Re-usable Error Handling in Java

利用 Groovy 來實現例外處理的重複利用。

底下是範例。




檔案：Test.groovy
編譯：groovyc Test.groovy

class HandleException
{
    def static ignore_exception(obj, method, param)
    {
        try {
            return obj."${method}"(param)
        } catch (Exception e) {
            println "Exception found but ignored"
            return null
        }
    }
}

檔案：Hello.java
編譯：javac Hello.java

public class Hello
{
    public int say(String what) throws Exception
    {
        System.out.print("Hello ");

        if (!(null == what)) {
            System.out.println(what);
            return 1;
        } else {
            throw new Exception();
        }
    }
}

檔案：UseHello.java
編譯：javac -cp .:$GROOVY_HOME/embeddable/groovy-all-1.7.7.jar UseHello.java

public class UseHello
{
    public static void main(String[] args)
    {
        Hello h = new Hello();

        Object ret1 = HandleException.ignore_exception(h, "say", null);
        if (null == ret1) {
            System.out.println("Return null");
        } else {
            System.out.println("Return " + ret1.toString());
        }

        Object ret2 = HandleException.ignore_exception(h, "say", "World");
        if (null == ret2) {
            System.out.println("Return null");
        } else {
            System.out.println("Return " + ret2.toString());
        }
    }
}

執行：java -cp .:$GROOVY_HOME/embeddable/groovy-all-1.7.7.jar UseHello