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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.annotation.NotThreadSafe;
37  import org.apache.http.io.HttpMessageWriter;
38  import org.apache.http.io.SessionOutputBuffer;
39  import org.apache.http.message.BasicLineFormatter;
40  import org.apache.http.message.LineFormatter;
41  import org.apache.http.params.HttpParams;
42  import org.apache.http.util.Args;
43  import org.apache.http.util.CharArrayBuffer;
44  
45  /**
46   * Abstract base class for HTTP message writers that serialize output to
47   * an instance of {@link SessionOutputBuffer}.
48   *
49   * @since 4.0
50   */
51  @SuppressWarnings("deprecation")
52  @NotThreadSafe
53  public abstract class AbstractMessageWriter<T extends HttpMessage> implements HttpMessageWriter<T> {
54  
55      protected final SessionOutputBuffer sessionBuffer;
56      protected final CharArrayBuffer lineBuf;
57      protected final LineFormatter lineFormatter;
58  
59      /**
60       * Creates an instance of AbstractMessageWriter.
61       *
62       * @param buffer the session output buffer.
63       * @param formatter the line formatter.
64       * @param params HTTP parameters.
65       *
66       * @deprecated (4.3) use
67       *   {@link AbstractMessageWriter#AbstractMessageWriter(SessionOutputBuffer, LineFormatter)}
68       */
69      @Deprecated
70      public AbstractMessageWriter(final SessionOutputBuffer buffer,
71                                   final LineFormatter formatter,
72                                   final HttpParams params) {
73          super();
74          Args.notNull(buffer, "Session input buffer");
75          this.sessionBuffer = buffer;
76          this.lineBuf = new CharArrayBuffer(128);
77          this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
78      }
79  
80      /**
81       * Creates an instance of AbstractMessageWriter.
82       *
83       * @param buffer the session output buffer.
84       * @param formatter the line formatter If <code>null</code> {@link BasicLineFormatter#INSTANCE}
85       *   will be used.
86       *
87       * @since 4.3
88       */
89      public AbstractMessageWriter(
90              final SessionOutputBuffer buffer,
91              final LineFormatter formatter) {
92          super();
93          this.sessionBuffer = Args.notNull(buffer, "Session input buffer");
94          this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
95          this.lineBuf = new CharArrayBuffer(128);
96      }
97  
98      /**
99       * Subclasses must override this method to write out the first header line
100      * based on the {@link HttpMessage} passed as a parameter.
101      *
102      * @param message the message whose first line is to be written out.
103      * @throws IOException in case of an I/O error.
104      */
105     protected abstract void writeHeadLine(T message) throws IOException;
106 
107     @Override
108     public void write(final T message) throws IOException, HttpException {
109         Args.notNull(message, "HTTP message");
110         writeHeadLine(message);
111         for (final HeaderIterator it = message.headerIterator(); it.hasNext(); ) {
112             final Header header = it.nextHeader();
113             this.sessionBuffer.writeLine
114                 (lineFormatter.formatHeader(this.lineBuf, header));
115         }
116         this.lineBuf.clear();
117         this.sessionBuffer.writeLine(this.lineBuf);
118     }
119 
120 }