# Class JMXConnectorFactory

java.lang.Object
javax.management.remote.JMXConnectorFactory

public class JMXConnectorFactory extends Object

Factory to create JMX API connector clients. There are no instances of this class.

Connections are usually made using the `connect` method of this class. More advanced applications can separate the creation of the connector client, using `newJMXConnector` and the establishment of the connection itself, using `JMXConnector.connect(Map)`.

Each client is created by an instance of `JMXConnectorProvider`. This instance is found as follows. Suppose the given `JMXServiceURL` looks like `"service:jmx:protocol:remainder"`. Then the factory will attempt to find the appropriate `JMXConnectorProvider` for `protocol`. Each occurrence of the character `+` or `-` in `protocol` is replaced by `.` or `_`, respectively.

A provider package list is searched for as follows:

1. If the `environment` parameter to `newJMXConnector` contains the key `jmx.remote.protocol.provider.pkgs` then the associated value is the provider package list.
2. Otherwise, if the system property `jmx.remote.protocol.provider.pkgs` exists, then its value is the provider package list.
3. Otherwise, there is no provider package list.

The provider package list is a string that is interpreted as a list of non-empty Java package names separated by vertical bars (`|`). If the string is empty, then so is the provider package list. If the provider package list is not a String, or if it contains an element that is an empty string, a `JMXProviderException` is thrown.

If the provider package list exists and is not empty, then for each element `pkg` of the list, the factory will attempt to load the class

> `pkg.protocol.ClientProvider`

If the `environment` parameter to `newJMXConnector` contains the key `jmx.remote.protocol.provider.class.loader` then the associated value is the class loader to use to load the provider. If the associated value is not an instance of `ClassLoader`, an `IllegalArgumentException` is thrown.

If the `jmx.remote.protocol.provider.class.loader` key is not present in the `environment` parameter, the calling thread's context class loader is used.

If the attempt to load this class produces a `ClassNotFoundException`, the search for a handler continues with the next element of the list.

Otherwise, a problem with the provider found is signalled by a `JMXProviderException` whose `cause` indicates the underlying exception, as follows:

- if the attempt to load the class produces an exception other than `ClassNotFoundException`, that is the cause;
- if `Class.newInstance()` for the class produces an exception, that is the cause.

If no provider is found by the above steps, including the default case where there is no provider package list, then the implementation will use its own provider for `protocol`, or it will throw a `MalformedURLException` if there is none. An implementation may choose to find providers by other means. For example, it may support service providers, where the service interface is `JMXConnectorProvider`.

Every implementation must support the RMI connector protocol with the default RMI transport, specified with string `rmi`.

Once a provider is found, the result of the `newJMXConnector` method is the result of calling `newJMXConnector` on the provider.

The `Map` parameter passed to the `JMXConnectorProvider` is a new read-only `Map` that contains all the entries that were in the `environment` parameter to `JMXConnectorFactory.newJMXConnector`, if there was one. Additionally, if the `jmx.remote.protocol.provider.class.loader` key is not present in the `environment` parameter, it is added to the new read-only `Map`. The associated value is the calling thread's context class loader.

Since:
  1.5

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final String`
  `DEFAULT_CLASS_LOADER`
  Name of the attribute that specifies the default class loader.
  `static final String`
  `PROTOCOL_PROVIDER_CLASS_LOADER`
  Name of the attribute that specifies the class loader for loading protocol providers.
  `static final String`
  `PROTOCOL_PROVIDER_PACKAGES`
  Name of the attribute that specifies the provider packages that are consulted when looking for the handler for a protocol.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static JMXConnector`
  `connect(JMXServiceURL serviceURL)`
  Creates a connection to the connector server at the given address.
  `static JMXConnector`
  `connect(JMXServiceURL serviceURL, Map<String,?> environment)`
  Creates a connection to the connector server at the given address.
  `static JMXConnector`
  `newJMXConnector(JMXServiceURL serviceURL, Map<String,?> environment)`
  Creates a connector client for the connector server at the given address.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### DEFAULT_CLASS_LOADER

    public static final String DEFAULT_CLASS_LOADER

    Name of the attribute that specifies the default class loader. This class loader is used to deserialize return values and exceptions from remote `MBeanServerConnection` calls. The value associated with this attribute is an instance of `ClassLoader`.

    See Also:
      - Constant Field Values

  - ### PROTOCOL_PROVIDER_PACKAGES

    public static final String PROTOCOL_PROVIDER_PACKAGES

    Name of the attribute that specifies the provider packages that are consulted when looking for the handler for a protocol. The value associated with this attribute is a string with package names separated by vertical bars (`|`).

    See Also:
      - Constant Field Values

  - ### PROTOCOL_PROVIDER_CLASS_LOADER

    public static final String PROTOCOL_PROVIDER_CLASS_LOADER

    Name of the attribute that specifies the class loader for loading protocol providers. The value associated with this attribute is an instance of `ClassLoader`.

    See Also:
      - Constant Field Values

- ## Method Details

  - ### connect

    public static JMXConnector connect(JMXServiceURL serviceURL) throws IOException

    Creates a connection to the connector server at the given address.

    This method is equivalent to `connect(serviceURL, null)`.

    Parameters:
      `serviceURL` - the address of the connector server to connect to.
    Returns:
      a `JMXConnector` whose `connect` method has been called.
    Throws:
      `NullPointerException` - if `serviceURL` is null.
      `IOException` - if the connector client or the connection cannot be made because of a communication problem.
      `SecurityException` - if the connection cannot be made for security reasons.

  - ### connect

    public static JMXConnector connect(JMXServiceURL serviceURL, Map<String,?> environment) throws IOException

    Creates a connection to the connector server at the given address.

    This method is equivalent to:

        JMXConnector conn = JMXConnectorFactory.newJMXConnector(serviceURL,
                                                                environment);
        conn.connect(environment);

    Parameters:
      `serviceURL` - the address of the connector server to connect to.
      `environment` - a set of attributes to determine how the connection is made. This parameter can be null. Keys in this map must be Strings. The appropriate type of each associated value depends on the attribute. The contents of `environment` are not changed by this call.
    Returns:
      a `JMXConnector` representing the newly-made connection. Each successful call to this method produces a different object.
    Throws:
      `NullPointerException` - if `serviceURL` is null.
      `IOException` - if the connector client or the connection cannot be made because of a communication problem.
      `SecurityException` - if the connection cannot be made for security reasons.

  - ### newJMXConnector

    public static JMXConnector newJMXConnector(JMXServiceURL serviceURL, Map<String,?> environment) throws IOException

    Creates a connector client for the connector server at the given address. The resultant client is not connected until its `connect` method is called.

    Parameters:
      `serviceURL` - the address of the connector server to connect to.
      `environment` - a set of attributes to determine how the connection is made. This parameter can be null. Keys in this map must be Strings. The appropriate type of each associated value depends on the attribute. The contents of `environment` are not changed by this call.
    Returns:
      a `JMXConnector` representing the new connector client. Each successful call to this method produces a different object.
    Throws:
      `NullPointerException` - if `serviceURL` is null.
      `IOException` - if the connector client cannot be made because of a communication problem.
      `MalformedURLException` - if there is no provider for the protocol in `serviceURL`.
      `JMXProviderException` - if there is a provider for the protocol in `serviceURL` but it cannot be used for some reason.