gecko-dev/js/rhino/docs/rhino15R1.html
2005-09-19 11:37:42 +00:00

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<meta name="Author" content="Norris Boyd">
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<meta name="KeyWords" content="Rhino, JavaScript, Java">
<title>What's New in Rhino 1.5</title>
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<h1>
What's New in Rhino 1.5 Release 1</h1></center>
<h2>
ECMA 262 Edition 3 Conformance</h2>
Rhino 1.5 implements JavaScript 1.5, which conforms to ECMA 262 Edition
3 (sometimes referred to as "ECMAScript"). Edition 3 standardized several
features of JavaScript that were present in JavaScript 1.4, including:
<ul>
<li>
regular expressions</li>
<li>
<tt>switch</tt> statements</li>
<li>
<tt>do</tt>...<tt>while</tt> loops</li>
<li>
statement labels and labelled <tt>break</tt> and <tt>continue</tt></li>
<li>
object literals</li>
<li>
nested functions</li>
<li>
exception handling</li>
<li>
the <tt>instanceof</tt> operator</li>
<li>
the <tt>in</tt> operator</li>
</ul>
In addition, new features were added to Edition 3 and JavaScript 1.5, including:
<ul>
<li>
Perl 5 regular expressions, including operators like greedy quantifiers</li>
<li>
errors as exceptions</li>
<li>
number formatting (<tt>Number.prototype.toFixed</tt>, <tt>Number.prototype.toExponential</tt>,
and <tt>Number.prototype.toGeneral</tt>)</li>
</ul>
<h2>
Changes since Rhino 1.4 Release 3</h2>
Other significant changes to Rhino since the initial release to open source
(1.4 Release 3) are listed below. Bug fixes won't be mentioned here, just
API changes or significant functionality changes.
<h3>
Compilation mode</h3>
Rhino has two modes of execution available. Interpretive mode has an interpreter
loop implemented in Java. Compilation mode compiles JavaScript code to
Java bytecodes in class files. This compilation can be done as part of
script evaluation using the same APIs already available for the interpreter,
or in a separate compile-time step. The code for the interpreter is located
in the <tt>org.mozilla.javascript.optimizer</tt> package.
<br>&nbsp;
<h3>
JavaScript Compiler</h3>
The distribution now contains an extra class that can be invoked from the
command line. This is <tt>jsc</tt>, the JavaScript compiler. This tool
can be used to create Java classes from JavaScript. Options exist to allow
creation of Java classes that implement arbitrary interfaces and extend
arbitrary base classes, allowing JavaScript scripts to implement important
protocols like applets and servlets. See <a href="jsc.html">http://www.mozilla.org/rhino/jsc.html</a>.
<br>&nbsp;
<h3>
LiveConnect 3</h3>
Rhino now supports the LiveConnect 3 specification, or LC3. The most notable
change is support for overloaded method resolution. See <a href="http://www.mozilla.org/js/liveconnect/lc3_proposal.html">LiveConnect
Release 3 Goals/Features</a>.
<br>&nbsp;
<h3>
JavaBeans properties reflected as Java properties</h3>
Java classes with getFoo/setFoo methods will have a "foo" property in the
JavaScript reflection. Boolean methods are also reflected.
<br>&nbsp;
<h3>
Dynamic scope support</h3>
Rhino 1.5 implements support for dynamic scopes, which are particularly
useful for multithreaded environments like server embeddings.
<br>&nbsp;
<h3>
New semantics for <tt>ScriptableObject.defineClass</tt></h3>
The old rules for defining JavaScript objects using a Java class were getting
baroque. Those rules are still supported, but a cleaner definition is now
supported. See the <a href="apidocs/org/mozilla/javascript/ScriptableObject.html#defineClass(org.mozilla.javascript.Scriptable, java.lang.Class)">javadoc</a>
for details.
<br>&nbsp;
<h3>
Support for the Java 2 <tt>-jar</tt> option</h3>
It's now possible to start the shell using the new <tt>-jar</tt> option
in Java 2.
<br>&nbsp;
<h3>
Shell changes</h3>
Two changes here: addition of the "environment" and "history" top-level
variables.
<br>&nbsp;
<h3>
Java classes visible to scripts</h3>
An attendee at JavaOne raised the point that many embeddings may not want
scripts to be able to access all Java classes. This is an excellent point,
and I've implemented an addition to the <a href="apidocs/org/mozilla/javascript/SecuritySupport.html">SecuritySupport</a>
interface that allows embedders to choose which classes are exposed to
scripts.
<br>&nbsp;
<h3>
SecuritySupport and JavaAdapter</h3>
Andrew Wason pointed a problem with the new JavaAdapter feature (which
allows JavaScript objects to implement arbitrary Java interfaces by generating
class files). It didn't support the <a href="apidocs/org/mozilla/javascript/SecuritySupport.html">SecuritySupport</a>
interface, which allows Rhino to delegate the creation of classes from
byte arrays to a routine provided by the embedding. This ability is important
from a security standpoint because class creation is considered a privileged
action.
<p>I've checked in changes that fix this problem. If a SecuritySupport
class is specified when a Context is created, uses of JavaAdapter will
will delegate class creation to the SecuritySupport class.
<br>&nbsp;
<h3>
Context.exit()</h3>
Context.exit() has been changed from an instance method to a static method.
This makes it match the Context.enter() method, which is also static. See
the <a href="apidocs/org/mozilla/javascript/Context.html#exit()">javadoc</a>
for more information on its operation.
<br>&nbsp;
<h3>
Context.enter(Context)</h3>
A new overloaded form of Context.enter has been added. Without the addition
of this method it was not possible to attach an existing context to a thread.
See the <a href="apidocs/org/mozilla/javascript/Context.html#enter(org.mozilla.javascript.Context)">javadoc</a>
for more information on its operation.
<br>&nbsp;
<h3>
Listeners for Context</h3>
Context now supports property change listeners for a couple of its properties.
<h3>
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