Class: JMX::MBean

Inherits:
Object
  • Object
show all
Defined in:
lib/jmx4r.rb

Constant Summary collapse

JThread = 
java.lang.Thread
@@connection = 
nil

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(object_name, connection = nil) ⇒ MBean

Creates a new MBean.

object_name

a string corresponding to a valid ObjectName

connection

a connection to a MBean server. If none is passed, use the global connection created by MBean.establish_connection



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# File 'lib/jmx4r.rb', line 83

def initialize(object_name, connection=nil)
  @connection = connection || @@connection
  @object_name = object_name
  info = @connection.getMBeanInfo @object_name
  @attributes = Hash.new
  info.attributes.each do | mbean_attr |
    @attributes[mbean_attr.name.snake_case] = mbean_attr.name
  end
  @operations = Hash.new
  info.operations.each do |mbean_op|
    param_types = mbean_op.signature.map {|param| param.type}
    @operations[mbean_op.name.snake_case] = [mbean_op.name, param_types]
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

:nodoc:



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# File 'lib/jmx4r.rb', line 98

def method_missing(method, *args, &block) #:nodoc:
  method_in_snake_case = method.to_s.snake_case # this way Java/JRuby styles are compatible

  if @operations.keys.include?(method_in_snake_case)
    op_name, param_types = @operations[method_in_snake_case]
    @connection.invoke @object_name,
                       op_name,
                       args.to_java(:Object),
                       param_types.to_java(:String)
  else
    super
  end
end

Instance Attribute Details

#attributes ⇒ Object (readonly)

Returns the value of attribute attributes.



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# File 'lib/jmx4r.rb', line 68

def attributes
  @attributes
end

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/jmx4r.rb', line 68

def connection
  @connection
end

#object_name ⇒ Object (readonly)

Returns the value of attribute object_name.



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# File 'lib/jmx4r.rb', line 68

def object_name
  @object_name
end

#operations ⇒ Object (readonly)

Returns the value of attribute operations.



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# File 'lib/jmx4r.rb', line 68

def operations
  @operations
end

Class Method Details

.connection(args = {}) ⇒ Object 



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# File 'lib/jmx4r.rb', line 136

def self.connection(args={})
  if args.has_key? :host or args.has_key? :port
    return create_connection(args)
  else
    @@connection ||= MBean.establish_connection(args)
  end
end

.create_connection(args = {}) ⇒ Object

Create a connection to a remote MBean server.

The args accepts the following keys:

:host

the host of the MBean server (defaults to “localhost”)

:port

the port of the MBean server (defaults to 3000)

:url

the url of the MBean server. No default. if the url is specified, the host & port parameters are not taken into account

:command

the pattern matches the command line of the local JVM process including the MBean server. (command lines are listed on the connection dialog in JConsole). No default. this feature needs a JDK (>=5) installed on the local system. if the command is specified, the host & port or the url parameters are not taken into account

:username

the name of the user (if the MBean server requires authentication). No default

:password

the password of the user (if the MBean server requires authentication). No default

:credentials

custom credentials (if the MBean server requires authentication). No default. It has precedence over :username and :password (i.e. if :credentials is specified, :username & :password are ignored)

:provider_package

use to fill the JMXConnectorFactory::PROTOCOL_PROVIDER_PACKAGES. No default



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# File 'lib/jmx4r.rb', line 180

def self.create_connection(args={})
  host= args[:host] || "localhost"
  port = args[:port] || 3000
  username = args[:username]
  password = args[:password]
  credentials = args[:credentials]
  provider_package = args[:provider_package]

  if args[:command]
    url = JDKHelper.find_local_url(args[:command]) or
      raise "no locally attacheable VMs"
  else
    # host & port are not taken into account if url is set (see issue #7)
    standard_url = "service:jmx:rmi:///jndi/rmi://#{host}:#{port}/jmxrmi"
    url = args[:url] || standard_url
  end

  unless credentials
    if !username.nil? and username.length > 0
      user_password_credentials = [username, password]
      credentials = user_password_credentials.to_java(:String)
    end
  end

  env = HashMap.new
  env.put(JMXConnector::CREDENTIALS, credentials) if credentials
  # only fill the Context and JMXConnectorFactory properties if provider_package is set
  if provider_package
    env.put(Context::SECURITY_PRINCIPAL, username) if username
    env.put(Context::SECURITY_CREDENTIALS, password) if password
    env.put(JMXConnectorFactory::PROTOCOL_PROVIDER_PACKAGES, provider_package)
  end

  # the context class loader is set to JRuby's classloader when
  # creating the JMX Connection so that classes loaded using
  # JRuby "require" (and not from its classpath) can also be
  # accessed (see issue #6)
  begin
    context_class_loader = JThread.current_thread.context_class_loader
    JThread.current_thread.context_class_loader = JRuby.runtime.getJRubyClassLoader

    puts url
    puts $CLASSPATH

    connector = JMXConnectorFactory::connect JMXServiceURL.new(url), env
    MBeanServerConnectionProxy.new connector
  ensure
    # ... and we reset the previous context class loader
    JThread.current_thread.context_class_loader = context_class_loader
  end
end

.create_mbean(object_name, connection) ⇒ Object 



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# File 'lib/jmx4r.rb', line 258

def self.create_mbean(object_name, connection)
  info = connection.getMBeanInfo object_name
  mbean = MBean.new object_name, connection
  # define attribute accessor methods for the mbean
  info.attributes.each do |mbean_attr|
    mbean.meta_def mbean_attr.name.snake_case do
      connection.getAttribute object_name, mbean_attr.name
    end
    if mbean_attr.isWritable
      mbean.meta_def "#{mbean_attr.name.snake_case}=" do |value|
        attribute = Attribute.new mbean_attr.name, value
        connection.setAttribute object_name, attribute
      end
    end
  end
  mbean
end

.establish_connection(args = {}) ⇒ Object

establish a connection to a remote MBean server which will be used by all subsequent MBeans.

See MBean.create_connection for a list of the keys that are accepted in arguments.

Examples

JMX::MBean.establish_connection :port => "node23", :port => 1090
JMX::MBean.establish_connection :port => "node23", :username => "jeff", :password => "secret"
JMX::MBean.establish_connection :command => /jconsole/i



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# File 'lib/jmx4r.rb', line 125

def self.establish_connection(args={})
  @@connection ||= create_connection args
end

.find_all_by_name(name, args = {}) ⇒ Object

Returns an array of MBeans corresponding to all the MBeans registered for the ObjectName passed in parameter (which may be a pattern).

The args accepts the same keys than #create_connection and an additional one:

:connection

a MBean server connection (as returned by #create_connection) No default. It has precedence over :host and :port (i.e if :connection is specified, :host and :port are ignored)



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# File 'lib/jmx4r.rb', line 243

def self.find_all_by_name(name, args={})
  object_name = ObjectName.new(name)
  connection = args[:connection] || MBean.connection(args)
  object_names = connection.queryNames(object_name, nil)
  object_names.map { |on| create_mbean on, connection }
end

.find_by_name(name, args = {}) ⇒ Object

Same as #find_all_by_name but the ObjectName passed in parameter can not be a pattern. Only one single MBean is returned.



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# File 'lib/jmx4r.rb', line 253

def self.find_by_name(name, args={})
  connection = args[:connection] || MBean.connection(args)
  create_mbean ObjectName.new(name), connection
end

.pretty_print(object_name, args = {}) ⇒ Object 



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# File 'lib/jmx4r.rb', line 276

def self.pretty_print (object_name, args={})
  connection = args[:connection] || MBean.connection(args)
  info = connection.getMBeanInfo ObjectName.new(object_name)
  puts "object_name: #{object_name}"
  puts "class: #{info.class_name}"
  puts "description: #{info.description}"
  puts "operations:"
  info.operations.each do | op |
    puts "  #{op.name}"
    op.signature.each do | param |
      puts "    #{param.name} (#{param.type} #{param.description})"
    end
    puts "    ----"
    puts "    description: #{op.description}"
    puts "    return_type: #{op.return_type}"
    puts "    impact: #{op.impact}"
  end
  puts "attributes:"
  info.attributes.each do | attr |
    puts "  #{attr.name}"
    puts "    description: #{attr.description}"
    puts "    type: #{attr.type}"
    puts "    readable: #{attr.readable}"
    puts "    writable: #{attr.writable}"
    puts "    is: #{attr.is}"
  end
end

.remove_connection(args = {}) ⇒ Object 



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# File 'lib/jmx4r.rb', line 129

def self.remove_connection(args={})
  if @@connection
    @@connection.close rescue nil
  end
  @@connection = nil
end

Instance Method Details

#meta_def(name, &blk) ⇒ Object 



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# File 'lib/jmx4r.rb', line 71

def meta_def name, &blk
  metaclass.instance_eval do
      define_method name, &blk
  end
end

#metaclass ⇒ Object 



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# File 'lib/jmx4r.rb', line 70

def metaclass; class << self; self; end; end