* @param reader the reader to retrieve the raw content in ZUML.	 * @param extension the default extension if the content doesn't specify	 * an language. In other words, if	 * the content doesn't specify an language, {@link LanguageDefinition#getByExtension}	 * is called.	 * If extension is null and the content doesn't specify a language,	 * the language called "xul/html" is assumed.	 * @param parent the parent component, or null if you want it to be	 * a root component. If parent is null, the page is assumed to be	 * the current page, which is determined by the execution context.	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @see #createComponents(PageDefinition, Component, Map)	 * @see #createComponents(String, Component, Map)	 * @see #createComponentsDirectly(Document, String, Component, Map)	 * @see #createComponentsDirectly(String, String, Component, Map)	 */	public Component createComponentsDirectly(Reader reader, String extension,	Component parent, Map arg) throws IOException;	/** Creates components that don't belong to any page	 * from the specified page definition.	 *	 * @param pagedef the page definition to use. It cannot be null.	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @return the first component being created.	 * @see #createComponents(String, Map)	 * @since 2.4.0	 */	public Component[] createComponents(PageDefinition pagedef, Map arg);	/** Creates components that don't belong to any page	 * from a page file specified by an URI.	 *	 * <p>It loads the page definition from the specified URI (by	 * use {@link #getPageDefinition} ), and then	 * invokes {@link #createComponents(PageDefinition,Component,Map)}	 * to create components.	 *	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @see #createComponents(PageDefinition, Map)	 * @see #createComponentsDirectly(String, String, Map)	 * @see #createComponentsDirectly(Document, String, Map)	 * @see #createComponentsDirectly(Reader, String, Map)	 * @since 2.4.0	 */	public Component[] createComponents(String uri, Map arg);	/** Creates components that don't belong to any page	 * from the raw content specified by a string.	 *	 * <p>The raw content is parsed to a page defintion by use of	 * {@link #getPageDefinitionDirectly(String, String)}, and then	 * invokes {@link #createComponents(PageDefinition,Component,Map)}	 * to create components.	 *	 * @param content the raw content of the page. It must be in ZUML.	 * @param extension the default extension if the content doesn't specify	 * an language. In other words, if	 * the content doesn't specify an language, {@link LanguageDefinition#getByExtension}	 * is called.	 * If extension is null and the content doesn't specify a language,	 * the language called "xul/html" is assumed.	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @see #createComponents(PageDefinition, Map)	 * @see #createComponents(String, Map)	 * @see #createComponentsDirectly(Document, String, Map)	 * @see #createComponentsDirectly(Reader, String, Map)	 * @since 2.4.0	 */	public Component[] createComponentsDirectly(String content, String extension,	Map arg);	/** Creates components that don't belong to any page	 * from the raw content specified by a DOM tree.	 *	 * <p>The raw content is parsed to a page defintion by use of	 * {@link #getPageDefinitionDirectly(Document, String)}, and then	 * invokes {@link #createComponents(PageDefinition,Component,Map)}	 * to create components.	 *	 * @param content the raw content in DOM.	 * @param extension the default extension if the content doesn't specify	 * an language. In other words, if	 * the content doesn't specify an language, {@link LanguageDefinition#getByExtension}	 * is called.	 * If extension is null and the content doesn't specify a language,	 * the language called "xul/html" is assumed.	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @see #createComponents(PageDefinition, Map)	 * @see #createComponents(String, Map)	 * @see #createComponentsDirectly(Document, String, Map)	 * @see #createComponentsDirectly(Reader, String, Map)	 * @since 2.4.0	 */	public Component[] createComponentsDirectly(Document content, String extension,	Map arg);	/** Creates components that don't belong to any page	 * from the raw content read from the specified reader.	 *	 * <p>The raw content is loaded and parsed to a page defintion by use of	 * {@link #getPageDefinitionDirectly(Reader,String)}, and then	 * invokes {@link #createComponents(PageDefinition,Component,Map)}	 * to create components.	 *	 * @param reader the reader to retrieve the raw content in ZUML.	 * @param extension the default extension if the content doesn't specify	 * an language. In other words, if	 * the content doesn't specify an language, {@link LanguageDefinition#getByExtension}	 * is called.	 * If extension is null and the content doesn't specify a language,	 * the language called "xul/html" is assumed.	 * @param arg a map of parameters that is accessible by the arg variable	 * in EL, or by {@link Execution#getArg}.	 * Ignored if null.	 * @see #createComponents(PageDefinition, Map)	 * @see #createComponents(String, Map)	 * @see #createComponentsDirectly(Document, String, Map)	 * @see #createComponentsDirectly(String, String, Map)	 * @since 2.4.0	 */	public Component[] createComponentsDirectly(Reader reader, String extension,	Map arg) throws IOException;	/** Sends a temporary redirect response to the client using the specified	 * redirect location URL.	 *	 * <p>It is the same as sendRedirect(url, null).	 *	 * <p>After calling this method, the caller shall end the processing	 * immediately (by returning). All pending requests and events will	 * be dropped.	 *	 * @param uri the URI to redirect to, or null to reload the same page	 */	public void sendRedirect(String uri);	/** Sends a temporary redirect response to the client using the specified	 * redirect location URL and redirect to the specified browser window.	 *	 * <p>After calling this method, the caller shall end the processing	 * immediately (by returning). All pending requests and events will	 * be dropped.	 *	 * <p>Note: if you specify target other than null and "_self", it'll	 * fail if the browser prevent the server to popup a window.	 *	 * @param uri the URI to redirect to, or null to reload the same page	 * @param target the name of the browser window that send-redirect will	 * load the sepcified URI, or null if the current browser window	 * is used.	 */	public void sendRedirect(String uri, String target);	/** Returns the parameters (aka., arg) if {@link #pushArg} is called recently,	 * or an empty map if not available.	 *	 * <p>The use of parameters is application dependent.	 * ZK only provides the way to store ({@link #pushArg} and to	 * restore {@link #popArg}. And, let the parameters being accessible in	 * EL by referring it as the arg variable.	 *	 * <p>Currently, {@link #createComponents(String,Component,Map)}	 * and similar methods use this mechanism to let caller customize a page	 * definition.	 *	 * <p>Notice that {@link #createComponents(String,Component,Map)}	 * pops arg after creating components, and before processing any event.	 * In other words, it is not aviable for event listener, including onCreate.	 * However, {@link org.zkoss.zk.ui.event.CreateEvent#getArg} preserves	 * the map for its event listeners.	 */	public Map getArg();	/** Pushes the parameters (aka., arg) that EL could refer it by the arg variable.	 * Remember to call {@link #popArg} in the finally clause.	 * @see #getArg	 */	public void pushArg(Map arg);	/** Pops the parameters (aka., arg) that is pushed by {@link #pushArg}.	 * <p>It never throws an exception.	 * @see #getArg	 */	public void popArg();	/** Adds an asynchronous response ({@link AuResponse}) which will be	 * sent to client at the end of the execution.	 *	 * <p>If {@link AuResponse#getDepends} is not null, the response	 * depends on the returned componet. In other words, the response	 * is removed if the component is removed.	 * If it is null, the response is component-independent.	 *	 * @param key could be anything. The second invocation of this method	 * in the same execution with the same key will override the previous one.	 */	public void addAuResponse(String key, AuResponse resposne);	/** Returns whether the client is a browser.	 */	public boolean isBrowser();	/** Returns whether the client is a robot (such as Web crawlers).	 *	 * <p>Because there are too many robots, it returns true if the user-agent	 * is not recognized.	 */	public boolean isRobot();	/** Returns whether the client is Internet Explorer.	 * If true, it also implies {@link #isExplorer7} is true.	 */	public boolean isExplorer();	/** Returns whether the client is Internet Explorer 7 or later.	 */	public boolean isExplorer7();	/** Returns whether the client is Gecko based, such as Mozilla, Firefox and Camino.	 */	public boolean isGecko();	/** Returns whether the client is Safari.	 */	public boolean isSafari();	/** Returns whether the client is a mobile device supporting MIL	 * (Mobile Interactive Language).	 * @since 2.4.1	 */	public boolean isMilDevice();	/** Returns the native request, or null if not available.	 *	 * <p>The returned object depends on the Web container.	 * If it is based Java servlet container, an instance of	 * javax.servlet.ServletRequest is returned.	 */	public Object getNativeRequest();	/** Returns the native response, or null if not available.	 *	 * <p>The returned object depends on the Web container.	 * If it is based Java servlet container, an instance of	 * javax.servlet.ServletResponse is returned.	 */	public Object getNativeResponse();	/** Returns the value of the specified request attribute.	 */	public Object getAttribute(String name);	/** Sets the value of the specified request attribute.	 *	 * @param value the value. If null, the attribute is removed.	 */	public void setAttribute(String name, Object value);	/** Removes the specified request attribute.	 */	public void removeAttribute(String name);	/** Returns a map of request attributes associated with this session.	 */	public Map getAttributes();}