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JSP API

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This tutorial lists down the API’s used in the Java Server Pages (JSP) programming. API stands for Application Programming Interface that allows programmers for building software applications in java. JSP API is categorized into following packages:

Packages Description
javax.el It provides classes and interfaces used by JSP to evaluate expressions.
javax.servelt.jsp It contains classes and interfaces that describe JSP page implementation.
javax.servlet.jsp.el It contains classes ang interfaces that define JSP page implementation supported by JSP container.
javax.servlet.jsp.tagext It is used to define tag libraries which means for identifying custom tags in JSP page.

Following sections will detail about classes and interfaces in each of the above packages:

Package javax.servlet.jsp

It contains classes and interfaces that describe JSP page implementation.

Interfaces

Interface Description
JspPage It contains interaction of JSP page implementation.JspPage page has following methods :

  • JspInit:it is used to initialize JSP page.
  • JspDestroy:It is used to remove JSP page.
HttpJspPage It contains interaction of JSP page implementation with HTTP protocol.It has method called _jspService used to process user request.

Classes

Class Description
JsPWriter It is used to display contents/output in JSP page.
JspError It is used to display errors on error pages.
JspContext It collects information which is not a part of servlets.
JspEngineInfo It gives information of current JSP engine.
JspFactory It defines classes and interfaces to use JSP page implementation.
JspException It is used to display exceptions occurred in JSP pages.

Package javax.el

This package has classes and interfaces for the expression language definitions.

Interfaces

Interface Description
ELContextListener It is used for receiving notification.

Classes

Classes Description
ArrayELResolver Performs property resolution on arrays.
BeanELResolver Performs property resolution on JavaBeans.
CompositeELResolver It can be used as stop condition for iterating its component resolvers.
ELContext Stores state of EL expressions.
ELContextEvent Indicates ELContext has been created.
ELResolver Defines resolution rules to resolve EL expressions.
ELUtil Defines utility methods for EL implementation.
Expression It is base class for ValueExpression and Method Expression.
Expressionfactory It is used to convert string into value or method expressions.
FunctionMapper It is used to map function names and methods.
ListELResolver Performs property resolution on objects of List class.
MapELResolver Performs property resolution on objects of map class.
MethodExpression It is used to parse expressions to method.
MethodInfo It defines information about Method Expression.
ResourceBundleELResolver Performs property resultion on objects of ResourceBundle class.
ValueExpression It is used to parse expressions to value.
VariableMapper It is used map between expressions and variables.

Exceptions

Exception Name Description
ELException Represents the exceptions occurred during evaluation of expressions.
MethodNotFoundException It returns exception when method could not found while evaluating expressions.
PropertyNotFoundException It returns exception when property could not found while evaluating expressions.
PropertyNotWritableException It returns exception when property could not written to value on a ValueExpression.

Package javax.servlet.jsp.el

Interfaces

Interface Name Description
FunctionMapper It is used to map between function names and methods.
VariableResolver it is used to resolve references of variables at evaluation time.

Classes

Class Name Description
Expression It is base class for Value Expression and Method Expression.
ExpressionEvaluator It is used to evaluate variables and expressions at run time.
ImplicitObjectElResolver It describes behavior of implicit objects in JSP specification.
ImplicitObjectELResolver.EnumeratedMap It provides enumeration of keys and getValue method.
ImplicitObjectElResolver.implicitObjects it is used to create implicit map and list objects.
ScopedAttributeELResolver It performs property resolution on scoped attributes.

Exceptions

Exception name Description
ELException It represents exceptions that occurred during expression evaluation.
ELParseException It represents parsing exceptions occurred during expression evaluation.

Package javax.servlet.jsp.tagext

This package has classes and interfaces for writing the custom tags.

Interfaces

Interface Name Description
BodyTag It includes contents of evaluating body.
DynamicAttributs A tag must implement this interface to define dynamic attributes.
iterationTag It is used to control re-evaluation of body.
JspIdConsumer It defines ID for user provided by compiler.
JspTag It provides base class for tag and Simpletag.
SimpleTag It defines interface for simple tag handlers.
tag it does not manipulate its body.
TryCatchFinally It provides extra methods to manage resources.

Classes

Class Name Description
BodyContent It is a subclass of JspWriter. It has methods to convert its contents into a String, to read its contents, and to clear the contents.
BodyTagSupport It implements the BodyTag interface and we can add additional functionalities to set property of bodyContent .
FunctionInfo It provides information in TagLibrary.This class is instantiated from the Tag Library Descriptor file (TLD) and is available only at translation time.
Jspfragment It is an object that represents JSP code.
PageData It provides information on a JSP page.
SimpletagSupport It is used as base class for simple tag handlers. It adds additional methods for the properties in SimpleTag.
TagAdapter It is used to allow collaboration between classic Tag handlers and SimpleTag handlers.
TagAttributeInfo It provides information on attributes of a tag.
TagData It gives value information for a tag instance only at translation time.
TagExtraInfo It is used to describe additional information which is not defined in TLD( Tag Library Descriptor)file.
TagFileInfo It provides information for a tagfile in TagLibrary only at translation time.
TagInfo It provides information for a tag in TagLibrary only at translation time.
TagLibrarynfo It provides information associated with a taglib directive.
TagLibraryValidator It is validator class for a JSP page and operates on the XML view associated with the JSP page.
TagSupport It is base class for defining new tag handlers.
TagVariableInfo It provides variable information for a tag in Tag Library only at translation time.
ValidationMessage It display validation message from either TagLibraryValidator and TagExtraInfo.
VariableInfo It provides information on scripting variables that are created or modified at run time.

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He is Founder and Chief Editor of JavaBeat. He has more than 8+ years of experience on developing Web applications. He writes about Spring, DOJO, JSF, Hibernate and many other emerging technologies in this blog.