registryexplorerframe.java

本书是一本为Java学习者在基础内容学习结束后进行课程设计时提供参考的指导书

package apibook.c8.s3;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.rmi.*;

//测试类rmi.registry包
public class RegistryExplorerFrame extends JFrame {
  JPanel contentPane;
  BorderLayout borderLayout1 = new BorderLayout();
  private JTextArea _resultsArea;
  private JTextField _portTextField;
  private JButton _queryRegistryButton;

  //Construct the frame
  public RegistryExplorerFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  //Component initialization
  private void jbInit() throws Exception  {
    contentPane = (JPanel) this.getContentPane();
    contentPane.setLayout(borderLayout1);
    this.setSize(new Dimension(400, 300));
    this.setTitle("RegistryExplorer");
    buildGUI();
    setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
  }

  //Overridden so we can exit when window is closed
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }
//初始化图形界面
  private void buildGUI() {
      JPanel mainPanel = new JPanel(new BorderLayout());

      _resultsArea = new JTextArea();
      mainPanel.add(new JScrollPane(_resultsArea), BorderLayout.CENTER);
      _queryRegistryButton = new JButton("Check Registry Contents");
      _queryRegistryButton.addActionListener(new QueryRegistry());
      mainPanel.add(_queryRegistryButton, BorderLayout.SOUTH);
      getContentPane().add(mainPanel);
      setSize(250, 200);
  }

  private void displayInformationForName(String name) throws Exception {
      Object value = Naming.lookup(name);//查找远程对象

      if (null == value) {
          _resultsArea.append("Server named " + name + " is not in registry\n");
          return;
      }
      //获取接口
      Collection interfaces = getRemoteInterfacesForObject(value);

      if (null == interfaces) {
          _resultsArea.append("Object named " + name + " is not a server\n");
          return;
      }
      _resultsArea.append("Server named " + name + " implements the following remote interfaces\n");
      Iterator i = interfaces.iterator();

      while (i.hasNext()) {//输出结果
          _resultsArea.append("\t" + i.next() + "\n");
      }
      return;
  }

//查找对象的接口
  private Collection getRemoteInterfacesForObject(Object object) {
      Class objectType = object.getClass();
      Class[] interfaces = objectType.getInterfaces();
      Class remoteInterface = Remote.class;

      if ((null == interfaces) || (0 == interfaces.length)) {
          return null;
      }
      ArrayList returnValue = new ArrayList();
      int counter;

      for (counter = 0; counter < interfaces.length; counter++) {
          if (remoteInterface.isAssignableFrom(interfaces[counter])) {
              returnValue.add(interfaces[counter]);
          }
      }
      return returnValue;
  }

//查询注册表
  private class QueryRegistry implements ActionListener {
      public void actionPerformed(ActionEvent event) {
          try {
              String[] names = Naming.list("//localhost:1099");//注册表列表

              if ((null == names) || (0 == names.length)) {
                  _resultsArea.setText("The Registry is Empty");
                  return;
              }
              _resultsArea.setText("");
              int counter;

              for (counter = 0; counter < names.length; counter++) {
                  displayInformationForName(names[counter]);//显示
              }
          } catch (Exception exception) {
              System.out.println(exception);
              exception.printStackTrace();
          }
      }
  }
}