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JarInputStream

public class JarInputStream
extends ZipInputStream

java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ java.util.zip.InflaterInputStream
         ↳ java.util.zip.ZipInputStream
           ↳ java.util.jar.JarInputStream


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.

Summary

Inherited constants

Inherited fields

Public constructors

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.

Public methods

Manifest getManifest()

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

ZipEntry getNextEntry()

Reads the next ZIP file entry and positions the 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.

Protected methods

ZipEntry createZipEntry(String name)

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

Inherited methods

Public constructors

JarInputStream

added in API level 1
public JarInputStream (InputStream in)

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 InputStream: the actual input stream

Throws
IOException if an I/O error has occurred

JarInputStream

added in API level 1
public JarInputStream (InputStream in, 
                boolean verify)

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 InputStream: the actual input stream

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

Throws
IOException if an I/O error has occurred

Public methods

getManifest

added in API level 1
public Manifest getManifest ()

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

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

getNextEntry

added in API level 1
public ZipEntry getNextEntry ()

Reads the next ZIP file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Returns
ZipEntry the next ZIP file entry, or null if there are no more entries

Throws
ZipException if a ZIP file error has occurred
IOException if an I/O error has occurred
SecurityException if any of the jar file entries are incorrectly signed.

getNextJarEntry

added in API level 1
public JarEntry getNextJarEntry ()

Reads the next JAR file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Returns
JarEntry the next JAR file entry, or null if there are no more entries

Throws
ZipException if a ZIP file error has occurred
IOException if an I/O error has occurred
SecurityException if any of the jar file entries are incorrectly signed.

read

added in API level 1
public int read (byte[] b, 
                int off, 
                int len)

Reads from the current JAR file entry into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned. If verification has been enabled, any invalid signature on the current entry will be reported at some point before the end of the entry is reached.

Parameters
b byte: the buffer into which the data is read

off int: the start offset in the destination array b

len int: the maximum number of bytes to read

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

Throws
NullPointerException If b is null.
IndexOutOfBoundsException If off is negative, len is negative, or len is greater than b.length - off
ZipException if a ZIP file error has occurred
IOException if an I/O error has occurred
SecurityException if any of the jar file entries are incorrectly signed.

Protected methods

createZipEntry

added in API level 1
protected ZipEntry createZipEntry (String name)

Creates a new JarEntry (ZipEntry) for the specified JAR file entry name. The manifest attributes of the specified JAR file entry name will be copied to the new JarEntry.

Parameters
name String: the name of the JAR/ZIP file entry

Returns
ZipEntry the JarEntry object just created