Use PicoContainer with two IntelliJ-Plugins

Question

I have two Plugins for IntelliJ. PluginTwo depends on PluginOne, so Two is started after One. Both Plugins depends on a third Core-Module.

The Structure:

I want to access the Dummy-Class via the Context-Class in PluginTwo. The Context class is part of the Core-Module and uses a PicoContainer to provide access on the Dummy-Class. PluginOne creates a Context with the PicoContainer on startup. Now I want to access the Dummy-Class from PluginTwo via the PicoContainer.

I got this Error:

    2018-09-28 14:25:19,208 [  12588]  ERROR - roject.impl.ProjectManagerImpl - PluginTwoProjectComponent@94a5de2 
java.lang.LinkageError: loader constraint violation: loader (instance of com/intellij/ide/plugins/cl/PluginClassLoader) previously initiated loading for a different type with name "Context"
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:642)
    at com.intellij.util.lang.UrlClassLoader._defineClass(UrlClassLoader.java:276)
    at com.intellij.util.lang.UrlClassLoader.defineClass(UrlClassLoader.java:272)
    at com.intellij.util.lang.UrlClassLoader._findClass(UrlClassLoader.java:241)
    at com.intellij.ide.plugins.cl.PluginClassLoader.a(PluginClassLoader.java:142)
    at com.intellij.ide.plugins.cl.PluginClassLoader.a(PluginClassLoader.java:74)
    at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:61)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at PluginTwoProjectComponent.projectOpened(PluginTwoProjectComponent.java:16)

...

The PicoContainer is createt in the Context-Class:

private static Context instance;

private final MutablePicoContainer picoContainer;

public static synchronized Context getInstance() {
    if (instance == null) {
        instance = new Context();
    }
    return instance;
}

public Context() {
    picoContainer = new DefaultPicoContainer();
    picoContainer.addComponent(DummyClass.class);
}

public <T> T getComponent(Class<T> clazz) {
    return picoContainer.getComponent(clazz);
}

The PluginOneProjectComponent get an instance of the Context

public class PluginOneProjectComponent implements ProjectComponent {

    private static Context context;

    private Project project;

    public PluginOneProjectComponent(Project project) {
        this.project = project;
    }

    @Override
    public void projectOpened() {
        System.out.println("PluginOneProjectComponent started with project " + project.getName());
        context = Context.getInstance();

        DummyClass dummy = context.getComponent(DummyClass.class);
        System.out.println("DummyText from PluginOne " + dummy.getText());
        System.out.println("DummyNumber from PluginOne " + dummy.getNumber());
    }

    public static Context getContext() {
        return context;
    }
}

From the PluginTwo I want to use the Context from PluginOne to access the DummyClass. But this don't work.

public class PluginTwoProjectComponent implements ProjectComponent {

    Project project;

    public PluginTwoProjectComponent(Project project) {
        this.project = project;
    }

    @Override
    public void projectOpened() {
        System.out.println("PluginTwoProjectComponent started with project " + project.getName());
        Context context = PluginOneProjectComponent.getContext();
        DummyClass dummy = context.getComponent(DummyClass.class);
        System.out.println("DummyText from Plugin Two" + dummy.getText());
        System.out.println("DummyNumber from Plugin Two" + dummy.getNumber());
    }
}

So the output is only.

PluginOneProjectComponent started with project HelloWorld
DummyText from PluginOne Some Text
DummyNumber from PluginOne 42
PluginTwoProjectComponent started with project HelloWorld

When i call getComponent(DummyClass.class) on the context in the debugger i only get null as result.

Can someone help me? Is there a better way to access my Context-Class from an PluginOne?

I reproduced the error in this small project to share it with you. I only need the PicoContainer from PluginOne to use it in PluginTwo. The complete source is available here: https://github.com/jafey/intellij-plugin-picocontainer-poc

Answer 1

As I understand you should rely on Services concept to communicate between plugins, since they're loaded in separate classloaders the type X in the first plugin is not really the same as type X in second plugin.

Also the concept of pico context meant to be private to the plugin