com.clra.web
Class NameSelectorTag

java.lang.Object
  |
  +--javax.servlet.jsp.tagext.TagSupport
        |
        +--com.clra.web.NameSelectorTag

All Implemented Interfaces:

Serializable, javax.servlet.jsp.tagext.Tag

public class NameSelectorTag

extends javax.servlet.jsp.tagext.TagSupport

Allows the user to choose a group of items, selected by the first letter of their name.

Selection is case-insensitive and limited to 8 predefined groups, like the buttons on a telephone:

2. ABC - names less than 'D'
3. DEF - names between 'D' and 'F'
4. GHI - names between 'G' and 'I'
5. JKL - names between 'J' and 'L'
6. MNO - names between 'M' and 'O'
7. PQRS - names between 'P' and 'S'
8. TUV - names between 'T' and 'V'
9. WXYZ - names greater than or equal to 'W'

Note that the first group, ABC, may contain names like "3Com", whereas the last group, WXYZ, may contain names like "Ėtvos". Also note that the group is indexed from '2', not '0'.

Version:

$Revision: 1.2 $ $Date: 2002/02/18 18:06:41 $

Author:

Rick Hall

See Also:

Serialized Form

Field Summary

protected static org.apache.struts.util.MessageResources	messages The message resources for this package
protected String	page The context-relative URI

Fields inherited from class javax.servlet.jsp.tagext.TagSupport

id, pageContext

Fields inherited from interface javax.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

NameSelectorTag()

Method Summary

protected String	createLink(int group, javax.servlet.http.HttpServletRequest request) Creates a link from the currentGroup request
protected String	createLink(int group, String contextPath, String page) Create a link from the specified page
protected String	createQueryString(int group, Hashtable queryParams) Form a query string from current parameter and the specified group
protected void	doEndLink()
int	doEndTag() Render the end of the selector
protected void	doGroupLeadingSeparationText(int unused) Writes the text that separates group links
protected void	doGroupLink(int group) Write a group link
protected void	doGroupLinks() Writes an alphabet's worth of group links
protected void	doGroupText(int group) Writes a Integer-based group (2 - 9) as user-friendly text
protected void	doGroupTrailingSeparationText(int unused) Writes the text that separates group links
protected void	doStartLink(int group)
int	doStartTag() Render the beginning of the selector
Integer	getCurrentGroup() Return the currently selected group (2 - 9, or null)
String	getPage() Return the context-relative URI
static Integer	groupFromContext(javax.servlet.jsp.PageContext context) A utility which determines what group should be currently selected based on the page context.
protected static Map	groups() The groups used by this selector
void	release() Release any acquired resources.
static void	resetGroupInContexts(javax.servlet.jsp.PageContext context, Integer group) A utility which resets request and session attributes so that only the session attribute AN_GROUP holds the currently selected name.
void	setCurrentGroup(Integer currentGroup) Set the currently selected group (2 - 9, or null)
void	setPage(String page) Set the context-relative URI

Methods inherited from class javax.servlet.jsp.tagext.TagSupport

findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue

Methods inherited from class java.lang.Object

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

Field Detail

messages

protected static org.apache.struts.util.MessageResources messages

The message resources for this package

page

protected String page

The context-relative URI

Constructor Detail

NameSelectorTag

public NameSelectorTag()

Method Detail

groups

protected static Map groups()

The groups used by this selector

getPage

public String getPage()

Return the context-relative URI

setPage

public void setPage(String page)

Set the context-relative URI

getCurrentGroup

public Integer getCurrentGroup()

Return the currently selected group (2 - 9, or null)

setCurrentGroup

public void setCurrentGroup(Integer currentGroup)
                     throws javax.servlet.jsp.JspException

Set the currently selected group (2 - 9, or null)

groupFromContext

public static Integer groupFromContext(javax.servlet.jsp.PageContext context)

A utility which determines what group should be currently selected based on the page context. The algorithm is:

1. Check for a request parameter named INameList.AN_GROUP. If found, and it is a valid Integer in the range 2 - 9, use it.
2. Check for a request attribute named INameList.AN_GROUP. If found, and it is valid, use it.
3. Check for a session attribute named INameList.AN_GROUP. If found, and it is valid, use it.
4. If a valid group hasn't been determined yet, return the index of the first group, ABC (index 2).

resetGroupInContexts

public static void resetGroupInContexts(javax.servlet.jsp.PageContext context,
                                        Integer group)

A utility which resets request and session attributes so that only the session attribute AN_GROUP holds the currently selected name. The algorithm is:

1. Check for a request attribute named INameList.AN_GROUP. If found, remove it.
2. Check for a session attribute named INameList.AN_GROUP. If found, reset to the specified value; otherwise create and set it.

If the specified name is invalid (not between 2 - 9, inclusive), no action is taken and an error is logged.

createQueryString

protected String createQueryString(int group,
                                   Hashtable queryParams)

Form a query string from current parameter and the specified group

createLink

protected String createLink(int group,
                            String contextPath,
                            String page)
                     throws javax.servlet.jsp.JspException

Create a link from the specified page

createLink

protected String createLink(int group,
                            javax.servlet.http.HttpServletRequest request)

Creates a link from the currentGroup request

doStartLink

protected void doStartLink(int group)
                    throws javax.servlet.jsp.JspException

doEndLink

protected void doEndLink()
                  throws javax.servlet.jsp.JspException

doGroupText

protected void doGroupText(int group)
                    throws javax.servlet.jsp.JspException

Writes a Integer-based group (2 - 9) as user-friendly text

doGroupLeadingSeparationText

protected void doGroupLeadingSeparationText(int unused)
                                     throws javax.servlet.jsp.JspException

Writes the text that separates group links

doGroupTrailingSeparationText

protected void doGroupTrailingSeparationText(int unused)
                                      throws javax.servlet.jsp.JspException

Writes the text that separates group links

doGroupLink

protected void doGroupLink(int group)
                    throws javax.servlet.jsp.JspException

Write a group link

doGroupLinks

protected void doGroupLinks()
                     throws javax.servlet.jsp.JspException

Writes an alphabet's worth of group links

doStartTag

public int doStartTag()
               throws javax.servlet.jsp.JspException

Render the beginning of the selector

Overrides:

doStartTag in class javax.servlet.jsp.tagext.TagSupport

doEndTag

public int doEndTag()
             throws javax.servlet.jsp.JspException

Render the end of the selector

Overrides:

doEndTag in class javax.servlet.jsp.tagext.TagSupport

release

public void release()

Release any acquired resources.

Overrides:

release in class javax.servlet.jsp.tagext.TagSupport