Interface Jar

All Superinterfaces:
All Known Implementing Classes:
AbstractInputStreamJar, JarFileUrlJar, JarFileUrlNestedJar, ReferenceCountedJar, 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 Details

    • getJarFileURL

      URL getJarFileURL()
      The URL for accessing the JAR file.
    • 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.
      name - Entry to obtain an InputStream for
      An InputStream for the specified entry or null if the entry does not exist
      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.
      name - Entry to obtain the modification time for
      The time (in the same format as System.currentTimeMillis() that the resource was last modified. Returns -1 if the entry does not exist
      IOException - if an I/O error occurs while processing the JAR file
    • exists

      boolean exists(String name) throws IOException
      Determine if the given resource in present in the JAR.
      name - Entry to look for
      true if the entry is present in the JAR, otherwise false
      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.
      The entry name
    • getEntryInputStream

      InputStream getEntryInputStream() throws IOException
      Obtains the input stream for the current entry.
      The input stream
      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.
      entry - The entry to generate the URL for
      a URL for the specified entry in the JAR
    • getManifest

      Manifest getManifest() throws IOException
      Obtain the manifest for the JAR file.
      The manifest for this JAR file.
      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.
      IOException - If the pointer cannot be reset