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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  
28  package org.apache.http.impl.io;
29  
30  import java.io.IOException;
31  
32  import org.apache.http.Header;
33  import org.apache.http.HeaderIterator;
34  import org.apache.http.HttpException;
35  import org.apache.http.HttpMessage;
36  import org.apache.http.io.HttpMessageWriter;
37  import org.apache.http.io.SessionOutputBuffer;
38  import org.apache.http.message.BasicLineFormatter;
39  import org.apache.http.message.LineFormatter;
40  import org.apache.http.params.HttpParams;
41  import org.apache.http.util.Args;
42  import org.apache.http.util.CharArrayBuffer;
43  
44  /**
45   * Abstract base class for HTTP message writers that serialize output to
46   * an instance of {@link SessionOutputBuffer}.
47   *
48   * @since 4.0
49   */
50  @SuppressWarnings("deprecation")
51  public abstract class AbstractMessageWriter<T extends HttpMessage> implements HttpMessageWriter<T> {
52  
53      protected final SessionOutputBuffer sessionBuffer;
54      protected final CharArrayBuffer lineBuf;
55      protected final LineFormatter lineFormatter;
56  
57      /**
58       * Creates an instance of AbstractMessageWriter.
59       *
60       * @param buffer the session output buffer.
61       * @param formatter the line formatter.
62       * @param params HTTP parameters.
63       *
64       * @deprecated (4.3) use
65       *   {@link AbstractMessageWriter#AbstractMessageWriter(SessionOutputBuffer, LineFormatter)}
66       */
67      @Deprecated
68      public AbstractMessageWriter(final SessionOutputBuffer buffer,
69                                   final LineFormatter formatter,
70                                   final HttpParams params) {
71          super();
72          Args.notNull(buffer, "Session input buffer");
73          this.sessionBuffer = buffer;
74          this.lineBuf = new CharArrayBuffer(128);
75          this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
76      }
77  
78      /**
79       * Creates an instance of AbstractMessageWriter.
80       *
81       * @param buffer the session output buffer.
82       * @param formatter the line formatter If {@code null} {@link BasicLineFormatter#INSTANCE}
83       *   will be used.
84       *
85       * @since 4.3
86       */
87      public AbstractMessageWriter(
88              final SessionOutputBuffer buffer,
89              final LineFormatter formatter) {
90          super();
91          this.sessionBuffer = Args.notNull(buffer, "Session input buffer");
92          this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
93          this.lineBuf = new CharArrayBuffer(128);
94      }
95  
96      /**
97       * Subclasses must override this method to write out the first header line
98       * based on the {@link HttpMessage} passed as a parameter.
99       *
100      * @param message the message whose first line is to be written out.
101      * @throws IOException in case of an I/O error.
102      */
103     protected abstract void writeHeadLine(T message) throws IOException;
104 
105     @Override
106     public void write(final T message) throws IOException, HttpException {
107         Args.notNull(message, "HTTP message");
108         writeHeadLine(message);
109         for (final HeaderIterator it = message.headerIterator(); it.hasNext(); ) {
110             final Header header = it.nextHeader();
111             this.sessionBuffer.writeLine
112                 (lineFormatter.formatHeader(this.lineBuf, header));
113         }
114         this.lineBuf.clear();
115         this.sessionBuffer.writeLine(this.lineBuf);
116     }
117 
118 }