2.2 Limitations of the HTML Protocol Adaptor

The HTML protocol adaptor has the following limitations:

• The minimum value for the reload period is 5 seconds. The value 0 defaults to no reloading.

• Arrays of classes are always displayed in read-only mode.

• Arrays of dimension 2 and higher are not fully expanded.

• Supported attribute types for reading and writing are as follows.

  • boolean boolean[] Boolean Boolean[]

  • byte Byte Byte[]

  • char char[] Character Character[]

  • Date Date[] (for example, July 21st, 2002 8:49:04 PM CEST)

  • double double[] Double Double[]

  • float float[] Float Float[]

  • int int[] Integer Integer[]

  • long Long Long[]

  • Number

  • javax.management.ObjectName javax.management.ObjectName[]

  • short Short Short[]

  • String String[]

  In addition, com.sun.jdmk.Enumerated is supported for readable attributes. Because com.sun.jdmk.Enumerated is an abstract class, only write-only attributes whose actual subclass is declared in the signature of its setter can be set through the HTML adaptor.

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  Note –

  For unsupported read-only attribute types, if not null, the toString() method is called. If the getter of a read-only or a read-write attribute throws an exception, the thrown exception name and message are displayed. In this case, this attribute cannot be set through the HTML adaptor even if it is a read-write attribute.

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• Supported operation and constructor parameter types are as follows:

  • boolean Boolean

  • byte Byte

  • char Character

  • Date (for example, July 21st, 2002 8:49:04 PM CEST)

  • double Double

  • float Float

  • int Integer

  • long Long

  • Number

  • javax.management.ObjectName

  • short Short

  • String

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  Note –

  When reading a value of type Number, the server tries to convert it first to an Integer, then a Long, then a Float, and finally a Double. The server stops at the first primitive type that succeeds.

  Use the “Reload” button displayed in the HTML page of an MBean view rather than the reload button of the web browser. Otherwise, you might reinvoke the setters of all attributes, if this was your last action.

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