PSI Facade

Many plugins create an interface/class with the named with the suffix PsiFacade. Typically this class will be registered as a project service and is used to provide a simpler method of querying, and working with PSI Elements.

Creating

plugin.xml

<!-- Extension points defined by the plugin.
         Read more: https://plugins.jetbrains.com/docs/intellij/plugin-extension-points.html -->
<extensions defaultExtensionNs="com.intellij">
         <projectService serviceInterface="com.example.psi.ExamplePsiFacade"
                  serviceImplementation="com.example.psi.ExamplePsiFacadeImpl"/>
</extensions>

ExamplePsiFacade.java

package com.example.psi;

import com.intellij.openapi.project.Project;
import org.jetbrains.annotations.NotNull;

public abstract class ExamplePsiFacade {
    @NotNull
    public static ExamplePsiFacade getInstance(@NotNull Project project) {
        return project.getService(ExamplePsiFacade.class);
    }

    @NotNull
    public abstract Project getProject();
}

ExamplePsiFacade.java

package com.example.psi;

import com.intellij.openapi.project.Project;
import org.jetbrains.annotations.NotNull;

public class ExamplePsiFacadeImpl extends ExamplePsiFacade {
    private final Project myProject;

    public ExamplePsiFacadeImpl(@NotNull Project project) {
        this.myProject = project;
    }

    @Override
    @NotNull
    public Project getProject() {
        return this.myProject;
    }
}

Common Methods

Method	Notes
getInstance()	get the service instance
getProject()	get the project the user is working on

Examples

• JavaPsiFacade / JavaPsiFacadeImpl

Reference

• https://plugins.jetbrains.com/docs/intellij/psi.html
• https://plugins.jetbrains.com/docs/intellij/plugin-services.html#0