DERSequence


1   /**
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  
18  package org.apache.geronimo.util.asn1;
19  
20  import java.io.ByteArrayOutputStream  ;
21  import java.io.IOException  ;
22  import java.util.Enumeration  ;
23  
24  public class DERSequence
25      extends ASN1Sequence
26  {
27      /**
28       * create an empty sequence
29       */
30      public DERSequence()
31      {
32      }
33  
34      /**
35       * create a sequence containing one object
36       */
37      public DERSequence(
38          DEREncodable    obj)
39      {
40          this.addObject(obj);
41      }
42  
43      /**
44       * create a sequence containing a vector of objects.
45       */
46      public DERSequence(
47          DEREncodableVector   v)
48      {
49          for (int i = 0; i != v.size(); i++)
50          {
51              this.addObject(v.get(i));
52          }
53      }
54  
55      /**
56       * create a sequence containing an array of objects.
57       */
58      public DERSequence(
59          ASN1Encodable[]   a)
60      {
61          for (int i = 0; i != a.length; i++)
62          {
63              this.addObject(a[i]);
64          }
65      }
66  
67      /*
68       * A note on the implementation:
69       * <p>
70       * As DER requires the constructed, definite-length model to
71       * be used for structured types, this varies slightly from the
72       * ASN.1 descriptions given. Rather than just outputing SEQUENCE,
73       * we also have to specify CONSTRUCTED, and the objects length.
74       */
75      void encode(
76          DEROutputStream out)
77          throws IOException  
78      {
79          ByteArrayOutputStream     bOut = new ByteArrayOutputStream  ();
80          DEROutputStream         dOut = new DEROutputStream(bOut);
81          Enumeration               e = this.getObjects();
82  
83          while (e.hasMoreElements())
84          {
85              Object      obj = e.nextElement();
86  
87              dOut.writeObject(obj);
88          }
89  
90          dOut.close();
91  
92          byte[]  bytes = bOut.toByteArray();
93  
94          out.writeEncoded(SEQUENCE | CONSTRUCTED, bytes);
95      }
96  }
97
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