/**
 * 
 */
package at.gv.egiz.pdfas.framework.vfilter;

import java.util.List;

import at.gv.egiz.pdfas.exceptions.framework.VerificationFilterException;
import at.gv.egiz.pdfas.framework.input.PdfDataSource;
import at.gv.egiz.pdfas.framework.input.TextDataSource;

/**
 * Extracts all signatures from a given PDF document or text.
 * 
 * @see VerificationFilterParameters
 * 
 * @author wprinz
 */
public interface VerificationFilter
{

  /**
   * Extracts the signatures from the given PDF.
   * 
   * @param pdf
   *          The PDF.
   * @param blocks
   *          The List of Incremental Update blocks. Usually this comes from a
   *          preprocessing step.
   * @param parameters
   *          The algorithm parameters.
   * @return Returns a List of SignatureHolders containing the signatures. May
   *         be empty in case no signatures have been found.
   * @throws VerificationFilterException
   *           Thrown if something goes wrong.
   */
  public List extractSignatureHolders(PdfDataSource pdf, List blocks, VerificationFilterParameters parameters) throws VerificationFilterException;

  /**
   * Extracts the text signatures from the given free-text.
   * 
   * @param text
   *          The free-text.
   * @param parameters
   *          The algorithm parameters.
   * @return Returns a List of SignatureHolders containing the signatures. May
   *         be empty in case no signatures have been found.
   * @throws VerificationFilterException
   *           Thrown if something goes wrong.
   */
  public List extractSignaturHolders(TextDataSource text, VerificationFilterParameters parameters) throws VerificationFilterException;
}