/*************************************************************************
 *                                                                       *
 *  CERT-CVC: EAC 1.11 Card Verifiable Certificate Library               * 
 *                                                                       *
 *  This software is free software; you can redistribute it and/or       *
 *  modify it under the terms of the GNU Lesser General Public           *
 *  License as published by the Free Software Foundation; either         *
 *  version 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.ejbca.cvc;

import java.io.DataOutputStream;
import java.io.IOException;

/**
 * Represents a data field (difference from sequence is no sub fields).
 * 
 * @author Keijo Kurkinen, Swedish National Police Board
 * @version $Id: AbstractDataField.java 23378 2016-05-09 12:55:41Z netmackan $
 *
 */
public abstract class AbstractDataField extends CVCObject {

    private static final long serialVersionUID = 1L;

    /**
     * Constructor, must supply the tag
     * 
     * @param pType
     */
    public AbstractDataField(CVCTagEnum pType) {
	super(pType);
    }

    /**
     * Generates a DER-encoded byte array from this object
     * 
     * @return
     */
    protected abstract byte[] getEncoded();

    /**
     * Generates a DER-encoded byte array from this object, including tag and length
     * 
     * @param out
     *            to write to
     * @return number of bytes written
     */
    @Override
    protected int encode(DataOutputStream out) throws IOException {
	int s0 = out.size();
	out.write(toByteArray(getTag().getValue()));

	byte[] databytes = getEncoded();
	int len = databytes.length;
	out.write(encodeLength(len));
	out.write(databytes);
	return out.size() - s0;
    }

    /**
     * Returns this field as text
     */
    @Override
    public String getAsText(String tab, boolean showTagNo) {
	StringBuffer sb = new StringBuffer();
	// Concatenates CVCObject.getAsText() and this.valueAsText()
	sb.append(super.getAsText(tab, showTagNo)).append(valueAsText());
	return sb.toString();
    }

    /**
     * Returns this field's data as text
     * 
     * @return
     */
    protected abstract String valueAsText();

}