intellij-sdk-code-samples/src/com/simpleplugin/SimpleStructureViewElement.java

package com.simpleplugin;

import com.intellij.ide.structureView.StructureViewTreeElement;
import com.intellij.ide.util.treeView.smartTree.SortableTreeElement;
import com.intellij.ide.util.treeView.smartTree.TreeElement;
import com.intellij.navigation.ItemPresentation;
import com.intellij.navigation.NavigationItem;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiNamedElement;
import com.intellij.psi.util.PsiTreeUtil;
import com.simpleplugin.psi.SimpleFile;
import com.simpleplugin.psi.SimpleProperty;

import java.util.ArrayList;
import java.util.List;

public class SimpleStructureViewElement implements StructureViewTreeElement, SortableTreeElement {
    private PsiElement element;

    public SimpleStructureViewElement(PsiElement element) {
        this.element = element;
    }

    @Override
    public Object getValue() {
        return element;
    }

    @Override
    public void navigate(boolean requestFocus) {
        if (element instanceof NavigationItem) {
            ((NavigationItem) element).navigate(requestFocus);
        }
    }

    @Override
    public boolean canNavigate() {
        return element instanceof NavigationItem &&
                ((NavigationItem)element).canNavigate();
    }

    @Override
    public boolean canNavigateToSource() {
        return element instanceof NavigationItem &&
                ((NavigationItem)element).canNavigateToSource();
    }

    @Override
    public String getAlphaSortKey() {
        return element instanceof PsiNamedElement ? ((PsiNamedElement) element).getName() : null;
    }

    @Override
    public ItemPresentation getPresentation() {
        return element instanceof NavigationItem ?
                ((NavigationItem) element).getPresentation() : null;
    }

    @Override
    public TreeElement[] getChildren() {
        if (element instanceof SimpleFile) {
            SimpleProperty[] properties = PsiTreeUtil.getChildrenOfType(element, SimpleProperty.class);
            List<TreeElement> treeElements = new ArrayList<TreeElement>(properties.length);
            for (SimpleProperty property : properties) {
                treeElements.add(new SimpleStructureViewElement(property));
            }
            return treeElements.toArray(new TreeElement[treeElements.size()]);
        } else {
            return EMPTY_ARRAY;
        }
    }
}