PyFromImportStatement.java

/*
 * Copyright 2000-2014 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.jetbrains.python.psi;

import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFileSystemItem;
import com.intellij.psi.StubBasedPsiElement;
import com.intellij.psi.util.QualifiedName;
import com.jetbrains.python.psi.stubs.PyFromImportStatementStub;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.List;

/**
 * Describes "from ... import" statements.
 */
public interface PyFromImportStatement extends PyImportStatementBase, StubBasedPsiElement<PyFromImportStatementStub>,
                                               PyImplicitImportNameDefiner {
  boolean isStarImport();

  /**
   * Returns a reference the module from which import is required.
   * @return reference to module. If the 'from' reference is relative and consists entirely of dots, null is returned.
   */
  @Nullable PyReferenceExpression getImportSource();

  @Nullable
  QualifiedName getImportSourceQName();

  /**
   * @return the star in "from ... import *"
   */
  @Nullable PyStarImportElement getStarImportElement();

  /**
   * @return number of dots in relative "from" clause, or 0 in absolute import.
   */
  int getRelativeLevel();

  /**
   * @return true iff the statement is an import from __future__.
   */
  boolean isFromFuture();

  /**
   * If the from ... import statement uses an import list in parentheses, returns the opening parenthesis.
   *
   * @return opening parenthesis token or null
   */
  @Nullable
  PsiElement getLeftParen();

  /**
   * If the from ... import statement uses an import list in parentheses, returns the closing parenthesis.
   *
   * @return closing parenthesis token or null
   */
  @Nullable
  PsiElement getRightParen();

  /**
   * Resolves the import source qualified name to a file or directory. Note: performs a Python only resolve,
   * doesn't handle extension points such as import from Java classes.
   *
   * @return the resolved import source (file or directory containing __init__.py), or null if the import is unresolved.
   */
  @Nullable
  PsiFileSystemItem resolveImportSource();

  /**
   * Resolves the import source qualified name to a number of possible files or directories. Note: performs a Python only resolve,
   * doesn't handle extension points such as import from Java classes.
   *
   * @return possible candidates the resolved import source (file or directory containing __init__.py), or an empty list if the import is unresolved.
   */
  @NotNull
  List<PsiElement> resolveImportSourceCandidates();
}