When customising JIRA, it is sometimes necessary to make code modifications. Most classes in JIRA conform to an interface (eg. the Webwork action classes, and *Manager classes), so it is possible to write your own implementation of JIRA interfaces and use yours instead of the default. This page describes the basics of how to plug modified classes into JIRA with minimal pain.

If you wanted to register your overridden version of a pico-registered class, you could just register yours instead of the default in ComponentRegistrar above.

Overriding components in JIRA with an extension pico-container

Please note that this is deprecated and unsupported from JIRA 4.3 onwards

Sometimes it may be necessary for a plugin writer to override a component that JIRA ships with to provide some custom behaviour.  You can do this by providing an extension pico container via a jira-application.properties property. In jira-application.properties, register an extension container provider:

jira.extension.container.provider = com.mycompany.jira.MyContainerProvider

In this class, you can register your own implementations of interfaces, which will be used in preference to the defaults in ComponentManager:

package com.mycompany.jira;

import org.picocontainer.PicoContainer;
import org.picocontainer.defaults.DefaultPicoContainer;
import com.atlassian.jira.config.component.ProfilingComponentAdapterFactory;
import com.atlassian.jira.web.action.issue.BugAssociatorPrefs;
import com.atlassian.jira.security.PermissionManager;
import com.atlassian.jira.permission.PermissionSchemeManager;

import com.mycompany.jira.MyBugAssociatorPrefs;
import com.mycompany.jira.MyPermissionManager;
import com.mycompany.jira.MyPermissionSchemeManager;

public class MyContainerProvider implements ContainerProvider
{
    private DefaultPicoContainer container;

    public PicoContainer getContainer(PicoContainer parent)
    {
        if (container == null)
            buildContainer(parent);
        return container;
    }

    private void buildContainer(PicoContainer parent)
    {
        this.container = new DefaultPicoContainer(new ProfilingComponentAdapterFactory(), parent);
        container.registerComponentImplementation(BugAssociatorPrefs.class, MyBugAssociatorPrefs.class);
        container.registerComponentImplementation(PermissionManager.class, MyPermissionManager.class);
        container.registerComponentImplementation(PermissionSchemeManager.class, MyPermissionSchemeManager.class);
    }
}

Here we have registered our own implementations of three classes, after delegating to the default (so ours will take precedence). You can now keep MyContainerProvider and your modified com.mycompany.jira.* classes in their own jar, which can be dropped into any JIRA instance to customize it to your needs.