JavaTM 2 Platform
Standard Ed. 5.0

javax.management.modelmbean
Class DescriptorSupport

java.lang.Object
  extended by javax.management.modelmbean.DescriptorSupport
All Implemented Interfaces:
Serializable, Cloneable, Descriptor

public class DescriptorSupport
extends Object
implements Descriptor

This class represents the metadata set for a ModelMBean element. A descriptor is part of the ModelMBeanInfo, ModelMBeanNotificationInfo, ModelMBeanAttributeInfo, ModelMBeanConstructorInfo, and ModelMBeanParameterInfo.

A descriptor consists of a collection of fields. Each field is in fieldname=fieldvalue format. Field names are not case sensitive, case will be preserved on field values.

All field names and values are not predefined. New fields can be defined and added by any program. Some fields have been predefined for consistency of implementation and support by the ModelMBeanInfo, ModelMBeanAttributeInfo, ModelMBeanConstructorInfo, ModelMBeanNotificationInfo, ModelMBeanOperationInfo and ModelMBean classes.

Since:
1.5
See Also:
Serialized Form

Constructor Summary
DescriptorSupport()
          Descriptor default constructor.
DescriptorSupport(DescriptorSupport inDescr)
          Descriptor constructor taking a Descriptor as parameter.
DescriptorSupport(int initNumFields)
          Descriptor constructor.
DescriptorSupport(String inStr)
          Descriptor constructor taking an XML String.
DescriptorSupport(String[] fields)
          Constructor taking fields in the fieldName=fieldValue format.
DescriptorSupport(String[] fieldNames, Object[] fieldValues)
          Constructor taking field names and field values.
 
Method Summary
 Object clone()
          Returns a new Descriptor which is a duplicate of the Descriptor.
 String[] getFieldNames()
          Returns all the fields names in the descriptor.
 String[] getFields()
          Returns all the fields in the descriptor.
 Object getFieldValue(String inFieldName)
          Returns the value for a specific fieldname.
 Object[] getFieldValues(String[] fieldNames)
          Returns all the field values in the descriptor as an array of Objects.
 boolean isValid()
          Returns true if all of the fields have legal values given their names.
 void removeField(String fieldName)
          Removes a field from the descriptor.
 void setField(String inFieldName, Object fieldValue)
          Sets the string value for a specific fieldname.
 void setFields(String[] fieldNames, Object[] fieldValues)
          Sets all Fields in the list to the new value with the same index in the fieldValue array.
 String toString()
          Returns a human readable string representing the descriptor.
 String toXMLString()
          Returns an XML String representing the descriptor.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

DescriptorSupport

public DescriptorSupport()
Descriptor default constructor. Default initial descriptor size is 20. It will grow as needed.
Note that the created empty descriptor is not a valid descriptor (the method isValid returns false)


DescriptorSupport

public DescriptorSupport(int initNumFields)
                  throws MBeanException,
                         RuntimeOperationsException
Descriptor constructor. Takes as parameter the initial capacity of the Map that stores the descriptor fields. Capacity will grow as needed.
Note that the created empty descriptor is not a valid descriptor (the method isValid returns false).

Parameters:
initNumFields - The initial capacity of the Map that stores the descriptor fields.
Throws:
RuntimeOperationsException - for illegal value for initNumFields (<= 0)
MBeanException - Wraps a distributed communication Exception.

DescriptorSupport

public DescriptorSupport(DescriptorSupport inDescr)
Descriptor constructor taking a Descriptor as parameter. Creates a new descriptor initialized to the values of the descriptor passed in parameter.

Parameters:
inDescr - the descriptor to be used to initialize the constructed descriptor. If it is null or contains no descriptor fields, an empty Descriptor will be created.

DescriptorSupport

public DescriptorSupport(String inStr)
                  throws MBeanException,
                         RuntimeOperationsException,
                         XMLParseException

Descriptor constructor taking an XML String.

The format of the XML string is not defined, but an implementation must ensure that the string returned by toXMLString() on an existing descriptor can be used to instantiate an equivalent descriptor using this constructor.

In this implementation, all field values will be created as Strings. If the field values are not Strings, the programmer will have to reset or convert these fields correctly.

Parameters:
inStr - An XML-formatted string used to populate this Descriptor. The format is not defined, but any implementation must ensure that the string returned by method toXMLString on an existing descriptor can be used to instantiate an equivalent descriptor when instantiated using this constructor.
Throws:
RuntimeOperationsException - If the String inStr passed in parameter is null
XMLParseException - XML parsing problem while parsing the input String
MBeanException - Wraps a distributed communication Exception.

DescriptorSupport

public DescriptorSupport(String[] fieldNames,
                         Object[] fieldValues)
                  throws RuntimeOperationsException
Constructor taking field names and field values. The array and array elements cannot be null.

Parameters:
fieldNames - String array of field names. No elements of this array can be null.
fieldValues - Object array of the corresponding field values. Elements of the array can be null. The fieldValue must be valid for the fieldName (as defined in method isValid)

Note: array sizes of parameters should match. If both arrays are null or empty, then an empty descriptor is created.

Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. The array lengths must be equal. If the descriptor construction fails for any reason, this exception will be thrown.

DescriptorSupport

public DescriptorSupport(String[] fields)
Constructor taking fields in the fieldName=fieldValue format.

Parameters:
fields - String array with each element containing a field name and value. If this array is null or empty, then the default constructor will be executed. Null strings or empty strings will be ignored.

All field values should be Strings. If the field values are not Strings, the programmer will have to reset or convert these fields correctly.

Note: Each string should be of the form fieldName=fieldValue.

Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. The field must contain an "=". "=fieldValue", "fieldName", and "fieldValue" are illegal. FieldName cannot be null. "fieldName=" will cause the value to be null. If the descriptor construction fails for any reason, this exception will be thrown.
Method Detail

getFieldValue

public Object getFieldValue(String inFieldName)
                     throws RuntimeOperationsException
Returns the value for a specific fieldname.

Specified by:
getFieldValue in interface Descriptor
Parameters:
inFieldName - The field name in question; if not found, null is returned.
Returns:
An Object representing the field value
Throws:
RuntimeOperationsException - for illegal value (null or empty string) for field Names.

setField

public void setField(String inFieldName,
                     Object fieldValue)
              throws RuntimeOperationsException
Sets the string value for a specific fieldname. The value must be valid for the field (as defined in method isValid). If the field does not exist, it is added at the end of the Descriptor. If it does exist, the value is replaced.

Specified by:
setField in interface Descriptor
Parameters:
inFieldName - The field name to be set. Must not be null or empty string.
fieldValue - The field value to be set for the field name. Can be null or empty string.
Throws:
RuntimeOperationsException - for illegal value for field Names.

getFields

public String[] getFields()
Returns all the fields in the descriptor. The order is not the order in which the fields were set.

Specified by:
getFields in interface Descriptor
Returns:
String array of fields in the format fieldName=fieldValue. If there are no fields in the descriptor, then an empty String array is returned. If a fieldValue is not a String then the toString() method is called on it and its returned value is used as the value for the field enclosed in parenthesis.
See Also:
setFields(java.lang.String[], java.lang.Object[])

getFieldNames

public String[] getFieldNames()
Returns all the fields names in the descriptor. The order is not the order in which the fields were set.

Specified by:
getFieldNames in interface Descriptor
Returns:
String array of fields names. If the descriptor is empty, you will get an empty array.

getFieldValues

public Object[] getFieldValues(String[] fieldNames)
Returns all the field values in the descriptor as an array of Objects. The returned values are in the same order as the fieldNames String array parameter.

Specified by:
getFieldValues in interface Descriptor
Parameters:
fieldNames - String array of the names of the fields that the values should be returned for.
If the array is empty then an empty array will be returned.
If the array is 'null' then all values will be returned. The order is not the order in which the fields were set.
If a field name in the array does not exist, then null is returned for the matching array element being returned.
Returns:
Object array of field values. If the descriptor is empty, you will get an empty array.

setFields

public void setFields(String[] fieldNames,
                      Object[] fieldValues)
               throws RuntimeOperationsException
Sets all Fields in the list to the new value with the same index in the fieldValue array. Array sizes must match. The field value will be validated before it is set (by calling the method isValid). If it is not valid, then an exception will be thrown. If the arrays are empty, then no change will take effect.

Specified by:
setFields in interface Descriptor
Parameters:
fieldNames - String array of field names. The array and array elements cannot be null.
fieldValues - Object array of the corresponding field values. The array cannot be null. Elements of the array can be null.
Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. Neither can be null. The array lengths must be equal.
See Also:
getFields()

clone

public Object clone()
             throws RuntimeOperationsException
Returns a new Descriptor which is a duplicate of the Descriptor.

Specified by:
clone in interface Descriptor
Overrides:
clone in class Object
Returns:
a clone of this instance.
Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. If the descriptor construction fails for any reason, this exception will be thrown.
See Also:
Cloneable

removeField

public void removeField(String fieldName)
Removes a field from the descriptor.

Specified by:
removeField in interface Descriptor
Parameters:
fieldName - String name of the field to be removed. If the field is not found no exception is thrown.

isValid

public boolean isValid()
                throws RuntimeOperationsException
Returns true if all of the fields have legal values given their names.

This implementation does not support interoperating with a directory or lookup service. Thus, conforming to the specification, no checking is done on the "export" field.

Otherwise this implementation returns false if:

Specified by:
isValid in interface Descriptor
Returns:
true if the values are legal.
Throws:
RuntimeOperationsException - If the validity checking fails for any reason, this exception will be thrown.

toXMLString

public String toXMLString()

Returns an XML String representing the descriptor.

The format is not defined, but an implementation must ensure that the string returned by this method can be used to build an equivalent descriptor when instantiated using the constructor DescriptorSupport(String inStr).

Fields which are not String objects will have toString() called on them to create the value. The value will be enclosed in parentheses. It is not guaranteed that you can reconstruct these objects unless they have been specifically set up to support toString() in a meaningful format and have a matching constructor that accepts a String in the same format.

If the descriptor is empty the following String is returned: <Descriptor></Descriptor>

Returns:
the XML string.
Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. If the XML formated string construction fails for any reason, this exception will be thrown.

toString

public String toString()
Returns a human readable string representing the descriptor. The string will be in the format of "fieldName=fieldValue,fieldName2=fieldValue2,..."
If there are no fields in the descriptor, then an empty String is returned.
If a fieldValue is an object then the toString() method is called on it and its returned value is used as the value for the field enclosed in parenthesis.

Overrides:
toString in class Object
Returns:
a string representation of the object.
Throws:
RuntimeOperationsException - for illegal value for field Names or field Values. If the descriptor string fails for any reason, this exception will be thrown.

JavaTM 2 Platform
Standard Ed. 5.0

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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