* Components are laid out in the user interface hierarchically. The layout is * managed by layout components, or more generally by components that implement * the {@link ComponentContainer} interface. Such a container is the * parent of the contained components. *
* ** The {@link #getParent()} method allows retrieving the parent component of a * component. While there is a {@link #setParent(Component) setParent()}, you * rarely need it as you normally add components with the * {@link ComponentContainer#addComponent(Component) addComponent()} method of * the layout or other {@code ComponentContainer}, which automatically sets the * parent. *
* ** A component becomes attached to an application (and the * {@link #attach()} is called) when it or one of its parents is attached to the * main window of the application through its containment hierarchy. *
* * @author Vaadin Ltd. * @since 3.0 */ public interface Component extends ClientConnector, Sizeable, Serializable { /** * Gets all user-defined CSS style names of a component. If the component * has multiple style names defined, the return string is a space-separated * list of style names. Built-in style names defined in Vaadin or GWT are * not returned. * ** The style names are returned only in the basic form in which they were * added; each user-defined style name shows as two CSS style class names in * the rendered HTML: one as it was given and one prefixed with the * component-specific style name. Only the former is returned. *
* * @return the style name or a space-separated list of user-defined style * names of the component * @see #setStyleName(String) * @see #addStyleName(String) * @see #removeStyleName(String) */ public String getStyleName(); /** * Sets one or more user-defined style names of the component, replacing any * previous user-defined styles. Multiple styles can be specified as a * space-separated list of style names. The style names must be valid CSS * class names and should not conflict with any built-in style names in * Vaadin or GWT. * *
* Label label = new Label("This text has a lot of style");
* label.setStyleName("myonestyle myotherstyle");
*
*
* * Each style name will occur in two versions: one as specified and one that * is prefixed with the style name of the component. For example, if you * have a {@code Button} component and give it "{@code mystyle}" style, the * component will have both "{@code mystyle}" and "{@code v-button-mystyle}" * styles. You could then style the component either with: *
* *
* .myonestyle {background: blue;}
*
*
* * or *
* *
* .v-button-myonestyle {background: blue;}
*
*
* * It is normally a good practice to use {@link #addStyleName(String) * addStyleName()} rather than this setter, as different software * abstraction layers can then add their own styles without accidentally * removing those defined in other layers. *
* * @param style * the new style or styles of the component as a space-separated * list * @see #getStyleName() * @see #addStyleName(String) * @see #removeStyleName(String) */ public void setStyleName(String style); /** * Adds one or more style names to this component. Multiple styles can be * specified as a space-separated list of style names. The style name will * be rendered as a HTML class name, which can be used in a CSS definition. * *
* Label label = new Label("This text has style");
* label.addStyleName("mystyle");
*
*
* * Each style name will occur in two versions: one as specified and one that * is prefixed with the style name of the component. For example, if you * have a {@code Button} component and give it "{@code mystyle}" style, the * component will have both "{@code mystyle}" and "{@code v-button-mystyle}" * styles. You could then style the component either with: *
* *
* .mystyle {font-style: italic;}
*
*
* * or *
* *
* .v-button-mystyle {font-style: italic;}
*
*
* @param style
* the new style to be added to the component
* @see #getStyleName()
* @see #setStyleName(String)
* @see #removeStyleName(String)
*/
public void addStyleName(String style);
/**
* Removes one or more style names from component. Multiple styles can be
* specified as a space-separated list of style names.
*
* * The parameter must be a valid CSS style name. Only user-defined style * names added with {@link #addStyleName(String) addStyleName()} or * {@link #setStyleName(String) setStyleName()} can be removed; built-in * style names defined in Vaadin or GWT can not be removed. *
* * * This method will trigger a {@link RepaintRequestEvent}. * * @param style * the style name or style names to be removed * @see #getStyleName() * @see #setStyleName(String) * @see #addStyleName(String) */ public void removeStyleName(String style); /** * Gets the primary style name of the component. See * {@link Component#setPrimaryStyleName(String)} for a better description of * the primary stylename. */ public String getPrimaryStyleName(); /** * Changes the primary style name of the component. * ** The primary style name identifies the component when applying the CSS * theme to the Component. By changing the style name all CSS rules targeted * for that style name will no longer apply, and might result in the * component not working as intended. *
* ** To preserve the original style of the component when changing to a new * primary style you should make your new primary style inherit the old * primary style using the SASS @include directive. See more in the SASS * tutorials. *
* * @param style * The new primary style name */ public void setPrimaryStyleName(String style); /** * Tests whether the component is enabled or not. A user can not interact * with disabled components. Disabled components are rendered in a style * that indicates the status, usually in gray color. Children of a disabled * component are also disabled. Components are enabled by default. * ** As a security feature, all updates for disabled components are blocked on * the server-side. *
* ** Note that this method only returns the status of the component and does * not take parents into account. Even though this method returns true the * component can be disabled to the user if a parent is disabled. *
* * @returntrue if the component and its parent are enabled,
* false otherwise.
* @see VariableOwner#isEnabled()
*/
public boolean isEnabled();
/**
* Enables or disables the component. The user can not interact with
* disabled components, which are shown with a style that indicates the
* status, usually shaded in light gray color. Components are enabled by
* default.
*
*
* Button enabled = new Button("Enabled");
* enabled.setEnabled(true); // The default
* layout.addComponent(enabled);
*
* Button disabled = new Button("Disabled");
* disabled.setEnabled(false);
* layout.addComponent(disabled);
*
*
* * This method will trigger a {@link RepaintRequestEvent} for the component * and, if it is a {@link ComponentContainer}, for all its children * recursively. *
* * @param enabled * a boolean value specifying if the component should be enabled * or not */ public void setEnabled(boolean enabled); /** * Tests the visibility property of the component. * ** Visible components are drawn in the user interface, while invisible ones * are not. The effect is not merely a cosmetic CSS change - no information * about an invisible component will be sent to the client. The effect is * thus the same as removing the component from its parent. Making a * component invisible through this property can alter the positioning of * other components. *
* ** A component is visible only if all its parents are also visible. This is * not checked by this method though, so even if this method returns true, * the component can be hidden from the user because a parent is set to * invisible. *
* * @returntrue if the component has been set to be visible in
* the user interface, false if not
* @see #setVisible(boolean)
* @see #attach()
*/
public boolean isVisible();
/**
* Sets the visibility of the component.
*
* * Visible components are drawn in the user interface, while invisible ones * are not. The effect is not merely a cosmetic CSS change - no information * about an invisible component will be sent to the client. The effect is * thus the same as removing the component from its parent. *
* *
* TextField readonly = new TextField("Read-Only");
* readonly.setValue("You can't see this!");
* readonly.setVisible(false);
* layout.addComponent(readonly);
*
*
* * A component is visible only if all of its parents are also visible. If a * component is explicitly set to be invisible, changes in the visibility of * its parents will not change the visibility of the component. *
* * @param visible * the boolean value specifying if the component should be * visible after the call or not. * @see #isVisible() */ public void setVisible(boolean visible); /** * Sets the parent connector of the component. * ** This method automatically calls {@link #attach()} if the component * becomes attached to the session, regardless of whether it was attached * previously. Conversely, if the component currently is attached to the * session, {@link #detach()} is called for the connector before attaching * it to a new parent. *
** This method is rarely called directly. * {@link ComponentContainer#addComponent(Component)} or a * {@link HasComponents} specific method is normally used for adding * components to a parent and the used method will call this method * implicitly. *
* * @param parent * the parent connector * @throws IllegalStateException * if a parent is given even though the connector already has a * parent */ public void setParent(HasComponents parent); /** * Gets the parent component of the component. * ** Components can be nested but a component can have only one parent. A * component that contains other components, that is, can be a parent, * should usually inherit the {@link ComponentContainer} interface. *
* * @return the parent component */ @Override public HasComponents getParent(); /** * Gets the caption of the component. * ** See {@link #setCaption(String)} for a detailed description of the * caption. *
* * @return the caption of the component or {@code null} if the caption is * not set. * @see #setCaption(String) */ public String getCaption(); /** * Sets the caption of the component. * ** A caption is an explanatory textual label accompanying a user * interface component, usually shown above, left of, or inside the * component. Icon (see {@link #setIcon(Resource) setIcon()} is * closely related to caption and is usually displayed horizontally before * or after it, depending on the component and the containing layout. *
* ** The caption can usually also be given as the first parameter to a * constructor, though some components do not support it. *
* *
* RichTextArea area = new RichTextArea();
* area.setCaption("You can edit stuff here");
* area.setValue("<h1>Helpful Heading</h1>"
* + "<p>All this is for you to edit.</p>");
*
*
* * The contents of a caption are automatically quoted, so no raw HTML can be * rendered in a caption. The validity of the used character encoding, * usually UTF-8, is not checked. *
* ** The caption of a component is, by default, managed and displayed by the * layout component or component container in which the component is placed. * For example, the {@link VerticalLayout} component shows the captions * left-aligned above the contained components, while the {@link FormLayout} * component shows the captions on the left side of the vertically laid * components, with the captions and their associated components * left-aligned in their own columns. The {@link CustomComponent} does not * manage the caption of its composition root, so if the root component has * a caption, it will not be rendered. Some components, such as * {@link Button} and {@link Panel}, manage the caption themselves and * display it inside the component. *
* ** This method will trigger a {@link RepaintRequestEvent}. A * reimplementation should call the superclass implementation. *
* * @param caption * the new caption for the component. If the caption is * {@code null}, no caption is shown and it does not normally * take any space */ public void setCaption(String caption); /** * Gets the icon resource of the component. * ** See {@link #setIcon(Resource)} for a detailed description of the icon. *
* * @return the icon resource of the component or {@code null} if the * component has no icon * @see #setIcon(Resource) */ public Resource getIcon(); /** * Sets the icon of the component. * ** An icon is an explanatory graphical label accompanying a user interface * component, usually shown above, left of, or inside the component. Icon is * closely related to caption (see {@link #setCaption(String) setCaption()}) * and is usually displayed horizontally before or after it, depending on * the component and the containing layout. *
* ** The image is loaded by the browser from a resource, typically a * {@link com.vaadin.server.ThemeResource}. *
* *
* // Component with an icon from a custom theme
* TextField name = new TextField("Name");
* name.setIcon(new ThemeResource("icons/user.png"));
* layout.addComponent(name);
*
* // Component with an icon from another theme ('runo')
* Button ok = new Button("OK");
* ok.setIcon(new ThemeResource("../runo/icons/16/ok.png"));
* layout.addComponent(ok);
*
*
* * The icon of a component is, by default, managed and displayed by the * layout component or component container in which the component is placed. * For example, the {@link VerticalLayout} component shows the icons * left-aligned above the contained components, while the {@link FormLayout} * component shows the icons on the left side of the vertically laid * components, with the icons and their associated components left-aligned * in their own columns. The {@link CustomComponent} does not manage the * icon of its composition root, so if the root component has an icon, it * will not be rendered. *
* ** An icon will be rendered inside an HTML element that has the * {@code v-icon} CSS style class. The containing layout may enclose an icon * and a caption inside elements related to the caption, such as * {@code v-caption} . *
* * This method will trigger a {@link RepaintRequestEvent}. * * @param icon * the icon of the component. If null, no icon is shown and it * does not normally take any space. * @see #getIcon() * @see #setCaption(String) */ public void setIcon(Resource icon); /** * Gets the UI the component is attached to. * *
* If the component is not attached to a UI through a component containment
* hierarchy, null is returned.
*
null if it is not
* attached to a UI
*/
@Override
public UI getUI();
/**
* {@inheritDoc}
*
* * Reimplementing the {@code attach()} method is useful for tasks that need * to get a reference to the parent, window, or application object with the * {@link #getParent()}, {@link #getUI()}, and {@link #getSession()} * methods. A component does not yet know these objects in the constructor, * so in such case, the methods will return {@code null}. For example, the * following is invalid: *
* *
* public class AttachExample extends CustomComponent {
* public AttachExample() {
* // ERROR: We can't access the application object yet.
* ClassResource r = new ClassResource("smiley.jpg",
* getApplication());
* Embedded image = new Embedded("Image:", r);
* setCompositionRoot(image);
* }
* }
*
*
* * Adding a component to an application triggers calling the * {@link #attach()} method for the component. Correspondingly, removing a * component from a container triggers calling the {@link #detach()} method. * If the parent of an added component is already connected to the * application, the {@code attach()} is called immediately from * {@link #setParent(Component)}. *
* *
* public class AttachExample extends CustomComponent {
* public AttachExample() {
* }
*
* @Override
* public void attach() {
* super.attach(); // Must call.
*
* // Now we know who ultimately owns us.
* ClassResource r = new ClassResource("smiley.jpg",
* getApplication());
* Embedded image = new Embedded("Image:", r);
* setCompositionRoot(image);
* }
* }
*
*/
@Override
public void attach();
/**
* Gets the locale of the component.
*
*
* If a component does not have a locale set, the locale of its parent is
* returned, and so on. Eventually, if no parent has locale set, the locale
* of the application is returned. If the application does not have a locale
* set, it is determined by Locale.getDefault().
*
* As the component must be attached before its locale can be acquired, * using this method in the internationalization of component captions, etc. * is generally not feasible. For such use case, we recommend using an * otherwise acquired reference to the application locale. *
* * @return Locale of this component or {@code null} if the component and * none of its parents has a locale set and the component is not yet * attached to an application. */ public Locale getLocale(); /** * Adds an unique id for component that is used in the client-side for * testing purposes. Keeping identifiers unique is the responsibility of the * programmer. * * @param id * An alphanumeric id */ public void setId(String id); /** * Gets currently set debug identifier * * @return current id, null if not set */ public String getId(); /** ** Gets the components description, used in tooltips and can be displayed * directly in certain other components such as forms. The description can * be used to briefly describe the state of the component to the user. The * description string may contain certain XML tags: *
* **
| Tag | *Description | *Example | *
| <b> | *bold | *bold text | *
| <i> | *italic | *italic text | *
| <u> | *underlined | *underlined text | *
| <br> | *linebreak | *N/A | *
| <ul> * <li>item1 * <li>item1 * </ul> |
* item list | *
*
|
*
* These tags may be nested. *
* * @return component's descriptionString
*/
public String getDescription();
/* Declarative support */
/**
* Reads the component state from the given design.
* * The component is responsible not only for updating its own state but also * for ensuring that its children update their state based on the design. *
* It is assumed that the component is in its default state when this method * is called. Reading should only take into consideration attributes * specified in the design and not reset any unspecified attributes to their * defaults. *
* This method must not modify the design. * * @since 7.4 * @param design * The element to obtain the state from * @param designContext * The DesignContext instance used for parsing the design */ public void readDesign(Element design, DesignContext designContext); /** * Writes the component state to the given design. *
* The component is responsible not only for writing its own state but also * for ensuring that its children write their state to the design. *
* This method must not modify the component state. * * @since 7.4 * @param design * The element to write the component state to. Any previous * attributes or child nodes are not cleared. * @param designContext * The DesignContext instance used for writing the design * */ public void writeDesign(Element design, DesignContext designContext); /* Component event framework */ /** * Superclass of all component originated events. * *
* Events are the basis of all user interaction handling in Vaadin. To * handle events, you provide a listener object that receives the events of * the particular event type. *
* *
* Button button = new Button("Click Me!");
* button.addListener(new Button.ClickListener() {
* public void buttonClick(ClickEvent event) {
* getWindow().showNotification("Thank You!");
* }
* });
* layout.addComponent(button);
*
*
* * Notice that while each of the event types have their corresponding * listener types; the listener interfaces are not required to inherit the * {@code Component.Listener} interface. *
* * @see Component.Listener */ @SuppressWarnings("serial") public static class Event extends ConnectorEvent { /** * Constructs a new event with the specified source component. * * @param source * the source component of the event */ public Event(Component source) { super(source); } /** * Gets the component where the event occurred. * * @return the source component of the event */ public Component getComponent() { return (Component) getSource(); } } /** * Listener interface for receivingComponent.Events.
*
* * Listener interfaces are the basis of all user interaction handling in * Vaadin. You have or create a listener object that receives the events. * All event types have their corresponding listener types; they are not, * however, required to inherit the {@code Component.Listener} interface, * and they rarely do so. *
* ** This generic listener interface is useful typically when you wish to * handle events from different component types in a single listener method * ({@code componentEvent()}. If you handle component events in an anonymous * listener class, you normally use the component specific listener class, * such as {@link com.vaadin.ui.Button.ClickEvent}. *
* *
* class Listening extends CustomComponent implements Listener {
* Button ok; // Stored for determining the source of an event
*
* Label status; // For displaying info about the event
*
* public Listening() {
* VerticalLayout layout = new VerticalLayout();
*
* // Some miscellaneous component
* TextField name = new TextField("Say it all here");
* name.addListener(this);
* layout.addComponent(name);
*
* // Handle button clicks as generic events instead
* // of Button.ClickEvent events
* ok = new Button("OK");
* ok.addListener(this);
* layout.addComponent(ok);
*
* // For displaying information about an event
* status = new Label("");
* layout.addComponent(status);
*
* setCompositionRoot(layout);
* }
*
* public void componentEvent(Event event) {
* // Act according to the source of the event
* if (event.getSource() == ok
* && event.getClass() == Button.ClickEvent.class)
* getWindow().showNotification("Click!");
*
* // Display source component and event class names
* status.setValue(
* "Event from " + event.getSource().getClass().getName()
* + ": " + event.getClass().getName());
* }
* }
*
* Listening listening = new Listening();
* layout.addComponent(listening);
*
*
* @see Component#addListener(Listener)
*/
public interface Listener extends ConnectorEventListener {
/**
* Notifies the listener of a component event.
*
* * As the event can typically come from one of many source components, * you may need to differentiate between the event source by component * reference, class, etc. *
* *
* public void componentEvent(Event event) {
* // Act according to the source of the event
* if (event.getSource() == ok
* && event.getClass() == Button.ClickEvent.class)
* getWindow().showNotification("Click!");
*
* // Display source component and event class names
* status.setValue(
* "Event from " + event.getSource().getClass().getName() + ": "
* + event.getClass().getName());
* }
*
*
* @param event
* the event that has occurred.
*/
public void componentEvent(Component.Event event);
}
/**
* Registers a new (generic) component event listener for the component.
*
*
* class Listening extends CustomComponent implements Listener {
* // Stored for determining the source of an event
* Button ok;
*
* Label status; // For displaying info about the event
*
* public Listening() {
* VerticalLayout layout = new VerticalLayout();
*
* // Some miscellaneous component
* TextField name = new TextField("Say it all here");
* name.addListener(this);
* layout.addComponent(name);
*
* // Handle button clicks as generic events instead
* // of Button.ClickEvent events
* ok = new Button("OK");
* ok.addListener(this);
* layout.addComponent(ok);
*
* // For displaying information about an event
* status = new Label("");
* layout.addComponent(status);
*
* setCompositionRoot(layout);
* }
*
* public void componentEvent(Event event) {
* // Act according to the source of the event
* if (event.getSource() == ok)
* getWindow().showNotification("Click!");
*
* status.setValue(
* "Event from " + event.getSource().getClass().getName()
* + ": " + event.getClass().getName());
* }
* }
*
* Listening listening = new Listening();
* layout.addComponent(listening);
*
*
* @param listener
* the new Listener to be registered.
* @return a registration object for removing this listener
* @see Component.Event
* @see Registration
*/
public Registration addListener(Component.Listener listener);
/**
* Removes a previously registered component event listener from this
* component.
*
* @param listener
* the listener to be removed.
* @see #addListener(Listener)
*
* @deprecated As of 8.0, replaced by {@link Registration#remove()} in the
* registration object returned from
* {@link #addListener(Component.Listener)}.
*/
@Deprecated
public void removeListener(Component.Listener listener);
/**
* Class of all component originated error events.
*
* * The component error event is normally fired by * {@link AbstractComponent#setComponentError(ErrorMessage)}. The component * errors are set by the framework in some situations and can be set by user * code. They are indicated in a component with an error indicator. *
*/ @SuppressWarnings("serial") public static class ErrorEvent extends Event { private final ErrorMessage message; /** * Constructs a new event with a specified source component. * * @param message * the error message. * @param component * the source component. */ public ErrorEvent(ErrorMessage message, Component component) { super(component); this.message = message; } /** * Gets the error message. * * @return the error message. */ public ErrorMessage getErrorMessage() { return message; } } /** * A sub-interface implemented by components that can obtain input focus. * This includes all {@code LegacyField} components as well as some other * components, such as {@code Upload}. * ** Focus can be set with {@link #focus()}. This interface does not provide * an accessor that would allow finding out the currently focused component; * focus information can be acquired for some (but not all) * {@code LegacyField} components through the * {@link com.vaadin.event.FieldEvents.FocusListener} and * {@link com.vaadin.event.FieldEvents.BlurListener} interfaces. *
* * @see FieldEvents */ public interface Focusable extends Component { /** * Sets the focus to this component. * *
* Form loginBox = new Form();
* loginBox.setCaption("Login");
* layout.addComponent(loginBox);
*
* // Create the first field which will be focused
* TextField username = new TextField("User name");
* loginBox.addField("username", username);
*
* // Set focus to the user name
* username.focus();
*
* TextField password = new TextField("Password");
* loginBox.addField("password", password);
*
* Button login = new Button("Login");
* loginBox.getFooter().addComponent(login);
*
*
* * Notice that this interface does not provide an accessor that would * allow finding out the currently focused component. Focus information * can be acquired for some (but not all) {@code LegacyField} components * through the {@link com.vaadin.event.FieldEvents.FocusListener} and * {@link com.vaadin.event.FieldEvents.BlurListener} interfaces. *
* * @see com.vaadin.event.FieldEvents * @see com.vaadin.event.FieldEvents.FocusEvent * @see com.vaadin.event.FieldEvents.FocusListener * @see com.vaadin.event.FieldEvents.BlurEvent * @see com.vaadin.event.FieldEvents.BlurListener */ public void focus(); /** * Gets the tabulator index of the {@code Focusable} component. * * @return tab index set for the {@code Focusable} component * @see #setTabIndex(int) */ public int getTabIndex(); /** * Sets the tabulator index of the {@code Focusable} component. * The tab index property is used to specify the order in which the * fields are focused when the user presses the Tab key. Components with * a defined tab index are focused sequentially first, and then the * components with no tab index. * *
* Form loginBox = new Form();
* loginBox.setCaption("Login");
* layout.addComponent(loginBox);
*
* // Create the first field which will be focused
* TextField username = new TextField("User name");
* loginBox.addField("username", username);
*
* // Set focus to the user name
* username.focus();
*
* TextField password = new TextField("Password");
* loginBox.addField("password", password);
*
* Button login = new Button("Login");
* loginBox.getFooter().addComponent(login);
*
* // An additional component which natural focus order would
* // be after the button.
* CheckBox remember = new CheckBox("Remember me");
* loginBox.getFooter().addComponent(remember);
*
* username.setTabIndex(1);
* password.setTabIndex(2);
* remember.setTabIndex(3); // Different than natural place
* login.setTabIndex(4);
*
*
* * After all focusable user interface components are done, the browser * can begin again from the component with the smallest tab index, or it * can take the focus out of the page, for example, to the location bar. *
* ** If the tab index is not set (is set to zero), the default tab order * is used. The order is somewhat browser-dependent, but generally * follows the HTML structure of the page. *
* ** A negative value means that the component is completely removed from * the tabulation order and can not be reached by pressing the Tab key * at all. *
* * @param tabIndex * the tab order of this component. Indexes usually start * from 1. Zero means that default tab order should be used. * A negative value means that the field should not be * included in the tabbing sequence. * @see #getTabIndex() */ public void setTabIndex(int tabIndex); } }