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14. Structure View Factory

The structure view in the IntelliJ Platform-based IDE can be customized for a specific file type, including Simple Language. Creating a structure view factory allows showing the structure of any file in a Structure Tool Window for easy navigation between items.

14.1. Define a Structure View Factory
14.2. Define a Structure View Model
14.3. Define a Structure View Element
14.4. Register the Structure View Factory
14.5. Run the Project

14.1. Define a Structure View Factory

The structure view factory implements PsiStructureViewFactory. The getStructureViewBuilder() implementation reuses the IntelliJ Platform class TreeBasedStructureViewBuilder. At this point the project will not compile until SimpleStructureViewModel is implemented below.

// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

package org.intellij.sdk.language;

import com.intellij.ide.structureView.StructureViewBuilder;
import com.intellij.ide.structureView.StructureViewModel;
import com.intellij.ide.structureView.TreeBasedStructureViewBuilder;
import com.intellij.lang.PsiStructureViewFactory;
import com.intellij.openapi.editor.Editor;
import com.intellij.psi.PsiFile;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class SimpleStructureViewFactory implements PsiStructureViewFactory {
  @Nullable
  @Override
  public StructureViewBuilder getStructureViewBuilder(@NotNull final PsiFile psiFile) {
    return new TreeBasedStructureViewBuilder() {
      @NotNull
      @Override
      public StructureViewModel createStructureViewModel(@Nullable Editor editor) {
        return new SimpleStructureViewModel(psiFile);
      }
    };
  }
}

14.2. Define a Structure View Model

The SimpleStructureViewModel is created by implementing StructureViewModel, which defines the model for data displayed in the standard structure view. It also extends StructureViewModelBase, an implementation that links the model to a text editor.

// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

package org.intellij.sdk.language;

import com.intellij.ide.structureView.*;
import com.intellij.ide.util.treeView.smartTree.Sorter;
import com.intellij.psi.PsiFile;
import org.intellij.sdk.language.psi.SimpleFile;
import org.jetbrains.annotations.NotNull;

public class SimpleStructureViewModel extends StructureViewModelBase implements
      StructureViewModel.ElementInfoProvider {
  public SimpleStructureViewModel(PsiFile psiFile) {
    super(psiFile, new SimpleStructureViewElement(psiFile));
  }
  
  @NotNull
  public Sorter[] getSorters() {
    return new Sorter[]{Sorter.ALPHA_SORTER};
  }
  
  
  @Override
  public boolean isAlwaysShowsPlus(StructureViewTreeElement element) {
    return false;
  }
  
  @Override
  public boolean isAlwaysLeaf(StructureViewTreeElement element) {
    return element instanceof SimpleFile;
  }
}

14.3. Define a Structure View Element

The SimpleStructureViewElement implements StructureViewTreeElement and SortableTreeElement. The StructureViewTreeElement represents an element in the Structure View tree model. The SortableTreeElement represents an item in a smart tree that allows using text other than the presentable text as a key for alphabetic sorting.

// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

package org.intellij.sdk.language;

import com.intellij.ide.projectView.PresentationData;
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.psi.NavigatablePsiElement;
import com.intellij.psi.util.PsiTreeUtil;
import org.intellij.sdk.language.psi.SimpleFile;
import org.intellij.sdk.language.psi.SimpleProperty;
import org.intellij.sdk.language.psi.impl.SimplePropertyImpl;
import org.jetbrains.annotations.NotNull;

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

public class SimpleStructureViewElement implements StructureViewTreeElement, SortableTreeElement {
  private final NavigatablePsiElement myElement;

  public SimpleStructureViewElement(NavigatablePsiElement element) {
    this.myElement = element;
  }

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

  @Override
  public void navigate(boolean requestFocus) {
    myElement.navigate(requestFocus);
  }

  @Override
  public boolean canNavigate() {
    return myElement.canNavigate();
  }

  @Override
  public boolean canNavigateToSource() {
    return myElement.canNavigateToSource();
  }

  @NotNull
  @Override
  public String getAlphaSortKey() {
    String name = myElement.getName();
    return name != null ? name : "";
  }

  @NotNull
  @Override
  public ItemPresentation getPresentation() {
    ItemPresentation presentation = myElement.getPresentation();
    return presentation != null ? presentation : new PresentationData();
  }

  @NotNull
  @Override
  public TreeElement[] getChildren() {
    if (myElement instanceof SimpleFile) {
      List<SimpleProperty> properties = PsiTreeUtil.getChildrenOfTypeAsList(myElement, SimpleProperty.class);
      List<TreeElement> treeElements = new ArrayList<>(properties.size());
      for (SimpleProperty property : properties) {
        treeElements.add(new SimpleStructureViewElement((SimplePropertyImpl) property));
      }
      return treeElements.toArray(new TreeElement[0]);
    }
    return EMPTY_ARRAY;
  }
}

14.4. Register the Structure View Factory

The SimpleStructureViewFactory implementation is registered with the IntelliJ Platform in the plugin configuration file using the com.intellij.lang.psiStructureViewFactory extension point.

<extensions defaultExtensionNs="com.intellij">
  <lang.psiStructureViewFactory language="Simple" 
          implementationClass="org.intellij.sdk.language.SimpleStructureViewFactory"/>
</extensions>

14.5. Run the Project

Rebuild the project, and run simple_language_plugin in a Development Instance. Open the test.simple file and choose View | Tool Windows | Structure. The IDE now supports a structure view of the Simple Language:

Structure View

Last modified: 19 February 2020