1 package org.codehaus.plexus.languages.java.version;
2
3 import java.io.IOException;
4 import java.io.UncheckedIOException;
5 import java.nio.file.Files;
6 import java.nio.file.Path;
7
8 /*
9 * Licensed to the Apache Software Foundation (ASF) under one
10 * or more contributor license agreements. See the NOTICE file
11 * distributed with this work for additional information
12 * regarding copyright ownership. The ASF licenses this file
13 * to you under the Apache License, Version 2.0 (the
14 * "License"); you may not use this file except in compliance
15 * with the License. You may obtain a copy of the License at
16 *
17 * http://www.apache.org/licenses/LICENSE-2.0
18 *
19 * Unless required by applicable law or agreed to in writing,
20 * software distributed under the License is distributed on an
21 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
22 * KIND, either express or implied. See the License for the
23 * specific language governing permissions and limitations
24 * under the License.
25 */
26
27 /**
28 * Reads the bytecode of a Java class to detect the major, minor and Java
29 * version that was compiled.
30 *
31 * @author Jorge Solórzano
32 */
33 public final class JavaClassfileVersion {
34
35 private final int major;
36 private final int minor;
37
38 JavaClassfileVersion(int major, int minor) {
39 if (major < 45) {
40 throw new IllegalArgumentException("Java class major version must be 45 or above.");
41 }
42 this.major = major;
43 this.minor = minor;
44 }
45
46 /**
47 * Reads the bytecode of a Java class file and returns the
48 * {@link JavaClassfileVersion}.
49 *
50 * @param bytes {@code byte[]} of the Java class file
51 * @return the {@link JavaClassfileVersion} of the byte array
52 */
53 public static JavaClassfileVersion of(byte[] bytes) {
54 return JavaClassfileVersionParser.of(bytes);
55 }
56
57 /**
58 * Reads the bytecode of a Java class file and returns the
59 * {@link JavaClassfileVersion}.
60 *
61 * @param path {@link Path} of the Java class file
62 * @return the {@link JavaClassfileVersion} of the path java class
63 */
64 public static JavaClassfileVersion of(Path path) {
65 try {
66 byte[] readAllBytes = Files.readAllBytes(path);
67 return of(readAllBytes);
68 } catch (IOException ex) {
69 throw new UncheckedIOException(ex);
70 }
71 }
72
73 /**
74 * JavaVersion of the class file version detected.
75 *
76 * @return JavaVersion based on the major version of the class file.
77 */
78 public JavaVersion javaVersion() {
79 int javaVer = major - 44;
80 String javaVersion = javaVer < 9 ? "1." + javaVer : Integer.toString(javaVer);
81
82 return JavaVersion.parse(javaVersion);
83 }
84
85 /**
86 * Returns the major version of the parsed classfile.
87 *
88 * @return the major classfile version
89 */
90 public int majorVersion() {
91 return major;
92 }
93
94 /**
95 * Returns the minor version of the parsed classfile.
96 *
97 * @return the minor classfile version
98 */
99 public int minorVersion() {
100 return minor;
101 }
102
103 /**
104 * Returns if the classfile use preview features.
105 *
106 * @return {@code true} if the classfile use preview features.
107 */
108 public boolean isPreview() {
109 return minor == 65535;
110 }
111
112 /**
113 * Returns a String representation of the Java class file version, e.g.
114 * {@code 65.0 (Java 21)}.
115 *
116 * @return String representation of the Java class file version
117 */
118 @Override
119 public String toString() {
120 return major + "." + minor + " (Java " + javaVersion() + ")";
121 }
122
123 @Override
124 public int hashCode() {
125 final int prime = 31;
126 int result = 1;
127 result = prime * result + major;
128 result = prime * result + minor;
129 return result;
130 }
131
132 @Override
133 public boolean equals(Object obj) {
134 if (this == obj) return true;
135 if (!(obj instanceof JavaClassfileVersion)) return false;
136 JavaClassfileVersion other = (JavaClassfileVersion) obj;
137 if (major != other.major) return false;
138 if (minor != other.minor) return false;
139 return true;
140 }
141 }