ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

javafe.filespace
Class ZipTree

java.lang.Object
  extended byjavafe.filespace.Tree
      extended byjavafe.filespace.HashTree
          extended byjavafe.filespace.ExtTree
              extended byjavafe.filespace.ZipTree

class ZipTree
extends ExtTree

A ZipTree is a Tree that mirrors the contents of a zipfile; the constructor takes in a pathname and returns a tree representing the filesystem contained in that zipfile.

ZipTree works by scanning the zipfile at object creation time, building up a hierarchical list of all the files in the zipfile. Later modifications to the zipfile will not be reflected in the ZipTree.

The data field of every (sub)node in a ZipTree contains a non-null ZipGenericFile representing the file it mirrors (or would mirror if a corresponding entry existed) in the underlying zipfile.

Note: ZipTree interior or root nodes (and only interior or root nodes) may contain ZipGenericFiles that do not have a corresponding zip entry because there may be no zip entries for those directories. E.g., the zipfile might contain a file for X/Y but not for X

We use "./" as the ZipGenericFile name to represent the missing root directory (no ZipTree actually has a root directory as far as we can tell). This gives the right isDirectory behavior (since it ends with a "/"), but the wrong local name ("."). This is the best we can do, though, since the other alternative ("") gives the reverse behavior, which is worse for us since we rely on the isDirectory bit and only use local names for non-directories.


Field Summary
protected  java.util.Hashtable edges
          The mapping between our outgoing edge's labels and the subTrees they point to.
protected  java.util.zip.ZipFile zip
          The zipfile we are a snapshot of
 
Fields inherited from class javafe.filespace.Tree
data
 
Constructor Summary
ZipTree(java.io.File zipfile)
          Create a ZipTree to mirror a zipfile's contents.
 
Method Summary
 ExtTree addChild(java.lang.String label, java.lang.Object newData)
          Create a new direct child of us with label label and data newData.
 ExtTree addPath(java.lang.String[] path)
          This is an extended version of addChild that takes a path (a list of labels) instead of a single label.
private  void addZipEntry(java.util.zip.ZipEntry z)
          Add a ZipEntry to this tree according to its pathname:
 java.util.Enumeration children()
          An enumeration of this node's direct children.
 Tree getChild(java.lang.String label)
          Fetch our direct child along the edge labelled label.
private  void loadZipData()
          Create a tree of ZipEntry's from the pathnames of the ZipEntry's in zip
static void main(java.lang.String[] args)
          A simple test driver
protected static void missingEntry(Tree node, java.util.zip.ZipFile zip)
          Initialize a node's data field to a ZipGenericFile that represents the file that it would correspond to if the tree it belongs to mirrored zip.
 
Methods inherited from class javafe.filespace.Tree
getChildrenCount, getLabel, getParent, getQualifiedChild, getQualifiedName, getRootNode, getSimpleName, isLeaf, print, printDetails
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

zip

protected java.util.zip.ZipFile zip
The zipfile we are a snapshot of


edges

protected java.util.Hashtable edges
The mapping between our outgoing edge's labels and the subTrees they point to. No entry for a label means no edge with that label exists.

Invariant: all elements of edges are Trees and all keys are Strings.

Constructor Detail

ZipTree

public ZipTree(java.io.File zipfile)
        throws java.io.IOException,
               java.util.zip.ZipException
Create a ZipTree to mirror a zipfile's contents.

May throw an IOException (e.g., file doesn't exist) or a ZipException (e.g., file is not a properly formatted zipfile).

Method Detail

missingEntry

protected static void missingEntry(Tree node,
                                   java.util.zip.ZipFile zip)
Initialize a node's data field to a ZipGenericFile that represents the file that it would correspond to if the tree it belongs to mirrored zip.


loadZipData

private void loadZipData()
Create a tree of ZipEntry's from the pathnames of the ZipEntry's in zip


addZipEntry

private void addZipEntry(java.util.zip.ZipEntry z)
Add a ZipEntry to this tree according to its pathname:


main

public static void main(java.lang.String[] args)
A simple test driver


addChild

public ExtTree addChild(java.lang.String label,
                        java.lang.Object newData)
Create a new direct child of us with label label and data newData. The new child will have no direct children.

If a child by the name of label already exists, then this routine leaves the tree unchanged.

In either case, the (resulting) child with label label is returned.


addPath

public ExtTree addPath(java.lang.String[] path)
This is an extended version of addChild that takes a path (a list of labels) instead of a single label. It returns the child located by following path from this node. It creates any necessary nodes along the way using addChild with null for newData. Path must be non-null.


children

public java.util.Enumeration children()
An enumeration of this node's direct children. Each child occurs exactly once in the enumeration. The order is unspecified and may differ from call to call.

Note: The Objects returned by the resulting enumeration's nextElement method are guaranteed to be of type Tree and non-null.

Specified by:
children in class Tree

getChild

public Tree getChild(java.lang.String label)
Fetch our direct child along the edge labelled label. Iff there is no such child, return null.

Overrides:
getChild in class Tree

ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

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