public class HotSwapper extends Object
Note: The new definition of the reloaded class must declare the same set of methods and fields as the original definition. The schema change between the original and new definitions is not allowed by the JPDA.
To use this class, the JVM must be launched with the following command line options:
For Java 1.4,
java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000
For Java 5,
java -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=8000
Note that 8000 is the port number used by HotSwapper.
Any port number can be specified. Since HotSwapper does not
launch another JVM for running a target application, this port number
is used only for inter-thread communication.
Furthermore, JAVA_HOME/lib/tools.jar must be included
in the class path.
Using HotSwapper is easy. See the following example:
CtClass clazz = ...
byte[] classFile = clazz.toBytecode();
HotSwapper hs = new HostSwapper(8000); // 8000 is a port number.
hs.reload("Test", classFile);
reload()
first unload the Test class and load a new version of
the Test class.
classFile is a byte array containing the new contents of
the class file for the Test class. The developers can
repatedly call reload() on the same HotSwapper
object so that they can reload a number of classes.
| Constructor and Description |
|---|
HotSwapper(int port)
Connects to the JVM.
|
HotSwapper(String port)
Connects to the JVM.
|
| Modifier and Type | Method and Description |
|---|---|
void |
reload(Map classFiles)
Reloads a class.
|
void |
reload(String className,
byte[] classFile)
Reloads a class.
|
public HotSwapper(int port)
throws IOException,
com.sun.jdi.connect.IllegalConnectorArgumentsException
port - the port number used for the connection to the JVM.IOExceptioncom.sun.jdi.connect.IllegalConnectorArgumentsExceptionpublic HotSwapper(String port) throws IOException, com.sun.jdi.connect.IllegalConnectorArgumentsException
port - the port number used for the connection to the JVM.IOExceptioncom.sun.jdi.connect.IllegalConnectorArgumentsExceptionpublic void reload(String className, byte[] classFile)
className - the fully-qualified class name.classFile - the contents of the class file.public void reload(Map classFiles)
classFiles - a map between fully-qualified class names
and class files. The type of the class names
is String and the type of the
class files is byte[].Copyright © 2016 Shigeru Chiba, www.javassist.org. All Rights Reserved.