core/src/main/java/org/apache/abdera2/extra/AbderaResult.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  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.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
package org.apache.abdera2.extra;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;

import javax.xml.transform.Result;
import javax.xml.transform.stream.StreamResult;

import org.apache.abdera2.Abdera;
import org.apache.abdera2.model.Document;
import org.apache.abdera2.model.Element;

/**
 * Provides a simple (and likely somewhat inefficient) implementation of javax.xml.transform.Result that allows Abdera
 * objects to be used with the javax.xml.transform API's Only use this once per transform!!!
 */
public final class AbderaResult extends StreamResult implements Result {

  private final Abdera abdera;
  private final ByteArrayOutputStream out = 
    new ByteArrayOutputStream();
  private Document<?> doc;

  public AbderaResult() {
      this(Abdera.getInstance());
  }

  public AbderaResult(Abdera abdera) {
      this.abdera = abdera;
  }

  @SuppressWarnings("unchecked")
  public <T extends Element> Document<T> getDocument() {
      if (doc == null) {
          ByteArrayInputStream in = 
            new ByteArrayInputStream(out.toByteArray());
          doc = abdera.getParser().parse(in);
      }
      return (Document<T>)doc;
  }

  @Override
  public OutputStream getOutputStream() {
      return out;
  }

  @Override
  public Writer getWriter() {
      return new OutputStreamWriter(getOutputStream());
  }

  @Override
  public void setOutputStream(OutputStream out) {
      throw new UnsupportedOperationException();
  }

  @Override
  public void setWriter(Writer out) {
      throw new UnsupportedOperationException();
  }

}