jadex.bytecode.vmhacks

Class VmHacks.Unsafe

java.lang.Object

jadex.bytecode.vmhacks.VmHacks.Unsafe

Enclosing class:

VmHacks

public static final class VmHacks.Unsafe
extends java.lang.Object

Access to unsafe operations.

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.io.File	TEMP_JAR_DIR Directory for temporary jar files.

Method Summary

Modifier and Type	Method and Description
void	appendToBootstrapClassLoaderSearch(java.lang.String classname, byte[] classcontent) Appends a new class to the bootstrap classloader.
void	appendToBootstrapClassLoaderSearch(java.lang.String classname, java.io.InputStream classcontent) Appends a new class to the bootstrap classloader.
java.lang.Class<?>	defineClass(java.lang.String name, byte[] b, int off, int len, java.lang.ClassLoader loader, java.security.ProtectionDomain pd) Access to sun.misc.Unsafe or equivalent.
boolean	hasAsm() Tests if ASM is available.
boolean	hasIndirectRedefinition() Checks if redefineClassIndirect() is available.
boolean	hasInstrumentation() Checks if instrumentation is available.
boolean	hasNative() Tests if native access is available.
protected void	init() Initialization step after constructor to allow bootstrapping.
void	redefineClass(java.lang.Class<?> clazz, byte[] bytecode) Redefine class byte code.
java.lang.Class<?>	redefineClassIndirect(java.lang.Class<?> clazz, byte[] bytecode) Redefine class byte code.
protected void	runInstrumentationCommand(VmHacks.InstrumentationCommand command) Run an instrumentation command
void	setAccessible(java.lang.reflect.AccessibleObject accobj, boolean flag) Sets reflective object accessible without checks if native support is available.
java.lang.String	toString() Debug message.
boolean	tryChangeUser(java.lang.String username) Attempts to change the user of the process to the given name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

TEMP_JAR_DIR

protected static final java.io.File TEMP_JAR_DIR

Directory for temporary jar files.

Method Detail

hasAsm

public boolean hasAsm()

Tests if ASM is available.

Returns:

True, if ASM is available.

hasNative

public boolean hasNative()

Tests if native access is available.

Returns:

True, if native access is available.

hasInstrumentation

public boolean hasInstrumentation()

Checks if instrumentation is available.

Returns:

True, if instrumentation is available.

hasIndirectRedefinition

public boolean hasIndirectRedefinition()

Checks if redefineClassIndirect() is available.

Returns:

True, if indirect redefinition is available.

tryChangeUser

public boolean tryChangeUser(java.lang.String username)

Attempts to change the user of the process to the given name. If set to null, a list of default user accounts is tried.

Parameters:

username - The target user name, set to null for a list of default user account.

Returns:

True, if successful, false if the attempt probably failed.

setAccessible

public void setAccessible(java.lang.reflect.AccessibleObject accobj,
                          boolean flag)

Sets reflective object accessible without checks if native support is available.

Parameters:

accobj - The accessible object.

flag - The flag value.

defineClass

public java.lang.Class<?> defineClass(java.lang.String name,
                                      byte[] b,
                                      int off,
                                      int len,
                                      java.lang.ClassLoader loader,
                                      java.security.ProtectionDomain pd)

Access to sun.misc.Unsafe or equivalent.

redefineClassIndirect

public java.lang.Class<?> redefineClassIndirect(java.lang.Class<?> clazz,
                                                byte[] bytecode)

Redefine class byte code. Check HAS_INSTRUMENTATION before use. Uses indirect route via classloader enhancement, more likely to work.

Parameters:

clazz - Class to be redefined.

bytecode - The new byte code.

Returns:

Redefined class.

redefineClass

public void redefineClass(java.lang.Class<?> clazz,
                          byte[] bytecode)

Redefine class byte code. Check HAS_INSTRUMENTATION before use.

Parameters:

clazz - Class to be redefined.

bytecode - The new byte code.

appendToBootstrapClassLoaderSearch

public void appendToBootstrapClassLoaderSearch(java.lang.String classname,
                                               byte[] classcontent)

Appends a new class to the bootstrap classloader.

Parameters:

classname - The class name.

classcontent - The bytecode.

appendToBootstrapClassLoaderSearch

public void appendToBootstrapClassLoaderSearch(java.lang.String classname,
                                               java.io.InputStream classcontent)

Appends a new class to the bootstrap classloader.

Parameters:

classname - The class name.

classcontent - The bytecode.

toString

public java.lang.String toString()

Debug message.

Overrides:

toString in class java.lang.Object

init

protected void init()

Initialization step after constructor to allow bootstrapping.

runInstrumentationCommand

protected void runInstrumentationCommand(VmHacks.InstrumentationCommand command)

Run an instrumentation command