platform/lang-impl/src/com/intellij/util/TextFieldCompletionProvider.java

package com.intellij.util;

import com.intellij.codeInsight.completion.CompletionResultSet;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.editor.Editor;
import com.intellij.openapi.editor.ex.EditorEx;
import com.intellij.openapi.fileTypes.FileType;
import com.intellij.openapi.fileTypes.PlainTextLanguage;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.Key;
import com.intellij.psi.PsiDocumentManager;
import com.intellij.psi.PsiFile;
import com.intellij.psi.PsiFileFactory;
import com.intellij.ui.EditorTextField;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * @author sergey.evdokimov
 */
public abstract class TextFieldCompletionProvider {

  static final Key<TextFieldCompletionProvider> COMPLETING_TEXT_FIELD_KEY = Key.create("COMPLETING_TEXT_FIELD_KEY");

  protected boolean myCaseInsensitivity;

  protected TextFieldCompletionProvider() {
    this(false);
  }

  protected TextFieldCompletionProvider(boolean caseInsensitivity) {
    myCaseInsensitivity = caseInsensitivity;
  }

  public void apply(@NotNull EditorTextField field, @NotNull String text) {
    Project project = field.getProject();
    if (project != null) {
      field.setDocument(createDocument(project, text));
    }
  }
  
  public void apply(@NotNull EditorTextField field) {
    apply(field, "");
  }

  private Document createDocument(final Project project, @NotNull String text) {
    final FileType fileType = PlainTextLanguage.INSTANCE.getAssociatedFileType();
    assert fileType != null;

    final long stamp = LocalTimeCounter.currentTime();
    final PsiFile psiFile = PsiFileFactory.getInstance(project)
      .createFileFromText("Dummy." + fileType.getDefaultExtension(), fileType, text, stamp, true, false);

    psiFile.putUserData(COMPLETING_TEXT_FIELD_KEY, this);

    final Document document = PsiDocumentManager.getInstance(project).getDocument(psiFile);
    assert document != null;
    return document;
  }

  public boolean isCaseInsensitivity() {
    return myCaseInsensitivity;
  }

  @NotNull
  protected String getPrefix(@NotNull String currentTextPrefix) {
    return currentTextPrefix;
  }

  protected abstract void addCompletionVariants(@NotNull String text, int offset, @NotNull String prefix, @NotNull CompletionResultSet result);

  @NotNull
  public EditorTextField createEditor(Project project) {
    return createEditor(project, true);
  }
  
  @NotNull
  public EditorTextField createEditor(Project project, final boolean shouldHaveBorder) {
    return createEditor(project, shouldHaveBorder, null);
  }
  
  @NotNull
  public EditorTextField createEditor(Project project,
                                      final boolean shouldHaveBorder,
                                      @Nullable final Consumer<Editor> editorConstructionCallback)
  {
    return new EditorTextField(createDocument(project, ""), project, PlainTextLanguage.INSTANCE.getAssociatedFileType()) {
      @Override
      protected boolean shouldHaveBorder() {
        return shouldHaveBorder;
      }

      @Override
      protected void updateBorder(@NotNull EditorEx editor) {
        if (shouldHaveBorder) {
          super.updateBorder(editor);
        }
        else {
          editor.setBorder(null);
        }
      }

      @Override
      protected EditorEx createEditor() {
        EditorEx result = super.createEditor();
        if (editorConstructionCallback != null) {
          editorConstructionCallback.consume(result);
        }
        return result;
      }
    };
  }
}