sessioncontextimpl.java

一个简单的visio程序。

package servlet.http;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Enumeration;
import java.util.Hashtable;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionContext;

// Referenced classes of package servlet.http:
//            HttpSessionImpl

public class SessionContextImpl
    implements HttpSessionContext
{

    public SessionContextImpl()
    {
        sessions = new Hashtable();
        initializeSessionIdTemplate();
    }

    public HttpSession getSession(String s)
    {
        return (HttpSession)sessions.get(s);
    }

    public Enumeration getIds()
    {
        return sessions.keys();
    }

    public synchronized String setSession(HttpSessionImpl httpsessionimpl)
    {
        String s = generateSessionId();
        sessions.put(s, httpsessionimpl);
        return s;
    }

    public void removeSession(String s)
    {
        if(getSession(s) != null)
            sessions.remove(s);
    }

    public InetAddress getLocalHost()
    {
        if(mLocalHost == null)
            synchronized(this) 
            {
                if(mLocalHost == null)
                    try
                    {
                        mLocalHost = InetAddress.getLocalHost();
                    }
                    catch(UnknownHostException ex)
                    {
                        try
                        {
                            mLocalHost = InetAddress.getByName("127.0.0.1");
                        }
                        catch(UnknownHostException ex2) {}
                    }
            }
        return mLocalHost;
    }

    protected void initializeSessionIdTemplate()
    {
        mSessionIdTemplate = new byte[14];
        int i = 8;
        byte abyte0[] = getLocalHost().getAddress();
        System.arraycopy(abyte0, 0, mSessionIdTemplate, i, 4);
        i += 4;
        int j = 0;
        mSessionIdTemplate[i++] = (byte)(j >> 8 & 0xff);
        mSessionIdTemplate[i++] = (byte)(j & 0xff);
    }

    synchronized int generateSessionIdCount()
    {
        return mSessionIdCounter++;
    }

    String generateSessionId()
    {
        byte abyte0[] = new byte[mSessionIdTemplate.length];
        System.arraycopy(mSessionIdTemplate, 0, abyte0, 0, mSessionIdTemplate.length);
        int i = 0;
        int j = generateSessionIdCount();
        int k = j;
        long l = System.currentTimeMillis();
        k = k * 39 + (int)(l >> 32 & -1L);
        k = k * 39 + (int)(l & -1L);
        abyte0[i++] = (byte)(k >> 24 & 0xff);
        abyte0[i++] = (byte)(k >> 16 & 0xff);
        abyte0[i++] = (byte)(k >> 8 & 0xff);
        abyte0[i++] = (byte)(k & 0xff);
        abyte0[i++] = (byte)(j >> 24 & 0xff);
        abyte0[i++] = (byte)(j >> 16 & 0xff);
        abyte0[i++] = (byte)(j >> 8 & 0xff);
        abyte0[i++] = (byte)(j & 0xff);
        return convertSessionIdBytesToSessionId(abyte0);
    }

    String convertSessionIdBytesToSessionId(byte abyte0[])
    {
        int i = abyte0.length * 8;
        int j = i / 5;
        if(j % 5 != 0)
            j++;
        char ac[] = new char[j];
        int k = 0;
        int l = 0;
        int i1 = 0;
        while(k < abyte0.length) 
        {
            int j1 = 0;
            if(l <= 3)
            {
                j1 = abyte0[k] >> 3 - l & 0x1f;
            }
            else
            {
                j1 = abyte0[k] << 5 - (8 - l);
                if(k + 1 < abyte0.length)
                {
                    int k1 = abyte0[k + 1] >> 8 - (5 - (8 - l));
                    k1 &= sSecondByteMasks[5 - (8 - l)];
                    j1 |= k1;
                }
                j1 &= 0x1f;
            }
            ac[i1++] = sBitChars[j1];
            if((l += 5) >= 8)
            {
                k++;
                l -= 8;
            }
        }

        return new String(ac);
    }

    private int mSessionIdCounter;
    private InetAddress mLocalHost;
    private byte mSessionIdTemplate[];
    private static final char sBitChars[] = {
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 
        'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 
        'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', 
        '4', '5'
    };
    private static final int sSecondByteMasks[] = {
        0, 1, 3, 7, 31
    };
    private Hashtable sessions;

}