org.apache.tomcat

Interface Jar

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

AbstractInputStreamJar, JarFileUrlJar, JarFileUrlNestedJar, UrlJar

public interface Jar
extends AutoCloseable

Provides an abstraction for use by the various classes that need to scan JARs. The classes provided by the JRE for accessing JARs (JarFile and JarInputStream) have significantly different performance characteristics depending on the form of the URL used to access the JAR. For file based JAR URLs, JarFile is faster but for non-file based URLs, JarFile creates a copy of the JAR in the temporary directory so JarInputStream is faster.

Method Summary

Modifier and Type	Method and Description
void	close() Close any resources associated with this JAR.
boolean	entryExists(String name) Determines if a specific entry exists within the JAR.
InputStream	getEntryInputStream() Obtains the input stream for the current entry.
String	getEntryName() Obtains the name of the current entry.
InputStream	getInputStream(String name) Obtain an InputStream for a given entry in a JAR.
URL	getJarFileURL()
long	getLastModified(String name) Obtain the last modified time for the given resource in the JAR.
Manifest	getManifest() Obtain the manifest for the JAR file.
String	getURL(String entry) Obtain, in String form, the URL for an entry in this JAR.
void	nextEntry() Moves the internal pointer to the next entry in the JAR.
void	reset() Resets the internal pointer used to track JAR entries to the beginning of the JAR.

Method Detail

getJarFileURL

URL getJarFileURL()

Returns:

The URL for accessing the JAR file.

entryExists

boolean entryExists(String name)
             throws IOException

Determines if a specific entry exists within the JAR.

Parameters:

name - Entry to look for

Returns:

true if the specified entry exists else false

Throws:

IOException - if an I/O error occurs while processing the JAR file entries

getInputStream

InputStream getInputStream(String name)
                    throws IOException

Obtain an InputStream for a given entry in a JAR. The caller is responsible for closing the stream.

Parameters:

name - Entry to obtain an InputStream for

Returns:

An InputStream for the specified entry or null if the entry does not exist

Throws:

IOException - if an I/O error occurs while processing the JAR file

getLastModified

long getLastModified(String name)
              throws IOException

Obtain the last modified time for the given resource in the JAR.

Parameters:

name - Entry to obtain the modification time for

Returns:

The time (in the same format as System.currentTimeMillis() that the resource was last modified. Returns -1 if the entry does not exist

Throws:

IOException - if an I/O error occurs while processing the JAR file

close

void close()

Close any resources associated with this JAR.

Specified by:

close in interface AutoCloseable

nextEntry

void nextEntry()

Moves the internal pointer to the next entry in the JAR.

getEntryName

String getEntryName()

Obtains the name of the current entry.

Returns:

The entry name

getEntryInputStream

InputStream getEntryInputStream()
                         throws IOException

Obtains the input stream for the current entry.

Returns:

The input stream

Throws:

IOException - If the stream cannot be obtained

getURL

String getURL(String entry)

Obtain, in String form, the URL for an entry in this JAR. Note that for JARs nested in WAR files, the Tomcat specific war:file:... form will not be used, rather the jar:jar:file:... form (that the JRE does not understand will be used). Note that this means that any code using these URLs will need to understand the jar:jar:file:... form and use the JarFactory to ensure resources are accessed correctly.

Parameters:

entry - The entry to generate the URL for

Returns:

a URL for the specified entry in the JAR

getManifest

Manifest getManifest()
              throws IOException

Obtain the manifest for the JAR file.

Returns:

The manifest for this JAR file.

Throws:

IOException - If an I/O error occurs trying to obtain the manifest

reset

void reset()
    throws IOException

Resets the internal pointer used to track JAR entries to the beginning of the JAR.

Throws:

IOException - If the pointer cannot be reset