001 /* CipherOutputStream.java -- Filters output through a cipher. 002 Copyright (C) 2004 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package javax.crypto; 040 041 import java.io.FilterOutputStream; 042 import java.io.IOException; 043 import java.io.OutputStream; 044 045 /** 046 * A filtered output stream that transforms data written to it with a 047 * {@link Cipher} before sending it to the underlying output stream. 048 * 049 * @author Casey Marshall (csm@gnu.org) 050 */ 051 public class CipherOutputStream extends FilterOutputStream 052 { 053 /** The underlying cipher. */ 054 private Cipher cipher; 055 056 /** 057 * Create a new cipher output stream. The cipher argument must have already 058 * been initialized. 059 * 060 * @param out The sink for transformed data. 061 * @param cipher The cipher to transform data with. 062 */ 063 public CipherOutputStream(OutputStream out, Cipher cipher) 064 { 065 super(out); 066 this.cipher = (cipher != null) ? cipher : new NullCipher(); 067 } 068 069 /** 070 * Create a cipher output stream with no cipher. 071 * 072 * @param out The sink for transformed data. 073 */ 074 protected CipherOutputStream(OutputStream out) 075 { 076 super(out); 077 } 078 079 /** 080 * Close this output stream, and the sink output stream. 081 * <p> 082 * This method will first invoke the {@link Cipher#doFinal()} method of the 083 * underlying {@link Cipher}, and writes the output of that method to the 084 * sink output stream. 085 * 086 * @throws IOException If an I/O error occurs, or if an error is caused by 087 * finalizing the transformation. 088 */ 089 public void close() throws IOException 090 { 091 try 092 { 093 out.write(cipher.doFinal()); 094 out.flush(); 095 out.close(); 096 } 097 catch (Exception cause) 098 { 099 IOException ioex = new IOException(String.valueOf(cause)); 100 ioex.initCause(cause); 101 throw ioex; 102 } 103 } 104 105 /** 106 * Flush any pending output. 107 * 108 * @throws IOException If an I/O error occurs. 109 */ 110 public void flush() throws IOException 111 { 112 out.flush(); 113 } 114 115 /** 116 * Write a single byte to the output stream. 117 * 118 * @param b The next byte. 119 * @throws IOException If an I/O error occurs, or if the underlying cipher is 120 * not in the correct state to transform data. 121 */ 122 public void write(int b) throws IOException 123 { 124 write(new byte[] { (byte) b }, 0, 1); 125 } 126 127 /** 128 * Write a byte array to the output stream. 129 * 130 * @param buf The next bytes. 131 * @throws IOException If an I/O error occurs, or if the underlying cipher is 132 * not in the correct state to transform data. 133 */ 134 public void write(byte[] buf) throws IOException 135 { 136 write(buf, 0, buf.length); 137 } 138 139 /** 140 * Write a portion of a byte array to the output stream. 141 * 142 * @param buf The next bytes. 143 * @param off The offset in the byte array to start. 144 * @param len The number of bytes to write. 145 * @throws IOException If an I/O error occurs, or if the underlying cipher is 146 * not in the correct state to transform data. 147 */ 148 public void write(byte[] buf, int off, int len) throws IOException 149 { 150 byte[] b = cipher.update(buf, off, len); 151 if (b != null) 152 out.write(b); 153 } 154 }