gecko-dev/js/rhino/examples/Foo.java

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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is Rhino code, released
* May 6, 1998.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1997-1999 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU Public License (the "GPL"), in which case the
* provisions of the GPL are applicable instead of those above.
* If you wish to allow use of your version of this file only
* under the terms of the GPL and not to allow others to use your
* version of this file under the NPL, indicate your decision by
* deleting the provisions above and replace them with the notice
* and other provisions required by the GPL. If you do not delete
* the provisions above, a recipient may use your version of this
* file under either the NPL or the GPL.
*/
import org.mozilla.javascript.*;
/**
* An example host object class.
*
* Here's a shell session showing the Foo object in action:
* <pre>
* js> defineClass("Foo")
* js> foo = new Foo(); <i>A constructor call, see <a href="#Foo">Foo</a> below.</i>
* [object Foo] <i>The "Foo" here comes from <a href"#getClassName">getClassName</a>.</i>
* js> foo.counter; <i>The counter property is defined by the <code>defineProperty</code></i>
* 0 <i>call below and implemented by the <a href="#getCounter">getCounter</a></i>
* js> foo.counter; <i>method below.</i>
* 1
* js> foo.counter;
* 2
* js> foo.resetCounter(); <i>Results in a call to <a href="#resetCounter">resetCounter</a>.</i>
* js> foo.counter; <i>Now the counter has been reset.</i>
* 0
* js> foo.counter;
* 1
* js> bar = new Foo(37); <i>Create a new instance.</i>
* [object Foo]
* js> bar.counter; <i>This instance's counter is distinct from</i>
* 37 <i>the other instance's counter.</i>
* js> foo.varargs(3, "hi"); <i>Calls <a href="#varargs">varargs</a>.</i>
* this = [object Foo]; args = [3, hi]
* js> foo[7] = 34; <i>Since we extended ScriptableObject, we get</i>
* 34 <i>all the behavior of a JavaScript object</i>
* js> foo.a = 23; <i>for free.</i>
* 23
* js> foo.a + foo[7];
* 57
* js>
* </pre>
*
* @see org.mozilla.javascript.Context
* @see org.mozilla.javascript.Scriptable
* @see org.mozilla.javascript.ScriptableObject
*
* @author Norris Boyd
*/
public class Foo extends ScriptableObject {
/**
* The zero-parameter constructor.
*
* When Context.defineClass is called with this class, it will
* construct Foo.prototype using this constructor.
*/
public Foo() {
}
/**
* The Java method defining the JavaScript Foo constructor.
*
* Takes an initial value for the counter property.
* Note that in the example Shell session above, we didn't
* supply a argument to the Foo constructor. This means that
* the Undefined value is used as the value of the argument,
* and when the argument is converted to an integer, Undefined
* becomes 0.
*/
public Foo(int counterStart) {
counter = counterStart;
}
/**
* Returns the name of this JavaScript class, "Foo".
*/
public String getClassName() {
return "Foo";
}
/**
* The Java method defining the JavaScript resetCounter function.
*
* Resets the counter to 0.
*/
public void jsFunction_resetCounter() {
counter = 0;
}
/**
* The Java method implementing the getter for the counter property.
* <p>
* If "setCounter" had been defined in this class, the runtime would
* call the setter when the property is assigned to.
*/
public int jsGet_counter() {
return counter++;
}
/**
* An example of a variable-arguments method.
*
* All variable arguments methods must have the same number and
* types of parameters, and must be static. <p>
* @param cx the Context of the current thread
* @param thisObj the JavaScript 'this' value.
* @param args the array of arguments for this call
* @param funObj the function object of the invoked JavaScript function
* This value is useful to compute a scope using
* Context.getTopLevelScope().
* @return computes the string values and types of 'this' and
* of each of the supplied arguments and returns them in a string.
*
* @exception ThreadAssociationException if the current
* thread is not associated with a Context
* @see org.mozilla.javascript.ScriptableObject#getTopLevelScope
*/
public static Object jsFunction_varargs(Context cx, Scriptable thisObj,
Object[] args, Function funObj)
{
StringBuffer buf = new StringBuffer();
buf.append("this = ");
buf.append(Context.toString(thisObj));
buf.append("; args = [");
for (int i=0; i < args.length; i++) {
buf.append(Context.toString(args[i]));
if (i+1 != args.length)
buf.append(", ");
}
buf.append("]");
return buf.toString();
}
/**
* A piece of private data for this class.
*/
private int counter;
}