/**
 *  ServingXML
 *  
 *  Copyright (C) 2006  Daniel Parker
 *    daniel.parker@servingxml.com 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 * 
 **/

package com.servingxml.components.recordio;

import com.servingxml.app.Flow;
import com.servingxml.app.ServiceContext;
import com.servingxml.util.Name;
import com.servingxml.util.QualifiedName;
import com.servingxml.util.SystemConstants;
import com.servingxml.util.ServingXmlException;

/**
 *
 * 
 * @author  Daniel A. Parker
 */

public interface RecordWriter {
  public static final RecordWriter NULL = new NullRecordWriter();
  public static final RecordWriter DEFAULT_DISCARD_WRITER = new DefaultDiscardWriter();

  void startRecordStream(ServiceContext context, Flow flow);

  void endRecordStream(ServiceContext context, Flow flow);

  void writeRecord(ServiceContext context, Flow flow);

  void close();

  static class DefaultDiscardWriter implements RecordWriter {
    private static Name MESSAGE_NAME = new QualifiedName(SystemConstants.SERVINGXML_NS_URI, "message");

    public final void startRecordStream(ServiceContext context, Flow flow) {
    }

    public final void endRecordStream(ServiceContext context, Flow flow) {
    }

    public final void writeRecord(ServiceContext context, Flow flow) {
      String s = flow.getParameters().getString(MESSAGE_NAME);
      String message = s == null ? "Unknown exception." : s;
      throw new ServingXmlException(s);
    }

    public final void close() {
    }
  }

  static class NullRecordWriter implements RecordWriter {
    public final void startRecordStream(ServiceContext context, Flow flow) {
    }

    public final void endRecordStream(ServiceContext context, Flow flow) {
    }

    public final void writeRecord(ServiceContext context, Flow flow) {
    }

    public final void close() {
    }
  }
}                                          


