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Transcript of Introducing JavaBeans Lesson 2A / Slide 1 of 30 JDBC and JavaBeans Pre-assessment Questions 1.Which...
Introducing JavaBeans
Lesson 2A / Slide 1 of 30JDBC and JavaBeans
Pre-assessment Questions1. Which of the given symbols is used as a placeholder for PreparedStatement?
a. #b. *c. ?d. %
2. In SQL Server 2000, a _______ is generated when you execute a stored procedure. a. Query planb. Queryc. ResultSetd. Rowset
Introducing JavaBeans
Lesson 2A / Slide 2 of 30JDBC and JavaBeans
Pre-assessment Questions (Contd.)3. Which of the following parameters cannot be used in a stored procedure?
a. IN
b. OUT
c. OUTIN
d. INOUT
4. Which of the following enables you to retrieve the information about a ResultSet?a. DatabaseMetaData
b. ResultSetData
c. RowSetData
d. ResultSetMetaData
Introducing JavaBeans
Lesson 2A / Slide 3 of 30JDBC and JavaBeans
Pre-assessment Questions (Contd.)5. The batch update operations can throw two types of exceptions,
__________and ___________. a. SQLException and BatchUpdateExceptionb. SQLException and UpdateExceptionc. BatchException and BatchUpdateExceptiond. BatchException and SQLException
Introducing JavaBeans
Lesson 2A / Slide 4 of 30JDBC and JavaBeans
Solutions to Pre-assessment Questions
1. c. ?2. a. Query plan3. c. OUTIN4. d. ResultSetMetaData5. a. SQLException and BatchUpdateException
Introducing JavaBeans
Lesson 2A / Slide 5 of 30JDBC and JavaBeans
ObjectivesIn this lesson, you will learn about:
• Features of JavaBeans
• Associating predefined events with sample JavaBeans
• Testing JavaBeans using BDK
• Creating sample JavaBean applet using BDK
• Creating user-defined JavaBean
• Creating manifest and JAR files for a JavaBean
Introducing JavaBeans
Lesson 2A / Slide 6 of 30JDBC and JavaBeans
JavaBean Concepts• A software component is a reusable object that can be plugged into any target
software application.
• You can develop software components using various programming languages, such as C, C++, Java, and Visual Basic.
• JavaBeans are reusable and platform-independent software components developed using the Java programming language.
• The classes and interfaces defined in the java.beans package enable you to create JavaBeans.
• The JavaBean components can exist in one of the following three phases of development:
• Construction phase
• Build phase
• Execution phase
Introducing JavaBeans
Lesson 2A / Slide 7 of 30JDBC and JavaBeans
JavaBean Concepts (Contd.)• Elements of a JavaBean
• Properties: Refer to the private data members of a JavaBean that define the behavior of the JavaBeans.
• Methods: Refer to public member functions of a JavaBean that are used to modify the JavaBean properties.
• Events: Refer to the messages that one JavaBean components sends to another JavaBean components.
Introducing JavaBeans
Lesson 2A / Slide 8 of 30JDBC and JavaBeans
JavaBean Concepts (Contd.)• The JavaBean Component Specification
• Customization: Is the ability of JavaBean to allow its properties to be changed in build and execution phase.
• Persistence: Is the ability of JavaBean to save its state to disk or storage device and restore the saved state when the JavaBean is reloaded.
• Communication: Is the ability of JavaBean to notify change in its properties to other JavaBeans or the container.
• Introspection: Is the ability of a JavaBean to allow an external application to query the properties, methods, and events supported by it.
Introducing JavaBeans
Lesson 2A / Slide 9 of 30JDBC and JavaBeans
JavaBean Concepts (Contd.)• Services of JavaBean Components
• Builder support: Enables you to create and group multiple JavaBeans in an application.
• Layout: Allows multiple JavaBeans to be arranged in a development environment.
• Interface publishing: Enables multiple JavaBeans in an application to communicate with each other.
• Event handling: Refers to firing and handling of events associated with a JavaBean.
• Persistence: Enables you to save the last state of JavaBean.
Introducing JavaBeans
Lesson 2A / Slide 10 of 30JDBC and JavaBeans
JavaBean Concepts (Contd.) • Types of JavaBeans
• Control JavaBeans: Are used to create GUI components that can be plugged into any application.
• Container JavaBeans: Are used to hold other JavaBeans.
• Invisible Runtime JavaBeans: Are used to create components that perform a specific task in the background of an application.
Introducing JavaBeans
Lesson 2A / Slide 11 of 30JDBC and JavaBeans
Beans Development Kit • Is a development environment to create, configure, and test JavaBeans.
• The features of BDK environment are:
• Provides a GUI to create, configure, and test JavaBeans.
• Enables you to modify JavaBean properties and link multiple JavaBeans in an application using BDK.
• Provides a set of sample JavaBeans.
• Enables you to associate pre-defined events with sample JavaBeans.
Introducing JavaBeans
Lesson 2A / Slide 12 of 30JDBC and JavaBeans
Beans Development Kit (Contd.)
• Identifying BDK Components
• Execute the run.bat file of BDK to start the BDK development environment.
• The components of BDK development environment are:
• ToolBox
• BeanBox
• Properties
• Method Tracer
Introducing JavaBeans
Lesson 2A / Slide 13 of 30JDBC and JavaBeans
Beans Development Kit (Contd.)
• ToolBox window: Lists the sample JavaBeans of BDK.
• The following figure shows the ToolBox window:
Introducing JavaBeans
Lesson 2A / Slide 14 of 30JDBC and JavaBeans
Beans Development Kit (Contd.)
• BeanBox window: Is a workspace for creating the layout of JavaBean application.
• The following figure shows the BeanBox window:
Introducing JavaBeans
Lesson 2A / Slide 15 of 30JDBC and JavaBeans
Beans Development Kit (Contd.)
• Properties window: Displays all the exposed properties of a JavaBean. You can modify JavaBean properties in the properties window.
• The following figure shows the Properties window:
Introducing JavaBeans
Lesson 2A / Slide 16 of 30JDBC and JavaBeans
Beans Development Kit (Contd.)
• Method Tracer window: Displays the debugging messages and method calls for a JavaBean application.
• The following figure shows the Method Tracer window:
Introducing JavaBeans
Lesson 2A / Slide 17 of 30JDBC and JavaBeans
Demonstration-Creating Sample JavaBean Applet using BDK
• Problem Statement
• Create an applet that shows the sample Molecule JavaBean rotating along its X-axis.
Introducing JavaBeans
Lesson 2A / Slide 18 of 30JDBC and JavaBeans
Demonstration-Creating Sample JavaBean Applet using BDK (Contd.)• Solution
• To create an applet that shows a Molecule JavaBean rotating along its X-axis, you need to perform the following tasks: 1. Associating pre-defined event with sample JavaBeans.2. Converting the JavaBean to an applet.
Introducing JavaBeans
Lesson 2A / Slide 19 of 30JDBC and JavaBeans
User-Defined JavaBean• The coding conventions to create a user-defined JavaBean are:
• Implement the java.io.Serializable interface.
• Define an empty constructor to initialize the instances of a JavaBean.
• Define the accessor and mutator methods for the exposed properties of a JavaBean.
Introducing JavaBeans
Lesson 2A / Slide 20 of 30JDBC and JavaBeans
User-Defined JavaBean (Contd.)• Accessor and Mutator Methods:
• Are used to access the exposed properties of a JavaBean.
• The accessor methods:
• Are used to retrieve the values of JavaBean properties.
• Are also called get methods.
• The mutator methods:
• Are used to specify the values of JavaBean properties.
• Are also called set methods.
Introducing JavaBeans
Lesson 2A / Slide 21 of 30JDBC and JavaBeans
User-Defined JavaBean (Contd.)• Manifest and JAR Files
• Manifest File
• The manifest file for a JavaBean application contains a list of all the class files that make up a JavaBean.
• The entry in the manifest file enables the target application to recognize the JavaBean classes for an application.
• For example, the entry for the SpellCheck JavaBean in the manifest file is as shown:Name: SpellCheck.class
Java-Bean: True
Introducing JavaBeans
Lesson 2A / Slide 22 of 30JDBC and JavaBeans
User-Defined JavaBean (Contd.)• Manifest File (Contd.)
• The rules to create a manifest file are:
• Press the Enter key after typing each line in the manifest file.
• Leave a space after the colon.
• Type a hyphen between Java and Bean.
• No blank line between the Name and the Java-Bean entry.
Introducing JavaBeans
Lesson 2A / Slide 23 of 30JDBC and JavaBeans
User-Defined JavaBean (Contd.)• Java Archive File
• The files of a JavaBean application are compressed and grouped as JAR files to reduce the size and the download time of the files.
• The syntax to create a JAR file from the command prompt is:jar <options> <file_names>
• The file_names is a list of files for a JavaBean application that are stored in the JAR file.
Introducing JavaBeans
Lesson 2A / Slide 24 of 30JDBC and JavaBeans
User-Defined JavaBean (Contd.)• Java Archive File (Contd.)
• The various options that you can specify while creating a JAR file are:
•c: Indicates the new JAR file is created.
•f: Indicates that the first file in the file_names list is the name of the JAR file.
•m: Indicates that the second file in the file_names list is the name of the manifest file.
•t: Indicates that all the files and resources in the JAR file are to be displayed in a tabular format.
•v: Indicates that the JAR file should generate a verbose output.
•x: Indicates that the files and resources of a JAR file are to be extracted.
•o: Indicates that the JAR file should not be compressed.
•m: Indicates that the manifest file is not created.
Introducing JavaBeans
Lesson 2A / Slide 25 of 30JDBC and JavaBeans
Demonstration-Creating User-Defined JavaBean
• Problem Statement
• Create a user-defined JavaBean having a label. Allow the user to change the caption of the user-defined JavaBean at runtime.
Introducing JavaBeans
Lesson 2A / Slide 26 of 30JDBC and JavaBeans
Demonstration-Creating User-Defined JavaBean (Contd.)• Solution
• To create a user-defined JavaBean that changes the caption of a label, you need to perform the following tasks:1. Code the user-defined JavaBean2. Package the JavaBean3. Load and test the JavaBean
Introducing JavaBeans
Lesson 2A / Slide 27 of 30JDBC and JavaBeans
Summary In this lesson, you learned:
• A component is a reusable object that can be plugged into any target software application.
• JavaBeans are reusable and platform-independent software components that are created using the Java programming language.
• The various features of JavaBean are:
• Customization
• Persistence
• Communication
• Introspection
Introducing JavaBeans
Lesson 2A / Slide 28 of 30JDBC and JavaBeans
Summary (Contd.) • JavaBean components provide the following services to the container in
which they are grouped together:
• Builder support
• Layout
• Interface publishing
• Event handling
• Persistence
• There are three types of JavaBeans, Control JavaBeans, Container JavaBeans, and Invisible runtime JavaBeans.
• BDK is a development environment to test and create JavaBeans.
• The ToolBox window of BDK displays the sample JavaBeans defined in the BDK.
• The BeanBox window of BDK enables you to test JavaBeans and create applications using various JavaBeans as components.
Introducing JavaBeans
Lesson 2A / Slide 29 of 30JDBC and JavaBeans
Summary (Contd.) • The properties window displays the properties of the currently selected
JavaBean component.
• The method tracer window of BDK displays the debugging messages and method calls for the BDK environment.
• BDK provides pre-defined events that can be associated with the sample JavaBean components in an application.
• The pre-defined events for the sample JavaBeans are displayed in the EventTargetDialog window of BDK.
• The MakeApplet utility of BDK enables you to create an applet file for a JavaBean application. The applet file can be run using a Web browser or the applet viewer utility of Java.
• You can also create user-defined JavaBeans using the classes and interfaces provided by the java.beans package.
Introducing JavaBeans
Lesson 2A / Slide 30 of 30JDBC and JavaBeans
Summary (Contd.) • The accessor and mutator methods of user-defined JavaBean are used to
retrieve and specify the value of JavaBean properties.
• The user-defined JavaBean implements the java.io.Serializable interface.
• A manifest file is a text file that provides information about the class files that represent a JavaBean.
• JAR files are platform-independent files that are used to package all the classes and the associated resources for a JavaBean application.
• The JAR file for the user-defined JavaBean is loaded in the ToolBox window using the FileLoadJar command of the BeanBox window.