2001-04-24 20:31:31 +00:00
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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta name="Author" content="Norris Boyd">
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<meta name="GENERATOR" content="Mozilla/4.72 [en]C-NSCP (WinNT; U) [Netscape]">
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<title>JavaScript Requirements and Limitations</title>
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</head>
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<body bgcolor="#FFFFFF">
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<center>
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<h1>
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Requirements and Limitations</h1></center>
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<h2>
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<b>Requirements</b></h2>
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Rhino requires version 1.1 or greater of Java.
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<p>To use the JavaAdapter feature or an optimization level of 0 or greater,
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Rhino must be running under a security manager that allows the definition
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of class loaders.
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<p>
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<hr WIDTH="100%">
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<h2>
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<b>Limitations</b></h2>
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<h3>
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<b>Platforms and </b>JITs</h3>
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Many platforms and JREs have problems converting decimal numbers to and
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from strings. These errors are usually boundary case errors and will show
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up as test failures in section 7.7.3.
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<p>Windows versions of the Symantec JIT prior to 3.00.029(i) will report
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internal errors for some generated class files.
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<p>On the Symantec JIT and the AIX JVM, accessing a static field of a class
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that has not yet loaded may not give the correct value of the field. For
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example, accessing
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<tt>java.io.File.separatorChar</tt> before <tt>java.io.File</tt>
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has been loaded will return a value of 0. (This is a bug in the JIT; accessing
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the field should cause the class to be loaded.)
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<p>The AIX Java version "JDK 1.1.6 IBM build a116-19980924 (JIT enabled:
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jitc)" core dumps running several classes generated by Rhino. It also has
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errors in java.lang.Math.pow that are reflected as failures in the JavaScript
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Math object's pow method.
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<p>IBM Java for Linux version "JDK 1.1.8 IBM build l118-19991013 (JIT enabled:
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jitc)" has errors in java.lang.Math.pow that are reflected as test failures
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in the JavaScript Math object's pow method.
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<p>Solaris JDK 1.1.6 has errors in java.lang.Math.atan2 that are reflected
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as test failures in the JavaScript Math object's atan2 method.
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<br>
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<h3>
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<b>LiveConnect</b></h3>
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If a JavaObject's field's name collides with that of a method, the value
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of that field is retrieved lazily, and can be counter-intuitively affected
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by later assignments:
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<blockquote><tt>javaObj.fieldAndMethod = 5;</tt>
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<br><tt>var field = javaObj.fieldAndMethod;</tt>
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<br><tt>javaObj.fieldAndMethod = 7;</tt>
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<br><tt>// now, field == 7</tt></blockquote>
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You can work around this by forcing the field value to be converted to
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a JavaScript type when you take its value:
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<blockquote><tt>javaObj.fieldAndMethod = 5;</tt>
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<br><tt>var field = javaObj.fieldAndMethod + 0; // force conversion now</tt>
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<br><tt>javaObj.fieldAndMethod = 7;</tt>
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<br><tt>// now, field == 5</tt></blockquote>
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<h3>
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<b>JSObject</b></h3>
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Rhino does NOT support the <tt>netscape.javascript.JSObject</tt> class.
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<br>
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<h3>
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<b>Date object</b></h3>
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The JavaScript Date object depends on time facilities of the underlying
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Java runtime to determine daylight savings time dates. Earlier JRE versions
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may report a date for the daylight savings changeover that is a week off.
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JRE 1.1.6 reports the correct date.
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<p>Under the 1.1.6 JRE, evaluating <tt>(new Date(1998, 9, 25, 2)).toString()</tt>
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returns:
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<pre> Sun Oct 25 02:00:00 GMT-0800 (PST) 1998</pre>
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Earlier versions may return:
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<pre> Sun Oct 25 02:00:00 GMT-0700 (PDT) 1998</pre>
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(the JRE doesn't report the changeover until Nov. 1.)
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<p>The Microsoft SDK 3.1 for Java also exhibits this problem.
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<p>
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<hr WIDTH="100%">
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2005-09-19 11:37:42 +00:00
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<br><a href="#">back to top</a>
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2001-04-24 20:31:31 +00:00
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</html>
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