Package com.globalmentor.util.zip

Class ZipManager

  • All Implemented Interfaces:
    URIInputStreamable
    public class ZipManager
extends java.lang.Object
implements URIInputStreamable
    Facilitates access to a zip file. Keeps track of zip contents by zip entry name as a URI as if each zip entry were unarchived in the current location of the zip file.

    This class cannot descend from ZipFile because a ZipFile cannot be arbitrarily opened and closed.

    Author:
    Garret Wilson
    See Also:
    ZipFile

    • Constructor Summary

      Constructors 
      Constructor Description
      ZipManager​(java.io.File zippedFile, java.net.URI baseURI)
      Constructs a zip manager to manage entries in a zip file stored in the specified file.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()  
      java.net.URI getBaseURI()  
      java.io.File getFile()  
      java.io.InputStream getInputStream​(java.net.URI uri)
      Returns an input stream from given URI.
      java.net.URI getURI​(java.lang.String href)
      Creates a URI from the file location, based on the zip file's URI.
      java.net.URI getURI​(java.util.zip.ZipEntry zipEntry)
      Creates a URI to represent the given zip entry, based upon the zip entry's path relative to the URI of the zip file itself.
      java.util.zip.ZipEntry getZipEntry​(java.net.URI uri)
      Gets the zip entry that corresponds to the given URI.
      java.util.Iterator<java.util.zip.ZipEntry> getZipEntryIterator()  
      protected java.util.Map<java.net.URI,​java.util.zip.ZipEntry> getZipEntryMap()  
      java.util.zip.ZipFile grabZipFile()
      Opens the zip file if needed and increases the reference count to indicate the zip file should be held open.
      protected void loadZipEntries()
      Loads and maps the entries of the zip file.
      void releaseZipFile()
      Releases the hold on the zip file.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • ZipManager

        public ZipManager​(java.io.File zippedFile,
                  java.net.URI baseURI)
           throws java.io.IOException
        Constructs a zip manager to manage entries in a zip file stored in the specified file.
        Parameters:
        zippedFile - The file in which the zipped information is stored.
        baseURI - The base URI to use in determining zip entry URIs.
        Throws:
        java.io.IOException - Thrown if there is an error accessing the given zip file.

    • Method Detail

      • getFile

        public java.io.File getFile()
        Returns:
        The file containing the zipped information.

      • getBaseURI

        public java.net.URI getBaseURI()
        Returns:
        The base URI to use in determining zip entry URIs.

      • getZipEntryMap

        protected java.util.Map<java.net.URI,​java.util.zip.ZipEntry> getZipEntryMap()
        Returns:
        A map for storing zip entries, each keyed to a URI of what their filename would be if uncompressed.

      • getZipEntry

        public java.util.zip.ZipEntry getZipEntry​(java.net.URI uri)
        Gets the zip entry that corresponds to the given URI.
        Parameters:
        uri - The URI for which a URI should be returned.
        Returns:
        The zip entry corresponding to the given URI, or null if there is no corresponding zip entry.

      • getZipEntryIterator

        public java.util.Iterator<java.util.zip.ZipEntry> getZipEntryIterator()
        Returns:
        An iterator to all zip entries in the zip file in an undefined order.

      • grabZipFile

        public java.util.zip.ZipFile grabZipFile()
                                  throws java.io.IOException
        Opens the zip file if needed and increases the reference count to indicate the zip file should be held open. Every call to this method should eventually be followed by a single call to releaseZipFile().

        This method is thread-safe.

        Returns:
        ZipFile An object allowing access to the zip file's contents.
        Throws:
        java.io.IOException - Thrown if there is an error opening the zip file.
        See Also:
        releaseZipFile()

      • releaseZipFile

        public void releaseZipFile()
                    throws java.io.IOException
        Releases the hold on the zip file. When no callers hold the zip file (the hold count reaches zero), the zip file is closed and the zip file variable is set to null.

        This method is thread-safe.

        Throws:
        java.io.IOException - Thrown if there is an error closing the zip file.

      • loadZipEntries

        protected void loadZipEntries()
                       throws java.io.IOException
        Loads and maps the entries of the zip file. For each zip entry, a URI is created for the canonical filename of the entry as if it were extracted with its current path under the directory of the zip file.
        Throws:
        java.io.IOException - Thrown if there is an error opening and reading from the zip file.

      • close

        public void close()
           throws java.io.IOException
        Throws:
        java.io.IOException

      • getURI

        public java.net.URI getURI​(java.lang.String href)
        Creates a URI from the file location, based on the zip file's URI.
        Parameters:
        href - The location, either a URI or a filename, of the file.
        Returns:
        A URI representing the specified file.
        Throws:
        java.lang.IllegalArgumentException - if the given string violates RFC 2396.
        See Also:
        URIs

      • getURI

        public java.net.URI getURI​(java.util.zip.ZipEntry zipEntry)
        Creates a URI to represent the given zip entry, based upon the zip entry's path relative to the URI of the zip file itself.
        Parameters:
        zipEntry - The zip entry for which a URI should be returned.
        Returns:
        A URI representing the specified zip entry.
        Throws:
        java.lang.IllegalArgumentException - if the the zip entry does not have a valid filename (a URI cannot be constructed from the filename).

      • getInputStream

        public java.io.InputStream getInputStream​(java.net.URI uri)
                                   throws java.io.FileNotFoundException,
                                          java.io.IOException
        Returns an input stream from given URI. If the URI can be matched with a zip file entry, an input stream to that entry will be returned. The input stream will be left open and should be closed after use.
        Specified by:
        getInputStream in interface URIInputStreamable
        Parameters:
        uri - A complete URI to a file.
        Returns:
        An input stream to the contents of the file represented by the given URI.
        Throws:
        java.io.FileNotFoundException - Thrown if the file referenced by the URI could not be located.
        java.io.IOException - Thrown if an I/O error occurred.