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 package org.apache.commons.compress.archivers.sevenz;
18
19 import java.io.IOException;
20 import java.io.InputStream;
21 import java.io.OutputStream;
22 import java.util.Objects;
23 import java.util.stream.Stream;
24
25 import org.apache.commons.compress.utils.ByteUtils;
26
27 /**
28 * Abstracts a base Codec class.
29 */
30 abstract class AbstractCoder {
31
32 /**
33 * If the option represents a number, return its integer value, otherwise return the given default value.
34 *
35 * @param options A Number.
36 * @param defaultValue A default value if options is not a number.
37 * @return The given number or default value.
38 */
39 protected static int toInt(final Object options, final int defaultValue) {
40 return options instanceof Number ? ((Number) options).intValue() : defaultValue;
41 }
42
43 private final Class<?>[] optionClasses;
44
45 /**
46 * Constructs a new instance.
47 *
48 * @param optionClasses types that can be used as options for this codec.
49 */
50 protected AbstractCoder(final Class<?>... optionClasses) {
51 this.optionClasses = Objects.requireNonNull(optionClasses, "optionClasses");
52 }
53
54 /**
55 * Decodes using stream that reads from in using the configured coder and password.
56 *
57 * @return a stream that reads from in using the configured coder and password.
58 */
59 abstract InputStream decode(String archiveName, InputStream in, long uncompressedLength, Coder coder, byte[] password, int maxMemoryLimitInKb)
60 throws IOException;
61
62 /**
63 * Encodes using a stream that writes to out using the given configuration.
64 *
65 * @return a stream that writes to out using the given configuration.
66 * @throws IOException Optionally thrown by subclassses.
67 */
68 OutputStream encode(final OutputStream out, final Object options) throws IOException {
69 throw new UnsupportedOperationException("Method doesn't support writing");
70 }
71
72 /**
73 * Gets property bytes to write in a Folder block.
74 *
75 * @return property bytes to write in a Folder block.
76 * @throws IOException Optionally thrown by subclassses.
77 */
78 byte[] getOptionsAsProperties(final Object options) throws IOException {
79 return ByteUtils.EMPTY_BYTE_ARRAY;
80 }
81
82 /**
83 * Gets configuration options that have been used to create the given InputStream from the given Coder.
84 *
85 * @return configuration options that have been used to create the given InputStream from the given Coder
86 * @throws IOException Optionally thrown by subclassses.
87 */
88 Object getOptionsFromCoder(final Coder coder, final InputStream in) throws IOException {
89 return null;
90 }
91
92 /**
93 * Tests whether this method can extract options from the given object.
94 *
95 * @return whether this method can extract options from the given object.
96 */
97 boolean isOptionInstance(final Object opts) {
98 return Stream.of(optionClasses).anyMatch(c -> c.isInstance(opts));
99 }
100 }