[6785] | 1 | /**************************************************************** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one * |
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| 3 | * or more contributor license agreements. See the NOTICE file * |
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| 4 | * distributed with this work for additional information * |
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| 5 | * regarding copyright ownership. The ASF licenses this file * |
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| 6 | * to you under the Apache License, Version 2.0 (the * |
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| 7 | * "License"); you may not use this file except in compliance * |
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| 8 | * with the License. You may obtain a copy of the License at * |
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| 9 | * * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 * |
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| 11 | * * |
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| 12 | * Unless required by applicable law or agreed to in writing, * |
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| 13 | * software distributed under the License is distributed on an * |
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| 14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * |
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| 15 | * KIND, either express or implied. See the License for the * |
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| 16 | * specific language governing permissions and limitations * |
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| 17 | * under the License. * |
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| 18 | ****************************************************************/ |
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| 19 | |
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| 20 | package org.apache.james.mime4j.samples.transform; |
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| 21 | |
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| 22 | import java.io.ByteArrayInputStream; |
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| 23 | import java.io.IOException; |
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| 24 | import java.util.Date; |
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| 25 | import java.util.Random; |
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| 26 | |
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| 27 | import org.apache.james.mime4j.dom.Body; |
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| 28 | import org.apache.james.mime4j.dom.Entity; |
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| 29 | import org.apache.james.mime4j.dom.Message; |
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| 30 | import org.apache.james.mime4j.dom.Multipart; |
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| 31 | import org.apache.james.mime4j.dom.TextBody; |
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| 32 | import org.apache.james.mime4j.dom.field.ParseException; |
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| 33 | import org.apache.james.mime4j.field.address.AddressBuilder; |
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| 34 | import org.apache.james.mime4j.message.BodyPart; |
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| 35 | import org.apache.james.mime4j.message.MessageImpl; |
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| 36 | import org.apache.james.mime4j.message.MimeBuilder; |
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| 37 | import org.apache.james.mime4j.message.MimeWriter; |
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| 38 | import org.apache.james.mime4j.message.MultipartImpl; |
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| 39 | import org.apache.james.mime4j.storage.DefaultStorageProvider; |
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| 40 | import org.apache.james.mime4j.storage.StorageBodyFactory; |
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| 41 | import org.apache.james.mime4j.storage.StorageProvider; |
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| 42 | import org.apache.james.mime4j.storage.TempFileStorageProvider; |
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| 43 | |
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| 44 | /** |
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| 45 | * This code should illustrate how to transform a message into another message |
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| 46 | * without modifying the original. |
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| 47 | */ |
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| 48 | public class TransformMessage { |
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| 49 | |
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| 50 | // Host name used in message identifiers. |
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| 51 | private static final String HOSTNAME = "localhost"; |
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| 52 | |
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| 53 | public static void main(String[] args) throws Exception { |
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| 54 | // Explicitly set a strategy for storing body parts. Usually not |
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| 55 | // necessary; for most applications the default setting is appropriate. |
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| 56 | StorageProvider storageProvider = new TempFileStorageProvider(); |
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| 57 | DefaultStorageProvider.setInstance(storageProvider); |
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| 58 | |
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| 59 | // Create a template message. It would be possible to load a message |
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| 60 | // from an input stream but for this example a message object is created |
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| 61 | // from scratch for demonstration purposes. |
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| 62 | Message template = createTemplate(); |
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| 63 | |
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| 64 | // Create a new message by transforming the template. |
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| 65 | Message transformed = transform(template); |
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| 66 | |
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| 67 | // Print transformed message. |
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| 68 | System.out.println("\n\nTransformed message:\n--------------------\n"); |
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| 69 | MimeWriter.DEFAULT.writeMessage(transformed, System.out); |
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| 70 | |
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| 71 | // Messages should be disposed of when they are no longer needed. |
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| 72 | // Disposing of a message also disposes of all child elements (e.g. body |
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| 73 | // parts) of the message. |
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| 74 | transformed.dispose(); |
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| 75 | |
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| 76 | // Print original message to illustrate that it was not affected by the |
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| 77 | // transformation. |
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| 78 | System.out.println("\n\nOriginal template:\n------------------\n"); |
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| 79 | MimeWriter.DEFAULT.writeMessage(template, System.out); |
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| 80 | |
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| 81 | // Original message is no longer needed. |
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| 82 | template.dispose(); |
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| 83 | |
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| 84 | // At this point all temporary files have been deleted because all |
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| 85 | // messages and body parts have been disposed of properly. |
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| 86 | } |
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| 87 | |
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| 88 | /** |
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| 89 | * Copies the given message and makes some arbitrary changes to the copy. |
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| 90 | * @throws ParseException on bad arguments |
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| 91 | */ |
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| 92 | private static Message transform(Message original) throws IOException, ParseException { |
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| 93 | // Create a copy of the template. The copy can be modified without |
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| 94 | // affecting the original. |
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| 95 | Message message = MimeBuilder.DEFAULT.copy(original); |
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| 96 | |
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| 97 | // In this example we know we have a multipart message. Use |
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| 98 | // Message#isMultipart() if uncertain. |
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| 99 | Multipart multipart = (Multipart) message.getBody(); |
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| 100 | |
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| 101 | // Insert a new text/plain body part after every body part of the |
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| 102 | // template. |
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| 103 | final int count = multipart.getCount(); |
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| 104 | for (int i = 0; i < count; i++) { |
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| 105 | String text = "Text inserted after part " + (i + 1); |
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| 106 | BodyPart bodyPart = createTextPart(text); |
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| 107 | multipart.addBodyPart(bodyPart, 2 * i + 1); |
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| 108 | } |
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| 109 | |
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| 110 | // For no particular reason remove the second binary body part (now |
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| 111 | // at index four). |
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| 112 | Entity removed = multipart.removeBodyPart(4); |
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| 113 | |
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| 114 | // The removed body part no longer has a parent entity it belongs to so |
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| 115 | // it should be disposed of. |
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| 116 | removed.dispose(); |
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| 117 | |
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| 118 | // Set some headers on the transformed message |
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| 119 | message.createMessageId(HOSTNAME); |
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| 120 | message.setSubject("Transformed message"); |
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| 121 | message.setDate(new Date()); |
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| 122 | message.setFrom(AddressBuilder.DEFAULT.parseMailbox("John Doe <jdoe@machine.example>")); |
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| 123 | |
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| 124 | return message; |
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| 125 | } |
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| 126 | |
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| 127 | /** |
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| 128 | * Creates a multipart/mixed message that consists of three parts (one text, |
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| 129 | * two binary). |
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| 130 | */ |
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| 131 | private static Message createTemplate() throws IOException { |
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| 132 | Multipart multipart = new MultipartImpl("mixed"); |
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| 133 | |
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| 134 | BodyPart part1 = createTextPart("This is the first part of the template.."); |
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| 135 | multipart.addBodyPart(part1); |
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| 136 | |
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| 137 | BodyPart part2 = createRandomBinaryPart(200); |
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| 138 | multipart.addBodyPart(part2); |
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| 139 | |
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| 140 | BodyPart part3 = createRandomBinaryPart(300); |
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| 141 | multipart.addBodyPart(part3); |
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| 142 | |
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| 143 | MessageImpl message = new MessageImpl(); |
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| 144 | message.setMultipart(multipart); |
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| 145 | |
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| 146 | message.setSubject("Template message"); |
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| 147 | |
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| 148 | return message; |
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| 149 | } |
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| 150 | |
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| 151 | /** |
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| 152 | * Creates a text part from the specified string. |
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| 153 | */ |
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| 154 | private static BodyPart createTextPart(String text) { |
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| 155 | TextBody body = new StorageBodyFactory().textBody(text, "UTF-8"); |
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| 156 | |
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| 157 | BodyPart bodyPart = new BodyPart(); |
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| 158 | bodyPart.setText(body); |
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| 159 | bodyPart.setContentTransferEncoding("quoted-printable"); |
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| 160 | |
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| 161 | return bodyPart; |
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| 162 | } |
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| 163 | |
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| 164 | /** |
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| 165 | * Creates a binary part with random content. |
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| 166 | */ |
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| 167 | private static BodyPart createRandomBinaryPart(int numberOfBytes) |
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| 168 | throws IOException { |
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| 169 | byte[] data = new byte[numberOfBytes]; |
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| 170 | new Random().nextBytes(data); |
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| 171 | |
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| 172 | Body body = new StorageBodyFactory() |
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| 173 | .binaryBody(new ByteArrayInputStream(data)); |
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| 174 | |
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| 175 | BodyPart bodyPart = new BodyPart(); |
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| 176 | bodyPart.setBody(body, "application/octet-stream"); |
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| 177 | bodyPart.setContentTransferEncoding("base64"); |
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| 178 | |
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| 179 | return bodyPart; |
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| 180 | } |
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| 181 | |
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| 182 | } |
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