PackCompressor


1   /*
2    * $Id: PackCompressor.java 1708 2007-01-13 18:31:26Z jponge $
3    * IzPack - Copyright 2001-2007 Julien Ponge, All Rights Reserved.
4    * 
5    * http://www.izforge.com/izpack/
6    * http://developer.berlios.de/projects/izpack/
7    * 
8    * Copyright 2005 Klaus Bartz
9    *
10   * Licensed under the Apache License, Version 2.0 (the "License");
11   * you may not use this file except in compliance with the License.
12   * You may obtain a copy of the License at
13   * 
14   *     http://www.apache.org/licenses/LICENSE-2.0
15   *     
16   * Unless required by applicable law or agreed to in writing, software
17   * distributed under the License is distributed on an "AS IS" BASIS,
18   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19   * See the License for the specific language governing permissions and
20   * limitations under the License.
21   */
22  package com.izforge.izpack.compressor;
23  
24  import java.io.OutputStream  ;
25  
26  import com.izforge.izpack.compiler.Compiler;
27  
28  
29  /**
30   * IzPack will be able to support different compression methods for the
31   * packs included in the installation jar file.
32   * This interface declares the handler of one compression format.
33   * 
34   * @author Klaus Bartz
35   */
36  
37  public interface PackCompressor
38  {
39  
40      /**
41       * Returns a newly created output stream which write method
42       * writes the given input encoded to the defined output stream.
43       * Attention! This method will be returned a valid output stream
44       * only if it is used in the IzPack compiler, or if this pack compressor
45       * needs no external classes. A call in the
46       * installation should be throw if external classes are used.
47       * The implementation should load the needed classes via reflection
48       * because classes are not present in the installation.
49       * @param os output stream to be used as listener
50       * @return a newly created encoding output stream 
51       * @throws Exception
52       */
53      OutputStream   getOutputStream(OutputStream   os) throws Exception  ;
54      
55      /**
56       * Returns all symbolic names which are used for this compressor.
57       * @return all symbolic names which are used for this compressor
58       */
59      String   []getCompressionFormatSymbols();
60      
61      /**
62       * Returns the path where the compiler can find the classes;
63       * normaly this is a path to a jar file.
64       * If no additional classes are needed, this method should return null.
65       * @return the path where the compiler can find the classes
66       */
67      String  [] getContainerPaths();
68      
69      /**
70       * Returns the qualified names of all needed classes for decoding.
71       * All class files should be placed in the container which will
72       * be referred by the method getContainerPath.
73       * If no additional classes are needed, this method should return null.
74       * @return qualified names of all needed classes for decoding
75       */
76      String  [][] getDecoderClassNames();
77   
78      /**
79       * Returns the qualified name of the encoding output stream.
80       * The class file should be placed in the container which will
81       * be referred by the method getContainerPath.
82       * @return qualified name of the encoding output stream
83       */
84      String   getEncoderClassName();
85   
86      /**
87       * Returns the qualified name of the class which should be used
88       * as InputStream in the installer. This class mapps the "real"
89       * decoder or - if useable - the decoder name will be returned self.
90       * If useStandardCompression is true, this method returns null.
91       * @return the qualified name of the class which should be used
92       * as InputStream in the installer
93       */
94      String   getDecoderMapperName();
95      /**
96       * Returns whether the standard comression should be used with
97       * this pack compressor or not. If this method returns true,
98       * the returns values of the methods getContainerPath and 
99       * getDecoderClassNames are not valid (should be null).
100      * @return whether the standard comression should be used or not
101      */
102     boolean useStandardCompression();
103 
104     /**
105      * Receives the current used compiler.
106      * Needed at loading encoder classes and error handling.
107      * @param compiler current active compiler
108      */
109     void setCompiler(Compiler   compiler);
110     
111     /**
112      * Returns whether a buffered output stream should be used
113      * intermediate between the output stream of this compressor
114      * and the destination.
115      * @return wether a buffered output stream should be used
116      * intermediate between the output stream of this compressor
117      * and the destination.
118      */
119     boolean needsBufferedOutputStream();
120     
121     /**
122      * Receives the compression level to be used.
123      * @param level compression level to be used
124      */
125     void setCompressionLevel(int level);
126     
127     /**
128      * Returns the compression level to be used.
129      * @return the compression level to be used
130      */
131     int getCompressionLevel();
132     
133     
134     
135 }
136
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