org.codehaus.plexus.archiver.zip
Class ZipFile

java.lang.Object
  extended byorg.codehaus.plexus.archiver.zip.ZipFile

public class ZipFile
extends java.lang.Object

Replacement for java.util.ZipFile.

This class adds support for file name encodings other than UTF-8 (which is required to work on ZIP files created by native zip tools and is able to skip a preamble like the one found in self extracting archives. Furthermore it returns instances of org.apache.tools.zip.ZipEntry instead of java.util.zip.ZipEntry.

It doesn't extend java.util.zip.ZipFile as it would have to reimplement all methods anyway. Like java.util.ZipFile, it uses RandomAccessFile under the covers and supports compressed and uncompressed entries.

The method signatures mimic the ones of java.util.zip.ZipFile, with a couple of exceptions:

Version:
$Revision: 2436 $ $Date: 2005-09-01 19:20:41 +0200 (Thu, 01 Sep 2005) $ from org.apache.ant.tools.zip.ZipFile v1.13

Nested Class Summary
private  class ZipFile.BoundedInputStream
          InputStream that delegates requests to the underlying RandomAccessFile, making sure that only bytes from a certain range can be read.
 
Field Summary
private  java.io.RandomAccessFile archive
          The actual data source.
private static int CFD_LOCATOR_OFFSET
           
private static int CFH_LEN
           
private  java.util.Hashtable dataOffsets
          Maps ZipEntrys to Longs, recording the offsets of the actual file data.
private  java.lang.String encoding
          The encoding to use for filenames and the file comment.
private  java.util.Hashtable entries
          Maps ZipEntrys to Longs, recording the offsets of the local file headers.
private static long LFH_OFFSET_FOR_FILENAME_LENGTH
          Number of bytes in local file header up to the "length of filename" entry.
private static int MIN_EOCD_SIZE
           
private  java.util.Hashtable nameMap
          Maps String to ZipEntrys, name -> actual entry.
 
Constructor Summary
ZipFile(java.io.File f)
          Opens the given file for reading, assuming the platform's native encoding for file names.
ZipFile(java.io.File f, java.lang.String encoding)
          Opens the given file for reading, assuming the specified encoding for file names.
ZipFile(java.lang.String name)
          Opens the given file for reading, assuming the platform's native encoding for file names.
ZipFile(java.lang.String name, java.lang.String encoding)
          Opens the given file for reading, assuming the specified encoding for file names.
 
Method Summary
 void close()
          Closes the archive.
protected static java.util.Date fromDosTime(ZipLong l)
          Convert a DOS date/time field to a Date object.
 java.lang.String getEncoding()
          The encoding to use for filenames and the file comment.
 java.util.Enumeration getEntries()
          Returns all entries.
 ZipEntry getEntry(java.lang.String name)
          Returns a named entry - or null if no entry by that name exists.
 java.io.InputStream getInputStream(ZipEntry ze)
          Returns an InputStream for reading the contents of the given entry.
protected  java.lang.String getString(byte[] bytes)
          Retrieve a String from the given bytes using the encoding set for this ZipFile.
private  void populateFromCentralDirectory()
          Reads the central directory of the given archive and populates the internal tables with ZipEntry instances.
private  void positionAtCentralDirectory()
          Searches for the "End of central dir record", parses it and positions the stream at the first central directory record.
private  void resolveLocalFileHeaderData()
          Walks through all recorded entries and adds the data available from the local file header.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

entries

private java.util.Hashtable entries
Maps ZipEntrys to Longs, recording the offsets of the local file headers.


nameMap

private java.util.Hashtable nameMap
Maps String to ZipEntrys, name -> actual entry.


dataOffsets

private java.util.Hashtable dataOffsets
Maps ZipEntrys to Longs, recording the offsets of the actual file data.


encoding

private java.lang.String encoding
The encoding to use for filenames and the file comment.

For a list of possible values see http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html. Defaults to the platform's default character encoding.


archive

private java.io.RandomAccessFile archive
The actual data source.


CFH_LEN

private static final int CFH_LEN
See Also:
Constant Field Values

MIN_EOCD_SIZE

private static final int MIN_EOCD_SIZE
See Also:
Constant Field Values

CFD_LOCATOR_OFFSET

private static final int CFD_LOCATOR_OFFSET
See Also:
Constant Field Values

LFH_OFFSET_FOR_FILENAME_LENGTH

private static final long LFH_OFFSET_FOR_FILENAME_LENGTH
Number of bytes in local file header up to the "length of filename" entry.

See Also:
Constant Field Values
Constructor Detail

ZipFile

public ZipFile(java.io.File f)
        throws java.io.IOException
Opens the given file for reading, assuming the platform's native encoding for file names.

Parameters:
f - the archive.
Throws:
java.io.IOException - if an error occurs while reading the file.

ZipFile

public ZipFile(java.lang.String name)
        throws java.io.IOException
Opens the given file for reading, assuming the platform's native encoding for file names.

Parameters:
name - name of the archive.
Throws:
java.io.IOException - if an error occurs while reading the file.

ZipFile

public ZipFile(java.lang.String name,
               java.lang.String encoding)
        throws java.io.IOException
Opens the given file for reading, assuming the specified encoding for file names.

Parameters:
name - name of the archive.
encoding - the encoding to use for file names
Throws:
java.io.IOException - if an error occurs while reading the file.

ZipFile

public ZipFile(java.io.File f,
               java.lang.String encoding)
        throws java.io.IOException
Opens the given file for reading, assuming the specified encoding for file names.

Parameters:
f - the archive.
encoding - the encoding to use for file names
Throws:
java.io.IOException - if an error occurs while reading the file.
Method Detail

getEncoding

public java.lang.String getEncoding()
The encoding to use for filenames and the file comment.

Returns:
null if using the platform's default character encoding.

close

public void close()
           throws java.io.IOException
Closes the archive.

Throws:
java.io.IOException - if an error occurs closing the archive.

getEntries

public java.util.Enumeration getEntries()
Returns all entries.

Returns:
all entries as ZipEntry instances

getEntry

public ZipEntry getEntry(java.lang.String name)
Returns a named entry - or null if no entry by that name exists.

Parameters:
name - name of the entry.
Returns:
the ZipEntry corresponding to the given name - or null if not present.

getInputStream

public java.io.InputStream getInputStream(ZipEntry ze)
                                   throws java.io.IOException,
                                          java.util.zip.ZipException
Returns an InputStream for reading the contents of the given entry.

Parameters:
ze - the entry to get the stream for.
Returns:
a stream to read the entry from.
Throws:
java.io.IOException
java.util.zip.ZipException

populateFromCentralDirectory

private void populateFromCentralDirectory()
                                   throws java.io.IOException
Reads the central directory of the given archive and populates the internal tables with ZipEntry instances.

The ZipEntrys will know all data that can be obtained from the central directory alone, but not the data that requires the local file header or additional data to be read.

Throws:
java.io.IOException

positionAtCentralDirectory

private void positionAtCentralDirectory()
                                 throws java.io.IOException
Searches for the "End of central dir record", parses it and positions the stream at the first central directory record.

Throws:
java.io.IOException

resolveLocalFileHeaderData

private void resolveLocalFileHeaderData()
                                 throws java.io.IOException
Walks through all recorded entries and adds the data available from the local file header.

Also records the offsets for the data to read from the entries.

Throws:
java.io.IOException

fromDosTime

protected static java.util.Date fromDosTime(ZipLong l)
Convert a DOS date/time field to a Date object.

Parameters:
l - contains the stored DOS time.
Returns:
a Date instance corresponding to the given time.

getString

protected java.lang.String getString(byte[] bytes)
                              throws java.util.zip.ZipException
Retrieve a String from the given bytes using the encoding set for this ZipFile.

Parameters:
bytes - the byte array to transform
Returns:
String obtained by using the given encoding
Throws:
java.util.zip.ZipException - if the encoding cannot be recognized.