MethodInfo (Javassist API)

java.lang.Object
- javassist.bytecode.MethodInfo

public class MethodInfo
extends java.lang.Object

method_info structure.

The bytecode sequence of the method is represented by a CodeAttribute object.

The following code adds the default constructor to a class: of int type:

 ClassFile cf = ...
 Bytecode code = new Bytecode(cf.getConstPool());
 code.addAload(0);
 code.addInvokespecial("java/lang/Object", MethodInfo.nameInit, "()V");
 code.addReturn(null);
 code.setMaxLocals(1);

 MethodInfo minfo = new MethodInfo(cf.getConstPool(), MethodInfo.nameInit, "()V");
 minfo.setCodeAttribute(code.toCodeAttribute());
 cf.addMethod(minfo);

See Also:: getCodeAttribute(), CodeAttribute, Bytecode, CtBehavior.getMethodInfo(), CtBehavior.getMethodInfo()

Field Summary

Fields
Modifier and Type	Field and Description
`static boolean`	`doPreverify` If this value is true, Javassist maintains a `StackMap` attribute generated by the `preverify` tool of J2ME (CLDC).
`static java.lang.String`	`nameClinit` The name of class initializer (static initializer): `<clinit>`.
`static java.lang.String`	`nameInit` The name of constructors: `<init>`.

Constructor Summary

Constructors
Constructor and Description
`MethodInfo(ConstPool cp, java.lang.String methodname, MethodInfo src, java.util.Map classnameMap)` Constructs a copy of `method_info` structure.
`MethodInfo(ConstPool cp, java.lang.String methodname, java.lang.String desc)` Constructs a `method_info` structure.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addAttribute(AttributeInfo info)` Appends an attribute.
`int`	`getAccessFlags()` Returns access flags.
`AttributeInfo`	`getAttribute(java.lang.String name)` Returns the attribute with the specified name.
`java.util.List`	`getAttributes()` Returns all the attributes.
`CodeAttribute`	`getCodeAttribute()` Returns a Code attribute.
`ConstPool`	`getConstPool()` Returns a constant pool table used by this method.
`java.lang.String`	`getDescriptor()` Returns a method descriptor.
`ExceptionsAttribute`	`getExceptionsAttribute()` Returns an Exceptions attribute.
`int`	`getLineNumber(int pos)` Returns the line number of the source line corresponding to the specified bytecode contained in this method.
`java.lang.String`	`getName()` Returns a method name.
`boolean`	`isConstructor()` Returns true if this is a constructor.
`boolean`	`isMethod()` Returns true if this is not a constructor or a class initializer (static initializer).
`boolean`	`isStaticInitializer()` Returns true if this is a class initializer (static initializer).
`void`	`rebuildStackMap(ClassPool pool)` Rebuilds a stack map table.
`void`	`rebuildStackMapForME(ClassPool pool)` Rebuilds a stack map table for J2ME (CLDC).
`void`	`rebuildStackMapIf6(ClassPool pool, ClassFile cf)` Rebuilds a stack map table if the class file is for Java 6 or later.
`void`	`removeCodeAttribute()` Removes a Code attribute.
`void`	`removeExceptionsAttribute()` Removes an Exception attribute.
`void`	`setAccessFlags(int acc)` Sets access flags.
`void`	`setCodeAttribute(CodeAttribute cattr)` Adds a Code attribute.
`void`	`setDescriptor(java.lang.String desc)` Sets a method descriptor.
`void`	`setExceptionsAttribute(ExceptionsAttribute cattr)` Adds an Exception attribute.
`void`	`setName(java.lang.String newName)` Sets a method name.
`void`	`setSuperclass(java.lang.String superclass)` Changes a super constructor called by this constructor.
`java.lang.String`	`toString()` Returns a string representation of the object.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - doPreverify
```
public static boolean doPreverify
```
    If this value is true, Javassist maintains a StackMap attribute generated by the preverify tool of J2ME (CLDC). The initial value of this field is false.
  - nameInit
```
public static final java.lang.String nameInit
```
    The name of constructors: <init>.
    
    See Also:
    
    Constant Field Values
  - nameClinit
```
public static final java.lang.String nameClinit
```
    The name of class initializer (static initializer): <clinit>.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - MethodInfo
```
public MethodInfo(ConstPool cp,
                  java.lang.String methodname,
                  java.lang.String desc)
```
    Constructs a method_info structure. The initial value of access_flags is zero.
    
    Parameters:
    
    cp - a constant pool table
    
    methodname - method name
    
    desc - method descriptor
    
    See Also:
    
    Descriptor
  - MethodInfo
```
public MethodInfo(ConstPool cp,
                  java.lang.String methodname,
                  MethodInfo src,
                  java.util.Map classnameMap)
           throws BadBytecode
```
    Constructs a copy of method_info structure. Class names appearing in the source method_info are renamed according to classnameMap.
    Note: only Code and Exceptions attributes are copied from the source. The other attributes are ignored.
    
    Parameters:
    
    cp - a constant pool table
    
    methodname - a method name
    
    src - a source method_info
    
    classnameMap - specifies pairs of replaced and substituted name.
    
    Throws:
    
    BadBytecode
    
    See Also:
    
    Descriptor
- Method Detail
  - toString
```
public java.lang.String toString()
```
    Returns a string representation of the object.
    
    Overrides:
    
    toString in class java.lang.Object
  - getName
```
public java.lang.String getName()
```
    Returns a method name.
  - setName
```
public void setName(java.lang.String newName)
```
    Sets a method name.
  - isMethod
```
public boolean isMethod()
```
    Returns true if this is not a constructor or a class initializer (static initializer).
  - getConstPool
```
public ConstPool getConstPool()
```
    Returns a constant pool table used by this method.
  - isConstructor
```
public boolean isConstructor()
```
    Returns true if this is a constructor.
  - isStaticInitializer
```
public boolean isStaticInitializer()
```
    Returns true if this is a class initializer (static initializer).
  - getAccessFlags
```
public int getAccessFlags()
```
    Returns access flags.
    
    See Also:
    
    AccessFlag
  - setAccessFlags
```
public void setAccessFlags(int acc)
```
    Sets access flags.
    
    See Also:
    
    AccessFlag
  - getDescriptor
```
public java.lang.String getDescriptor()
```
    Returns a method descriptor.
    
    See Also:
    
    Descriptor
  - setDescriptor
```
public void setDescriptor(java.lang.String desc)
```
    Sets a method descriptor.
    
    See Also:
    
    Descriptor
  - getAttributes
```
public java.util.List getAttributes()
```
    Returns all the attributes. The returned List object is shared with this object. If you add a new attribute to the list, the attribute is also added to the method represented by this object. If you remove an attribute from the list, it is also removed from the method.
    
    Returns:
    
    a list of AttributeInfo objects.
    
    See Also:
    
    AttributeInfo
  - getAttribute
```
public AttributeInfo getAttribute(java.lang.String name)
```
    Returns the attribute with the specified name. If it is not found, this method returns null.
    
    Parameters:
    
    name - attribute name
    
    Returns:
    
    an AttributeInfo object or null.
    
    See Also:
    
    getAttributes()
  - addAttribute
```
public void addAttribute(AttributeInfo info)
```
    Appends an attribute. If there is already an attribute with the same name, the new one substitutes for it.
    
    See Also:
    
    getAttributes()
  - getExceptionsAttribute
```
public ExceptionsAttribute getExceptionsAttribute()
```
    Returns an Exceptions attribute.
    
    Returns:
    
    an Exceptions attribute or null if it is not specified.
  - getCodeAttribute
```
public CodeAttribute getCodeAttribute()
```
    Returns a Code attribute.
    
    Returns:
    
    a Code attribute or null if it is not specified.
  - removeExceptionsAttribute
```
public void removeExceptionsAttribute()
```
    Removes an Exception attribute.
  - setExceptionsAttribute
```
public void setExceptionsAttribute(ExceptionsAttribute cattr)
```
    Adds an Exception attribute.
    The added attribute must share the same constant pool table as this method_info structure.
  - removeCodeAttribute
```
public void removeCodeAttribute()
```
    Removes a Code attribute.
  - setCodeAttribute
```
public void setCodeAttribute(CodeAttribute cattr)
```
    Adds a Code attribute.
    The added attribute must share the same constant pool table as this method_info structure.
  - rebuildStackMapIf6
```
public void rebuildStackMapIf6(ClassPool pool,
                               ClassFile cf)
                        throws BadBytecode
```
    Rebuilds a stack map table if the class file is for Java 6 or later. Java 5 or older Java VMs do not recognize a stack map table. If doPreverify is true, this method also rebuilds a stack map for J2ME (CLDC).
    
    Parameters:
    
    pool - used for making type hierarchy.
    
    cf - rebuild if this class file is for Java 6 or later.
    
    Throws:
    
    BadBytecode
    
    Since:
    
    3.6
    
    See Also:
    
    rebuildStackMap(ClassPool), rebuildStackMapForME(ClassPool), doPreverify
  - rebuildStackMap
```
public void rebuildStackMap(ClassPool pool)
                     throws BadBytecode
```
    Rebuilds a stack map table. If no stack map table is included, a new one is created. If this MethodInfo does not include a code attribute, nothing happens.
    
    Parameters:
    
    pool - used for making type hierarchy.
    
    Throws:
    
    BadBytecode
    
    Since:
    
    3.6
    
    See Also:
    
    StackMapTable
  - rebuildStackMapForME
```
public void rebuildStackMapForME(ClassPool pool)
                          throws BadBytecode
```
    Rebuilds a stack map table for J2ME (CLDC). If no stack map table is included, a new one is created. If this MethodInfo does not include a code attribute, nothing happens.
    
    Parameters:
    
    pool - used for making type hierarchy.
    
    Throws:
    
    BadBytecode
    
    Since:
    
    3.12
    
    See Also:
    
    StackMap
  - getLineNumber
```
public int getLineNumber(int pos)
```
    Returns the line number of the source line corresponding to the specified bytecode contained in this method.
    
    Parameters:
    
    pos - the position of the bytecode (>= 0). an index into the code array.
    
    Returns:
    
    -1 if this information is not available.
  - setSuperclass
```
public void setSuperclass(java.lang.String superclass)
                   throws BadBytecode
```
    Changes a super constructor called by this constructor.
    This method modifies a call to super(), which should be at the head of a constructor body, so that a constructor in a different super class is called. This method does not change actual parameters. Hence the new super class must have a constructor with the same signature as the original one.
    This method should be called when the super class of the class declaring this method is changed.
    This method does not perform anything unless this MethodInfo represents a constructor.
    
    Parameters:
    
    superclass - the new super class
    
    Throws:
    
    BadBytecode

Class MethodInfo

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

doPreverify

nameInit

nameClinit

Constructor Detail

MethodInfo

MethodInfo

Method Detail

toString

getName

setName

isMethod

getConstPool

isConstructor

isStaticInitializer

getAccessFlags

setAccessFlags

getDescriptor

setDescriptor

getAttributes

getAttribute

addAttribute

getExceptionsAttribute

getCodeAttribute

removeExceptionsAttribute

setExceptionsAttribute

removeCodeAttribute

setCodeAttribute

rebuildStackMapIf6

rebuildStackMap

rebuildStackMapForME

getLineNumber

setSuperclass