asn1choice.java

来自「一个非常好的ssh客户端实现」· Java 代码 · 共 78 行

/******************************************************************************
 *
 * Copyright (c) 1999-2003 AppGate Network Security AB. All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code as
 * defined in and that are subject to the MindTerm Public Source License,
 * Version 2.0, (the 'License'). You may not use this file except in compliance
 * with the License.
 * 
 * You should have received a copy of the MindTerm Public Source License
 * along with this software; see the file LICENSE.  If not, write to
 * AppGate Network Security AB, Otterhallegatan 2, SE-41118 Goteborg, SWEDEN
 *
 *****************************************************************************/

package com.mindbright.asn1;

import java.io.IOException;

import java.util.Hashtable;

public class ASN1Choice extends ASN1DynamicType {

    protected Hashtable members;

    public ASN1Choice() {
	super();
	members = new Hashtable();
    }

    public final void setMember(int id, Class ofType) {
	members.put(new Integer(id), ofType);
    }

    public final void setMember(int id, ASN1Object value) {
	members.put(new Integer(id), value);
    }

    public final void setMember(ASN1Object value) {
	members.put(new Integer(value.getTag()), value);
    }

    public final Object getMember(int tag) {
	return members.get(memberMapping(tag));
    }

    protected ASN1Object bindType(int tag) throws IOException {
	Object o = getMember(tag);
	if(o == null) {
	    throw new IOException("Invalid member of " + getType() + " (" +
				  tag + ")");
	}
	ASN1Object value = null;
	if(o instanceof Class) {
	    try {
		Class c = (Class)o;
		value = (ASN1Object)c.newInstance();
	    } catch (Exception e) {
		throw new IOException("Error decoding " + getType() + ": " +
				      e.getMessage());
	    }
	} else if(o instanceof ASN1Object) {
	    value = (ASN1Object)o;
	} else {
	    throw new IOException("Error decoding " + getType() +
				  ", invalid member: " + o);
	}

	return value;
    }

    protected Object memberMapping(int tag) {
	return new Integer(tag);
    }

}