uk.ac.ed.epcc.webapp.editors.mail

Class MessageWalker

java.lang.Object

uk.ac.ed.epcc.webapp.editors.mail.MessageWalker

public class MessageWalker
extends java.lang.Object

Class that traverses the tree structure of a Mail message (or a MultiPart) applying a visitor class. As the tree is walked it builds a path object that represents the position in the tree. This can be used to identify a node in HTML forms etc. This class has 2 modes. In one mode it walks the tree visiting every node. Leaf nodes are visited once but parent nodes are visited on entry and exit. Each parent node has the option of aborting further exploration of its children. In the second mode the class is given a target path and it traverses directly to the identified node. This second mode is intended to be used to apply a modification to the target node in a Servlet after a post. We use the same class for both functions to help ensure that the interpretation of the path is the same in both operations. There is a potential problem where the walker is used to modify the message structure as this will change the path definition. This is safe in the second mode provided the Visitor returns false to abort exploration of the children. If message structure is modified in the first mode then paths may not be well defined. Note if you modify a nested message it has to be saved, it is not sufficient to just save the parent message.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MessageWalker.WalkerException Exception thrown to abort processing in the MessageWalker

Field Summary

Fields

Modifier and Type	Field and Description
protected AppContext	conn

Constructor Summary

Constructors

Constructor and Description
MessageWalker(AppContext conn)

Method Summary

Modifier and Type	Method and Description
static java.util.LinkedList<java.lang.String>	addPath(java.util.LinkedList<java.lang.String> path, java.lang.String... extra) Append a non-significant (Ignored by the walker) extra path on the end of a walker path.
AppContext	getContext()
MimeMessage	getCurrentMessage()
protected Logger	getLogger()
protected int	getMessageLevel()
java.util.List<java.lang.String>	getPath()
boolean	isAlternative()
boolean	isSubMessage() Are we in a nested message
boolean	matchPath()
void	setTarget(java.util.List<java.lang.String> target)
void	setTarget(java.util.List<java.lang.String> src_target, boolean walk_all) Set the target node for the operation.
protected boolean	showAsLink(MimePart parent, java.lang.String string)
void	visitMessage(MimeMessage m, Visitor v) Visit a Mail message.
void	visitMultiPart(MimePart parent, MimeMultipart mp, Visitor v)

Methods inherited from class java.lang.Object

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

Field Detail

conn

protected AppContext conn

Constructor Detail

MessageWalker

public MessageWalker(AppContext conn)

Method Detail

setTarget

public void setTarget(java.util.List<java.lang.String> src_target,
                      boolean walk_all)
               throws MessageWalker.WalkerException

Set the target node for the operation. Normally this makes the MessageWalker navigate directly to the target node. If walk_all is true then all nodes will be traversed (for example to format an entire mail message with special treatment of the target node. Do not set walk_all=true and a path if the message is going to be changed by the walker.

Parameters:

src_target -

walk_all -

Throws:

MessageWalker.WalkerException

getContext

public AppContext getContext()

getLogger

protected Logger getLogger()

getCurrentMessage

public MimeMessage getCurrentMessage()

getPath

public java.util.List<java.lang.String> getPath()

setTarget

public void setTarget(java.util.List<java.lang.String> target)

isSubMessage

public boolean isSubMessage()

Are we in a nested message

Returns:

boolean

getMessageLevel

protected int getMessageLevel()

visitMessage

public final void visitMessage(MimeMessage m,
                               Visitor v)
                        throws MessageWalker.WalkerException

Visit a Mail message. This is a top level call to process a message.

Parameters:

m - MimeMessage

v - Visitor

Throws:

MessageWalker.WalkerException

visitMultiPart

public final void visitMultiPart(MimePart parent,
                                 MimeMultipart mp,
                                 Visitor v)
                          throws MessageWalker.WalkerException

Throws:

MessageWalker.WalkerException

isAlternative

public boolean isAlternative()

matchPath

public boolean matchPath()

showAsLink

protected boolean showAsLink(MimePart parent,
                             java.lang.String string)

addPath

public static java.util.LinkedList<java.lang.String> addPath(java.util.LinkedList<java.lang.String> path,
                                                             java.lang.String... extra)

Append a non-significant (Ignored by the walker) extra path on the end of a walker path.

Parameters:

path -

extra -

Returns:

combined path