[置顶] openHAB 体系结构与编程模型 (1) --- 术语

openHAB 术语

Item ： 对硬件设备属性的抽象 (

• Items are objects that can be read from or written to in order to interact with them.

• Items can be bound to bindings i.e. for reading the status from e.g. KNX or for updating them.)

Item UI Provider :

Item UI providers offer a dynamic way to configure the UI, so that not everything must be stored statically in the Sitemap. An item UI provider can for example define, what widget should be used for an item, if none is specified
and can dynamically define icons and labels (which might depend on the current state of the item) for the widgets.

An important use case for this feature is the dynamic display of item groups - all that there is stored in the Sitemap is the information that a certain group should be displayed; the
page is then dynamically assembled at runtime with whatever items are available at that time.

This interface describes the methods that need to be implemented by a provider that wants to define the appearance of an item in the UI. 

Item
UI Registry :

This interface is used by a service which combines the core item registry with an aggregation of item ui providers; it can be therefore widely used for all UI related information requests regarding items.

Item
Provider :

An item provider provides instances of GenericItem. These items can be constructed from some static configuration files or they can be derived from some dynamic logic.

Item
Registry :

The ItemRegistry is the central place, where items are kept in memory and their state is permanently tracked. So any code that requires the current state of items should use this service (instead of trying to keep their own local
copy of the items). Items are registered by ItemProviders, which can provision them from any source they like and also dynamically remove or add items.

Widget ：用户界面的基本元素 (描述的是内容而非展现 [Sitemaps can be composed by grouping various user interface elements into areas, which
will be rendered by openHAB.]), org.openhab.model.sitemap 工程的 src-gen 目录的 org.openhab.model.sitemap.Widget.java 中仅保存 Item 的全局唯一的名称（或者说ID）

/**
 */
package org.openhab.model.sitemap;

import org.eclipse.emf.ecore.EObject;

/**
 * <!-- begin-user-doc -->
 * A representation of the model object '<em><b>Widget</b></em>'.
 * <!-- end-user-doc -->
 *
 * <p>
 * The following features are supported:
 * <ul>
 *   <li>{@link org.openhab.model.sitemap.Widget#getItem <em>Item</em>}</li>
 *   <li>{@link org.openhab.model.sitemap.Widget#getLabel <em>Label</em>}</li>
 *   <li>{@link org.openhab.model.sitemap.Widget#getIcon <em>Icon</em>}</li>
 * </ul>
 * </p>
 *
 * @see org.openhab.model.sitemap.SitemapPackage#getWidget()
 * @model
 * @generated
 */
public interface Widget extends EObject
{
  /**
   * Returns the value of the '<em><b>Item</b></em>' attribute.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Item</em>' attribute isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Item</em>' attribute.
   * @see #setItem(String)
   * @see org.openhab.model.sitemap.SitemapPackage#getWidget_Item()
   * @model
   * @generated
   */
  String getItem();

  /**
   * Sets the value of the '{@link org.openhab.model.sitemap.Widget#getItem <em>Item</em>}' attribute.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Item</em>' attribute.
   * @see #getItem()
   * @generated
   */
  void setItem(String value);

  /**
   * Returns the value of the '<em><b>Label</b></em>' attribute.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Label</em>' attribute isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Label</em>' attribute.
   * @see #setLabel(String)
   * @see org.openhab.model.sitemap.SitemapPackage#getWidget_Label()
   * @model
   * @generated
   */
  String getLabel();

  /**
   * Sets the value of the '{@link org.openhab.model.sitemap.Widget#getLabel <em>Label</em>}' attribute.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Label</em>' attribute.
   * @see #getLabel()
   * @generated
   */
  void setLabel(String value);

  /**
   * Returns the value of the '<em><b>Icon</b></em>' attribute.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Icon</em>' attribute isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Icon</em>' attribute.
   * @see #setIcon(String)
   * @see org.openhab.model.sitemap.SitemapPackage#getWidget_Icon()
   * @model
   * @generated
   */
  String getIcon();

  /**
   * Sets the value of the '{@link org.openhab.model.sitemap.Widget#getIcon <em>Icon</em>}' attribute.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Icon</em>' attribute.
   * @see #getIcon()
   * @generated
   */
  void setIcon(String value);

} // Widget

Sitemap ：用户界面定义（树形结构，同样也是描述内容而非展现），由该 Sitemap 对应的全部 Widget 组成 (The
sitemap is a tree structure of widgets, which define the different pages of a UI and their content. Widgets can be associated to items, for which they should show the status and/or control elements.),  (demo.items 
  demo.sitemap)