/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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 android.webkit;

import android.os.Message;

/**
 * Manages settings state for a WebView. When a WebView is first created, it
 * obtains a set of default settings. These default settings will be returned
 * from any getter call. A WebSettings object obtained from
 * WebView.getSettings() is tied to the life of the WebView. If a WebView has
 * been destroyed, any method call on WebSettings will throw an
 * IllegalStateException.
 */
// This is (effectively) an abstract base class; concrete WebViewProviders must
// create a class derived from this, and return an instance of it in the
// WebViewProvider.getWebSettingsProvider() method implementation.
public class WebSettings {
    // TODO: Remove MustOverrideException and make all methods throwing it abstract instead;
    // needs API file update.
    private static class MustOverrideException extends RuntimeException {
        MustOverrideException() {
            super("abstract function called: must be overriden!");
        }
    }

    /**
     * Enum for controlling the layout of html.
     * NORMAL means no rendering changes.
     * SINGLE_COLUMN moves all content into one column that is the width of the
     * view.
     * NARROW_COLUMNS makes all columns no wider than the screen if possible.
     */
    // XXX: These must match LayoutAlgorithm in Settings.h in WebCore.
    public enum LayoutAlgorithm {
        NORMAL,
        /**
         * @deprecated This algorithm is now obsolete.
         */
        @Deprecated
        SINGLE_COLUMN,
        NARROW_COLUMNS
    }

    /**
     * Enum for specifying the text size.
     * SMALLEST is 50%
     * SMALLER is 75%
     * NORMAL is 100%
     * LARGER is 150%
     * LARGEST is 200%
     * @deprecated Use {@link WebSettings#setTextZoom(int)} and {@link WebSettings#getTextZoom()} instead.
     */
    public enum TextSize {
        SMALLEST(50),
        SMALLER(75),
        NORMAL(100),
        LARGER(150),
        LARGEST(200);
        TextSize(int size) {
            value = size;
        }
        int value;
    }

    /**
     * Enum for specifying the WebView's desired density.
     * FAR makes 100% looking like in 240dpi
     * MEDIUM makes 100% looking like in 160dpi
     * CLOSE makes 100% looking like in 120dpi
     */
    public enum ZoomDensity {
        FAR(150),      // 240dpi
        MEDIUM(100),    // 160dpi
        CLOSE(75);     // 120dpi
        ZoomDensity(int size) {
            value = size;
        }
        int value;
    }

    /**
     * Default cache usage pattern  Use with {@link #setCacheMode}.
     */
    public static final int LOAD_DEFAULT = -1;

    /**
     * Normal cache usage pattern  Use with {@link #setCacheMode}.
     */
    public static final int LOAD_NORMAL = 0;

    /**
     * Use cache if content is there, even if expired (eg, history nav)
     * If it is not in the cache, load from network.
     * Use with {@link #setCacheMode}.
     */
    public static final int LOAD_CACHE_ELSE_NETWORK = 1;

    /**
     * Don't use the cache, load from network
     * Use with {@link #setCacheMode}.
     */
    public static final int LOAD_NO_CACHE = 2;

    /**
     * Don't use the network, load from cache only.
     * Use with {@link #setCacheMode}.
     */
    public static final int LOAD_CACHE_ONLY = 3;

    public enum RenderPriority {
        NORMAL,
        HIGH,
        LOW
    }

    /**
     * The plugin state effects how plugins are treated on a page. ON means
     * that any object will be loaded even if a plugin does not exist to handle
     * the content. ON_DEMAND means that if there is a plugin installed that
     * can handle the content, a placeholder is shown until the user clicks on
     * the placeholder. Once clicked, the plugin will be enabled on the page.
     * OFF means that all plugins will be turned off and any fallback content
     * will be used.
     */
    public enum PluginState {
        ON,
        ON_DEMAND,
        OFF
    }

    /**
     * Hidden constructor to prevent clients from creating a new settings
     * instance or deriving the class.
     * @hide
     */
    protected WebSettings() {
    }

    /**
     * Enables dumping the pages navigation cache to a text file.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public void setNavDump(boolean enabled) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if dumping the navigation cache is enabled.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public boolean getNavDump() {
        throw new MustOverrideException();
    }

    /**
     * Set whether the WebView supports zoom
     */
    public void setSupportZoom(boolean support) {
        throw new MustOverrideException();
    }

    /**
     * Returns whether the WebView supports zoom
     */
    public boolean supportZoom() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether the zoom mechanism built into WebView is used.
     */
    public void setBuiltInZoomControls(boolean enabled) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the zoom mechanism built into WebView is being used.
     */
    public boolean getBuiltInZoomControls() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether the on screen zoom buttons are used.
     * A combination of built in zoom controls enabled
     * and on screen zoom controls disabled allows for pinch to zoom
     * to work without the on screen controls
     */
    public void setDisplayZoomControls(boolean enabled) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the on screen zoom buttons are being used.
     */
    public boolean getDisplayZoomControls() {
        throw new MustOverrideException();
    }

    /**
     * Enable or disable file access within WebView. File access is enabled by
     * default.  Note that this enables or disables file system access only.
     * Assets and resources are still accessible using file:///android_asset and
     * file:///android_res.
     */
    public void setAllowFileAccess(boolean allow) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if this WebView supports file access.
     */
    public boolean getAllowFileAccess() {
        throw new MustOverrideException();
    }

    /**
     * Enable or disable content url access within WebView.  Content url access
     * allows WebView to load content from a content provider installed in the
     * system.  The default is enabled.
     */
    public void setAllowContentAccess(boolean allow) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if this WebView supports content url access.
     */
    public boolean getAllowContentAccess() {
        throw new MustOverrideException();
    }

    /**
     * Set whether the WebView loads a page with overview mode.
     */
    public void setLoadWithOverviewMode(boolean overview) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if this WebView loads page with overview mode
     */
    public boolean getLoadWithOverviewMode() {
        throw new MustOverrideException();
    }

    /**
     * Set whether the WebView will enable smooth transition while panning or
     * zooming or while the window hosting the WebView does not have focus.
     * If it is true, WebView will choose a solution to maximize the performance.
     * e.g. the WebView's content may not be updated during the transition.
     * If it is false, WebView will keep its fidelity. The default value is false.
     */
    public void setEnableSmoothTransition(boolean enable) {
        throw new MustOverrideException();
    }
    /**
     * Returns true if the WebView enables smooth transition while panning or
     * zooming.
     */
    public boolean enableSmoothTransition() {
        throw new MustOverrideException();
    }

    /**
     * Set whether the WebView uses its background for over scroll background.
     * If true, it will use the WebView's background. If false, it will use an
     * internal pattern. Default is true.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public void setUseWebViewBackgroundForOverscrollBackground(boolean view) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if this WebView uses WebView's background instead of
     * internal pattern for over scroll background.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public boolean getUseWebViewBackgroundForOverscrollBackground() {
        throw new MustOverrideException();
    }

    /**
     * Store whether the WebView is saving form data.
     */
    public void setSaveFormData(boolean save) {
        throw new MustOverrideException();
    }

    /**
     *  Return whether the WebView is saving form data and displaying prior
     *  entries/autofill++.  Always false in private browsing mode.
     */
    public boolean getSaveFormData() {
        throw new MustOverrideException();
    }

    /**
     *  Store whether the WebView is saving password.
     */
    public void setSavePassword(boolean save) {
        throw new MustOverrideException();
    }

    /**
     *  Return whether the WebView is saving password.
     */
    public boolean getSavePassword() {
        throw new MustOverrideException();
    }

    /**
     * Set the text zoom of the page in percent. Default is 100.
     * @param textZoom A percent value for increasing or decreasing the text.
     */
    public synchronized void setTextZoom(int textZoom) {
        throw new MustOverrideException();
    }

    /**
     * Get the text zoom of the page in percent.
     * @return A percent value describing the text zoom.
     * @see setTextSizeZoom
     */
    public synchronized int getTextZoom() {
        throw new MustOverrideException();
    }

    /**
     * Set the text size of the page.
     * @param t A TextSize value for increasing or decreasing the text.
     * @see WebSettings.TextSize
     * @deprecated Use {@link #setTextZoom(int)} instead
     */
    public synchronized void setTextSize(TextSize t) {
        throw new MustOverrideException();
    }

    /**
     * Get the text size of the page. If the text size was previously specified
     * in percent using {@link #setTextZoom(int)}, this will return
     * the closest matching {@link TextSize}.
     * @return A TextSize enum value describing the text size.
     * @see WebSettings.TextSize
     * @deprecated Use {@link #getTextZoom()} instead
     */
    public synchronized TextSize getTextSize() {
        throw new MustOverrideException();
    }

    /**
     * Set the default zoom density of the page. This should be called from UI
     * thread.
     * @param zoom A ZoomDensity value
     * @see WebSettings.ZoomDensity
     */
    public void setDefaultZoom(ZoomDensity zoom) {
        throw new MustOverrideException();
    }

    /**
     * Get the default zoom density of the page. This should be called from UI
     * thread.
     * @return A ZoomDensity value
     * @see WebSettings.ZoomDensity
     */
    public ZoomDensity getDefaultZoom() {
        throw new MustOverrideException();
    }

    /**
     * Enables using light touches to make a selection and activate mouseovers.
     */
    public void setLightTouchEnabled(boolean enabled) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if light touches are enabled.
     */
    public boolean getLightTouchEnabled() {
        throw new MustOverrideException();
    }

    /**
     * @deprecated This setting controlled a rendering optimization
     * that is no longer present. Setting it now has no effect.
     */
    @Deprecated
    public synchronized void setUseDoubleTree(boolean use) {
        // Specified to do nothing, so no need for derived classes to override.
    }

    /**
     * @deprecated This setting controlled a rendering optimization
     * that is no longer present. Setting it now has no effect.
     */
    @Deprecated
    public synchronized boolean getUseDoubleTree() {
        // Returns false unconditionally, so no need for derived classes to override.
        return false;
    }

    /**
     * Tell the WebView about user-agent string.
     * @param ua 0 if the WebView should use an Android user-agent string,
     *           1 if the WebView should use a desktop user-agent string.
     *
     * @deprecated Please use setUserAgentString instead.
     */
    @Deprecated
    public synchronized void setUserAgent(int ua) {
        throw new MustOverrideException();
    }

    /**
     * Return user-agent as int
     * @return int  0 if the WebView is using an Android user-agent string.
     *              1 if the WebView is using a desktop user-agent string.
     *             -1 if the WebView is using user defined user-agent string.
     *
     * @deprecated Please use getUserAgentString instead.
     */
    @Deprecated
    public synchronized int getUserAgent() {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView to use the wide viewport
     */
    public synchronized void setUseWideViewPort(boolean use) {
        throw new MustOverrideException();
    }

    /**
     * @return True if the WebView is using a wide viewport
     */
    public synchronized boolean getUseWideViewPort() {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView whether it supports multiple windows. TRUE means
     *         that {@link WebChromeClient#onCreateWindow(WebView, boolean,
     *         boolean, Message)} is implemented by the host application.
     */
    public synchronized void setSupportMultipleWindows(boolean support) {
        throw new MustOverrideException();
    }

    /**
     * @return True if the WebView is supporting multiple windows. This means
     *         that {@link WebChromeClient#onCreateWindow(WebView, boolean,
     *         boolean, Message)} is implemented by the host application.
     */
    public synchronized boolean supportMultipleWindows() {
        throw new MustOverrideException();
    }

    /**
     * Set the underlying layout algorithm. This will cause a relayout of the
     * WebView.
     * @param l A LayoutAlgorithm enum specifying the algorithm to use.
     * @see WebSettings.LayoutAlgorithm
     */
    public synchronized void setLayoutAlgorithm(LayoutAlgorithm l) {
        throw new MustOverrideException();
    }

    /**
     * Return the current layout algorithm. The default is NARROW_COLUMNS.
     * @return LayoutAlgorithm enum value describing the layout algorithm
     *         being used.
     * @see WebSettings.LayoutAlgorithm
     */
    public synchronized LayoutAlgorithm getLayoutAlgorithm() {
        throw new MustOverrideException();
    }

    /**
     * Set the standard font family name.
     * @param font A font family name.
     */
    public synchronized void setStandardFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the standard font family name. The default is "sans-serif".
     * @return The standard font family name as a string.
     */
    public synchronized String getStandardFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the fixed font family name.
     * @param font A font family name.
     */
    public synchronized void setFixedFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the fixed font family name. The default is "monospace".
     * @return The fixed font family name as a string.
     */
    public synchronized String getFixedFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the sans-serif font family name.
     * @param font A font family name.
     */
    public synchronized void setSansSerifFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the sans-serif font family name.
     * @return The sans-serif font family name as a string.
     */
    public synchronized String getSansSerifFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the serif font family name. The default is "sans-serif".
     * @param font A font family name.
     */
    public synchronized void setSerifFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the serif font family name. The default is "serif".
     * @return The serif font family name as a string.
     */
    public synchronized String getSerifFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the cursive font family name.
     * @param font A font family name.
     */
    public synchronized void setCursiveFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the cursive font family name. The default is "cursive".
     * @return The cursive font family name as a string.
     */
    public synchronized String getCursiveFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the fantasy font family name.
     * @param font A font family name.
     */
    public synchronized void setFantasyFontFamily(String font) {
        throw new MustOverrideException();
    }

    /**
     * Get the fantasy font family name. The default is "fantasy".
     * @return The fantasy font family name as a string.
     */
    public synchronized String getFantasyFontFamily() {
        throw new MustOverrideException();
    }

    /**
     * Set the minimum font size.
     * @param size A non-negative integer between 1 and 72.
     * Any number outside the specified range will be pinned.
     */
    public synchronized void setMinimumFontSize(int size) {
        throw new MustOverrideException();
    }

    /**
     * Get the minimum font size. The default is 8.
     * @return A non-negative integer between 1 and 72.
     */
    public synchronized int getMinimumFontSize() {
        throw new MustOverrideException();
    }

    /**
     * Set the minimum logical font size.
     * @param size A non-negative integer between 1 and 72.
     * Any number outside the specified range will be pinned.
     */
    public synchronized void setMinimumLogicalFontSize(int size) {
        throw new MustOverrideException();
    }

    /**
     * Get the minimum logical font size. The default is 8.
     * @return A non-negative integer between 1 and 72.
     */
    public synchronized int getMinimumLogicalFontSize() {
        throw new MustOverrideException();
    }

    /**
     * Set the default font size.
     * @param size A non-negative integer between 1 and 72.
     * Any number outside the specified range will be pinned.
     */
    public synchronized void setDefaultFontSize(int size) {
        throw new MustOverrideException();
    }

    /**
     * Get the default font size. The default is 16.
     * @return A non-negative integer between 1 and 72.
     */
    public synchronized int getDefaultFontSize() {
        throw new MustOverrideException();
    }

    /**
     * Set the default fixed font size.
     * @param size A non-negative integer between 1 and 72.
     * Any number outside the specified range will be pinned.
     */
    public synchronized void setDefaultFixedFontSize(int size) {
        throw new MustOverrideException();
    }

    /**
     * Get the default fixed font size. The default is 16.
     * @return A non-negative integer between 1 and 72.
     */
    public synchronized int getDefaultFixedFontSize() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether the WebView should load image resources. Note that this method
     * controls loading of all images, including those embedded using the data
     * URI scheme. Use {@link #setBlockNetworkImage} to control loading only
     * of images specified using network URI schemes. Note that if the value of this
     * setting is changed from false to true, all images resources referenced
     * by content currently displayed by the WebView are loaded automatically.
     * @param flag Whether the WebView should load image resources.
     */
    public synchronized void setLoadsImagesAutomatically(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the WebView loads image resources. This includes
     * images embedded using the data URI scheme. The default is true.
     * @return True if the WebView loads image resources.
     */
    public synchronized boolean getLoadsImagesAutomatically() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether the WebView should not load image resources from the
     * network (resources accessed via http and https URI schemes).  Note
     * that this method has no effect unless
     * {@link #getLoadsImagesAutomatically} returns true. Also note that
     * disabling all network loads using {@link #setBlockNetworkLoads}
     * will also prevent network images from loading, even if this flag is set
     * to false. When the value of this setting is changed from true to false,
     * network images resources referenced by content currently displayed by
     * the WebView are fetched automatically.
     * @param flag Whether the WebView should not load image resources from
     * the network.
     * @see #setBlockNetworkLoads
     */
    public synchronized void setBlockNetworkImage(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the WebView does not load image resources from the network.
     * The default is false.
     * @return True if the WebView does not load image resources from the network.
     */
    public synchronized boolean getBlockNetworkImage() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether the WebView should not load resources from the network.
     * Use {@link #setBlockNetworkImage} to only avoid loading
     * image resources. Note that if the value of this setting is
     * changed from true to false, network resources referenced by content
     * currently displayed by the WebView are not fetched until
     * {@link android.webkit.WebView#reload} is called.
     * If the application does not have the
     * {@link android.Manifest.permission#INTERNET} permission, attempts to set
     * a value of false will cause a {@link java.lang.SecurityException}
     * to be thrown.
     * @param flag Whether the WebView should not load any resources
     * from the network.
     * @see android.webkit.WebView#reload
     */
    public synchronized void setBlockNetworkLoads(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the WebView does not load any resources from the network.
     * The default value is false if the application has the
     * {@link android.Manifest.permission#INTERNET} permission, otherwise it is
     * true.
     * @return True if the WebView does not load any resources from the network.
     */
    public synchronized boolean getBlockNetworkLoads() {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView to enable javascript execution.
     * @param flag True if the WebView should execute javascript.
     */
    public synchronized void setJavaScriptEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView to enable plugins.
     * @param flag True if the WebView should load plugins.
     * @deprecated This method has been deprecated in favor of
     *             {@link #setPluginState}
     */
    @Deprecated
    public synchronized void setPluginsEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView to enable, disable, or have plugins on demand. On
     * demand mode means that if a plugin exists that can handle the embedded
     * content, a placeholder icon will be shown instead of the plugin. When
     * the placeholder is clicked, the plugin will be enabled.
     * @param state One of the PluginState values.
     */
    public synchronized void setPluginState(PluginState state) {
        throw new MustOverrideException();
    }

    /**
     * Set a custom path to plugins used by the WebView. This method is
     * obsolete since each plugin is now loaded from its own package.
     * @param pluginsPath String path to the directory containing plugins.
     * @deprecated This method is no longer used as plugins are loaded from
     * their own APK via the system's package manager.
     */
    @Deprecated
    public synchronized void setPluginsPath(String pluginsPath) {
        // Specified to do nothing, so no need for derived classes to override.
    }

    /**
     * Set the path to where database storage API databases should be saved.
     * Nota that the WebCore Database Tracker only allows the path to be set once.
     * This will update WebCore when the Sync runs in the C++ side.
     * @param databasePath String path to the directory where databases should
     *     be saved. May be the empty string but should never be null.
     */
    public synchronized void setDatabasePath(String databasePath) {
        throw new MustOverrideException();
    }

    /**
     * Set the path where the Geolocation permissions database should be saved.
     * This will update WebCore when the Sync runs in the C++ side.
     * @param databasePath String path to the directory where the Geolocation
     *     permissions database should be saved. May be the empty string but
     *     should never be null.
     */
    public synchronized void setGeolocationDatabasePath(String databasePath) {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView to enable Application Caches API.
     * @param flag True if the WebView should enable Application Caches.
     */
    public synchronized void setAppCacheEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Set a custom path to the Application Caches files. The client
     * must ensure it exists before this call.
     * @param appCachePath String path to the directory containing Application
     * Caches files. The appCache path can be the empty string but should not
     * be null. Passing null for this parameter will result in a no-op.
     */
    public synchronized void setAppCachePath(String appCachePath) {
        throw new MustOverrideException();
    }

    /**
     * Set the maximum size for the Application Caches content.
     * @param appCacheMaxSize the maximum size in bytes.
     */
    public synchronized void setAppCacheMaxSize(long appCacheMaxSize) {
        throw new MustOverrideException();
    }

    /**
     * Set whether the database storage API is enabled.
     * @param flag boolean True if the WebView should use the database storage
     *     API.
     */
    public synchronized void setDatabaseEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Set whether the DOM storage API is enabled.
     * @param flag boolean True if the WebView should use the DOM storage
     *     API.
     */
    public synchronized void setDomStorageEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Returns true if the DOM Storage API's are enabled.
     * @return True if the DOM Storage API's are enabled.
     */
    public synchronized boolean getDomStorageEnabled() {
        throw new MustOverrideException();
    }
    /**
     * Return the path to where database storage API databases are saved for
     * the current WebView.
     * @return the String path to the database storage API databases.
     */
    public synchronized String getDatabasePath() {
        throw new MustOverrideException();
    }

    /**
     * Returns true if database storage API is enabled.
     * @return True if the database storage API is enabled.
     */
    public synchronized boolean getDatabaseEnabled() {
        throw new MustOverrideException();
    }

    /**
     * Sets whether Geolocation is enabled.
     * @param flag Whether Geolocation should be enabled.
     */
    public synchronized void setGeolocationEnabled(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Return true if javascript is enabled. <b>Note: The default is false.</b>
     * @return True if javascript is enabled.
     */
    public synchronized boolean getJavaScriptEnabled() {
        throw new MustOverrideException();
    }

    /**
     * Return true if plugins are enabled.
     * @return True if plugins are enabled.
     * @deprecated This method has been replaced by {@link #getPluginState}
     */
    @Deprecated
    public synchronized boolean getPluginsEnabled() {
        throw new MustOverrideException();
    }

    /**
     * Return the current plugin state.
     * @return A value corresponding to the enum PluginState.
     */
    public synchronized PluginState getPluginState() {
        throw new MustOverrideException();
    }

    /**
     * Returns the directory that contains the plugin libraries. This method is
     * obsolete since each plugin is now loaded from its own package.
     * @return An empty string.
     * @deprecated This method is no longer used as plugins are loaded from
     * their own APK via the system's package manager.
     */
    @Deprecated
    public synchronized String getPluginsPath() {
        // Unconditionally returns empty string, so no need for derived classes to override.
        return "";
    }

    /**
     * Tell javascript to open windows automatically. This applies to the
     * javascript function window.open().
     * @param flag True if javascript can open windows automatically.
     */
    public synchronized void setJavaScriptCanOpenWindowsAutomatically(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Return true if javascript can open windows automatically. The default
     * is false.
     * @return True if javascript can open windows automatically during
     *         window.open().
     */
    public synchronized boolean getJavaScriptCanOpenWindowsAutomatically() {
        throw new MustOverrideException();
    }
    /**
     * Set the default text encoding name to use when decoding html pages.
     * @param encoding The text encoding name.
     */
    public synchronized void setDefaultTextEncodingName(String encoding) {
        throw new MustOverrideException();
    }

    /**
     * Get the default text encoding name. The default is "Latin-1".
     * @return The default text encoding name as a string.
     */
    public synchronized String getDefaultTextEncodingName() {
        throw new MustOverrideException();
    }

    /**
     * Set the WebView's user-agent string. If the string "ua" is null or empty,
     * it will use the system default user-agent string.
     */
    public synchronized void setUserAgentString(String ua) {
        throw new MustOverrideException();
    }

    /**
     * Return the WebView's user-agent string.
     */
    public synchronized String getUserAgentString() {
        throw new MustOverrideException();
    }

    /**
     * Tell the WebView whether it needs to set a node to have focus when
     * {@link WebView#requestFocus(int, android.graphics.Rect)} is called.
     *
     * @param flag
     */
    public void setNeedInitialFocus(boolean flag) {
        throw new MustOverrideException();
    }

    /**
     * Set the priority of the Render thread. Unlike the other settings, this
     * one only needs to be called once per process. The default is NORMAL.
     *
     * @param priority RenderPriority, can be normal, high or low.
     */
    public synchronized void setRenderPriority(RenderPriority priority) {
        throw new MustOverrideException();
    }

    /**
     * Override the way the cache is used. The way the cache is used is based
     * on the navigation option. For a normal page load, the cache is checked
     * and content is re-validated as needed. When navigating back, content is
     * not revalidated, instead the content is just pulled from the cache.
     * This function allows the client to override this behavior.
     * @param mode One of the LOAD_ values.
     */
    public void setCacheMode(int mode) {
        throw new MustOverrideException();
    }

    /**
     * Return the current setting for overriding the cache mode. For a full
     * description, see the {@link #setCacheMode(int)} function.
     */
    public int getCacheMode() {
        throw new MustOverrideException();
    }
}