PC World Komputer 1996 May/PCW596.iso/wtest/clico/sunsoft/java/solaris.taz/solaris/hotjava/classsrc/browser/URLHistory.java

Java Source | 1995-05-15 | 4.4 KB | 172 lines

/*
 * @(#)URLHistory.java    1.5 95/03/20 Jonathan Payne
 *
 * Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

package browser;

import net.www.html.URL;
import java.util.Hashtable;
import java.util.Enumeration;
import net.www.html.MalformedURLException;
import java.io.*;

public class URLHistory {
    /** Hashtable of urls parsed from history file, plus new ones
    we have visited. */
    Hashtable    urlTable = new Hashtable();

    public URLHistory() {
    }

    final String makeString(char data[], int length) {
    char    chars[] = new char[length];

    System.arraycopy(data, 0, chars, 0, length);
    return new String(chars);
    }

    public boolean seen(URL u) {
    return urlTable.get(u.toExternalForm()) != null;
    }

    public void addUrl(URL u) {
    String    eform = u.toExternalForm();

    if (urlTable.get(eform) == null) {
        urlTable.put(eform, u);
        if (outputStream != null) {
        outputStream.println(eform + "\t0");
        outputStream.flush();
        }
    }
    }

    /** Format of stream is

    url[ \t]time

    It's a ' ' when parsing mosaic global history and a Tab
    when parsing netscapes.  HotJava's format uses a Tab,
    and currently sticks in 0 for the last time visited.  That's
    because there's no way to get the current time in hotjava. */
    public void parseStream(InputStream is) {
    /* just in case it's not buffered */
    is = new BufferedInputStream(is);

    DataInputStream    dis = new DataInputStream(is);
    char    buffer[] = new char[256];

    dis.readLine();    /* skip the file format line */
    int    lineNumber = 1;
    int    index = 0;
    int    separatorIndex = -1;
    int    c = -1;

    do {
        try {
inner:
        while (true) {
            switch (c = is.read()) {
            case '\n':
            lineNumber += 1;
            /* falls into ... */

            case -1:
            break inner;

            case ' ':
            case '\t':
            if (separatorIndex == -1) {
                separatorIndex = index;
            }
            /* falls into ... */

            default:
            buffer[index] = (char) c;
            /* Increment after array index in case index is
               out of bounds.  That way we can recover below. */
            index += 1;
            }
        }
        } catch (ArrayIndexOutOfBoundsException e) {
        if (index < buffer.length) {
            throw e;
        }
        char    newbuf[] = new char[(int)(buffer.length * 1.5)];
        System.arraycopy(buffer, 0, newbuf, 0, buffer.length);
        buffer = newbuf;
        buffer[index++] = (char) c;
        continue;
        }

        if (separatorIndex != -1) {
        try {
            String  s = makeString(buffer, separatorIndex);

            urlTable.put(s, s);
        } catch (MalformedURLException e) {
            System.out.println("URL history format error, line "
                       + lineNumber + ": "
                       + makeString(buffer, separatorIndex));
        }
        }
        separatorIndex = -1;
        index = 0;
    } while (c != -1);
    }

    public void writeHistoryFile(String filename) {
    FileOutputStream    fos = new FileOutputStream(filename);
    PrintStream        os;

    os = new PrintStream(new BufferedOutputStream(fos));
    writeHistoryStream(os);
    }

    public void writeHistoryStream(PrintStream os) {
    os.println("hotjava-global-history-1");
    Enumeration e = urlTable.elements();
    while (e.hasMoreElements()) {
        String  key = (String) e.nextElement();

        os.print(key);
        os.println("\t0");
    }
    }

    PrintStream    outputStream;

    public void openOutputStream(String filename) {
    try {
        // REMIND: This should open for appending!
        FileOutputStream    os = new FileOutputStream(filename);

        outputStream = new PrintStream(new BufferedOutputStream(os));
    } catch (Exception e) {
        System.err.println("Warning: not saving global history\nReason is: " + e);
    }
    }

    static public void main(String args[]) {
    URLHistory  h = new URLHistory();

    h.parseStream(new URL(null, args[0]).openStream());
    System.out.println("Parsed " + h.urlTable.size() + " entries from " + args[0]);
    }
}