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- package javassist.tools;
-
- import javassist.CannotCompileException;
- import javassist.CtBehavior;
-
- import java.util.HashMap;
- import java.util.UUID;
-
- /**
- * Creates bytecode that when executed calls back to the instance's result method.
- *
- * Inserts callbacks in <code>CtBehaviour</code>
- *
- */
- public abstract class Callback {
-
- public static HashMap<String, Callback> callbacks = new HashMap<String, Callback>();
-
- private final String sourceCode;
-
- /**
- * Constructs a new <code>Callback</code> object.
- *
- * @param src The source code representing the inserted callback bytecode.
- * Can be one or many single statements or blocks each returning one object.
- * If many single statements or blocks are used they must be comma separated.
- */
- public Callback(String src){
- String uuid = UUID.randomUUID().toString();
- callbacks.put(uuid, this);
- sourceCode = "((javassist.tools.Callback) javassist.tools.Callback.callbacks.get(\""+uuid+"\")).result(new Object[]{"+src+"});";
- }
-
- /**
- * Gets called when bytecode is executed
- *
- * @param objects Objects that the bytecode in callback returns
- */
- public abstract void result(Object... objects);
-
- @Override
- public String toString(){
- return sourceCode();
- }
-
- public String sourceCode(){
- return sourceCode;
- }
-
- /**
- * Inserts callback at the beginning of the body.
- *
- * @param callback The callback
- *
- * @see CtBehavior#insertBefore(String)
- */
- public static void insertBefore(CtBehavior behavior, Callback callback)
- throws CannotCompileException
- {
- behavior.insertBefore(callback.toString());
- }
-
- /**
- * Inserts callback at the end of the body.
- * The callback is inserted just before every return instruction.
- * It is not executed when an exception is thrown.
- *
- * @param behavior The behaviour to insert callback in
- * @param callback The callback
- *
- * @see CtBehavior#insertAfter(String, boolean)
- */
- public static void insertAfter(CtBehavior behavior,Callback callback)
- throws CannotCompileException
- {
- behavior.insertAfter(callback.toString(), false);
- }
-
- /**
- * Inserts callback at the end of the body.
- * The callback is inserted just before every return instruction.
- * It is not executed when an exception is thrown.
- *
- * @param behavior The behaviour to insert callback in
- * @param callback The callback representing the inserted.
- * @param asFinally True if the inserted is executed
- * Not only when the control normally returns
- * but also when an exception is thrown.
- * If this parameter is true, the inserted code cannot
- * access local variables.
- *
- * @see CtBehavior#insertAfter(String, boolean)
- */
- public static void insertAfter(CtBehavior behavior, Callback callback, boolean asFinally)
- throws CannotCompileException
- {
- behavior.insertAfter(callback.toString(), asFinally);
- }
-
- /**
- * Inserts callback at the specified line in the body.
- *
- * @param behavior The behaviour to insert callback in
- * @param callback The callback representing.
- * @param lineNum The line number. The callback is inserted at the
- * beginning of the code at the line specified by this
- * line number.
- *
- * @return The line number at which the callback has been inserted.
- *
- * @see CtBehavior#insertAt(int, String)
- */
- public static int insertAt(CtBehavior behavior, Callback callback, int lineNum)
- throws CannotCompileException
- {
- return behavior.insertAt(lineNum, callback.toString());
- }
- }
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