uk.ac.starlink.datanode.nodes

Class ZipArchiveDataNode

java.lang.Object

uk.ac.starlink.datanode.nodes.DefaultDataNode

uk.ac.starlink.datanode.nodes.ZipArchiveDataNode

All Implemented Interfaces:

DataNode

Direct Known Subclasses:

ZipFileDataNode, ZipStreamDataNode

public abstract class ZipArchiveDataNode
extends DefaultDataNode

DataNode representing a Zip archive. This abstract class embodies the common functionality required by its subclasses ZipFileDataNode and ZipStreamDataNode.

Author:

Mark Taylor (Starlink)

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ZipArchiveDataNode(DataSource datsrc) Constructs a ZipArchiveDataNode.

Method Summary

Modifier and Type	Method and Description
boolean	allowsChildren() The DefaultDataNode implementation of this method returns false.
Iterator	getChildIterator() The DefaultDataNode implementation of this method throws UnsupportedOperationException (DefaultDataNode.allowsChildren() is false).
protected abstract Iterator	getChildIteratorAtLevel(String level, DataNode parent) Returns an iterator over the DataNodes at a given level in the hierarchy of this archive.
protected abstract List	getEntries() Returns a list of all the ZipEntry objects in this zip archive.
protected List	getEntriesAtLevel(String level) Returns all the ZipEntry objects in this archive at a given level in the hierarchy.
String	getName() Gets the name of this object.
String	getNodeTLA() Returns the string "ZIP".
String	getNodeType() Returns a short sentence indicating what kind of node this is.
String	getPathSeparator() Returns a default separator string.
static boolean	isMagic(byte[] magic) Tests whether the presented byte array looks like the start of a Zip archive.

Methods inherited from class uk.ac.starlink.datanode.nodes.DefaultDataNode

beep, configureDetail, getChildMaker, getCreator, getDataObject, getDescription, getIcon, getLabel, getParentObject, getPathElement, hasDataObject, makeChild, makeErrorChild, registerDataObject, setChildMaker, setCreator, setDescription, setIconID, setLabel, setName, setParentObject, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ZipArchiveDataNode

protected ZipArchiveDataNode(DataSource datsrc)
                      throws NoSuchDataException

Constructs a ZipArchiveDataNode.

Parameters:

datsrc - a data source corresponding to the archive; this is used for checking the magic number to see whether it looks like a zip archive or not

Throws:

NoSuchDataException

Method Detail

getEntries

protected abstract List getEntries()
                            throws IOException

Returns a list of all the ZipEntry objects in this zip archive.

Returns:

a List of all the ZipEntry objects which make up this zip archive.

Throws:

IOException

getChildIteratorAtLevel

protected abstract Iterator getChildIteratorAtLevel(String level,
                                                    DataNode parent)
                                             throws IOException

Returns an iterator over the DataNodes at a given level in the hierarchy of this archive. The iterator creates DataNodes for each ZipEntry in this archive whose name begins with the supplied string level.

Parameters:

level - the required starting substring of the name of all ZipEntries to be represented in the result

parent - the DataNode whose children the resulting nodes will be

Returns:

an Iterator over DataNode objects corresponding to the ZipEntry objects specified by level

Throws:

IOException

isMagic

public static boolean isMagic(byte[] magic)

Tests whether the presented byte array looks like the start of a Zip archive.

Parameters:

magic - a byte array containing the first few bytes of a source which might be a zip

Returns:

true iff magic represents the magic number of a zip archive

getName

public String getName()

Description copied from interface: DataNode

Gets the name of this object. This is an intrinsic property of the object.

Specified by:

getName in interface DataNode

Overrides:

getName in class DefaultDataNode

Returns:

the name of the object

getPathSeparator

public String getPathSeparator()

Description copied from class: DefaultDataNode

Returns a default separator string.

Specified by:

getPathSeparator in interface DataNode

Overrides:

getPathSeparator in class DefaultDataNode

Returns:

"."

getNodeTLA

public String getNodeTLA()

Returns the string "ZIP".

Specified by:

getNodeTLA in interface DataNode

Overrides:

getNodeTLA in class DefaultDataNode

Returns:

"ZIP"

getNodeType

public String getNodeType()

Description copied from interface: DataNode

Returns a short sentence indicating what kind of node this is. The return value should be just a few words. As a rough guideline it should indicate what the implementing class is.

Specified by:

getNodeType in interface DataNode

Overrides:

getNodeType in class DefaultDataNode

Returns:

a short description of the type of this DataNode

allowsChildren

public boolean allowsChildren()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation of this method returns false.

Specified by:

allowsChildren in interface DataNode

Overrides:

allowsChildren in class DefaultDataNode

Returns:

true if the node is of a type which can have child nodes, false otherwise

getChildIterator

public Iterator getChildIterator()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation of this method throws UnsupportedOperationException (DefaultDataNode.allowsChildren() is false).

Specified by:

getChildIterator in interface DataNode

Overrides:

getChildIterator in class DefaultDataNode

Returns:

an Iterator over the children. Each object iterated over should be a DataNode. Behaviour is undefined if this method is called on an object for which allowsChildren returns false.

getEntriesAtLevel

protected List getEntriesAtLevel(String level)
                          throws IOException

Returns all the ZipEntry objects in this archive at a given level in the hierarchy. The selected entries are all those whose name starts with the supplied string level.

Parameters:

level - the required starting substring of the name of all ZipEntries to be returned

Returns:

a list of all the ZipEntry objects at the given level

Throws:

IOException