Chương 5 Java Beans

Môn Lập trình Java NC Môn Lập trình Java NC Chương 5: Java Beans Chương 5: Java Beans 2 Object Oriented Programming 2 - Chapter 6: Java Beans Content Content  Introduction Introduction  The Bean-Writing process The Bean-Writing process  Using Bean to build an Application Using Bean to build an Application  Naming Patterns for Bean Properties and Naming Patterns for Bean Properties and Events Events  Bean Property Types Bean Property Types  Adding Custom Bean Events Adding Custom Bean Events  Property Editors Property Editors  Going Beyond Naming Patterns Going Beyond Naming Patterns  Customizers Customizers  The Bean Context The Bean Context 3 Object Oriented Programming 2 - Chapter 6: Java Beans 1. Introduction 1. Introduction  What is a JavaBean? What is a JavaBean?  A JavaBean is a A JavaBean is a component component : :  a self-contained, reusable software unit a self-contained, reusable software unit  it can be it can be visually composed visually composed with other beans to with other beans to make bigger components, applets, applications, etc. make bigger components, applets, applications, etc. 4 Object Oriented Programming 2 - Chapter 6: Java Beans 1. Introduction (cont.) 1. Introduction (cont.)  A bean is designed to A bean is designed to expose expose its features: its features:  e.g. public methods, properties (data), events e.g. public methods, properties (data), events  Exposure allows beans to be used inside visual Exposure allows beans to be used inside visual building tools (e.g. JBuilder) building tools (e.g. JBuilder)  Exposure is based on coding rules that a Exposure is based on coding rules that a programmer must follow when writing a bean programmer must follow when writing a bean  these rules are mostly these rules are mostly standard naming standard naming conventions for methods conventions for methods 5 Object Oriented Programming 2 - Chapter 6: Java Beans 1. Introduction (cont.) 1. Introduction (cont.)  Beans are Beans are persistent persistent  their data is automatically stored when the program their data is automatically stored when the program using them finishes using them finishes  the data is restored when the program next starts the data is restored when the program next starts  persistence is implemented in JavaBeans by using persistence is implemented in JavaBeans by using Java's object Java's object serialization serialization features features 6 Object Oriented Programming 2 - Chapter 6: Java Beans 1. Introduction (cont.) 1. Introduction (cont.)  Simple Java object must support the following Simple Java object must support the following five features for it to become a JavaBean: five features for it to become a JavaBean:  Properties Properties  Customization Customization  Persistence Persistence  Communication Communication  Introspection Introspection 7 Object Oriented Programming 2 - Chapter 6: Java Beans 1. Introduction (cont.) 1. Introduction (cont.)  You can create three types of beans: You can create three types of beans:  Control beans Control beans  Container beans Container beans  Invisible run-time beans Invisible run-time beans 8 Object Oriented Programming 2 - Chapter 6: Java Beans 2. The Bean-Writing process 2. The Bean-Writing process How Builder Tools Use Beans How Builder Tools Use Beans ? ?  Builder tools (e.g JBuilder, Bean Builder) know Builder tools (e.g JBuilder, Bean Builder) know a bean's features by looking at its public a bean's features by looking at its public methods, properties and events methods, properties and events  called called introspection introspection  implemented using Java's reflection classes implemented using Java's reflection classes  A builder can also examine a bean's information A builder can also examine a bean's information object ( object ( BeanInfo BeanInfo ), if the programmer has ), if the programmer has included one. included one. 9 Object Oriented Programming 2 - Chapter 6: Java Beans 2. The Bean-Writing process (cont.) 2. The Bean-Writing process (cont.) How Builder Tools Use Beans How Builder Tools Use Beans ? ?  A builder will have visual support for setting/ A builder will have visual support for setting/ reading a bean's properties, and for accessing reading a bean's properties, and for accessing its methods. its methods.  A builder will be able to 'link' beans based on A builder will be able to 'link' beans based on events events  a a source bean source bean can send an event to a can send an event to a listener bean listener bean 10 Object Oriented Programming 2 - Chapter 6: Java Beans 2. The Bean-Writing process (cont.) 2. The Bean-Writing process (cont.) Using Java's Bean Builder Using Java's Bean Builder  Bean Builder Website: Bean Builder Website:  https://bean-builder.dev.java.net/ https://bean-builder.dev.java.net/  there's a "readme" link, and a good tutorial there's a "readme" link, and a good tutorial  Download Bean Builder v. Download Bean Builder v. 1 1 . . 0 beta 0 beta  from the "Documents and Files" link under "Project from the "Documents and Files" link under "Project Tools" Tools"  also at our Website on fivedots also at our Website on fivedots [...]... process (cont.) JavaBeans – Development Phases:  Construction phase   Build phase   Involves creation of a JavaBean and its user interface Involves placing the JavaBean into the target container Execution Phase  Involves execution of the container application in which the JavaBean is placed Object Oriented Programming 2 - Chapter 6: Java 11 2 The Bean-Writing process (cont.) JavaBeans – Development... Programming 2 - Chapter 6: Java 12 2 The Bean-Writing process (cont.) JavaBeans – Development Phases (cont.):  The Manifest file: Is used by the target application to recognize a JavaBean  Is saved with a mft extension  Contains a list of all class files that make up a JavaBean  Object Oriented Programming 2 - Chapter 6: Java 13 2 The Bean-Writing process (cont.) JavaBeans  The JAR – Development... Oriented Programming 2 - Chapter 6: Java 22 4 Naming Patterns for Bean Properties and Events Object Oriented Programming 2 - Chapter 6: Java 23 5 Bean Property Types  JavaBeans have 4 kinds of properties, which are supported in different ways: simple properties  indexed properties  bound properties  constrained properties  Object Oriented Programming 2 - Chapter 6: Java 24 5 Bean Property Types (cont.)... used to package a JavaBean for distribution  Contains the manifest file and all other files such as the class files and picture files of the bean  Has a jar extension  Object Oriented Programming 2 - Chapter 6: Java 14 3 Using Bean to build an Application in JAR Files  Packaging Beans  Composing Beans in a Builder Environment Object Oriented Programming 2 - Chapter 6: Java 15 3 Using Bean to build... Change Listeners Object Oriented Programming 2 - Chapter 6: Java 31 5 Bean Property Types (cont.) Example SliderFieldPanel Bean  A JSlider and a JTextField  A change to either should affect the other, and any listener objects should be notified Object Oriented Programming 2 - Chapter 6: Java 32 5 Bean Property Types (cont.) Listening Beans Format  Beans that are registered listeners for property changes... Object Oriented Programming 2 - Chapter 6: Java 25 5 Bean Property Types (cont.) Example  A fileName property (a String) is represented by: public String getFileName();  public void setFileName(String fn);   A running property (a boolean) is: public boolean isRunning();  public void setRunning(boolean b);  Object Oriented Programming 2 - Chapter 6: Java 26 5 Bean Property Types (cont.) Indexed Properties... Oriented Programming 2 - Chapter 6: Java 29 5 Bean Property Types (cont.) Bound Properties  A bean with a bound property will notify other listening objects /beans when the property changes  The programmer must add the listeners to a collection of PropertyChangeListeners  sometimes called registering the listeners Object Oriented Programming 2 - Chapter 6: Java 30 5 Bean Property Types (cont.)  When... other (cont.)  There may be resources) in a JAR file   each has its own Name and Java- Bean line Not all the beans; if a line is set  resources in a JAR file need to be class is a bean then the Java- Bean to true (otherwise false) beans will appear in the Toolbox window Object Oriented Programming 2 - Chapter 6: Java 18 3 Using Bean to build an Applicationfile (cont.) Create the JAR c:> jar cfm LogoAnimator.jar... and new values Object Oriented Programming 2 - Chapter 6: Java 33 5 Bean Property Types (cont.) Listening Beans Format (cont.) class Listener implements PropertyChangeListener { void propertyChange(PropertyChangeEvent ev) { Object newVal = ev.getNewValue(); Object oldVal = ev.getOldValue(); } } Object Oriented Programming 2 - Chapter 6: Java 34 5 Bean Property Types (cont.) Constrained Properties  A... directory of the JAR file Object Oriented Programming 2 - Chapter 6: Java 16 3 Using Bean to build an Application (cont.) manifest.tmp example Name: myPackage/myBeanClass.class Java- Bean: True  A Name line says where a bean is located in the JAR file  '/' is used instead of Java' s '.' Object Oriented Programming 2 - Chapter 6: Java 17 3 Using Bean to build an Applicationmany classes (and other (cont.) . restored when the program next starts  persistence is implemented in JavaBeans by using persistence is implemented in JavaBeans by using Java's object Java's object serialization serialization . Beans 2. The Bean-Writing process (cont.) 2. The Bean-Writing process (cont.) JavaBeans – Development Phases: JavaBeans – Development Phases:  Construction phase Construction phase  Involves. Beans 2. The Bean-Writing process (cont.) 2. The Bean-Writing process (cont.) JavaBeans – Development Phases (cont.): JavaBeans – Development Phases (cont.):  Construction Phase involves creation