Posted on 2008-02-15 14:34
dennis 閱讀(1517)
評論(1) 編輯 收藏 所屬分類:
動態語言 、
java
要在JRuby中實現java接口，接口
include進來，實現接口方法即可，例如實現java.lang.Runnable接口做線程處理：
require 'java'
include_class 'java.lang.Runnable'
class TestRunnable
include Runnable
def initialize(name)
@name=name
end
def run
puts "hello,"+@name
end
end
要在JRuby中繼承抽象類，實現其中的抽象方法，方法稍微麻煩點，需要cglib，到
這里下載cglib-nodep-2.1_3.jar，寫個通用庫abstract_class.rb方便處理:
load 'cglib-nodep-2.1_3.jar'
class Object
include Java
include_class "net.sf.cglib.proxy.Enhancer"
include_class "net.sf.cglib.proxy.NoOp"
class <<self
def method_missing(mname, *args, &block)
unless mname == :abstract_impl and respond_to?(:java_class) and JavaLang::reflect::Modifier.isAbstract(JavaLang::Class.for_name(java_class.name).modifiers)
super
else
generate_abstract_impl(args, &block)
end
end
private
def generate_abstract_impl(args, &block)
factory = Enhancer.new
factory.setSuperclass(java_class)
factory.setInterfaces(java_class.interfaces.to_java("java.lang.Class"))
factory.setCallback(NoOp::INSTANCE)
object_args = args.map { |arg| Java.ruby_to_java(arg) }
class_arguments = object_args.map {|arg| arg.java_class}.to_java("java.lang.Class")
generated_class = factory.create(class_arguments, object_args.to_java("java.lang.Object"))
ruby_class = Class.new(generated_class.class)
ruby_class.class_eval(&block)
return ruby_class.new(*args)
end
end
end
使用的話，require一下abstract_class，例如我們要繼承java.util.TimerTask，實現其中的run方法：
$:.unshift File.join(File.dirname(__FILE__),'.')
require 'java'
require 'abstract_class'
import java.util.TimerTask
import java.util.Timer
timer_task = TimerTask.abstract_impl do
def run
puts "timer task"
end
end
Timer.new.schedule(timer_task, 1000, 1000)