Class ExprEditor
- java.lang.Object
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- javassist.expr.ExprEditor
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public class ExprEditor extends java.lang.Object
A translator of method bodies.The users can define a subclass of this class to customize how to modify a method body. The overall architecture is similar to the strategy pattern.
If
instrument()
is called inCtMethod
, the method body is scanned from the beginning to the end. Whenever an expression, such as a method call and anew
expression (object creation), is found,edit()
is called inExprEdit
.edit()
can inspect and modify the given expression. The modification is reflected on the original method body. Ifedit()
does nothing, the original method body is not changed.The following code is an example:
CtMethod cm = ...; cm.instrument(new ExprEditor() { public void edit(MethodCall m) throws CannotCompileException { if (m.getClassName().equals("Point")) { System.out.println(m.getMethodName() + " line: " + m.getLineNumber()); } });
This code inspects all method calls appearing in the method represented by
cm
and it prints the names and the line numbers of the methods declared in classPoint
. This code does not modify the body of the method represented bycm
. If the method body must be modified, callreplace()
inMethodCall
.
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Constructor Summary
Constructors Constructor Description ExprEditor()
Default constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
doit(CtClass clazz, MethodInfo minfo)
Undocumented method.void
edit(Cast c)
Edits an expression for explicit type casting (overridable).void
edit(ConstructorCall c)
Edits a constructor call (overridable).void
edit(FieldAccess f)
Edits a field-access expression (overridable).void
edit(Handler h)
Edits a catch clause (overridable).void
edit(Instanceof i)
Edits an instanceof expression (overridable).void
edit(MethodCall m)
Edits a method call (overridable).void
edit(NewArray a)
Edits an expression for array creation (overridable).void
edit(NewExpr e)
Edits anew
expression (overridable).
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Method Detail
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doit
public boolean doit(CtClass clazz, MethodInfo minfo) throws CannotCompileException
Undocumented method. Do not use; internal-use only.- Throws:
CannotCompileException
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edit
public void edit(NewExpr e) throws CannotCompileException
Edits anew
expression (overridable). The default implementation performs nothing.- Parameters:
e
- thenew
expression creating an object.- Throws:
CannotCompileException
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edit
public void edit(NewArray a) throws CannotCompileException
Edits an expression for array creation (overridable). The default implementation performs nothing.- Parameters:
a
- thenew
expression for creating an array.- Throws:
CannotCompileException
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edit
public void edit(MethodCall m) throws CannotCompileException
Edits a method call (overridable). The default implementation performs nothing.- Throws:
CannotCompileException
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edit
public void edit(ConstructorCall c) throws CannotCompileException
Edits a constructor call (overridable). The constructor call is eithersuper()
orthis()
included in a constructor body. The default implementation performs nothing.- Throws:
CannotCompileException
- See Also:
edit(NewExpr)
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edit
public void edit(FieldAccess f) throws CannotCompileException
Edits a field-access expression (overridable). Field access means both read and write. The default implementation performs nothing.- Throws:
CannotCompileException
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edit
public void edit(Instanceof i) throws CannotCompileException
Edits an instanceof expression (overridable). The default implementation performs nothing.- Throws:
CannotCompileException
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edit
public void edit(Cast c) throws CannotCompileException
Edits an expression for explicit type casting (overridable). The default implementation performs nothing.- Throws:
CannotCompileException
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edit
public void edit(Handler h) throws CannotCompileException
Edits a catch clause (overridable). The default implementation performs nothing.- Throws:
CannotCompileException
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