org.mmbase.bridge.jsp.taglib
Class ContextTag

org.mmbase.bridge.jsp.taglib.ContextReferrerTag
  |
  +--org.mmbase.bridge.jsp.taglib.ContextTag

public class ContextTag

extends ContextReferrerTag

A ContextTag is like parentheses, and as such can act as a 'namespace' (if it has an id) or as 'scope' (if it doesn't).

The context can be seen as a container for variables and their values.

(ContextReferrer) Tags living under a context tag can 'register' themselves in the context (by use of the 'id' attribute') and in that way become a variable. Other tags can refer to such variables.

A ContextTag is a ContextReferrer itself too, and therefore it is possible to 'nest' contextes. And perhaps we will also make it possible to treat contextes as variables and e.g. pass them to another page as a whole.

It is also possible to put something into the Context by hand. For that you can use the `ImportTag'.

Writing out the value of a variable can be done with the `Write' Tag.

Author:

Michiel Meeuwissen

See Also:

ImportTag, WriteTag

Field Summary

static int	LOCATION_COOKIE
static int	LOCATION_MULTIPART
static int	LOCATION_NOTSET
static int	LOCATION_PAGE
static int	LOCATION_PARAMETERS
static int	LOCATION_PARENT
static int	LOCATION_SESSION

Fields inherited from class org.mmbase.bridge.jsp.taglib.ContextReferrerTag

contextId, PAGE_CATEGORY, pageContextTag, referid

Constructor Summary

ContextTag()

Method Summary

int	doAfterBody()
int	doStartTag()
java.lang.Object	findAndRegister(int from, java.lang.String referid, java.lang.String newid)
protected java.lang.Object	findAndRegister(int from, java.lang.String referid, java.lang.String newid, boolean check)
java.lang.Object	findAndRegister(java.lang.String id)
java.lang.Object	findAndRegister(java.lang.String externid, java.lang.String newid) Searches a key in request, postparameters, session, parent context and registers it in this one.
java.lang.String	findAndRegisterString(java.lang.String id)
byte[]	getBytes(java.lang.String key) hmm..
java.lang.Object	getContainerObject(java.lang.String key)
static boolean	isContextIdentifierChar(char c)
boolean	isPresent(java.lang.String key) 'present' means 'not null'.
static java.lang.String	locationToString(int i)
void	register(java.lang.String newid, java.lang.Object n)
protected void	register(java.lang.String newid, java.lang.Object n, boolean check) Register an Object with a key in the context.
void	registerNode(java.lang.String key, Node n) Precisely like 'register', only it wants a Node.
void	release() Release all allocated resources.
void	setPageContext(javax.servlet.jsp.PageContext pc)
static int	stringToLocation(java.lang.String s)
void	unRegister(java.lang.String key)

Methods inherited from class org.mmbase.bridge.jsp.taglib.ContextReferrerTag

findParentTag, findParentTag, getAttributeBoolean, getAttributeInteger, getAttributeInteger, getAttributeValue, getContextTag, getObject, getReferid, getString, setContext, setReferid

Field Detail

LOCATION_NOTSET

public static final int LOCATION_NOTSET

LOCATION_PAGE

public static final int LOCATION_PAGE

LOCATION_PARENT

public static final int LOCATION_PARENT

LOCATION_PARAMETERS

public static final int LOCATION_PARAMETERS

LOCATION_MULTIPART

public static final int LOCATION_MULTIPART

LOCATION_SESSION

public static final int LOCATION_SESSION

LOCATION_COOKIE

public static final int LOCATION_COOKIE

Constructor Detail

ContextTag

public ContextTag()

Method Detail

stringToLocation

public static int stringToLocation(java.lang.String s)
                            throws javax.servlet.jsp.JspTagException

locationToString

public static java.lang.String locationToString(int i)

release

public void release()

Description copied from class: ContextReferrerTag

Release all allocated resources.

Overrides:

release in class ContextReferrerTag

setPageContext

public void setPageContext(javax.servlet.jsp.PageContext pc)

Overrides:

setPageContext in class ContextReferrerTag

doStartTag

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

registerNode

public void registerNode(java.lang.String key,
                         Node n)
                  throws javax.servlet.jsp.JspTagException

Precisely like 'register', only it wants a Node.

Parameters:

key - the key (id) of the node to register

node - the node to put in the hashmap

findAndRegister

public java.lang.Object findAndRegister(int from,
                                        java.lang.String referid,
                                        java.lang.String newid)
                                 throws javax.servlet.jsp.JspTagException

findAndRegister

protected java.lang.Object findAndRegister(int from,
                                           java.lang.String referid,
                                           java.lang.String newid,
                                           boolean check)
                                    throws javax.servlet.jsp.JspTagException

findAndRegister

public java.lang.Object findAndRegister(java.lang.String externid,
                                        java.lang.String newid)
                                 throws javax.servlet.jsp.JspTagException

Searches a key in request, postparameters, session, parent context and registers it in this one. Returns null if it could not be found.

isContextIdentifierChar

public static boolean isContextIdentifierChar(char c)

register

protected void register(java.lang.String newid,
                        java.lang.Object n,
                        boolean check)
                 throws javax.servlet.jsp.JspTagException

Register an Object with a key in the context. If the Context is a session context, then it will be put in the session, otherwise in the hashmap.

register

public void register(java.lang.String newid,
                     java.lang.Object n)
              throws javax.servlet.jsp.JspTagException

unRegister

public void unRegister(java.lang.String key)
                throws javax.servlet.jsp.JspTagException

isPresent

public boolean isPresent(java.lang.String key)
                  throws javax.servlet.jsp.JspTagException

'present' means 'not null'. 'null' means 'registered, but not present'. Not registered is not present, of course.

findAndRegister

public java.lang.Object findAndRegister(java.lang.String id)
                                 throws javax.servlet.jsp.JspTagException

findAndRegisterString

public java.lang.String findAndRegisterString(java.lang.String id)
                                       throws javax.servlet.jsp.JspTagException

getContainerObject

public java.lang.Object getContainerObject(java.lang.String key)
                                    throws javax.servlet.jsp.JspTagException

getBytes

public byte[] getBytes(java.lang.String key)
                throws javax.servlet.jsp.JspTagException

hmm.. This kind of stuf must move to ImportTag, I think.

doAfterBody

public int doAfterBody()
                throws javax.servlet.jsp.JspTagException