clojure.asm

Class ClassWriter

java.lang.Object

clojure.asm.ClassWriter

All Implemented Interfaces:

ClassVisitor

public class ClassWriter
extends java.lang.Object
implements ClassVisitor

A ClassVisitor that generates classes in bytecode form. More precisely this visitor generates a byte array conforming to the Java class file format. It can be used alone, to generate a Java class "from scratch", or with one or more ClassReader and adapter class visitor to generate a modified class from one or more existing Java classes.

Author:

Eric Bruneton

Field Summary

Fields

Modifier and Type	Field and Description
private int	access The access flags of this class.
private AnnotationWriter	anns The runtime visible annotations of this class.
private Attribute	attrs The non standard attributes of this class.
(package private) static int	CLASS The type of CONSTANT_Class constant pool items.
static int	COMPUTE_FRAMES Flag to automatically compute the stack map frames of methods from scratch.
static int	COMPUTE_MAXS Flag to automatically compute the maximum stack size and the maximum number of local variables of methods.
private boolean	computeFrames true if the stack map frames must be recomputed from scratch.
private boolean	computeMaxs true if the maximum stack size and number of local variables must be automatically computed.
(package private) ClassReader	cr The class reader from which this class writer was constructed, if any.
(package private) static int	DOUBLE The type of CONSTANT_Double constant pool items.
private int	enclosingMethod The constant pool item that contains the name and descriptor of the enclosing method of this class.
private int	enclosingMethodOwner The constant pool item that contains the name of the enclosing class of this class.
(package private) static int	FIELD The type of CONSTANT_Fieldref constant pool items.
(package private) static int	FIELDORMETH_INSN The type of field and method invocations instructions.
(package private) FieldWriter	firstField The fields of this class.
(package private) MethodWriter	firstMethod The methods of this class.
(package private) static int	FLOAT The type of CONSTANT_Float constant pool items.
private AnnotationWriter	ianns The runtime invisible annotations of this class.
(package private) static int	IINC_INSN The type of the IINC instruction.
(package private) static int	IMETH The type of CONSTANT_InterfaceMethodref constant pool items.
(package private) static int	IMPLVAR_INSN The type of instructions with an implicit local variable index argument.
(package private) int	index Index of the next item to be added in the constant pool.
private ByteVector	innerClasses The InnerClasses attribute.
private int	innerClassesCount The number of entries in the InnerClasses attribute.
(package private) static int	INT The type of CONSTANT_Integer constant pool items.
private int	interfaceCount Number of interfaces implemented or extended by this class or interface.
private int[]	interfaces The interfaces implemented or extended by this class or interface.
(package private) boolean	invalidFrames true if the stack map tables of this class are invalid.
(package private) Item[]	items The constant pool's hash table data.
(package private) static int	ITFMETH_INSN The type of the INVOKEINTERFACE instruction.
(package private) Item	key A reusable key used to look for items in the items hash table.
(package private) Item	key2 A reusable key used to look for items in the items hash table.
(package private) Item	key3 A reusable key used to look for items in the items hash table.
(package private) static int	LABEL_INSN The type of instructions with a 2 bytes bytecode offset label.
(package private) static int	LABELW_INSN The type of instructions with a 4 bytes bytecode offset label.
(package private) FieldWriter	lastField The fields of this class.
(package private) MethodWriter	lastMethod The methods of this class.
(package private) static int	LDC_INSN The type of the LDC instruction.
(package private) static int	LDCW_INSN The type of the LDC_W and LDC2_W instructions.
(package private) static int	LONG The type of CONSTANT_Long constant pool items.
(package private) static int	LOOK_INSN The type of the LOOKUPSWITCH instruction.
(package private) static int	MANA_INSN The type of the MULTIANEWARRAY instruction.
(package private) static int	METH The type of CONSTANT_Methodref constant pool items.
private int	name The constant pool item that contains the internal name of this class.
(package private) static int	NAME_TYPE The type of CONSTANT_NameAndType constant pool items.
(package private) static int	NOARG_INSN The type of instructions without any argument.
(package private) ByteVector	pool The constant pool of this class.
(package private) static int	SBYTE_INSN The type of instructions with an signed byte argument.
(package private) static int	SHORT_INSN The type of instructions with an signed short argument.
private int	signature The constant pool item that contains the signature of this class.
private ByteVector	sourceDebug The SourceDebug attribute of this class.
private int	sourceFile The index of the constant pool item that contains the name of the source file from which this class was compiled.
(package private) static int	STR The type of CONSTANT_String constant pool items.
private int	superName The constant pool item that contains the internal name of the super class of this class.
(package private) static int	TABL_INSN The type of the TABLESWITCH instruction.
(package private) java.lang.String	thisName The internal name of this class.
(package private) int	threshold The threshold of the constant pool's hash table.
(package private) static byte[]	TYPE The instruction types of all JVM opcodes.
(package private) static int	TYPE_INSN The type of instructions with a type descriptor argument.
(package private) static int	TYPE_MERGED Merged type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.
(package private) static int	TYPE_NORMAL Normal type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.
(package private) static int	TYPE_UNINIT Uninitialized type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.
private short	typeCount Number of elements in the typeTable array.
(package private) Item[]	typeTable A type table used to temporarily store internal names that will not necessarily be stored in the constant pool.
(package private) static int	UTF8 The type of CONSTANT_Utf8 constant pool items.
(package private) static int	VAR_INSN The type of instructions with a local variable index argument.
(package private) int	version Minor and major version numbers of the class to be generated.
(package private) static int	WIDE_INSN The type of the WIDE instruction.

Constructor Summary

Constructors

Constructor and Description
ClassWriter(ClassReader classReader, int flags) Constructs a new ClassWriter object and enables optimizations for "mostly add" bytecode transformations.
ClassWriter(int flags) Constructs a new ClassWriter object.

Method Summary

Methods

Modifier and Type	Method and Description
private Item	addType(Item item) Adds the given Item to typeTable.
(package private) int	addType(java.lang.String type) Adds the given internal name to typeTable and returns its index.
(package private) int	addUninitializedType(java.lang.String type, int offset) Adds the given "uninitialized" type to typeTable and returns its index.
private Item	get(Item key) Returns the constant pool's hash table item which is equal to the given item.
protected java.lang.String	getCommonSuperClass(java.lang.String type1, java.lang.String type2) Returns the common super type of the two given types.
(package private) int	getMergedType(int type1, int type2) Returns the index of the common super type of the two given types.
int	newClass(java.lang.String value) Adds a class reference to the constant pool of the class being build.
(package private) Item	newClassItem(java.lang.String value) Adds a class reference to the constant pool of the class being build.
int	newConst(java.lang.Object cst) Adds a number or string constant to the constant pool of the class being build.
(package private) Item	newConstItem(java.lang.Object cst) Adds a number or string constant to the constant pool of the class being build.
(package private) Item	newDouble(double value) Adds a double to the constant pool of the class being build.
int	newField(java.lang.String owner, java.lang.String name, java.lang.String desc) Adds a field reference to the constant pool of the class being build.
(package private) Item	newFieldItem(java.lang.String owner, java.lang.String name, java.lang.String desc) Adds a field reference to the constant pool of the class being build.
(package private) Item	newFloat(float value) Adds a float to the constant pool of the class being build.
(package private) Item	newInteger(int value) Adds an integer to the constant pool of the class being build.
(package private) Item	newLong(long value) Adds a long to the constant pool of the class being build.
int	newMethod(java.lang.String owner, java.lang.String name, java.lang.String desc, boolean itf) Adds a method reference to the constant pool of the class being build.
(package private) Item	newMethodItem(java.lang.String owner, java.lang.String name, java.lang.String desc, boolean itf) Adds a method reference to the constant pool of the class being build.
int	newNameType(java.lang.String name, java.lang.String desc) Adds a name and type to the constant pool of the class being build.
private Item	newString(java.lang.String value) Adds a string to the constant pool of the class being build.
int	newUTF8(java.lang.String value) Adds an UTF8 string to the constant pool of the class being build.
private void	put(Item i) Puts the given item in the constant pool's hash table.
private void	put122(int b, int s1, int s2) Puts one byte and two shorts into the constant pool.
byte[]	toByteArray() Returns the bytecode of the class that was build with this class writer.
void	visit(int version, int access, java.lang.String name, java.lang.String signature, java.lang.String superName, java.lang.String[] interfaces) Visits the header of the class.
AnnotationVisitor	visitAnnotation(java.lang.String desc, boolean visible) Visits an annotation of the class.
void	visitAttribute(Attribute attr) Visits a non standard attribute of the class.
void	visitEnd() Visits the end of the class.
FieldVisitor	visitField(int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.Object value) Visits a field of the class.
void	visitInnerClass(java.lang.String name, java.lang.String outerName, java.lang.String innerName, int access) Visits information about an inner class.
MethodVisitor	visitMethod(int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.String[] exceptions) Visits a method of the class.
void	visitOuterClass(java.lang.String owner, java.lang.String name, java.lang.String desc) Visits the enclosing class of the class.
void	visitSource(java.lang.String file, java.lang.String debug) Visits the source of the class.

Methods inherited from class java.lang.Object

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

Field Detail

COMPUTE_MAXS

public static final int COMPUTE_MAXS

Flag to automatically compute the maximum stack size and the maximum number of local variables of methods. If this flag is set, then the arguments of the visitMaxs method of the MethodVisitor returned by the visitMethod method will be ignored, and computed automatically from the signature and the bytecode of each method.

See Also:

ClassWriter(int), Constant Field Values

COMPUTE_FRAMES

public static final int COMPUTE_FRAMES

Flag to automatically compute the stack map frames of methods from scratch. If this flag is set, then the calls to the MethodVisitor.visitFrame(int, int, java.lang.Object[], int, java.lang.Object[]) method are ignored, and the stack map frames are recomputed from the methods bytecode. The arguments of the visitMaxs method are also ignored and recomputed from the bytecode. In other words, computeFrames implies computeMaxs.

See Also:

ClassWriter(int), Constant Field Values

NOARG_INSN

static final int NOARG_INSN

The type of instructions without any argument.

See Also:

Constant Field Values

SBYTE_INSN

static final int SBYTE_INSN

The type of instructions with an signed byte argument.

See Also:

Constant Field Values

SHORT_INSN

static final int SHORT_INSN

The type of instructions with an signed short argument.

See Also:

Constant Field Values

VAR_INSN

static final int VAR_INSN

The type of instructions with a local variable index argument.

See Also:

Constant Field Values

IMPLVAR_INSN

static final int IMPLVAR_INSN

The type of instructions with an implicit local variable index argument.

See Also:

Constant Field Values

TYPE_INSN

static final int TYPE_INSN

The type of instructions with a type descriptor argument.

See Also:

Constant Field Values

FIELDORMETH_INSN

static final int FIELDORMETH_INSN

The type of field and method invocations instructions.

See Also:

Constant Field Values

ITFMETH_INSN

static final int ITFMETH_INSN

The type of the INVOKEINTERFACE instruction.

See Also:

Constant Field Values

LABEL_INSN

static final int LABEL_INSN

The type of instructions with a 2 bytes bytecode offset label.

See Also:

Constant Field Values

LABELW_INSN

static final int LABELW_INSN

The type of instructions with a 4 bytes bytecode offset label.

See Also:

Constant Field Values

LDC_INSN

static final int LDC_INSN

The type of the LDC instruction.

See Also:

Constant Field Values

LDCW_INSN

static final int LDCW_INSN

The type of the LDC_W and LDC2_W instructions.

See Also:

Constant Field Values

IINC_INSN

static final int IINC_INSN

The type of the IINC instruction.

See Also:

Constant Field Values

TABL_INSN

static final int TABL_INSN

The type of the TABLESWITCH instruction.

See Also:

Constant Field Values

LOOK_INSN

static final int LOOK_INSN

The type of the LOOKUPSWITCH instruction.

See Also:

Constant Field Values

MANA_INSN

static final int MANA_INSN

The type of the MULTIANEWARRAY instruction.

See Also:

Constant Field Values

WIDE_INSN

static final int WIDE_INSN

The type of the WIDE instruction.

See Also:

Constant Field Values

TYPE

static byte[] TYPE

The instruction types of all JVM opcodes.

CLASS

static final int CLASS

The type of CONSTANT_Class constant pool items.

See Also:

Constant Field Values

FIELD

static final int FIELD

The type of CONSTANT_Fieldref constant pool items.

See Also:

Constant Field Values

METH

static final int METH

The type of CONSTANT_Methodref constant pool items.

See Also:

Constant Field Values

IMETH

static final int IMETH

The type of CONSTANT_InterfaceMethodref constant pool items.

See Also:

Constant Field Values

STR

static final int STR

The type of CONSTANT_String constant pool items.

See Also:

Constant Field Values

INT

static final int INT

The type of CONSTANT_Integer constant pool items.

See Also:

Constant Field Values

FLOAT

static final int FLOAT

The type of CONSTANT_Float constant pool items.

See Also:

Constant Field Values

LONG

static final int LONG

The type of CONSTANT_Long constant pool items.

See Also:

Constant Field Values

DOUBLE

static final int DOUBLE

The type of CONSTANT_Double constant pool items.

See Also:

Constant Field Values

NAME_TYPE

static final int NAME_TYPE

The type of CONSTANT_NameAndType constant pool items.

See Also:

Constant Field Values

UTF8

static final int UTF8

The type of CONSTANT_Utf8 constant pool items.

See Also:

Constant Field Values

TYPE_NORMAL

static final int TYPE_NORMAL

Normal type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.

See Also:

Constant Field Values

TYPE_UNINIT

static final int TYPE_UNINIT

Uninitialized type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.

See Also:

Constant Field Values

TYPE_MERGED

static final int TYPE_MERGED

Merged type Item stored in the ClassWriter typeTable, instead of the constant pool, in order to avoid clashes with normal constant pool items in the ClassWriter constant pool's hash table.

See Also:

Constant Field Values

cr

ClassReader cr

The class reader from which this class writer was constructed, if any.

version

int version

Minor and major version numbers of the class to be generated.

index

int index

Index of the next item to be added in the constant pool.

pool

ByteVector pool

The constant pool of this class.

items

Item[] items

The constant pool's hash table data.

threshold

int threshold

The threshold of the constant pool's hash table.

key

Item key

A reusable key used to look for items in the items hash table.

key2

Item key2

A reusable key used to look for items in the items hash table.

key3

Item key3

A reusable key used to look for items in the items hash table.

typeTable

Item[] typeTable

A type table used to temporarily store internal names that will not necessarily be stored in the constant pool. This type table is used by the control flow and data flow analysis algorithm used to compute stack map frames from scratch. This array associates to each index i the Item whose index is i. All Item objects stored in this array are also stored in the items hash table. These two arrays allow to retrieve an Item from its index or, conversly, to get the index of an Item from its value. Each Item stores an internal name in its Item.strVal1 field.

typeCount

private short typeCount

Number of elements in the typeTable array.

access

private int access

The access flags of this class.

name

private int name

The constant pool item that contains the internal name of this class.

thisName

java.lang.String thisName

The internal name of this class.

signature

private int signature

The constant pool item that contains the signature of this class.

superName

private int superName

The constant pool item that contains the internal name of the super class of this class.

interfaceCount

private int interfaceCount

Number of interfaces implemented or extended by this class or interface.

interfaces

private int[] interfaces

The interfaces implemented or extended by this class or interface. More precisely, this array contains the indexes of the constant pool items that contain the internal names of these interfaces.

sourceFile

private int sourceFile

The index of the constant pool item that contains the name of the source file from which this class was compiled.

sourceDebug

private ByteVector sourceDebug

The SourceDebug attribute of this class.

enclosingMethodOwner

private int enclosingMethodOwner

The constant pool item that contains the name of the enclosing class of this class.

enclosingMethod

private int enclosingMethod

The constant pool item that contains the name and descriptor of the enclosing method of this class.

anns

private AnnotationWriter anns

The runtime visible annotations of this class.

ianns

private AnnotationWriter ianns

The runtime invisible annotations of this class.

attrs

private Attribute attrs

The non standard attributes of this class.

innerClassesCount

private int innerClassesCount

The number of entries in the InnerClasses attribute.

innerClasses

private ByteVector innerClasses

The InnerClasses attribute.

firstField

FieldWriter firstField

The fields of this class. These fields are stored in a linked list of FieldWriter objects, linked to each other by their FieldWriter.next field. This field stores the first element of this list.

lastField

FieldWriter lastField

The fields of this class. These fields are stored in a linked list of FieldWriter objects, linked to each other by their FieldWriter.next field. This field stores the last element of this list.

firstMethod

MethodWriter firstMethod

The methods of this class. These methods are stored in a linked list of MethodWriter objects, linked to each other by their MethodWriter.next field. This field stores the first element of this list.

lastMethod

MethodWriter lastMethod

The methods of this class. These methods are stored in a linked list of MethodWriter objects, linked to each other by their MethodWriter.next field. This field stores the last element of this list.

computeMaxs

private boolean computeMaxs

true if the maximum stack size and number of local variables must be automatically computed.

computeFrames

private boolean computeFrames

true if the stack map frames must be recomputed from scratch.

invalidFrames

boolean invalidFrames

true if the stack map tables of this class are invalid. The MethodWriter.resizeInstructions() method cannot transform existing stack map tables, and so produces potentially invalid classes when it is executed. In this case the class is reread and rewritten with the COMPUTE_FRAMES option (the resizeInstructions method can resize stack map tables when this option is used).

Constructor Detail

ClassWriter

public ClassWriter(int flags)

Constructs a new ClassWriter object.

Parameters:

flags - option flags that can be used to modify the default behavior of this class. See COMPUTE_MAXS, COMPUTE_FRAMES.

ClassWriter

public ClassWriter(ClassReader classReader,
           int flags)

Constructs a new ClassWriter object and enables optimizations for "mostly add" bytecode transformations. These optimizations are the following:

• The constant pool from the original class is copied as is in the new class, which saves time. New constant pool entries will be added at the end if necessary, but unused constant pool entries won't be removed.
• Methods that are not transformed are copied as is in the new class, directly from the original class bytecode (i.e. without emitting visit events for all the method instructions), which saves a lot of time. Untransformed methods are detected by the fact that the ClassReader receives MethodVisitor objects that come from a ClassWriter (and not from a custom ClassAdapter or any other ClassVisitor instance).

Parameters:

classReader - the ClassReader used to read the original class. It will be used to copy the entire constant pool from the original class and also to copy other fragments of original bytecode where applicable.

flags - option flags that can be used to modify the default behavior of this class. See COMPUTE_MAXS, COMPUTE_FRAMES.

Method Detail

visit

public void visit(int version,
         int access,
         java.lang.String name,
         java.lang.String signature,
         java.lang.String superName,
         java.lang.String[] interfaces)

Description copied from interface: ClassVisitor

Visits the header of the class.

Specified by:

visit in interface ClassVisitor

Parameters:

version - the class version.

access - the class's access flags (see Opcodes). This parameter also indicates if the class is deprecated.

name - the internal name of the class (see getInternalName).

signature - the signature of this class. May be null if the class is not a generic one, and does not extend or implement generic classes or interfaces.

superName - the internal of name of the super class (see getInternalName). For interfaces, the super class is Object. May be null, but only for the Object class.

interfaces - the internal names of the class's interfaces (see getInternalName). May be null.

visitSource

public void visitSource(java.lang.String file,
               java.lang.String debug)

Description copied from interface: ClassVisitor

Visits the source of the class.

Specified by:

visitSource in interface ClassVisitor

Parameters:

file - the name of the source file from which the class was compiled. May be null.

debug - additional debug information to compute the correspondance between source and compiled elements of the class. May be null.

visitOuterClass

public void visitOuterClass(java.lang.String owner,
                   java.lang.String name,
                   java.lang.String desc)

Description copied from interface: ClassVisitor

Visits the enclosing class of the class. This method must be called only if the class has an enclosing class.

Specified by:

visitOuterClass in interface ClassVisitor

Parameters:

owner - internal name of the enclosing class of the class.

name - the name of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.

desc - the descriptor of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.

visitAnnotation

public AnnotationVisitor visitAnnotation(java.lang.String desc,
                                boolean visible)

Description copied from interface: ClassVisitor

Visits an annotation of the class.

Specified by:

visitAnnotation in interface ClassVisitor

Parameters:

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitAttribute

public void visitAttribute(Attribute attr)

Description copied from interface: ClassVisitor

Visits a non standard attribute of the class.

Specified by:

visitAttribute in interface ClassVisitor

Parameters:

attr - an attribute.

visitInnerClass

public void visitInnerClass(java.lang.String name,
                   java.lang.String outerName,
                   java.lang.String innerName,
                   int access)

Description copied from interface: ClassVisitor

Visits information about an inner class. This inner class is not necessarily a member of the class being visited.

Specified by:

visitInnerClass in interface ClassVisitor

Parameters:

name - the internal name of an inner class (see getInternalName).

outerName - the internal name of the class to which the inner class belongs (see getInternalName). May be null for not member classes.

innerName - the (simple) name of the inner class inside its enclosing class. May be null for anonymous inner classes.

access - the access flags of the inner class as originally declared in the enclosing class.

visitField

public FieldVisitor visitField(int access,
                      java.lang.String name,
                      java.lang.String desc,
                      java.lang.String signature,
                      java.lang.Object value)

Description copied from interface: ClassVisitor

Visits a field of the class.

Specified by:

visitField in interface ClassVisitor

Parameters:

access - the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.

name - the field's name.

desc - the field's descriptor (see Type).

signature - the field's signature. May be null if the field's type does not use generic types.

value - the field's initial value. This parameter, which may be null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String (for int, float, long or String fields respectively). This parameter is only used for static fields. Its value is ignored for non static fields, which must be initialized through bytecode instructions in constructors or methods.

Returns:

a visitor to visit field annotations and attributes, or null if this class visitor is not interested in visiting these annotations and attributes.

visitMethod

public MethodVisitor visitMethod(int access,
                        java.lang.String name,
                        java.lang.String desc,
                        java.lang.String signature,
                        java.lang.String[] exceptions)

Description copied from interface: ClassVisitor

Visits a method of the class. This method must return a new MethodVisitor instance (or null) each time it is called, i.e., it should not return a previously returned visitor.

Specified by:

visitMethod in interface ClassVisitor

Parameters:

access - the method's access flags (see Opcodes). This parameter also indicates if the method is synthetic and/or deprecated.

name - the method's name.

desc - the method's descriptor (see Type).

signature - the method's signature. May be null if the method parameters, return type and exceptions do not use generic types.

exceptions - the internal names of the method's exception classes (see getInternalName). May be null.

Returns:

an object to visit the byte code of the method, or null if this class visitor is not interested in visiting the code of this method.

visitEnd

public void visitEnd()

Description copied from interface: ClassVisitor

Visits the end of the class. This method, which is the last one to be called, is used to inform the visitor that all the fields and methods of the class have been visited.

Specified by:

visitEnd in interface ClassVisitor

toByteArray

public byte[] toByteArray()

Returns the bytecode of the class that was build with this class writer.

Returns:

the bytecode of the class that was build with this class writer.

newConstItem

Item newConstItem(java.lang.Object cst)

Adds a number or string constant to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

cst - the value of the constant to be added to the constant pool. This parameter must be an Integer, a Float, a Long, a Double, a String or a Type.

Returns:

a new or already existing constant item with the given value.

newConst

public int newConst(java.lang.Object cst)

Adds a number or string constant to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

cst - the value of the constant to be added to the constant pool. This parameter must be an Integer, a Float, a Long, a Double or a String.

Returns:

the index of a new or already existing constant item with the given value.

newUTF8

public int newUTF8(java.lang.String value)

Adds an UTF8 string to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

value - the String value.

Returns:

the index of a new or already existing UTF8 item.

newClassItem

Item newClassItem(java.lang.String value)

Adds a class reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

value - the internal name of the class.

Returns:

a new or already existing class reference item.

newClass

public int newClass(java.lang.String value)

Adds a class reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

value - the internal name of the class.

Returns:

the index of a new or already existing class reference item.

newFieldItem

Item newFieldItem(java.lang.String owner,
                java.lang.String name,
                java.lang.String desc)

Adds a field reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

owner - the internal name of the field's owner class.

name - the field's name.

desc - the field's descriptor.

Returns:

a new or already existing field reference item.

newField

public int newField(java.lang.String owner,
           java.lang.String name,
           java.lang.String desc)

Adds a field reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

owner - the internal name of the field's owner class.

name - the field's name.

desc - the field's descriptor.

Returns:

the index of a new or already existing field reference item.

newMethodItem

Item newMethodItem(java.lang.String owner,
                 java.lang.String name,
                 java.lang.String desc,
                 boolean itf)

Adds a method reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

owner - the internal name of the method's owner class.

name - the method's name.

desc - the method's descriptor.

itf - true if owner is an interface.

Returns:

a new or already existing method reference item.

newMethod

public int newMethod(java.lang.String owner,
            java.lang.String name,
            java.lang.String desc,
            boolean itf)

Adds a method reference to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

owner - the internal name of the method's owner class.

name - the method's name.

desc - the method's descriptor.

itf - true if owner is an interface.

Returns:

the index of a new or already existing method reference item.

newInteger

Item newInteger(int value)

Adds an integer to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

value - the int value.

Returns:

a new or already existing int item.

newFloat

Item newFloat(float value)

Adds a float to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

value - the float value.

Returns:

a new or already existing float item.

newLong

Item newLong(long value)

Adds a long to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

value - the long value.

Returns:

a new or already existing long item.

newDouble

Item newDouble(double value)

Adds a double to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

value - the double value.

Returns:

a new or already existing double item.

newString

private Item newString(java.lang.String value)

Adds a string to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item.

Parameters:

value - the String value.

Returns:

a new or already existing string item.

newNameType

public int newNameType(java.lang.String name,
              java.lang.String desc)

Adds a name and type to the constant pool of the class being build. Does nothing if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Parameters:

name - a name.

desc - a type descriptor.

Returns:

the index of a new or already existing name and type item.

addType

int addType(java.lang.String type)

Adds the given internal name to typeTable and returns its index. Does nothing if the type table already contains this internal name.

Parameters:

type - the internal name to be added to the type table.

Returns:

the index of this internal name in the type table.

addUninitializedType

int addUninitializedType(java.lang.String type,
                       int offset)

Adds the given "uninitialized" type to typeTable and returns its index. This method is used for UNINITIALIZED types, made of an internal name and a bytecode offset.

Parameters:

type - the internal name to be added to the type table.

offset - the bytecode offset of the NEW instruction that created this UNINITIALIZED type value.

Returns:

the index of this internal name in the type table.

addType

private Item addType(Item item)

Adds the given Item to typeTable.

Parameters:

item - the value to be added to the type table.

Returns:

the added Item, which a new Item instance with the same value as the given Item.

getMergedType

int getMergedType(int type1,
                int type2)

Returns the index of the common super type of the two given types. This method calls getCommonSuperClass(java.lang.String, java.lang.String) and caches the result in the items hash table to speedup future calls with the same parameters.

Parameters:

type1 - index of an internal name in typeTable.

type2 - index of an internal name in typeTable.

Returns:

the index of the common super type of the two given types.

getCommonSuperClass

protected java.lang.String getCommonSuperClass(java.lang.String type1,
                                   java.lang.String type2)

Returns the common super type of the two given types. The default implementation of this method loads the two given classes and uses the java.lang.Class methods to find the common super class. It can be overriden to compute this common super type in other ways, in particular without actually loading any class, or to take into account the class that is currently being generated by this ClassWriter, which can of course not be loaded since it is under construction.

Parameters:

type1 - the internal name of a class.

type2 - the internal name of another class.

Returns:

the internal name of the common super class of the two given classes.

get

private Item get(Item key)

Returns the constant pool's hash table item which is equal to the given item.

Parameters:

key - a constant pool item.

Returns:

the constant pool's hash table item which is equal to the given item, or null if there is no such item.

put

private void put(Item i)

Puts the given item in the constant pool's hash table. The hash table must not already contains this item.

Parameters:

i - the item to be added to the constant pool's hash table.

put122

private void put122(int b,
          int s1,
          int s2)

Puts one byte and two shorts into the constant pool.

Parameters:

b - a byte.

s1 - a short.

s2 - another short.