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.hc.core5.http.io.entity;
29
30 import java.io.ByteArrayInputStream;
31 import java.io.ByteArrayOutputStream;
32 import java.io.IOException;
33 import java.io.InputStream;
34 import java.io.OutputStream;
35
36 import org.apache.hc.core5.annotation.Contract;
37 import org.apache.hc.core5.annotation.ThreadingBehavior;
38 import org.apache.hc.core5.http.ContentType;
39 import org.apache.hc.core5.io.IOCallback;
40 import org.apache.hc.core5.util.Args;
41
42 /**
43 * Entity that delegates the process of content generation to a {@link IOCallback}
44 * with {@link OutputStream} as output sink.
45 * <p>
46 * This class contains {@link ThreadingBehavior#IMMUTABLE_CONDITIONAL immutable attributes} but subclasses may contain
47 * additional immutable or mutable attributes.
48 * </p>
49 *
50 * @since 4.0
51 */
52 @Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
53 public final class EntityTemplate extends AbstractHttpEntity {
54
55 private final long contentLength;
56 private final IOCallback<OutputStream> callback;
57
58 /**
59 * Constructs a new instance with the given attributes kept as immutable.
60 * <p>
61 * The new instance:
62 * </p>
63 * <ul>
64 * <li>is not chunked.</li>
65 * </ul>
66 *
67 * @param contentLength The value for the {@code Content-Length} header for the size of the message body, in bytes.
68 * @param contentType The content-type, may be null.
69 * @param contentEncoding The content encoding string, may be null.
70 * @param callback A consumer that write the message body to an output stream.
71 */
72 public EntityTemplate(
73 final long contentLength, final ContentType contentType, final String contentEncoding,
74 final IOCallback<OutputStream> callback) {
75 super(contentType, contentEncoding);
76 this.contentLength = contentLength;
77 this.callback = Args.notNull(callback, "I/O callback");
78 }
79
80 @Override
81 public long getContentLength() {
82 return contentLength;
83 }
84
85 @Override
86 public InputStream getContent() throws IOException {
87 final ByteArrayOutputStream buf = new ByteArrayOutputStream();
88 writeTo(buf);
89 return new ByteArrayInputStream(buf.toByteArray());
90 }
91
92 /**
93 * {@inheritDoc}
94 * <p>
95 * This implementation always returns {@code true}.
96 * </p>
97 */
98 @Override
99 public boolean isRepeatable() {
100 return true;
101 }
102
103 @Override
104 public void writeTo(final OutputStream outStream) throws IOException {
105 Args.notNull(outStream, "Output stream");
106 this.callback.execute(outStream);
107 }
108
109 /**
110 * {@inheritDoc}
111 * <p>
112 * This implementation always returns {@code false}.
113 * </p>
114 */
115 @Override
116 public boolean isStreaming() {
117 return false;
118 }
119
120 /**
121 * {@inheritDoc}
122 * <p>
123 * This implementation is a no-op.
124 * </p>
125 */
126 @Override
127 public void close() throws IOException {
128 }
129
130 }