content/public/android/java/src/org/chromium/content/browser/NavigationController.java

// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.content.browser;

/**
 * The NavigationController Java wrapper to allow communicating with the native
 * NavigationController object.
 */
public interface NavigationController {
    /**
     * @return Whether back navigation is possible from the "current entry".
     */
    boolean canGoBack();

    /**
     * @return Whether forward navigation is possible from the "current entry".
     */
    boolean canGoForward();

    /**
     * @param offset The offset into the navigation history.
     * @return Whether we can move in history by given offset
     */
    boolean canGoToOffset(int offset);

    /**
     * Navigates to the specified offset from the "current entry". Does nothing if the offset is
     * out of bounds.
     * @param offset The offset into the navigation history.
     */
    void goToOffset(int offset);

    /**
     * Navigates to the specified index in the navigation entry for this page.
     * @param index The navigation index to navigate to.
     */
    void goToNavigationIndex(int index);

    /**
     * Goes to the navigation entry before the current one.
     */
    void goBack();

    /**
     * Goes to the navigation entry following the current one.
     */
    void goForward();
}