org.apache.jasper.runtime
类 TldScanner

java.lang.Object
  org.apache.jasper.runtime.TldScanner

所有已实现的接口：

ServletContainerInitializer

public class TldScanner
extends Object
implements ServletContainerInitializer

A container for all tag libraries that are defined "globally" for the web application. Tag Libraries can be defined globally in one of two ways: 1. Via elements in web.xml: the uri and location of the tag-library are specified in the element. 2. Via packaged jar files that contain .tld files within the META-INF directory, or some subdirectory of it. The taglib is 'global' if it has the element defined. A mapping between the taglib URI and its associated TaglibraryInfoImpl is maintained in this container. Actually, that's what we'd like to do. However, because of the way the classes TagLibraryInfo and TagInfo have been defined, it is not currently possible to share an instance of TagLibraryInfo across page invocations. A bug has been submitted to the spec lead. In the mean time, all we do is save the 'location' where the TLD associated with a taglib URI can be found. When a JSP page has a taglib directive, the mappings in this container are first searched (see method getLocation()). If a mapping is found, then the location of the TLD is returned. If no mapping is found, then the uri specified in the taglib directive is to be interpreted as the location for the TLD of this tag library.

作者：

Pierre Delisle, Jan Luehe, Kin-man Chung servlet 3.0 JSP plugin, tld cache etc

字段摘要

static int	ABS_URI The types of URI one may specify for a tag library
static int	NOROOT_REL_URI
static int	ROOT_REL_URI

构造方法摘要

TldScanner()
Default Constructor.

TldScanner(ServletContext ctxt, boolean isValidationEnabled)
Constructor used in Jasper

方法摘要

String[]	getLocation(String uri) Gets the 'location' of the TLD associated with the given taglib 'uri'.
void	onStartup(Set<Class<?>> c, ServletContext ctxt) Notifies this ServletContainerInitializer of the startup of the application represented by the given ServletContext.
static int	uriType(String uri) Returns the type of a URI: ABS_URI ROOT_REL_URI NOROOT_REL_URI

从类 java.lang.Object 继承的方法

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细信息

ABS_URI

public static final int ABS_URI

The types of URI one may specify for a tag library

另请参见：

常量字段值

ROOT_REL_URI

public static final int ROOT_REL_URI

另请参见：

常量字段值

NOROOT_REL_URI

public static final int NOROOT_REL_URI

另请参见：

常量字段值

构造方法详细信息

TldScanner

public TldScanner()

Default Constructor. This is only used for implementing ServletContainerInitializer. ServletContext will be supplied in the method onStartUp;

TldScanner

public TldScanner(ServletContext ctxt,
                  boolean isValidationEnabled)

Constructor used in Jasper

方法详细信息

onStartup

public void onStartup(Set<Class<?>> c,
                      ServletContext ctxt)
               throws ServletException

从接口 ServletContainerInitializer 复制的描述

Notifies this ServletContainerInitializer of the startup of the application represented by the given ServletContext.

If this ServletContainerInitializer is bundled in a JAR file inside the WEB-INF/lib directory of an application, its onStartup method will be invoked only once during the startup of the bundling application. If this ServletContainerInitializer is bundled inside a JAR file outside of any WEB-INF/lib directory, but still discoverable as described above, its onStartup method will be invoked every time an application is started.

指定者：

接口 ServletContainerInitializer 中的 onStartup

参数：

c - the Set of application classes that extend, implement, or have been annotated with the class types specified by the HandlesTypes annotation, or null if there are no matches, or this ServletContainerInitializer has not been annotated with HandlesTypes

ctxt - the ServletContext of the web application that is being started and in which the classes contained in c were found

抛出：

ServletException - if an error has occurred

getLocation

public String[] getLocation(String uri)
                     throws JasperException

Gets the 'location' of the TLD associated with the given taglib 'uri'. Returns null if the uri is not associated with any tag library 'exposed' in the web application. A tag library is 'exposed' either explicitly in web.xml or implicitly via the uri tag in the TLD of a taglib deployed in a jar file (WEB-INF/lib).

参数：

uri - The taglib uri

返回：

An array of two Strings: The first element denotes the real path to the TLD. If the path to the TLD points to a jar file, then the second element denotes the name of the TLD entry in the jar file. Returns null if the uri is not associated with any tag library 'exposed' in the web application. This method may be called when the scanning is in one of states: 1. Called from jspc script, then a full tld scan is required. 2. The is the first call after servlet initialization, then system jars that are knwon to have tlds but not listeners need to be scanned. 3. Sebsequent calls, no need to scans.

抛出：

JasperException

uriType

public static int uriType(String uri)

Returns the type of a URI: ABS_URI ROOT_REL_URI NOROOT_REL_URI