filelocator.java

这是一个基于java编写的torrent的P2P源码

// ===========================================================================
// CONTENT  : CLASS FileLocator
// AUTHOR   : Manfred Duchrow
// VERSION  : 1.3 - 14/03/2003
// HISTORY  :
//  17/05/2002  duma  CREATED
//	24/05/2002	duma	added		->	toURL(), isFile(), isDirectory(), getAbsolutePath()
//	21/06/2002	duma	added		->	realFile()
//	14/03/2003	duma	added		->	getStandardizedPath(), getStandardizedAbsolutePath()
//
// Copyright (c) 2002-2003, by Manfred Duchrow. All rights reserved.
// ===========================================================================
package org.pf.file ;

// ===========================================================================
// IMPORTS
// ===========================================================================
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.pf.text.StringUtil; 

/**
 * This class mainly supports access to files which can be in the normal
 * file directory structure or inside zip archives.
 * The main purpose is to provide methods that transparently treat files 
 * the same way whether they are in the normal directory structure or
 * inside archives.
 * The syntax is simply to allow archive names in a path name at any place
 * where a sub-directory name can be. <br>
 * Examples: <br>
 * <ul>
 *   <li>d:\temp\archive.zip\config\nls.properties</li>
 *	 <li>/usr/java/jdk1.3/src.jar/java/io/File.java</li>
 * </ul>
 * @author Manfred Duchrow
 * @version 1.3
 */
public class FileLocator
{
  // =========================================================================
  // CONSTANTS
  // =========================================================================
	private static final boolean DEBUG = false ;
	private static final String FILE_PROTOCOL_INDICATOR = "file:" + File.separator ;
	private static final String ARCHIVE_INDICATOR				= "!" + File.separator ;

  // =========================================================================
  // INSTANCE VARIABLES
  // =========================================================================
  private FileLocator parent = null ;
  protected FileLocator getParent() { return parent ; }
  protected void setParent( FileLocator newValue ) { parent = newValue ; }

  private File file = null ;
  protected File getFile() { return file ; }
  protected void setFile( File newValue ) { file = newValue ; }
  
  private ZipFile zipFile = null ;
  protected ZipFile getZipFile() { return zipFile ; }
  protected void setZipFile( ZipFile newValue ) { zipFile = newValue ; }  
   
  private boolean exists = true ;
  protected boolean getExists() { return exists ; }
  protected void setExists( boolean newValue ) { exists = newValue ; }
      
  private Exception exception = null ;
  protected Exception getException() { return exception ; }
  protected void setException( Exception newValue ) { exception = newValue ; }
      
  // =========================================================================
  // CLASS METHODS
  // =========================================================================
  /**
   * Create a file locator that corresponds to the given file name.
   */
  public static FileLocator create( File file )
  {
  	FileLocator locator = new FileLocator() ;
		
		return locator.createFrom( file ) ;
  } // create()

  // -------------------------------------------------------------------------

  /**
   * Create a file locator that corresponds to the given file name.
   */
  public static FileLocator create( String filename )
  {
		return create( new File( filename ) ) ;
  } // create()

  // -------------------------------------------------------------------------

  private static FileLocator newWith( FileLocator aParent, String[] pathElements )
		throws Exception
  {
  	FileLocator locator = new FileLocator() ;
		
		return locator.createFrom( aParent, pathElements ) ;
  } // newWith()

  // -------------------------------------------------------------------------

  // =========================================================================
  // CONSTRUCTORS
  // =========================================================================
  /**
   * Initialize the new instance with default values.
   */
  private FileLocator()
  {
    super() ;
  } // FileLocator()

  // -------------------------------------------------------------------------

  // =========================================================================
  // PUBLIC INSTANCE METHODS
  // =========================================================================

	/**
	 * Returns the file that contains the data the locator points to.
	 * If the locator points to a normal file in a directory, than
	 * this file will be returned.
	 * If the locator points to a file inside an archive, the file
	 * will be unzipped into the <i><b>temp</i></b> directory and this
	 * temp file will be returned.
	 * If the locator points to a none existing file, this method 
	 * returns false.
	 */
	public File realFile()
	{
		File aFile ;
		try
		{
			aFile = this.fileRef() ;
		}
		catch (Exception e)
		{
			aFile = null ;
		}
		return aFile ;
	} // realFile()

  // -------------------------------------------------------------------------

	/**
	 * Returns whether or not the file specified by this locator exists.
	 */
	public boolean exists()
	{
		return this.getExists() ;
	} // exists()

  // -------------------------------------------------------------------------

	/**
	 * Returns whether or not the name specified by this locator 
	 * points to a file.
	 */
	public boolean isFile()
	{
		try 
		{
			if ( this.exists() )
				return this.isFileElement( this.getFile() ) ;
			else
				return false ;
		} 
		catch(Exception e) 
		{
			return false ;
		}
	} // isFile()

  // -------------------------------------------------------------------------

	/**
	 * Returns whether or not the name specified by this locator 
	 * points to a directory.
	 */
	public boolean isDirectory()
	{
		try 
		{
			if ( this.exists() )
				return ! this.isFileElement( this.getFile() ) ;
			else
				return false ;
		} 
		catch(Exception e) 
		{
			return false ;
		}
	} // isDirectory()

  // -------------------------------------------------------------------------

	/**
	 * Returns the size of the file or 0 if it does not exist.
	 */
	public long size()
	{
		ZipEntry entry ;
		
		try 
		{
			if ( this.isInArchive() )
			{
				entry = this.archiveEntry() ;
				// if ( DEBUG ) com.mdcs.joi.Inspector.inspectWait( entry ) ;
				return entry.getSize() ;
			}
			else
			{
				return this.getFile().length() ;
			} 
		}
		catch(Exception ex) 
		{
			if ( DEBUG ) ex.printStackTrace() ;
			return 0L ;
		} 
	} // size()

  // -------------------------------------------------------------------------

	/**
	 * Returns the timestamp of when the file was last modified 
	 * or 0 in any case of error.
	 */
	public long lastModified()
	{
		ZipEntry entry ;
		
		try 
		{
			if ( this.isInArchive() )
			{
				entry = this.archiveEntry() ;
				return entry.getTime() ;
			}
			else
			{
				return this.getFile().lastModified() ;
			} 
		}
		catch(Exception ex) 
		{
			if ( DEBUG ) ex.printStackTrace() ;
			return 0L ;
		} 
	} // lastModified()

  // -------------------------------------------------------------------------

	/**
	 * Returns an opened input stream on the file defined by this locator.
	 */
	public InputStream getInputStream()
		throws Exception
	{
		ZipEntry entry ;
		
		if ( this.isInArchive() )
		{
			entry = this.archiveEntry() ;
			return this.container().getInputStream( entry ) ;
		}
		else
		{
			return new FileInputStream( this.getFile() ) ;
		} 
	} // getInputStream()

  // -------------------------------------------------------------------------

	/**
	 * Returns whether or not the file specified by this locator 
	 * is inside an archive.
	 */
	public boolean isInArchive()
	{
		return this.getParent() != null ;
	} // isInArchive()

  // -------------------------------------------------------------------------

	/**
	 * Returns the full pathname.
	 */
	public String getPath()
	{
		return this.fullFilePath( false ).getPath() ;
	} // getPath()

  // -------------------------------------------------------------------------

	/**
	 * Returns the full absolute pathname.
	 */
	public String getAbsolutePath()
	{
		return this.fullFilePath( true ).getPath() ;
	} // getAbsolutePath()

  // -------------------------------------------------------------------------

	/**
	 * Returns the full pathname in a standardized for.
	 * That is all ".." and "." elements are removed and forward slashes are 
	 * used as separators of the remaining elements.
	 */
	public String getStandardizedPath()
	{
		return this.fileUtil().standardize( this.getPath() ) ;
	} // getStandardizedPath()

  // -------------------------------------------------------------------------

	/**
	 * Returns the full absolute pathname in a standardized form.
	 * That is all ".." and "." elements are removed and forward slashes are 
	 * used as separators of the remaining elements.
	 */
	public String getStandardizedAbsolutePath()
	{
		return this.fileUtil().standardize( this.getAbsolutePath() ) ;
	} // getStandardizedAbsolutePath()

  // -------------------------------------------------------------------------

	/**
	 * Returns the last exception that occured while using this locator
	 * or null, if no exception was thrown at all.
	 */
	public Exception exception()
	{
		return this.getException() ;