com.fitbur.bytebuddy.ClassFileVersion Maven / Gradle / Ivy
package com.fitbur.bytebuddy;
import com.fitbur.bytebuddy.jar.asm.Opcodes;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* A wrapper object for representing a validated class file version in the format that is specified by the
* JVMS.
*/
public class ClassFileVersion implements Comparable {
/**
* Returns the minimal version number that is legal.
*/
protected static final int BASE_VERSION = 44;
/**
* The class file version of Java 1.
*/
public static final ClassFileVersion JAVA_V1 = new ClassFileVersion(Opcodes.V1_1);
/**
* The class file version of Java 2.
*/
public static final ClassFileVersion JAVA_V2 = new ClassFileVersion(Opcodes.V1_2);
/**
* The class file version of Java 3.
*/
public static final ClassFileVersion JAVA_V3 = new ClassFileVersion(Opcodes.V1_3);
/**
* The class file version of Java 4.
*/
public static final ClassFileVersion JAVA_V4 = new ClassFileVersion(Opcodes.V1_4);
/**
* The class file version of Java 5.
*/
public static final ClassFileVersion JAVA_V5 = new ClassFileVersion(Opcodes.V1_5);
/**
* The class file version of Java 6.
*/
public static final ClassFileVersion JAVA_V6 = new ClassFileVersion(Opcodes.V1_6);
/**
* The class file version of Java 7.
*/
public static final ClassFileVersion JAVA_V7 = new ClassFileVersion(Opcodes.V1_7);
/**
* The class file version of Java 8.
*/
public static final ClassFileVersion JAVA_V8 = new ClassFileVersion(Opcodes.V1_8);
/**
* The class file version of Java 9.
*/
public static final ClassFileVersion JAVA_V9 = JAVA_V8;
/**
* The version number that is represented by this class file version instance.
*/
private final int versionNumber;
/**
* Creates a wrapper for a given minor-major release of the Java class file file.
*
* @param versionNumber The minor-major release number.
*/
protected ClassFileVersion(int versionNumber) {
this.versionNumber = versionNumber;
}
/**
* Creates a wrapper for a given minor-major release of the Java class file file.
*
* @param versionNumber The minor-major release number.
* @return A representation of the version number.
*/
public static ClassFileVersion ofMinorMajor(int versionNumber) {
ClassFileVersion classFileVersion = new ClassFileVersion(versionNumber);
if (classFileVersion.getMajorVersion() <= BASE_VERSION) {
throw new IllegalArgumentException("Class version " + versionNumber + " is not valid");
}
return classFileVersion;
}
/**
* Creates a class file version for a given major release of Java. Currently, all versions reaching from
* Java 1 to Java 8 are supported.
*
* @param javaVersion The Java version.
* @return A wrapper for the given Java class file version.
*/
public static ClassFileVersion ofJavaVersion(int javaVersion) {
switch (javaVersion) {
case 1:
return JAVA_V1;
case 2:
return JAVA_V2;
case 3:
return JAVA_V3;
case 4:
return JAVA_V4;
case 5:
return JAVA_V5;
case 6:
return JAVA_V6;
case 7:
return JAVA_V7;
case 8:
return JAVA_V8;
case 9:
return JAVA_V9;
default:
throw new IllegalArgumentException("Unknown Java version: " + javaVersion);
}
}
/**
* Finds the highest class file version that is compatible to the current JVM version by parsing the java.version
* property which is provided by {@link java.lang.System#getProperty(String)}.
*
* @return The currently running Java process's class file version.
*/
public static ClassFileVersion forCurrentJavaVersion() {
String versionString = AccessController.doPrivileged(VersionPropertyAction.INSTANCE);
int[] versionIndex = {-1, 0, 0};
for (int i = 1; i < 3; i++) {
versionIndex[i] = versionString.indexOf('.', versionIndex[i - 1] + 1);
if (versionIndex[i] == -1) {
throw new IllegalStateException("This JVM's version string does not seem to be valid: " + versionString);
}
}
return ClassFileVersion.ofJavaVersion(Integer.parseInt(versionString.substring(versionIndex[1] + 1, versionIndex[2])));
}
/**
* Returns the minor-major release number of this class file version.
*
* @return The minor-major release number of this class file version.
*/
public int getMinorMajorVersion() {
return versionNumber;
}
/**
* Returns the major version this instance represents.
*
* @return The major version this instance represents.
*/
public int getMajorVersion() {
return versionNumber & 0xFF;
}
/**
* Returns the minor version this instance represents.
*
* @return The minor version this instance represents.
*/
public int getMinorVersion() {
return versionNumber >> 16;
}
/**
* Returns the Java runtime version number of this class file version.
*
* @return The Java runtime version.
*/
public int getJavaVersion() {
return getMajorVersion() - BASE_VERSION;
}
/**
* Checks if this class file version is at least of the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is at least of the given version.
*/
public boolean isAtLeast(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) > -1;
}
/**
* Checks if this class file version is less than the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is less than the given version.
*/
public boolean isLessThan(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) < 0;
}
@Override
public int compareTo(ClassFileVersion other) {
return Integer.signum(getMajorVersion() == other.getMajorVersion()
? getMinorVersion() - other.getMinorVersion()
: getMajorVersion() - other.getMajorVersion());
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& versionNumber == ((ClassFileVersion) other).versionNumber;
}
@Override
public int hashCode() {
return versionNumber;
}
@Override
public String toString() {
return "ClassFileVersion{versionNumber=" + versionNumber + '}';
}
/**
* A privileged action for reading the {@code java.version} property.
*/
protected enum VersionPropertyAction implements PrivilegedAction {
/**
* The singleton instance.
*/
INSTANCE;
/**
* The system property for this JVM's Java version.
*/
private static final String JAVA_VERSION_PROPERTY = "java.version";
@Override
public String run() {
return System.getProperty(JAVA_VERSION_PROPERTY);
}
@Override
public String toString() {
return "ClassFileVersion.VersionPropertyAction." + name();
}
}
}