algorithmidentifier.java

这是linux下ssl vpn的实现程序

/*
 *  SSL-Explorer
 *
 *  Copyright (C) 2003-2006 3SP LTD. All Rights Reserved
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2 of
 *  the License, or (at your option) any later version.
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
			
package com.maverick.crypto.asn1.x509;

import com.maverick.crypto.asn1.ASN1Encodable;
import com.maverick.crypto.asn1.ASN1EncodableVector;
import com.maverick.crypto.asn1.ASN1Sequence;
import com.maverick.crypto.asn1.ASN1TaggedObject;
import com.maverick.crypto.asn1.DEREncodable;
import com.maverick.crypto.asn1.DERObject;
import com.maverick.crypto.asn1.DERObjectIdentifier;
import com.maverick.crypto.asn1.DERSequence;

public class AlgorithmIdentifier
    extends ASN1Encodable
{
    private DERObjectIdentifier objectId;
    private DEREncodable        parameters;
    private boolean             parametersDefined = false;

    public static AlgorithmIdentifier getInstance(
        ASN1TaggedObject obj,
        boolean          explicit)
    {
        return getInstance(ASN1Sequence.getInstance(obj, explicit));
    }

    public static AlgorithmIdentifier getInstance(
        Object  obj)
    {
        if (obj instanceof AlgorithmIdentifier)
        {
            return (AlgorithmIdentifier)obj;
        }

        if (obj instanceof DERObjectIdentifier)
        {
            return new AlgorithmIdentifier((DERObjectIdentifier)obj);
        }

        if (obj instanceof String)
        {
            return new AlgorithmIdentifier((String)obj);
        }

        if (obj instanceof ASN1Sequence)
        {
            return new AlgorithmIdentifier((ASN1Sequence)obj);
        }

        throw new IllegalArgumentException("unknown object in factory");
    }

    public AlgorithmIdentifier(
        DERObjectIdentifier     objectId)
    {
        this.objectId = objectId;
    }

    public AlgorithmIdentifier(
        String     objectId)
    {
        this.objectId = new DERObjectIdentifier(objectId);
    }

    public AlgorithmIdentifier(
        DERObjectIdentifier     objectId,
        DEREncodable            parameters)
    {
        parametersDefined = true;
        this.objectId = objectId;
        this.parameters = parameters;
    }

    public AlgorithmIdentifier(
        ASN1Sequence   seq)
    {
        objectId = (DERObjectIdentifier)seq.getObjectAt(0);

        if (seq.size() == 2)
        {
            parametersDefined = true;
            parameters = seq.getObjectAt(1);
        }
        else
        {
            parameters = null;
        }
    }

    public DERObjectIdentifier getObjectId()
    {
        return objectId;
    }

    public DEREncodable getParameters()
    {
        return parameters;
    }

    /**
     * Produce an object suitable for an ASN1OutputStream.
     * <pre>
     *      AlgorithmIdentifier ::= SEQUENCE {
     *                            algorithm OBJECT IDENTIFIER,
     *                            parameters ANY DEFINED BY algorithm OPTIONAL }
     * </pre>
     */
    public DERObject toASN1Object()
    {
        ASN1EncodableVector  v = new ASN1EncodableVector();

        v.add(objectId);

        if (parametersDefined)
        {
            v.add(parameters);
        }

        return new DERSequence(v);
    }
}