OpenType (Java SE 26 & JDK 26)
Description: declaration: module: java.management, package: javax.management.openmbean, class: OpenType
Keywords: javax.management.openmbean.OpenType class

# Class OpenType<T>

java.lang.Object
javax.management.openmbean.OpenType<T>

Type Parameters:
  `T` - the Java type that instances described by this type must have. For example, `SimpleType.INTEGER` is a `SimpleType<Integer>` which is a subclass of `OpenType<Integer>`, meaning that an attribute, parameter, or return value that is described as a `SimpleType.INTEGER` must have Java type `Integer`.

All Implemented Interfaces:
  `Serializable`

Direct Known Subclasses:
  `ArrayType, CompositeType, SimpleType, TabularType`

public abstract class OpenType<T> extends Object implements Serializable
The `OpenType` class is the parent abstract class of all classes which describe the actual open type of open data values.

An open type is defined by:

- the fully qualified Java class name of the open data values this type describes; note that only a limited set of Java classes is allowed for open data values (see `ALLOWED_CLASSNAMES_LIST`),
- its name,
- its description.

Since:
  1.5
See Also:
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final String[]`
  `ALLOWED_CLASSNAMES`
  Deprecated.
  Use `ALLOWED_CLASSNAMES_LIST` instead.
  `static final List<String>`
  `ALLOWED_CLASSNAMES_LIST`
  List of the fully qualified names of the Java classes allowed for open data values.

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `OpenType(String className, String typeName, String description)`
  Constructs an `OpenType` instance (actually a subclass instance as `OpenType` is abstract), checking for the validity of the given parameters.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `abstract boolean`
  `equals(Object obj)`
  Compares the specified `obj` parameter with this open type instance for equality.
  `String`
  `getClassName()`
  Returns the fully qualified Java class name of the open data values this open type describes.
  `String`
  `getDescription()`
  Returns the text description of this `OpenType` instance.
  `String`
  `getTypeName()`
  Returns the name of this `OpenType` instance.
  `abstract int`
  `hashCode()`
  Returns a hash code value for this object.
  `boolean`
  `isArray()`
  Returns `true` if the open data values this open type describes are arrays, `false` otherwise.
  `abstract boolean`
  `isValue(Object obj)`
  Tests whether obj is a value for this open type.
  `abstract String`
  `toString()`
  Returns a string representation of this open type instance.

  ### Methods declared in class Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  Creates and returns a copy of this object.
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `Object`.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `final void`
  `wait()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `final void`
  `wait(long timeoutMillis)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
  `final void`
  `wait(long timeoutMillis, int nanos)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

- ## Field Details

  - ### ALLOWED_CLASSNAMES_LIST

    public static final List<String> ALLOWED_CLASSNAMES_LIST
    List of the fully qualified names of the Java classes allowed for open data values. A multidimensional array of any one of these classes or their corresponding primitive types is also an allowed class for open data values.

        ALLOWED_CLASSNAMES_LIST = {
               "java.lang.Void",
               "java.lang.Boolean",
               "java.lang.Character",
               "java.lang.Byte",
               "java.lang.Short",
               "java.lang.Integer",
               "java.lang.Long",
               "java.lang.Float",
               "java.lang.Double",
               "java.lang.String",
               "java.math.BigDecimal",
               "java.math.BigInteger",
               "java.util.Date",
               "javax.management.ObjectName",
               CompositeData.class.getName(),
               TabularData.class.getName() } ;

  - ### ALLOWED_CLASSNAMES

    @Deprecated public static final String[] ALLOWED_CLASSNAMES
    Deprecated.
    Use `ALLOWED_CLASSNAMES_LIST` instead.

- ## Constructor Details

  - ### OpenType

    protected OpenType(String className, String typeName, String description) throws OpenDataException
    Constructs an `OpenType` instance (actually a subclass instance as `OpenType` is abstract), checking for the validity of the given parameters. The validity constraints are described below for each parameter.
    Parameters:
      `className` - The fully qualified Java class name of the open data values this open type describes. The valid Java class names allowed for open data values are listed in `ALLOWED_CLASSNAMES_LIST`. A multidimensional array of any one of these classes or their corresponding primitive types is also an allowed class, in which case the class name follows the rules defined by the method `getName()` of `java.lang.Class`. For example, a 3-dimensional array of Strings has for class name "`[[[Ljava.lang.String;`" (without the quotes).
      `typeName` - The name given to the open type this instance represents; cannot be a null or empty string.
      `description` - The human readable description of the open type this instance represents; cannot be a null or empty string.
    Throws:
      `IllegalArgumentException` - if className, typeName or description is a null or empty string
      `OpenDataException` - if className is not one of the allowed Java class names for open data

- ## Method Details

  - ### getClassName

    public String getClassName()
    Returns the fully qualified Java class name of the open data values this open type describes. The only possible Java class names for open data values are listed in `ALLOWED_CLASSNAMES_LIST`. A multidimensional array of any one of these classes or their corresponding primitive types is also an allowed class, in which case the class name follows the rules defined by the method `getName()` of `java.lang.Class`. For example, a 3-dimensional array of Strings has for class name "`[[[Ljava.lang.String;`" (without the quotes), a 3-dimensional array of Integers has for class name "`[[[Ljava.lang.Integer;`" (without the quotes), and a 3-dimensional array of int has for class name "`[[[I`" (without the quotes)
    Returns:
      the class name.

  - ### getTypeName

    public String getTypeName()
    Returns the name of this `OpenType` instance.
    Returns:
      the type name.

  - ### getDescription

    public String getDescription()
    Returns the text description of this `OpenType` instance.
    Returns:
      the description.

  - ### isArray

    public boolean isArray()
    Returns `true` if the open data values this open type describes are arrays, `false` otherwise.
    Returns:
      true if this is an array type.

  - ### isValue

    public abstract boolean isValue(Object obj)
    Tests whether obj is a value for this open type.
    Parameters:
      `obj` - the object to be tested for validity.
    Returns:
      `true` if obj is a value for this open type, `false` otherwise.

  - ### equals

    public abstract boolean equals(Object obj)
    Compares the specified `obj` parameter with this open type instance for equality.
    Overrides:
      `equals` in class `Object`
    Parameters:
      `obj` - the object to compare to.
    Returns:
      true if this object and `obj` are equal.
    See Also:
      - `Object.hashCode()`
      - `HashMap`

  - ### hashCode

    public abstract int hashCode()
    Description copied from class: `Object`
    Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by `HashMap`.

    The general contract of `hashCode` is:

    - Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
    - If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result.
    - It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      a hash code value for this object
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(Object)`

  - ### toString

    public abstract String toString()
    Returns a string representation of this open type instance.
    Overrides:
      `toString` in class `Object`
    Returns:
      the string representation.