加载插件时调用运行() 方法是如何工作的？

Question

在 ImageJ 中，接口插件有一个方法运行() 像这样：

package ij.plugin;

/** Plugins that acquire images or display windows should
    implement this interface. Plugins that process images 
    should implement the PlugInFilter interface. */
public interface PlugIn {

    /** This method is called when the plugin is loaded.
        'arg', which may be blank, is the argument specified
        for this plugin in IJ_Props.txt. */ 
    public void run(String arg);

}

为什么在插件加载时可以自动调用运行()方法？

Answer 1

the run() method can be automatically called when the Plugin is loaded?

没有什么是自动的。 imagej 库中有一行代码表示：

thePlugIn.run(arg);

完整的片段是这样的（来自here）：

/** Runs the specified plugin and returns a reference to it. */
public static Object runPlugIn(String commandName, String className, String arg) {
    if (arg==null) arg = "";
    if (IJ.debugMode)
        IJ.log("runPlugIn: "+className+argument(arg));
    // Load using custom classloader if this is a user 
    // plugin and we are not running as an applet
    if (!className.startsWith("ij.") && applet==null)
        return runUserPlugIn(commandName, className, arg, false);
    Object thePlugIn=null;
    try {
        Class c = Class.forName(className);
        thePlugIn = c.newInstance();
        if (thePlugIn instanceof PlugIn)
            ((PlugIn)thePlugIn).run(arg);
        else
            new PlugInFilterRunner(thePlugIn, commandName, arg);
    }
    catch (ClassNotFoundException e) {
        if (IJ.getApplet()==null)
            log("Plugin or class not found: \"" + className + "\"\n(" + e+")");
    }
    catch (InstantiationException e) {log("Unable to load plugin (ins)");}
    catch (IllegalAccessException e) {log("Unable to load plugin, possibly \nbecause it is not public.");}
    redirectErrorMessages = false;
    return thePlugIn;
}

加载插件时调用运行() 方法是如何工作的？

How does it work that the method run() is called when the plugin is loaded?

java

imagej

加载插件时调用 运行() 方法是如何工作的？

How does it work that the method run() is called when the plugin is loaded?

java

imagej

加载插件时调用运行() 方法是如何工作的？