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--- workflow:custom_function [2019/03/14 09:03]
admin
+++ — (current)
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-~~NOTRANS~~
-~~Title: Custom function~~
-A function is the code block behind a task. It's very simple to create a new function because a function is defined as simple Java interface:
-<file java IFunction.java>
-public interface IFunction
-{
-    /**
-     * Gets the current workflow step.
-     *
-     * @return the current workflow step.
-     */
-    public IWorkflowStep getWorkflowStep();
-    /**
-     * Initializes the function.
-     *
-     * @param pStep the current workflow step
-     */
-    public void init(IWorkflowStep pStep);
-    /**
-     * Runs the function.
-     * If the function returns <code>true</code>, the function is fully done, and the workflow jumps to the next step.
-     * In case there are more then one next steps, the finish function of IWorkflowStep has to be called.
-     * An exception will be thrown otherwise.
-     * If finish is already called, it does not matter whether <code>true</code> or <code>false</code> is returned.
-     *
-     * @return <code>true</code>, if the function is done.
-     * @throws Throwable if function fails.
-     */
-    public boolean run() throws Throwable;
-    /**
-     * Notifies, that the workflow is cancelled.
-     *
-     * @throws Throwable if canceling fails.
-     */
-    public void cancel() throws Throwable;
-}
-</file>
-The interface already has an abstract implementation and so it's really super simple to create a new function. Our example will send an email, so it't the EmailFunction:
-<file java EmailFunction.java>
-public class EmailFunction extends AbstractFunction
-{
-    @Override
-    public boolean run() throws Throwable
-    {
-        XmlNode smtp = getApplicationZone().getConfig().getNode("/application/mail/smtp");
-        if (smtp == null)
-        {
-            throw new IllegalArgumentException("SMTP config not found (path /application/mail/smtp)!");
-        }
-        String host = smtp.getNodeValue("host");
-        String port = smtp.getNodeValue("port");
-        String username = smtp.getNodeValue("username");
-        String password = smtp.getNodeValue("password");
-        boolean tlsEnabled = Boolean.parseBoolean(smtp.getNodeValue("tlsenabled"));
-        String defaultsender = smtp.getNodeValue("defaultsender");
-        String from = getNotNullEvaluatedParameter("From");
-        String to = getNotNullEvaluatedParameter("To");
-        String cC = getEvaluatedParameter("CC");
-        String bCC = getEvaluatedParameter("BCC");
-        String subject = getNotNullEvaluatedParameter("Subject");
-        String body = getEvaluatedParameter("Body");
-        log("Mailserver: " + host + ":" + port + "/" + username);
-        Mail mail = new Mail(host, port, username, password);
-        mail.setTLSEnabled(tlsEnabled);
-        mail.send(CommonUtil.nvl(from, defaultsender), to, cC, bCC, subject, body, null, null);
-        log("From: " + CommonUtil.nvl(from, defaultsender));
-        log("To: " + to);
-        log("Subject: " + subject);
-        return true;
-    }
-}
-</file>
-The implementation is straight forward. It extends the AbstractFunction and implements run method. The email settings will be read from the [[jvx:common:setup:zones|application configuration]] and the email settings will be read from the input parameters. Finally, the email will be sent.
-But there's still one open question: How do we define the input parameters?
-Simply use the Functions screen and enter all required information:
-{{:workflow:wf_emailfunction.png?nolink|}}
-That's it. Start using your new function.