* __delete__ : function (name) { ... }
	* __getIds__ : function () { ... }
	* };
	*
	* var x = new JSAdapter(y);
	*
	* x.i; // calls y.__get__
	* i in x; // calls y.__has__
	* x.p = 10; // calls y.__put__
	* delete x.p; // calls y.__delete__
	* for (i in x) { print(i); } // calls y.__getIds__
	*
	* If a special JavaScript method is not found in the adaptee, then JSAdapter
	* forwards the property access to the adaptee itself.
	*
	* JavaScript caller of adapter object is isolated from the fact that
	* the property access/mutation/deletion are really calls to
	* JavaScript methods on adaptee. Use cases include 'smart'
	* properties, property access tracing/debugging, encaptulation with
	* easy client access - in short JavaScript becomes more "Self" like.
	*
	* Note that Rhino already supports special properties like __proto__
	* (to set, get prototype), __parent__ (to set, get parent scope). We
	* follow the same double underscore nameing convention here. Similarly
	* the name JSAdapter is derived from JavaAdapter -- which is a facility
	* to extend, implement Java classes/interfaces by JavaScript.
	*
	* @author A. Sundararajan
	* @since 1.6
	*/
	public final class JSAdapter implements Scriptable, Function {
	private JSAdapter(Scriptable obj) {
	setAdaptee(obj);
	}

	// initializer to setup JSAdapter prototype in the given scope
	public static void init(Context cx, Scriptable scope, boolean sealed)
	throws RhinoException {
	JSAdapter obj = new JSAdapter(cx.newObject(scope));
	obj.setParentScope(scope);
	obj.setPrototype(getFunctionPrototype(scope));
	obj.isPrototype = true;
	ScriptableObject.defineProperty(scope, "JSAdapter", obj,
	ScriptableObject.DONTENUM);
	}

	public String getClassName() {
	return "JSAdapter";
	}

	public Object get(String name, Scriptable start) {
	Function func = getAdapteeFunction(GET_PROP);
	if (func != null) {
	return call(func, new Object[] { name });
	} else {
	start = getAdaptee();
	return start.get(name, start);
	}
	}

	public Object get(int index, Scriptable start) {
	Function func = getAdapteeFunction(GET_PROP);
	if (func != null) {
	return call(func, new Object[] { new Integer(index) });
	} else {
	start = getAdaptee();
	return start.get(index, start);
	}
	}

	public boolean has(String name, Scriptable start) {
	Function func = getAdapteeFunction(HAS_PROP);
	if (func != null) {
	Object res = call(func, new Object[] { name });
	return Context.toBoolean(res);
	} else {
	start = getAdaptee();
	return start.has(name, start);
	}
	}

	public boolean has(int index, Scriptable start) {
	Function func = getAdapteeFunction(HAS_PROP);
	if (func != null) {
	Object res = call(func, new Object[] { new Integer(index) });
	return Context.toBoolean(res);
	} else {
	start = getAdaptee();
	return start.has(index, start);
	}
	}

	public void put(String name, Scriptable start, Object value) {
	if (start == this) {
	Function func = getAdapteeFunction(PUT_PROP);
	if (func != null) {
	call(func, new Object[] { name, value });
	} else {
	start = getAdaptee();
	start.put(name, start, value);
	}
	} else {
	start.put(name, start, value);
	}
	}

	public void put(int index, Scriptable start, Object value) {
	if (start == this) {
	Function func = getAdapteeFunction(PUT_PROP);
	if( func != null) {
	call(func, new Object[] { new Integer(index), value });
	} else {
	start = getAdaptee();
	start.put(index, start, value);
	}
	} else {
	start.put(index, start, value);
	}
	}

	public void delete(String name) {
	Function func = getAdapteeFunction(DEL_PROP);
	if (func != null) {
	call(func, new Object[] { name });
	} else {
	getAdaptee().delete(name);
	}
	}

	public void delete(int index) {
	Function func = getAdapteeFunction(DEL_PROP);
	if (func != null) {
	call(func, new Object[] { new Integer(index) });
	} else {
	getAdaptee().delete(index);
	}
	}

	public Scriptable getPrototype() {
	return prototype;
	}

	public void setPrototype(Scriptable prototype) {
	this.prototype = prototype;
	}

	public Scriptable getParentScope() {
	return parent;
	}

	public void setParentScope(Scriptable parent) {
	this.parent = parent;
	}

	public Object[] getIds() {
	Function func = getAdapteeFunction(GET_PROPIDS);
	if (func != null) {
	Object val = call(func, new Object[0]);
	// in most cases, adaptee would return native JS array
	if (val instanceof NativeArray) {
	NativeArray array = (NativeArray) val;
	Object[] res = new Object[(int)array.getLength()];
	for (int index = 0; index < res.length; index++) {
	res[index] = mapToId(array.get(index, array));
	}
	return res;
	} else if (val instanceof NativeJavaArray) {
	// may be attempt wrapped Java array
	Object tmp = ((NativeJavaArray)val).unwrap();
	Object[] res;
	if (tmp.getClass() == Object[].class) {
	Object[] array = (Object[]) tmp;
	res = new Object[array.length];
	for (int index = 0; index < array.length; index++) {
	res[index] = mapToId(array[index]);
	}
	} else {
	// just return an empty array
	res = Context.emptyArgs;
	}
	return res;
	} else {
	// some other return type, just return empty array
	return Context.emptyArgs;
	}
	} else {
	return getAdaptee().getIds();
	}
	}

	public boolean hasInstance(Scriptable scriptable) {
	if (scriptable instanceof JSAdapter) {
	return true;
	} else {
	Scriptable proto = scriptable.getPrototype();
	while (proto != null) {
	if (proto.equals(this)) return true;
	proto = proto.getPrototype();
	}
	return false;
	}
	}

	public Object getDefaultValue(Class hint) {
	return getAdaptee().getDefaultValue(hint);
	}

	public Object call(Context cx, Scriptable scope, Scriptable thisObj,
	Object[] args)
	throws RhinoException {
	if (isPrototype) {
	return construct(cx, scope, args);
	} else {
	Scriptable tmp = getAdaptee();
	if (tmp instanceof Function) {
	return ((Function)tmp).call(cx, scope, tmp, args);
	} else {
	throw Context.reportRuntimeError("TypeError: not a function");
	}
	}
	}

	public Scriptable construct(Context cx, Scriptable scope, Object[] args)
	throws RhinoException {
	if (isPrototype) {
	Scriptable topLevel = ScriptableObject.getTopLevelScope(scope);
	JSAdapter newObj;
	if (args.length > 0) {
	newObj = new JSAdapter(Context.toObject(args[0], topLevel));
	} else {
	throw Context.reportRuntimeError("JSAdapter requires adaptee");
	}
	return newObj;
	} else {
	Scriptable tmp = getAdaptee();
	if (tmp instanceof Function) {
	return ((Function)tmp).construct(cx, scope, args);
	} else {
	throw Context.reportRuntimeError("TypeError: not a constructor");
	}
	}
	}

	public Scriptable getAdaptee() {
	return adaptee;
	}

	public void setAdaptee(Scriptable adaptee) {
	if (adaptee == null) {
	throw new NullPointerException("adaptee can not be null");
	}
	this.adaptee = adaptee;
	}

	//-- internals only below this point

	// map a property id. Property id can only be an Integer or String
	private Object mapToId(Object tmp) {
	if (tmp instanceof Double) {
	return new Integer(((Double)tmp).intValue());
	} else {
	return Context.toString(tmp);
	}
	}

	private static Scriptable getFunctionPrototype(Scriptable scope) {
	return ScriptableObject.getFunctionPrototype(scope);
	}

	private Function getAdapteeFunction(String name) {
	Object o = ScriptableObject.getProperty(getAdaptee(), name);
	return (o instanceof Function)? (Function)o : null;
	}

	private Object call(Function func, Object[] args) {
	Context cx = Context.getCurrentContext();
	Scriptable thisObj = getAdaptee();
	Scriptable scope = func.getParentScope();
	try {
	return func.call(cx, scope, thisObj, args);
	} catch (RhinoException re) {
	throw Context.reportRuntimeError(re.getMessage());
	}
	}

	private Scriptable prototype;
	private Scriptable parent;
	private Scriptable adaptee;
	private boolean isPrototype;

	// names of adaptee JavaScript functions
	private static final String GET_PROP = "__get__";
	private static final String HAS_PROP = "__has__";
	private static final String PUT_PROP = "__put__";
	private static final String DEL_PROP = "__delete__";
	private static final String GET_PROPIDS = "__getIds__";
	}