java.util.jar
Class JarInputStream

java.lang.Object
  |
  +--java.io.InputStream
        |
        +--java.io.FilterInputStream
              |
              +--java.util.zip.InflaterInputStream
                    |
                    +--java.util.zip.ZipInputStream
                          |
                          +--java.util.jar.JarInputStream

All Implemented Interfaces:

java.util.zip.ZipConstants

public class JarInputStream

extends ZipInputStream

The JarInputStream class is used to read the contents of a JAR file from any input stream. It extends the class java.util.zip.ZipInputStream with support for reading an optional Manifest entry. The Manifest can be used to store meta-information about the JAR file and its entries.

Since:

1.2

See Also:

Manifest, ZipInputStream

Field Summary

Fields inherited from class java.util.zip.ZipInputStream

CENATT, CENATX, CENCOM, CENCRC, CENDSK, CENEXT, CENFLG, CENHDR, CENHOW, CENLEN, CENNAM, CENOFF, CENSIG, CENSIZ, CENTIM, CENVEM, CENVER, ENDCOM, ENDHDR, ENDOFF, ENDSIG, ENDSIZ, ENDSUB, ENDTOT, EXTCRC, EXTHDR, EXTLEN, EXTSIG, EXTSIZ, LOCCRC, LOCEXT, LOCFLG, LOCHDR, LOCHOW, LOCLEN, LOCNAM, LOCSIG, LOCSIZ, LOCTIM, LOCVER

Fields inherited from class java.util.zip.InflaterInputStream

buf, inf, len

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

JarInputStream(InputStream in)
Creates a new JarInputStream and reads the optional manifest.

JarInputStream(InputStream in, boolean verify)
Creates a new JarInputStream and reads the optional manifest.

Method Summary

protected ZipEntry	createZipEntry(String name) Creates a new JarEntry (ZipEntry) for the specified JAR file entry name.
Manifest	getManifest() Returns the Manifest for this JAR file, or null if none.
ZipEntry	getNextEntry() Reads the next ZIP file entry and positions stream at the beginning of the entry data.
JarEntry	getNextJarEntry() Reads the next JAR file entry and positions the stream at the beginning of the entry data.
int	read(byte[] b, int off, int len) Reads from the current JAR file entry into an array of bytes.

Methods inherited from class java.util.zip.ZipInputStream

available, close, closeEntry, skip

Methods inherited from class java.util.zip.InflaterInputStream

fill, read

Methods inherited from class java.io.FilterInputStream

mark, markSupported, read, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

JarInputStream

public JarInputStream(InputStream in)
               throws IOException

Creates a new JarInputStream and reads the optional manifest. If a manifest is present, also attempts to verify the signatures if the JarInputStream is signed.

Parameters:

in - the actual input stream

Throws:

IOException - if an I/O error has occurred

JarInputStream

public JarInputStream(InputStream in,
                      boolean verify)
               throws IOException

Creates a new JarInputStream and reads the optional manifest. If a manifest is present and verify is true, also attempts to verify the signatures if the JarInputStream is signed.

Parameters:

in - the actual input stream

verify - whether or not to verify the JarInputStream if it is signed.

Throws:

IOException - if an I/O error has occurred

Method Detail

getManifest

public Manifest getManifest()

Returns the Manifest for this JAR file, or null if none.

Returns:

the Manifest for this JAR file, or null if none.

getNextEntry

public ZipEntry getNextEntry()
                      throws IOException

Reads the next ZIP file entry and positions stream at the beginning of the entry data.

Overrides:

getNextEntry in class ZipInputStream

Returns:

the ZipEntry just read

Throws:

ZipException - if a ZIP file error has occurred

IOException - if an I/O error has occurred

getNextJarEntry

public JarEntry getNextJarEntry()
                         throws IOException

Reads the next JAR file entry and positions the stream at the beginning of the entry data.

Returns:

the next JAR file entry

Throws:

ZipException - if a ZIP file error has occurred

IOException - if an I/O error has occurred

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Reads from the current JAR file entry into an array of bytes. Blocks until some input is available.

Overrides:

read in class ZipInputStream

Parameters:

b - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of bytes to read

Returns:

the actual number of bytes read, or -1 if the end of the entry is reached

Throws:

ZipException - if a ZIP file error has occurred

IOException - if an I/O error has occurred

createZipEntry

protected ZipEntry createZipEntry(String name)

Creates a new JarEntry (ZipEntry) for the specified JAR file entry name.

Overrides:

createZipEntry in class ZipInputStream

Parameters:

name - the name of the JAR/ZIP file entry

Returns:

the JarEntry object just created