javax.servlet.jsp.jstl.core.Config Maven / Gradle / Ivy
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package javax.servlet.jsp.jstl.core;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.PageContext;
/**
* Class supporting access to configuration settings.
*/
public class Config {
/*
* I18N/Formatting actions related configuration data
*/
/**
* Name of configuration setting for application- (as opposed to browser-)
* based preferred locale
*/
public static final String FMT_LOCALE
= "javax.servlet.jsp.jstl.fmt.locale";
/**
* Name of configuration setting for fallback locale
*/
public static final String FMT_FALLBACK_LOCALE
= "javax.servlet.jsp.jstl.fmt.fallbackLocale";
/**
* Name of configuration setting for i18n localization context
*/
public static final String FMT_LOCALIZATION_CONTEXT
= "javax.servlet.jsp.jstl.fmt.localizationContext";
/**
* Name of localization setting for time zone
*/
public static final String FMT_TIME_ZONE
= "javax.servlet.jsp.jstl.fmt.timeZone";
/*
* SQL actions related configuration data
*/
/**
* Name of configuration setting for SQL data source
*/
public static final String SQL_DATA_SOURCE
= "javax.servlet.jsp.jstl.sql.dataSource";
/**
* Name of configuration setting for maximum number of rows to be included
* in SQL query result
*/
public static final String SQL_MAX_ROWS
= "javax.servlet.jsp.jstl.sql.maxRows";
/*
* Private constants
*/
private static final String PAGE_SCOPE_SUFFIX = ".page";
private static final String REQUEST_SCOPE_SUFFIX = ".request";
private static final String SESSION_SCOPE_SUFFIX = ".session";
private static final String APPLICATION_SCOPE_SUFFIX = ".application";
/**
* Looks up a configuration variable in the given scope.
*
* The lookup of configuration variables is performed as if each scope
* had its own name space, that is, the same configuration variable name
* in one scope does not replace one stored in a different scope.
*
* @param pc Page context in which the configuration variable is to be
* looked up
* @param name Configuration variable name
* @param scope Scope in which the configuration variable is to be looked
* up
*
* @return The java.lang.Object associated with the configuration
* variable, or null if it is not defined.
*/
public static Object get(PageContext pc, String name, int scope) {
switch (scope) {
case PageContext.PAGE_SCOPE:
return pc.getAttribute(name + PAGE_SCOPE_SUFFIX, scope);
case PageContext.REQUEST_SCOPE:
return pc.getAttribute(name + REQUEST_SCOPE_SUFFIX, scope);
case PageContext.SESSION_SCOPE:
return get(pc.getSession(), name);
case PageContext.APPLICATION_SCOPE:
return pc.getAttribute(name + APPLICATION_SCOPE_SUFFIX, scope);
default:
throw new IllegalArgumentException("unknown scope");
}
}
/**
* Looks up a configuration variable in the "request" scope.
*
*
The lookup of configuration variables is performed as if each scope
* had its own name space, that is, the same configuration variable name
* in one scope does not replace one stored in a different scope.
*
* @param request Request object in which the configuration variable is to
* be looked up
* @param name Configuration variable name
*
* @return The java.lang.Object associated with the configuration
* variable, or null if it is not defined.
*/
public static Object get(ServletRequest request, String name) {
return request.getAttribute(name + REQUEST_SCOPE_SUFFIX);
}
/**
* Looks up a configuration variable in the "session" scope.
*
*
The lookup of configuration variables is performed as if each scope
* had its own name space, that is, the same configuration variable name
* in one scope does not replace one stored in a different scope.
*
* @param session Session object in which the configuration variable is to
* be looked up
* @param name Configuration variable name
*
* @return The java.lang.Object associated with the configuration
* variable, or null if it is not defined, if session is null, or if the session
* is invalidated.
*/
public static Object get(HttpSession session, String name) {
Object ret = null;
if (session != null) {
try {
ret = session.getAttribute(name + SESSION_SCOPE_SUFFIX);
} catch (IllegalStateException ex) {} // when session is invalidated
}
return ret;
}
/**
* Looks up a configuration variable in the "application" scope.
*
* The lookup of configuration variables is performed as if each scope
* had its own name space, that is, the same configuration variable name
* in one scope does not replace one stored in a different scope.
*
* @param context Servlet context in which the configuration variable is
* to be looked up
* @param name Configuration variable name
*
* @return The java.lang.Object associated with the configuration
* variable, or null if it is not defined.
*/
public static Object get(ServletContext context, String name) {
return context.getAttribute(name + APPLICATION_SCOPE_SUFFIX);
}
/**
* Sets the value of a configuration variable in the given scope.
*
*
Setting the value of a configuration variable is performed as if
* each scope had its own namespace, that is, the same configuration
* variable name in one scope does not replace one stored in a different
* scope.
*
* @param pc Page context in which the configuration variable is to be set
* @param name Configuration variable name
* @param value Configuration variable value
* @param scope Scope in which the configuration variable is to be set
*/
public static void set(PageContext pc, String name, Object value,
int scope) {
switch (scope) {
case PageContext.PAGE_SCOPE:
pc.setAttribute(name + PAGE_SCOPE_SUFFIX, value, scope);
break;
case PageContext.REQUEST_SCOPE:
pc.setAttribute(name + REQUEST_SCOPE_SUFFIX, value, scope);
break;
case PageContext.SESSION_SCOPE:
pc.setAttribute(name + SESSION_SCOPE_SUFFIX, value, scope);
break;
case PageContext.APPLICATION_SCOPE:
pc.setAttribute(name + APPLICATION_SCOPE_SUFFIX, value, scope);
break;
default:
throw new IllegalArgumentException("unknown scope");
}
}
/**
* Sets the value of a configuration variable in the "request" scope.
*
*
Setting the value of a configuration variable is performed as if
* each scope had its own namespace, that is, the same configuration
* variable name in one scope does not replace one stored in a different
* scope.
*
* @param request Request object in which the configuration variable is to
* be set
* @param name Configuration variable name
* @param value Configuration variable value
*/
public static void set(ServletRequest request, String name, Object value) {
request.setAttribute(name + REQUEST_SCOPE_SUFFIX, value);
}
/**
* Sets the value of a configuration variable in the "session" scope.
*
*
Setting the value of a configuration variable is performed as if
* each scope had its own namespace, that is, the same configuration
* variable name in one scope does not replace one stored in a different
* scope.
*
* @param session Session object in which the configuration variable is to
* be set
* @param name Configuration variable name
* @param value Configuration variable value
*/
public static void set(HttpSession session, String name, Object value) {
session.setAttribute(name + SESSION_SCOPE_SUFFIX, value);
}
/**
* Sets the value of a configuration variable in the "application" scope.
*
*
Setting the value of a configuration variable is performed as if
* each scope had its own namespace, that is, the same configuration
* variable name in one scope does not replace one stored in a different
* scope.
*
* @param context Servlet context in which the configuration variable is to
* be set
* @param name Configuration variable name
* @param value Configuration variable value
*/
public static void set(ServletContext context, String name, Object value) {
context.setAttribute(name + APPLICATION_SCOPE_SUFFIX, value);
}
/**
* Removes a configuration variable from the given scope.
*
*
Removing a configuration variable is performed as if each scope had
* its own namespace, that is, the same configuration variable name in one
* scope does not impact one stored in a different scope.
*
* @param pc Page context from which the configuration variable is to be
* removed
* @param name Configuration variable name
* @param scope Scope from which the configuration variable is to be
* removed
*/
public static void remove(PageContext pc, String name, int scope) {
switch (scope) {
case PageContext.PAGE_SCOPE:
pc.removeAttribute(name + PAGE_SCOPE_SUFFIX, scope);
break;
case PageContext.REQUEST_SCOPE:
pc.removeAttribute(name + REQUEST_SCOPE_SUFFIX, scope);
break;
case PageContext.SESSION_SCOPE:
pc.removeAttribute(name + SESSION_SCOPE_SUFFIX, scope);
break;
case PageContext.APPLICATION_SCOPE:
pc.removeAttribute(name + APPLICATION_SCOPE_SUFFIX, scope);
break;
default:
throw new IllegalArgumentException("unknown scope");
}
}
/**
* Removes a configuration variable from the "request" scope.
*
*
Removing a configuration variable is performed as if each scope had
* its own namespace, that is, the same configuration variable name in one
* scope does not impact one stored in a different scope.
*
* @param request Request object from which the configuration variable is
* to be removed
* @param name Configuration variable name
*/
public static void remove(ServletRequest request, String name) {
request.removeAttribute(name + REQUEST_SCOPE_SUFFIX);
}
/**
* Removes a configuration variable from the "session" scope.
*
*
Removing a configuration variable is performed as if each scope had
* its own namespace, that is, the same configuration variable name in one
* scope does not impact one stored in a different scope.
*
* @param session Session object from which the configuration variable is
* to be removed
* @param name Configuration variable name
*/
public static void remove(HttpSession session, String name) {
session.removeAttribute(name + SESSION_SCOPE_SUFFIX);
}
/**
* Removes a configuration variable from the "application" scope.
*
*
Removing a configuration variable is performed as if each scope had
* its own namespace, that is, the same configuration variable name in one
* scope does not impact one stored in a different scope.
*
* @param context Servlet context from which the configuration variable is
* to be removed
* @param name Configuration variable name
*/
public static void remove(ServletContext context, String name) {
context.removeAttribute(name + APPLICATION_SCOPE_SUFFIX);
}
/**
* Finds the value associated with a specific configuration setting
* identified by its context initialization parameter name.
*
*
For each of the JSP scopes (page, request, session, application),
* get the value of the configuration variable identified by name
* using method get(). Return as soon as a non-null value is
* found. If no value is found, get the value of the context initialization
* parameter identified by name.
*
* @param pc Page context in which the configuration setting is to be
* searched
* @param name Context initialization parameter name of the configuration
* setting
*
* @return The java.lang.Object associated with the configuration
* setting identified by name, or null if it is not defined.
*/
public static Object find(PageContext pc, String name) {
Object ret = get(pc, name, PageContext.PAGE_SCOPE);
if (ret == null) {
ret = get(pc, name, PageContext.REQUEST_SCOPE);
if (ret == null) {
if (pc.getSession() != null) {
// check session only if a session is present
ret = get(pc, name, PageContext.SESSION_SCOPE);
}
if (ret == null) {
ret = get(pc, name, PageContext.APPLICATION_SCOPE);
if (ret == null) {
ret = pc.getServletContext().getInitParameter(name);
}
}
}
}
return ret;
}
}