| JavaTM 2 Platform Std. Ed. v1.6.0
javax.management
Class ImmutableDescriptor
java.lang.Object
 javax.management.ImmutableDescriptor
- All Implemented Interfaces:
- Serializable, Cloneable, Descriptor
public class ImmutableDescriptor - extends Object
- implements Descriptor
An immutable descriptor.
- Since:
- 1.6
- See Also:
- Serialized Form
|
Method Summary |
Descriptor |
clone()
Returns a descriptor which is equal to this descriptor. |
boolean |
equals(Object o)
Compares this descriptor to the given object. |
String[] |
getFieldNames()
Returns all the field names in the descriptor. |
String[] |
getFields()
Returns all of the fields contained in this descriptor as a string array. |
Object |
getFieldValue(String fieldName)
Returns the value for a specific field name, or null if no value
is present for that name. |
Object[] |
getFieldValues(String... fieldNames)
Returns all the field values in the descriptor as an array of Objects. |
int |
hashCode()
Returns the hash code value for this descriptor. |
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 fieldName,
Object fieldValue)
This operation is unsupported since this class is immutable. |
void |
setFields(String[] fieldNames,
Object[] fieldValues)
This operation is unsupported since this class is immutable. |
String |
toString()
Returns a string representation of the object. |
static ImmutableDescriptor |
union(Descriptor... descriptors)
Return an ImmutableDescriptor whose contents are the union of
the given descriptors. |
EMPTY_DESCRIPTOR
public static final ImmutableDescriptor EMPTY_DESCRIPTOR
- An empty descriptor.
ImmutableDescriptor
public ImmutableDescriptor(String[] fieldNames,
Object[] fieldValues)
- Construct a descriptor containing the given fields and values.
- Throws:
IllegalArgumentException - if either array is null, or
if the arrays have different sizes, or
if a field name is null or empty, or if the same field name
appears more than once.
ImmutableDescriptor
public ImmutableDescriptor(String... fields)
- Construct a descriptor containing the given fields. Each String
must be of the form
fieldName=fieldValue. The field name
ends at the first = character; for example if the String
is a=b=c then the field name is a and its value
is b=c.
- Throws:
IllegalArgumentException - if the parameter is null, or
if a field name is empty, or if the same field name appears
more than once, or if one of the strings does not contain
an = character.
ImmutableDescriptor
public ImmutableDescriptor(Map<String,?> fields)
Construct a descriptor where the names and values of the fields
are the keys and values of the given Map.
- Throws:
IllegalArgumentException - if the parameter is null, or
if a field name is null or empty, or if the same field name appears
more than once (which can happen because field names are not case
sensitive).
union
public static ImmutableDescriptor union(Descriptor... descriptors)
Return an ImmutableDescriptor whose contents are the union of
the given descriptors. Every field name that appears in any of
the descriptors will appear in the result with the
value that it has when the method is called. Subsequent changes
to any of the descriptors do not affect the ImmutableDescriptor
returned here.
In the simplest case, there is only one descriptor and the
returned ImmutableDescriptor is a copy of its fields at the
time this method is called:
Descriptor d = something();
ImmutableDescriptor copy = ImmutableDescriptor.union(d);
- Parameters:
descriptors - the descriptors to be combined. Any of the
descriptors can be null, in which case it is skipped.
- Returns:
- an
ImmutableDescriptor that is the union of the given
descriptors. The returned object may be identical to one of the
input descriptors if it is an ImmutableDescriptor that contains all of
the required fields.
- Throws:
IllegalArgumentException - if two Descriptors contain the
same field name with different associated values. Primitive array
values are considered the same if they are of the same type with
the same elements. Object array values are considered the same if
Arrays.deepEquals(Object[],Object[]) returns true.
getFieldValue
public final Object getFieldValue(String fieldName)
- Description copied from interface:
Descriptor
- Returns the value for a specific field name, or null if no value
is present for that name.
- Specified by:
getFieldValue in interface Descriptor
- Parameters:
fieldName - the field name.
- Returns:
- the corresponding value, or null if the field is not present.
getFields
public final String[] getFields()
- Description copied from interface:
Descriptor
- Returns all of the fields contained in this descriptor as a string array.
- Specified by:
getFields in interface Descriptor
- Returns:
- String array of fields in the format fieldName=fieldValue
If the value of a field is not a String, then the toString() method
will be called on it and the returned value, enclosed in parentheses,
used as the value for the field in the returned array. If the value
of a field is null, then the value of the field in the returned array
will be empty. If the descriptor is empty, you will get
an empty array. - See Also:
Descriptor.setFields(java.lang.String[], java.lang.Object[])
getFieldValues
public final Object[] getFieldValues(String... fieldNames)
- Description copied from interface:
Descriptor
- 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, as if the parameter were the array
returned by Descriptor.getFieldNames(). If a field name in the
array does not exist, including the case where it is null or
the empty string, then null is returned for the matching array
element being returned.
- Returns:
- Object array of field values. If the list of
fieldNames
is empty, you will get an empty array.
getFieldNames
public final String[] getFieldNames()
- Description copied from interface:
Descriptor
- Returns all the field names in the descriptor.
- Specified by:
getFieldNames in interface Descriptor
- Returns:
- String array of field names. If the descriptor is empty,
you will get an empty array.
equals
public boolean equals(Object o)
- Compares this descriptor to the given object. The objects are equal if
the given object is also a Descriptor, and if the two Descriptors have
the same field names (possibly differing in case) and the same
associated values. The respective values for a field in the two
Descriptors are equal if the following conditions hold:
- If one value is null then the other must be too.
- If one value is a primitive array then the other must be a primitive
array of the same type with the same elements.
- If one value is an object array then the other must be too and
Arrays.deepEquals(Object[],Object[]) must return true.
- Otherwise
Object.equals(Object) must return true.
- Specified by:
equals in interface Descriptor- Overrides:
equals in class Object
- Parameters:
o - the object to compare with.
- Returns:
true if the objects are the same; false
otherwise.- See Also:
Object.hashCode(),
Hashtable
hashCode
public int hashCode()
Returns the hash code value for this descriptor. The hash
code is computed as the sum of the hash codes for each field in
the descriptor. The hash code of a field with name n
and value v is n.toLowerCase().hashCode() ^ h.
Here h is the hash code of v, computed as
follows:
- If
v is null then h is 0.
- If
v is a primitive array then h is computed using
the appropriate overloading of java.util.Arrays.hashCode.
- If
v is an object array then h is computed using
Arrays.deepHashCode(Object[]).
- Otherwise
h is v.hashCode().
- Specified by:
hashCode in interface Descriptor- Overrides:
hashCode in class Object
- Returns:
- A hash code value for this object.
- See Also:
Object.equals(java.lang.Object),
Hashtable
toString
public String toString()
- Description copied from class:
Object
- Returns a string representation of the object. In general, the
toString method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
- Overrides:
toString in class Object
- Returns:
- a string representation of the object.
isValid
public boolean isValid()
- Returns true if all of the fields have legal values given their
names. This method always returns true, but a subclass can
override it to return false when appropriate.
- Specified by:
isValid in interface Descriptor
- Returns:
- true if the values are legal.
- Throws:
RuntimeOperationsException - if the validity checking fails.
The method returns false if the descriptor is not valid, but throws
this exception if the attempt to determine validity fails.
clone
public Descriptor clone()
Returns a descriptor which is equal to this descriptor.
Changes to the returned descriptor will have no effect on this
descriptor, and vice versa.
This method returns the object on which it is called.
A subclass can override it
to return another object provided the contract is respected.
- 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
setFields
public final void setFields(String[] fieldNames,
Object[] fieldValues)
throws RuntimeOperationsException
- This operation is unsupported since this class is immutable. If
this call would change a mutable descriptor with the same contents,
then a
RuntimeOperationsException wrapping an
UnsupportedOperationException is thrown. Otherwise,
the behavior is the same as it would be for a mutable descriptor:
either an exception is thrown because of illegal parameters, or
there is no 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 - if the change fails for any reason.
Wrapped exception is IllegalArgumentException if
fieldNames or fieldValues is null, or if
the arrays are of different lengths, or if there is an
illegal value in one of them.
Wrapped exception is UnsupportedOperationException
if the descriptor is immutable, and the call would change
its contents.- See Also:
Descriptor.getFields()
setField
public final void setField(String fieldName,
Object fieldValue)
throws RuntimeOperationsException
- This operation is unsupported since this class is immutable. If
this call would change a mutable descriptor with the same contents,
then a
RuntimeOperationsException wrapping an
UnsupportedOperationException is thrown. Otherwise,
the behavior is the same as it would be for a mutable descriptor:
either an exception is thrown because of illegal parameters, or
there is no effect.
- Specified by:
setField in interface Descriptor
- Parameters:
fieldName - The field name to be set. Cannot be null or empty.fieldValue - The field value to be set for the field
name. Can be null if that is a valid value for the field.
- Throws:
RuntimeOperationsException - if the field name or field value
is illegal (wrapped exception is IllegalArgumentException); or
if the descriptor is immutable (wrapped exception is
UnsupportedOperationException).
removeField
public final 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 name is illegal or the field is not found,
no exception is thrown.
- Throws:
RuntimeOperationsException - if a field of the given name
exists and the descriptor is immutable. The wrapped exception will
be an UnsupportedOperationException.
Copyright 2003 Sun Microsystems, Inc. All rights reserved
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