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Java > Open Source Codes > org > apache > geronimo > system > configuration > SieveEncodingInfo


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 /*
19  * This code has been borrowed from the Apache Xerces project. We're copying the code to
20  * keep from adding a dependency on Xerces in the Geronimo kernel.
21  */
22 package org.apache.geronimo.system.configuration;
23
24 import java.io.ByteArrayOutputStream JavaDoc;
25 import java.io.IOException JavaDoc;
26 import java.io.OutputStreamWriter JavaDoc;
27 import java.io.Writer JavaDoc;
28
29 /**
30  * This class represents an encoding.
31  *
32  * @version $Id: SieveEncodingInfo.java 476049 2006-11-17 04:35:17Z kevan $
33  */
34 public class SieveEncodingInfo extends EncodingInfo {
35
36     BAOutputStream checkerStream = null;
37     Writer JavaDoc checkerWriter = null;
38     String JavaDoc dangerChars = null;
39
40     /**
41      * Creates new <code>SeiveEncodingInfo</code> instance.
42      *
43      * @param dangers A sorted characters that are always printed as character references.
44      */
45     public SieveEncodingInfo(String JavaDoc mimeName, String JavaDoc javaName,
46                              int lastPrintable, String JavaDoc dangers) {
47         super(mimeName, javaName, lastPrintable);
48         this.dangerChars = dangers;
49     }
50
51     /**
52      * Creates new <code>SeiveEncodingInfo</code> instance.
53      */
54     public SieveEncodingInfo(String JavaDoc mimeName, int lastPrintable) {
55         this(mimeName, mimeName, lastPrintable, null);
56     }
57
58     /**
59      * Checks whether the specified character is printable or not.
60      *
61      * @param ch a code point (0-0x10ffff)
62      */
63     public boolean isPrintable(int ch) {
64         if (this.dangerChars != null && ch <= 0xffff) {
65             /**
66              * Searches this.dangerChars for ch.
67              * TODO: Use binary search.
68              */
69             if (this.dangerChars.indexOf(ch) >= 0)
70                 return false;
71         }
72
73         if (ch <= this.lastPrintable)
74             return true;
75
76         boolean printable = true;
77         synchronized (this) {
78             try {
79                 if (this.checkerWriter == null) {
80                     this.checkerStream = new BAOutputStream(10);
81                     this.checkerWriter = new OutputStreamWriter JavaDoc(this.checkerStream, this.javaName);
82                 }
83
84                 if (ch > 0xffff) {
85                     this.checkerWriter.write(((ch-0x10000)>>10)+0xd800);
86                     this.checkerWriter.write(((ch-0x10000)&0x3ff)+0xdc00);
87                     byte[] result = this.checkerStream.getBuffer();
88                     if (this.checkerStream.size() == 2 && result[0] == '?' && result[1] == '?')
89                         printable = false;
90                 } else {
91                     this.checkerWriter.write(ch);
92                     this.checkerWriter.flush();
93                     byte[] result = this.checkerStream.getBuffer();
94                     if (this.checkerStream.size() == 1 && result[0] == '?')
95                         printable = false;
96                 }
97                 this.checkerStream.reset();
98             } catch (IOException JavaDoc ioe) {
99                 printable = false;
100             }
101         }
102
103         return printable;
104     }
105
106     /**
107      * Why don't we use the original ByteArrayOutputStream?
108      * - Because the toByteArray() method of the ByteArrayOutputStream
109      * creates new byte[] instances for each call.
110      */
111     static class BAOutputStream extends ByteArrayOutputStream JavaDoc {
112         BAOutputStream() {
113             super();
114         }
115
116         BAOutputStream(int size) {
117             super(size);
118         }
119
120         byte[] getBuffer() {
121             return this.buf;
122         }
123     }
124
125 }
126
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