org.apache.commons.compress.archivers.zip
Class ZipFile

java.lang.Object
  extended by org.apache.commons.compress.archivers.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.commons.compress.archivers.zip.ZipArchiveEntry 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:


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.
private static class ZipFile.NameAndComment
           
private static class ZipFile.OffsetEntry
           
 
Field Summary
private  java.io.RandomAccessFile archive
          The actual data source.
(package private) static int BYTE_SHIFT
           
private static int CFD_LOCATOR_OFFSET
           
private static int CFH_LEN
           
private  java.lang.String encoding
          The encoding to use for filenames and the file comment.
private  java.util.Map entries
          Maps ZipArchiveEntrys to Longs, recording the offsets of the local file headers.
private static int HASH_SIZE
           
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 MAX_EOCD_SIZE
           
private static int MIN_EOCD_SIZE
           
private  java.util.Map nameMap
          Maps String to ZipArchiveEntrys, name -> actual entry.
(package private) static int NIBLET_MASK
           
private  java.util.Comparator OFFSET_COMPARATOR
          Compares two ZipArchiveEntries based on their offset within the archive.
private static int POS_0
           
private static int POS_1
           
private static int POS_2
           
private static int POS_3
           
private static int SHORT
           
private  boolean useUnicodeExtraFields
          Whether to look for and use Unicode extra fields.
private static int WORD
           
private  ZipEncoding zipEncoding
          The zip encoding to use for filenames and the file comment.
 
Constructor Summary
ZipFile(java.io.File f)
          Opens the given file for reading, assuming "UTF8" 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 and scanning for unicode extra fields.
ZipFile(java.io.File f, java.lang.String encoding, boolean useUnicodeExtraFields)
          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 "UTF8".
ZipFile(java.lang.String name, java.lang.String encoding)
          Opens the given file for reading, assuming the specified encoding for file names, scanning unicode extra fields.
 
Method Summary
 boolean canReadEntryData(ZipArchiveEntry ze)
          Whether this class is able to read the given entry.
 void close()
          Closes the archive.
static void closeQuietly(ZipFile zipfile)
          close a zipfile quietly; throw no io fault, do nothing on a null parameter
 java.lang.String getEncoding()
          The encoding to use for filenames and the file comment.
 java.util.Enumeration getEntries()
          Returns all entries.
 java.util.Enumeration getEntriesInPhysicalOrder()
          Returns all entries in physical order.
 ZipArchiveEntry getEntry(java.lang.String name)
          Returns a named entry - or null if no entry by that name exists.
 java.io.InputStream getInputStream(ZipArchiveEntry ze)
          Returns an InputStream for reading the contents of the given entry.
private  java.util.Map populateFromCentralDirectory()
          Reads the central directory of the given archive and populates the internal tables with ZipArchiveEntry 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(java.util.Map entriesWithoutUTF8Flag)
          Walks through all recorded entries and adds the data available from the local file header.
private  boolean startsWithLocalFileHeader()
          Checks whether the archive starts with a LFH.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

HASH_SIZE

private static final int HASH_SIZE
See Also:
Constant Field Values

SHORT

private static final int SHORT
See Also:
Constant Field Values

WORD

private static final int WORD
See Also:
Constant Field Values

NIBLET_MASK

static final int NIBLET_MASK
See Also:
Constant Field Values

BYTE_SHIFT

static final int BYTE_SHIFT
See Also:
Constant Field Values

POS_0

private static final int POS_0
See Also:
Constant Field Values

POS_1

private static final int POS_1
See Also:
Constant Field Values

POS_2

private static final int POS_2
See Also:
Constant Field Values

POS_3

private static final int POS_3
See Also:
Constant Field Values

entries

private final java.util.Map entries
Maps ZipArchiveEntrys to Longs, recording the offsets of the local file headers.


nameMap

private final java.util.Map nameMap
Maps String to ZipArchiveEntrys, name -> actual entry.


encoding

private final 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/j2se/1.5.0/docs/guide/intl/encoding.doc.html. Defaults to UTF-8.


zipEncoding

private final ZipEncoding zipEncoding
The zip encoding to use for filenames and the file comment.


archive

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


useUnicodeExtraFields

private final boolean useUnicodeExtraFields
Whether to look for and use Unicode extra fields.


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

MAX_EOCD_SIZE

private static final int MAX_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

OFFSET_COMPARATOR

private final java.util.Comparator OFFSET_COMPARATOR
Compares two ZipArchiveEntries based on their offset within the archive.

Won't return any meaningful results if one of the entries isn't part of the archive at all.

Since:
Commons Compress 1.1
Constructor Detail

ZipFile

public ZipFile(java.io.File f)
        throws java.io.IOException
Opens the given file for reading, assuming "UTF8" 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 "UTF8".

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, scanning unicode extra fields.

Parameters:
name - name of the archive.
encoding - the encoding to use for file names, use null for the platform's default encoding
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 and scanning for unicode extra fields.

Parameters:
f - the archive.
encoding - the encoding to use for file names, use null for the platform's default encoding
Throws:
java.io.IOException - if an error occurs while reading the file.

ZipFile

public ZipFile(java.io.File f,
               java.lang.String encoding,
               boolean useUnicodeExtraFields)
        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, use null for the platform's default encoding
useUnicodeExtraFields - whether to use InfoZIP Unicode Extra Fields (if present) to set the 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.

closeQuietly

public static void closeQuietly(ZipFile zipfile)
close a zipfile quietly; throw no io fault, do nothing on a null parameter

Parameters:
zipfile - file to close, can be null

getEntries

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

Entries will be returned in the same order they appear within the archive's central directory.

Returns:
all entries as ZipArchiveEntry instances

getEntriesInPhysicalOrder

public java.util.Enumeration getEntriesInPhysicalOrder()
Returns all entries in physical order.

Entries will be returned in the same order their contents appear within the archive.

Returns:
all entries as ZipArchiveEntry instances
Since:
Commons Compress 1.1

getEntry

public ZipArchiveEntry 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 ZipArchiveEntry corresponding to the given name - or null if not present.

canReadEntryData

public boolean canReadEntryData(ZipArchiveEntry ze)
Whether this class is able to read the given entry.

May return false if it is set up to use encryption or a compression method that hasn't been implemented yet.

Since:
Apache Commons Compress 1.1

getInputStream

public java.io.InputStream getInputStream(ZipArchiveEntry 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 - if unable to create an input stream from the zipenty
java.util.zip.ZipException - if the zipentry uses an unsupported feature

populateFromCentralDirectory

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

The ZipArchiveEntrys 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.

Returns:
a Map<ZipArchiveEntry, NameAndComment>> of zipentries that didn't have the language encoding flag set when 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(java.util.Map entriesWithoutUTF8Flag)
                                 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

startsWithLocalFileHeader

private boolean startsWithLocalFileHeader()
                                   throws java.io.IOException
Checks whether the archive starts with a LFH. If it doesn't, it may be an empty archive.

Throws:
java.io.IOException