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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.hc.core5.http.nio.entity;
28  
29  import java.io.IOException;
30  import java.io.UnsupportedEncodingException;
31  import java.nio.charset.Charset;
32  import java.nio.charset.StandardCharsets;
33  import java.nio.charset.UnsupportedCharsetException;
34  
35  import org.apache.hc.core5.concurrent.FutureCallback;
36  import org.apache.hc.core5.http.ContentType;
37  import org.apache.hc.core5.http.EntityDetails;
38  import org.apache.hc.core5.http.HttpException;
39  import org.apache.hc.core5.http.nio.AsyncEntityConsumer;
40  import org.apache.hc.core5.util.Args;
41  
42  /**
43   * Abstract text entity content consumer.
44   *
45   * @since 5.0
46   *
47   * @param <T> entity representation.
48   */
49  public abstract class AbstractCharAsyncEntityConsumer<T> extends AbstractCharDataConsumer implements AsyncEntityConsumer<T> {
50  
51      private volatile FutureCallback<T> resultCallback;
52      private volatile T content;
53  
54      /**
55       * Triggered to signal beginning of entity content stream.
56       *
57       * @param contentType the entity content type
58       */
59      protected abstract void streamStart(ContentType contentType) throws HttpException, IOException;
60  
61      /**
62       * Triggered to generate entity representation.
63       *
64       * @return the entity content
65       */
66      protected abstract T generateContent() throws IOException;
67  
68      @Override
69      public final void streamStart(
70              final EntityDetails entityDetails,
71              final FutureCallback<T> resultCallback) throws IOException, HttpException {
72          Args.notNull(resultCallback, "Result callback");
73          this.resultCallback = resultCallback;
74          try {
75              final ContentType contentType = entityDetails != null ? ContentType.parse(entityDetails.getContentType()) : null;
76              Charset charset = contentType != null ? contentType.getCharset() : null;
77              if (charset == null) {
78                  charset = StandardCharsets.US_ASCII;
79              }
80              setCharset(charset);
81              streamStart(contentType);
82          } catch (final UnsupportedCharsetException ex) {
83              throw new UnsupportedEncodingException(ex.getMessage());
84          }
85      }
86  
87      @Override
88      protected final void completed() throws IOException {
89          content = generateContent();
90          if (resultCallback != null) {
91              resultCallback.completed(content);
92          }
93          releaseResources();
94      }
95  
96      @Override
97      public final void failed(final Exception cause) {
98          if (resultCallback != null) {
99              resultCallback.failed(cause);
100         }
101         releaseResources();
102     }
103 
104     @Override
105     public final T getContent() {
106         return content;
107     }
108 
109 }