package at.gv.egiz.pdfas.api.io;

import java.io.IOException;
import java.io.OutputStream;

/**
 * Output document data sink.
 * 
 * <p>
 * Actually, the DataSink can be seen as a factory for creating OutputStreams
 * with mime type and character encoding provided. This allows the API user to
 * decide how data is to be stored (e.g. in a file, in a byte array, etc.).
 * </p>
 * 
 * @author wprinz
 */
public interface DataSink
{
  /**
   * Creates an OutputStream for binary data.
   * 
   * <p>
   * Note that the stream may be written only once. Creating another stream
   * overwrites the existing one.
   * </p>
   * 
   * @param mimeType
   *          The mime type of the output data.
   * @return Returns the created output stream.
   * @throws IOException
   *           Thrown if the stream cannot be created.
   */
  public OutputStream createOutputStream(String mimeType) throws IOException;

  /**
   * Creates an OutputStream for character data.
   * 
   * <p>
   * This is basically the same as {@link #createOutputStream(String)}, but
   * allows to specify the character encoding.
   * </p>
   * 
   * @param mimeType
   *          The mime type of the output data.
   * @param characterEncoding
   *          The character encoding of the data.
   * @return Returns the created output stream.
   * @throws IOException
   *           Thrown if the stream cannot be created.
   */
  public OutputStream createOutputStream(String mimeType, String characterEncoding) throws IOException;

  /**
   * Returns the mime type of the data stream.
   * 
   * <p>
   * This is only valid after a stream has been created.
   * </p>
   * 
   * @return Returns the mime type of the data stream.
   */
  public String getMimeType();

  /**
   * Returns the character encoding of the data stream.
   * 
   * <p>
   * This is only valid after a stream has been created. Null means that no
   * character encoding was specified for the data (e.g. if the data is binary).
   * </p>
   * 
   * @return Returns the character encoding of the data stream.
   */
  public String getCharacterEncoding();
}