content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.alibaba.compileflow.engine.core.builder.converter.writer;
  
  import com.alibaba.compileflow.engine.common.CompileFlowException;
  import com.alibaba.compileflow.engine.common.ErrorCode;
  import com.alibaba.compileflow.engine.core.definition.FlowModel;
  import com.sun.xml.txw2.output.IndentingXMLStreamWriter;
  
  import javax.xml.stream.XMLOutputFactory;
  import javax.xml.stream.XMLStreamWriter;
  import java.io.ByteArrayOutputStream;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  
  /**
   * @author yusu
   */
  public abstract class AbstractFlowStreamWriter<T extends FlowModel> extends AbstractFlowWriterSupport
          implements FlowStreamWriter<T> {
  
      @Override
      public OutputStream write(T flowModel) {
          ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
          XMLOutputFactory xof = XMLOutputFactory.newInstance();
  
          try (OutputStreamWriter osw = new OutputStreamWriter(outputStream)) {
              XMLStreamWriter xsw = new IndentingXMLStreamWriter(xof.createXMLStreamWriter(osw));
              doWrite(flowModel, xsw);
              xsw.flush();
          } catch (Exception e) {
              throw new CompileFlowException.SystemException(
                      ErrorCode.CF_RESOURCE_003,
                      "Failed to write flow model to XML stream",
                      e
              );
          }
  
          return outputStream;
      }
  
      protected abstract void doWrite(T flowModel, XMLStreamWriter xsw) throws Exception;
  
  }
  