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SWT中的Sytem Tray相关处理

carob — Sun, 19 Mar 2006 08:36:00 GMT

SWT已经提供了对部分�q�_��Q�比如window�Q�上的系�l�托盘的支持。但支持得还不够好，我最�q�需要在一个聊天工具实现Balloon效果(�_�附于系�l�托盘上的一个消息气泡效果，在IM软�g中普遍被支持)�Q�查一下SWT API,到目前�ؓ上�ƈ没有提供支持。但一个好消息是在月底交要出来�?.2M6中，��对部分API做调��_��增加对Balloon的支持�?br />

Milestone Plan 3.2 M6 March 31 , 2006

Implement custom draw for table and tree
Implement native drag source effects for cursor
Implement ImageTransfer support
Implement Balloon tooltips
Implement Accessibility on Mac OS X

�q�儿是EclipseZone上的一个针对这一效果的文章：TrayIcons and ToolTips http://www.eclipsezone.com/eclipse/forums/t66093.rhtml

甚至在官方网站上�Q�已�l�提供了�q�一个API的Snippet

//http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet225.java
/*******************************************************************************
* Copyright (c) 2000, 2006 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
*     IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.snippets;

/*
* Tooltip example snippet: create a balloon tooltip for a tray item
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*
* @since 3.0
*/
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet225 {

public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    Image image = null;
    final ToolTip tip = new ToolTip(shell, SWT.BALLOON | SWT.ICON_INFORMATION);
    tip.setMessage("Here is message for the user. When the message is too long it wraps. I should say something cool but nothing comes to my mind.");
    Tray tray = display.getSystemTray();
    if (tray != null) {
        TrayItem item = new TrayItem(tray, SWT.NONE);
        image = new Image(display, Snippet225.class.getResourceAsStream("eclipse.png"));
        item.setImage(image);
        tip.setText("Notification from a tray item");
        item.setToolTip(tip);
    } else {
        tip.setText("Notification from anywhere");
        tip.setLocation(400, 400);
    }
    Button button = new Button (shell, SWT.PUSH);
    button.setText("Press for balloon tip");
    button.addListener(SWT.Selection, new Listener() {
        public void handleEvent(Event event) {
            tip.setVisible(true);
        }
    });
    button.pack();
    shell.setBounds(50, 50, 300, 200);
    shell.open();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) display.sleep();
    }
    if (image != null) image.dispose();
    display.dispose();
}
}

除此之外�Q�也有其它的�W�三方API实现了此一效果。是�?a >www.novocode.com提供的BalloonWindow。其API可在上述的网站中获得�?/p>

carob 2006-03-19 16:36 发表评论

carob — Sun, 13 Mar 2005 10:25:00 GMT

从这儿可以看刎ͼ�注意如果客户端程序没有显式地指定源方法名和源�c�d��Q�则LogRecord �c�d��通过分析 call stack(调用�?来自动提取这些信息（�Ҏ��getSourceMethodname和方�?STRONG>getSourceClassName�Q?我们已经走在正确的道路上了，�l�箋�q�查getSourceMethodname()………�?BR>

    public String getSourceClassName() {
    if (needToInferCaller) {
        inferCaller();
    }
    return sourceClassName;
    }

�l�箋

// Private method to infer the caller's class and method names
    private void inferCaller() {
    needToInferCaller = false;
    // Get the stack trace.
    StackTraceElement stack[] = (new Throwable()).getStackTrace();
    // First, search back to a method in the Logger class.
    int ix = 0;
    while (ix < stack.length) {
        StackTraceElement frame = stack[ix];
        String cname = frame.getClassName();
        if (cname.equals("java.util.logging.Logger")) {
        break;
        }
        ix++;
    }
……………�?BR>……………�?/SPAN>

直至�q�儿�Q�我们终于可以松一口气了，因�ؓ我们已经扑ֈ�了其中的关键

StackTraceElement stack[] = (new Throwable()).getStackTrace();

      没错�Q�就是这个StackTraceElement数组记蝲了我们想要的信息�Q�类名，�Ҏ��名等�Q�，�q�和我们用到的Exception�c�M��的显�C��用栈是一个道理的�?BR>
      注意�Q�这儉K��过创徏一个Throwable实例�Q��ƈ利用在Throwable�c�M��提供�q�个getStackTrace()�Ҏ��Q�返回是StackTraceElement数组来获取到了调用栈信息�?BR>
      我们来看一个小例子

public class CallStack {
    String showTrace() {
        return new Throwable().getStackTrace()[0].toString();
    }

    public static void main(String[] args) {
        System.out.println(new CallStack().showTrace());
    }
}

      打印如下
      chapter5.CallStack.showTrace(CallStack.java:5)

      我们亦可以通过�q�样一个简单地实例化一个Throwable来获取相应的call strack�?BR>      不过�Q�一般的应用�U�程序里面不太会用到它，可能在工��L�软�g里面用得多一点了�Q�）

carob 2005-03-13 18:25 发表评论

如何获取call stack(调用�?信息——之一

carob — Sun, 13 Mar 2005 09:58:00 GMT

我们中的大多��C�h每天都会面对logging API�Q�JDK1.4中的Logger, Log4j�{�，从他们生成的log文�g中，我们可以知道日志产生的第一现场信息�Q�比如源文�g名，全限定类名，当前�Ҏ��名，以及记录日志是源代码中第几行�{�，那有没有考虑�q�这些信息是如何获取的呢�Q?BR>
我们先来看一�D�代�?BR>

………�?BR>………�?BR>void doSomething(){
logger.info("doSomething()调用成功");
}
………�?BR>………�?/SPAN>

�q�是我最常见的日志记录方式�?BR>
      我下面就开始我们的�q�踪以查出logging API是如何记录上面提到的�q�些metadata的�?BR>
      �q�儿以JDK1.4中的logging API为研�I�对象�?BR>
      先进入java.util.logging.Logger中，看一下info(String msg)�q�个�Ҏ��

    public void info(String msg) {
    if (Level.INFO.intValue() < levelValue) {
        return;
    }
    log(Level.INFO, msg);
    }

�l�箋�q�踪

    public void log(Level level, String msg) {
    if (level.intValue() < levelValue || levelValue == offValue) {
        return;
    }
    LogRecord lr = new LogRecord(level, msg);
    doLog(lr);
    }

�q�儿我们发现了一个值得��x��的类 LogRecord ,从名字上猜应该是和日志信息有关的一个类。我们来看一下它的Javadoc中的描述

/**
* LogRecord objects are used to pass logging requests between
* the logging framework and individual log Handlers.
*

* When a LogRecord is passed into the logging framework it
* logically belongs to the framework and should no longer be
* used or updated by the client application.
*

* Note that if the client application has not specified an
* explicit source method name and source class name, then the
* LogRecord class will infer them automatically when they are
* first accessed (due to a call on getSourceMethodName or
* getSourceClassName) by analyzing the call stack.

carob 2005-03-13 17:58 发表评论

应用Java Dynamic Proxy 实现�c�L��法的拦截(AOP)

carob — Fri, 04 Mar 2005 02:37:00 GMT

Java Dynamic Proxy 可以对类的指定方法实现拦截，但要求此�c�要实现某个Interface,拦截的方法出自此Interfacle。基于此�Q�我们可以实现简单的AOP�Q�要完成�Ҏ��的拦截，只需要一个InvocationHandler,�q�个InvocationHandler��x��拦截逻辑所在，实现了对目标object指定�Ҏ��的筛选及调用�?BR>
比如我们现有一对Interface/Implemention�Q�Speakable/Translater�?BR>Speakable接口指明了可以sayEnglish(),sayChinese()。我们目前的translater实现了这两个�Ҏ��。现在我们在此基��上，增加对translater的方法的logging功能�?BR>
在以前，我们可以�Q?BR>
1.直接改写原代码，增加logging功能�?ugly)
2.增加一个LoggingTranlater实现Speakable,采用delegation(Design Pattern)�Q�对�Ҏ��q�行增强。对此类proxy可以参考jive�Q�其中遍布proxy 。缺点就是每一个要增加的类都要实现一个代理类�Q�可以想象，代码量急剧膨胀�?BR>
现在让我们来看看Java Dynamic Proxy是如何达到这一点的�Q�声明我�l�出的代理是�C�Z��性的�Q�比较简陋，主要是给��Z��个实现方法，加以改进�Q�即可�Ş成一个比较通用的工兗��?BR>
先来看看我们的Interface/Implemention对：

package reflection.example;

public interface Speakable {
void sayEnglish();

void sayChinese();
}

package reflection.example;

public class Translater implements Speakable {

    public void sayEnglish() {
        System.out.println("Hello,i am robbie");

    }

    public void sayChinese() {
        System.out.println("你好�Q�我是饺�?/SPAN>");

    }

}

现在我们要进行logging功能了，��C��Q�我们只需提供一个InvocationHandler:

package reflection.example;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class LoggingInvoktionHandler implements InvocationHandler {
    private Object target = null;

    public LoggingInvoktionHandler(Object target) {
        this.target = target;
    }

    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {
        logging(method);
        return method.invoke(target, args);
    }

    private void logging(Method method) {
        if ("sayChinese".equals(method.getName())) {
            System.out.println("��译开�?/SPAN>");
        }

        if ("sayEnglish".equals(method.getName())) {
            System.out.println("Tranlation beginning");
        }
    }

}

�q�个LoggingInvocationHandler实现了InvocationHandler接中。方法的代理调用在invoke(…�?中，可以如我��d��logging()功能一��P��加入其它的�Q何想要的功能�Q�然后再�q�行 real target的方法调用�?BR>
如果��logging(Method method)中的逻辑抽出来，攑ֈ�外部文�g(XML)中进行配�|�读取。再�Ҏ��法名采用正则表达式。是不是更�ؓ通用了呢�Q?/P>

下面是客��L��调用�Q?BR>

package reflection.example;

import java.lang.reflect.Proxy;

public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Speakable speaker = new Translater();

        Speakable loggingSpeaker = (Speakable) Proxy.newProxyInstance(
                speaker.getClass().getClassLoader(),
                new Class[] { Speakable.class },
                new LoggingInvoktionHandler(speaker));

        loggingSpeaker.sayChinese();
        loggingSpeaker.sayEnglish();
    }
}

是不是非常简单呢�Q�：)

如果到此为止�Q�还是看不出Dynamic在哪儿的�Q�想��x��q�儿�l�出的示例与spring的AOP的不同，呵呵�Q�区别在于我�q�儿�l�出的Main亦是spring AOP的一部分�Q�在spring里， �Ҏ��个Interface的target的代理，采用了Reflection�Q�以辑ֈ�普遍适用的，不用象我�q�样直接昑ּ�地给出类名而已。若我把Main做成一个Helper�c�，同时�Q�把配置接口及他的实现类都放到外部XML中配�|�，是不是就有点象一个超�U�简化的spring AOP了？

当然spring不是完全用Java Dynamic Proxy的，因�ؓJava Dynamic Proxy的前提—�?STRONG>针对接口�~�程�Q�，针对普通的�cȝ��AOP�Q�Spring采用了字节码增强来实现�?BR>

carob 2005-03-04 10:37 发表评论

carob — Fri, 04 Mar 2005 01:28:00 GMT

比如�Q�有一个SQLUtil�c�，是一个Hibernate��目中的用来存储一�p�d��sql的类�Q�皆为常量。在其它的类中可以根据变量的名称来烦引相应的��|��问题在于名称在另外的�c�M��亦�ؓ变量�Q�直接烦引是没有办法的，但可以透过Java Reflection非常方便的实现。给出的是示意性代码，相应的Exception处理昄��不够 elegant

/*
* Created on 2005-3-3
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package reflection;

/**
* @author ruby
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class SQLUtil {
public static final String SELECT_SQL="from Ruby";

}

/*
* Created on 2005-3-3
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package reflection;

import java.lang.reflect.Field;

/**
* @author ruby
*
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
*/
public class Manager {

    public static String getValue(String sqlName) throws SecurityException,
            NoSuchFieldException, IllegalArgumentException,
            IllegalAccessException {

        Field f = SQLUtil.class.getField(sqlName);

        return f.get(null).toString();
    }

    public static void main(String[] args) throws SecurityException,
            NoSuchFieldException, IllegalArgumentException,
            IllegalAccessException {
        System.out.println(getValue("SELECT_SQL"));
    }
}

carob 2005-03-04 09:28 发表评论

搬到新家来：)

carob — Mon, 28 Feb 2005 12:10:00 GMT

�怸�了这儿的�~�辑器中的“代码”功能，贴出的代码很齐整�?BR>“博客园”还应做得再专业一�Ҏ��行，注册的时候，按着提示赎ͼ�竟然��D��是错误的�Q�注册到其它地方��M��?img src ="http://www.aygfsteel.com/carob/aggbug/1562.html" width = "1" height = "1" />

carob 2005-02-28 20:10 发表评论

Groovlets

carob — Mon, 28 Feb 2005 03:18:00 GMT

你能在Groovy里面写普通的Java Servlet�?BR>存在一�?STRONG>GroovyServlet�Q�自动编�?groovy文�g�Q��{变成字节码，装蝲�c�，�q�缓存它们，直到修改了源文�g�?BR>�q�儿有一个简单的例子来向你说明这事：
(注意讉K��session,output,request的隐式变量的用法)

import java.util.Date

if (session.counter == null) {
  session.counter = 1
}

println """
<html>
    <head>
        <title>Groovy Servlettitle>
    head>
    <body>
Hello, ${request.remoteHost}: ${session.counter}! ${new Date()}
    body>
html>
"""
session.counter = session.counter + 1

或者，用MarkupBuilder完成相同的功�?BR>

import java.util.Date
import groovy.xml.MarkupBuilder

if (session.counter == null) {
      session.counter = 1
}

html.html {    // html is implicitly bound to new MarkupBuilder(out)
  head {
      title("Groovy Servlet")
  }
  body {
    p("Hello, ${request.remoteHost}: ${session.counter}! ${new Date()}")
  }
}
session.counter = session.counter + 1

隐式变量

* �q�些变量在groovylet里面不能被再�ơ赋倹{��他们在�W�一�ơ访问时被绑定，允许诸如在用"out"之前调用对象"response"的方法�?BR>
建立Groovylet

��下面放入web.xml�?BR>


Groovy
groovy.servlet.GroovyServlet



Groovy
*.groovy

然后�Q�所有groovy jar文�g攑ֈ�WEB/lib目录�?只需攑օ�groovy.jar和asm.jar卛_��)

�?groovy文�g攑օ�根目�?放html文�g的地�?中，groovy servlet��会照管�q�些.groovy文�g

��p��个例子��用tomcat来说�Q�要�~�辑tomcat/conf/server.xml �Q�类��g��下面�q�样

"/groovy" docBase="c:/groovy-servlet"/>

carob 2005-02-28 11:18 发表评论

GSQL

carob — Mon, 28 Feb 2005 02:26:00 GMT

GSQL使用戯��非常��单地讉K��/修改关系型数据库�?BR>举例�Q?BR>

/**
* Test to verify valid construction of default DDL
*
* @author Jeremy Rayner
* @version $Revision: 1.2 $
*/
package org.javanicus.gsql

import java.io.*

class SqlGeneratorTest extends GroovyTestCase {
    property database
    property sqlGenerator

    void setUp() {
        typeMap = new TypeMap()
        build = new RelationalBuilder(typeMap)
        sqlGenerator = new SqlGenerator(typeMap,System.getProperty( "line.separator", "\n" ))

        database = build.database(name:'genealogy') {
          table(name:'event') {
              column(name:'event_id', type:'integer', size:10, primaryKey:true, required:true)
              column(name:'description', type:'varchar', size:30)
          }
          table(name:'individual') {
            column(name:'individual_id', type:'integer', size:10, required:true, primaryKey:true, autoIncrement:true)
            column(name:'surname', type:'varchar', size:15, required:true)
            column(name:'event_id', type:'integer', size:10)
            foreignKey(foreignTable:'event') {
                reference(local:'event_id',foreign:'event_id')
            }
            index(name:'surname_index') {
                indexColumn(name:'surname')
            }
          }
        }
    }

    void testGenerateDDL() {
        testWriter = new PrintWriter(new FileOutputStream("SqlGeneratorTest.sql"))
        sqlGenerator.writer = testWriter
        sqlGenerator.createDatabase(database,true)
        testWriter.flush()
   }

}

carob 2005-02-28 10:26 发表评论