ClassWriter

package saker.build.thirdparty.org.objectweb.asm

public class ClassWriter extends ClassVisitor

saker.build.thirdparty.org.objectweb.asm.ClassWriter

saker.build.thirdparty.org.objectweb.asm.ClassVisitor

java.lang.Object

A ClassVisitor that generates a corresponding ClassFile structure, as defined in the Java Virtual Machine Specification (JVMS). It can be used alone, to generate a Java class "from scratch", or with one or more ClassReader and adapter ClassVisitor to generate a modified class from one or more existing Java classes.

JVMS 4

Fields

public static final int	COMPUTE_FRAMES = 2 A flag to automatically compute the stack map frames of methods from scratch.
public static final int	COMPUTE_MAXS = 1 A flag to automatically compute the maximum stack size and the maximum number of local variables of methods.

Constructors

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

Methods

protected ClassLoader	getClassLoader() Returns the ClassLoader to be used by the default implementation of getCommonSuperClass(String, String), that of this ClassWriter's runtime type by default.
protected String	getCommonSuperClass(String type1, String type2) Returns the common super type of the two given types.
public int	newClass(String value) Adds a class reference to the constant pool of the class being build.
public int	newConst(Object value) Adds a number or string constant to the constant pool of the class being build.
public int	newConstantDynamic(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments) Adds a dynamic constant reference to the constant pool of the class being build.
public int	newField(String owner, String name, String descriptor) Adds a field reference to the constant pool of the class being build.
public int	newHandle(int tag, String owner, String name, String descriptor) this method is superseded by newHandle(int, String, String, String, boolean).
public int	newHandle(int tag, String owner, String name, String descriptor, boolean isInterface) Adds a handle to the constant pool of the class being build.
public int	newInvokeDynamic(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments) Adds an invokedynamic reference to the constant pool of the class being build.
public int	newMethod(String owner, String name, String descriptor, boolean isInterface) Adds a method reference to the constant pool of the class being build.
public int	newMethodType(String methodDescriptor) Adds a method type reference to the constant pool of the class being build.
public int	newModule(String moduleName) Adds a module reference to the constant pool of the class being build.
public int	newNameType(String name, String descriptor) Adds a name and type to the constant pool of the class being build.
public int	newPackage(String packageName) Adds a package reference to the constant pool of the class being build.
public int	newUTF8(String value) Adds an UTF8 string to the constant pool of the class being build.
public byte[]	toByteArray() Returns the content of the class file that was built by this ClassWriter.
public final void	visit(int version, int access, String name, String signature, String superName, String[] interfaces) Visits the header of the class.
public final AnnotationVisitor	visitAnnotation(String descriptor, boolean visible) Visits an annotation of the class.
public final void	visitAttribute(Attribute attribute) Visits a non standard attribute of the class.
public final void	visitEnd() Visits the end of the class.
public final FieldVisitor	visitField(int access, String name, String descriptor, String signature, Object value) Visits a field of the class.
public final void	visitInnerClass(String name, String outerName, String innerName, int access) Visits information about an inner class.
public final MethodVisitor	visitMethod(int access, String name, String descriptor, String signature, String[] exceptions) Visits a method of the class.
public final ModuleVisitor	visitModule(String name, int access, String version) Visit the module corresponding to the class.
public final void	visitNestHost(String nestHost) Visits the nest host class of the class.
public final void	visitNestMember(String nestMember) Visits a member of the nest.
public final void	visitOuterClass(String owner, String name, String descriptor) Visits the enclosing class of the class.
public final void	visitPermittedSubclass(String permittedSubclass) Visits a permitted subclasses.
public final RecordComponentVisitor	visitRecordComponent(String name, String descriptor, String signature) Visits a record component of the class.
public final void	visitSource(String file, String debug) Visits the source of the class.
public final AnnotationVisitor	visitTypeAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible) Visits an annotation on a type in the class signature.

Inherited methods
From: Object clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

public static final int COMPUTE_FRAMES = 2

A 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, Object[], int, Object[]) method are ignored, and the stack map frames are recomputed from the methods bytecode. The arguments of the MethodVisitor.visitMaxs(int, int) method are also ignored and recomputed from the bytecode. In other words, COMPUTE_FRAMES implies COMPUTE_MAXS.

ClassWriter(int)

public static final int COMPUTE_MAXS = 1

A 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 MethodVisitor.visitMaxs(int, int) method of the MethodVisitor returned by the visitMethod(int, String, String, String, String[]) method will be ignored, and computed automatically from the signature and the bytecode of each method.

Note: for classes whose version is Opcodes.V1_7 of more, this option requires valid stack map frames. The maximum stack size is then computed from these frames, and from the bytecode instructions in between. If stack map frames are not present or must be recomputed, used COMPUTE_FRAMES instead.

ClassWriter(int)

public ClassWriter(int flags)

Constructs a new ClassWriter object.

flagsoption flags that can be used to modify the default behavior of this class. Must be zero or more of COMPUTE_MAXS and COMPUTE_FRAMES.

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 and bootstrap methods from the original class are copied as is in the new class, which saves time. New constant pool entries and new bootstrap methods will be added at the end if necessary, but unused constant pool entries or bootstrap methods 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 any other ClassVisitor instance).

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

flagsoption flags that can be used to modify the default behavior of this class.Must be zero or more of COMPUTE_MAXS and COMPUTE_FRAMES. These option flags do not affect methods that are copied as is in the new class. This means that neither the maximum stack size nor the stack frames will be computed for these methods.

protected ClassLoader getClassLoader()

Returns the ClassLoader to be used by the default implementation of getCommonSuperClass(String, String), that of this ClassWriter's runtime type by default.

ClassLoader

protected String getCommonSuperClass(String type1, 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 overridden 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.

type1the internal name of a class.

type2the internal name of another class.

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

public int newClass(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.

valuethe internal name of the class.

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

public int newConst(Object value)

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.

valuethe 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.

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

public int newConstantDynamic(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments)

Adds a dynamic constant 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.

namename of the invoked method.

descriptorfield descriptor of the constant type.

bootstrapMethodHandlethe bootstrap method.

bootstrapMethodArgumentsthe bootstrap method constant arguments.

the index of a new or already existing dynamic constant reference item.

public int newField(String owner, String name, String descriptor)

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.

ownerthe internal name of the field's owner class.

namethe field's name.

descriptorthe field's descriptor.

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

@Deprecated

public int newHandle(int tag, String owner, String name, String descriptor)

this method is superseded by newHandle(int, String, String, String, boolean).

Adds a handle 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.

tagthe kind of this handle. Must be Opcodes.H_GETFIELD, Opcodes.H_GETSTATIC, Opcodes.H_PUTFIELD, Opcodes.H_PUTSTATIC, Opcodes.H_INVOKEVIRTUAL, Opcodes.H_INVOKESTATIC, Opcodes.H_INVOKESPECIAL, Opcodes.H_NEWINVOKESPECIAL or Opcodes.H_INVOKEINTERFACE.

ownerthe internal name of the field or method owner class.

namethe name of the field or method.

descriptorthe descriptor of the field or method.

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

public int newHandle(int tag, String owner, String name, String descriptor, boolean isInterface)

ownerthe internal name of the field or method owner class.

namethe name of the field or method.

descriptorthe descriptor of the field or method.

isInterfacetrue if the owner is an interface.

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

public int newInvokeDynamic(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments)

Adds an invokedynamic 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.

namename of the invoked method.

descriptordescriptor of the invoke method.

bootstrapMethodHandlethe bootstrap method.

bootstrapMethodArgumentsthe bootstrap method constant arguments.

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

public int newMethod(String owner, String name, String descriptor, boolean isInterface)

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.

ownerthe internal name of the method's owner class.

namethe method's name.

descriptorthe method's descriptor.

isInterfacetrue if owner is an interface.

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

public int newMethodType(String methodDescriptor)

Adds a method type 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.

methodDescriptormethod descriptor of the method type.

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

public int newModule(String moduleName)

Adds a module 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.

moduleNamename of the module.

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

public int newNameType(String name, String descriptor)

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.

namea name.

descriptora type descriptor.

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

public int newPackage(String packageName)

Adds a package 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.

packageNamename of the package in its internal form.

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

public int newUTF8(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.

valuethe String value.

the index of a new or already existing UTF8 item.

public byte[] toByteArray()

Returns the content of the class file that was built by this ClassWriter.

the binary content of the JVMS ClassFile structure that was built by this ClassWriter.

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

Overridden from: ClassVisitor

Visits the header of the class.

versionthe class version. The minor version is stored in the 16 most significant bits, and the major version in the 16 least significant bits.

accessthe class's access flags (see Opcodes). This parameter also indicates if the class is deprecated Opcodes.ACC_DEPRECATED or a record Opcodes.ACC_RECORD.

namethe internal name of the class (see Type.getInternalName()).

signaturethe 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.

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

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

public final AnnotationVisitor visitAnnotation(String descriptor, boolean visible)

Overridden from: ClassVisitor

Visits an annotation of the class.

descriptorthe class descriptor of the annotation class.

visibletrue if the annotation is visible at runtime.

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

public final void visitAttribute(Attribute attribute)

Overridden from: ClassVisitor

Visits a non standard attribute of the class.

attributean attribute.

public final void visitEnd()

Overridden from: 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.

public final FieldVisitor visitField(int access, String name, String descriptor, String signature, Object value)

Overridden from: ClassVisitor

Visits a field of the class.

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

namethe field's name.

descriptorthe field's descriptor (see Type).

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

valuethe 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.

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

public final void visitInnerClass(String name, String outerName, String innerName, int access)

Overridden from: ClassVisitor

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

namethe internal name of an inner class (see Type.getInternalName()).

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

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

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

public final MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions)

Overridden from: 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.

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

namethe method's name.

descriptorthe method's descriptor (see Type).

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

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

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.

public final ModuleVisitor visitModule(String name, int access, String version)

Overridden from: ClassVisitor

Visit the module corresponding to the class.

namethe fully qualified name (using dots) of the module.

accessthe module access flags, among ACC_OPEN, ACC_SYNTHETIC and


     ACC_MANDATED

versionthe module version, or null.

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

public final void visitNestHost(String nestHost)

Overridden from: ClassVisitor

Visits the nest host class of the class. A nest is a set of classes of the same package that share access to their private members. One of these classes, called the host, lists the other members of the nest, which in turn should link to the host of their nest. This method must be called only once and only if the visited class is a non-host member of a nest. A class is implicitly its own nest, so it's invalid to call this method with the visited class name as argument.

nestHostthe internal name of the host class of the nest.

public final void visitNestMember(String nestMember)

Overridden from: ClassVisitor

Visits a member of the nest. A nest is a set of classes of the same package that share access to their private members. One of these classes, called the host, lists the other members of the nest, which in turn should link to the host of their nest. This method must be called only if the visited class is the host of a nest. A nest host is implicitly a member of its own nest, so it's invalid to call this method with the visited class name as argument.

nestMemberthe internal name of a nest member.

public final void visitOuterClass(String owner, String name, String descriptor)

Overridden from: ClassVisitor

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

ownerinternal name of the enclosing class of the class.

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

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

public final void visitPermittedSubclass(String permittedSubclass)

Overridden from: ClassVisitor

Visits a permitted subclasses. A permitted subclass is one of the allowed subclasses of the current class.

permittedSubclassthe internal name of a permitted subclass.

public final RecordComponentVisitor visitRecordComponent(String name, String descriptor, String signature)

Overridden from: ClassVisitor

Visits a record component of the class.

namethe record component name.

descriptorthe record component descriptor (see Type).

signaturethe record component signature. May be null if the record component type does not use generic types.

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

public final void visitSource(String file, String debug)

Overridden from: ClassVisitor

Visits the source of the class.

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

debugadditional debug information to compute the correspondence between source and compiled elements of the class. May be null.

public final AnnotationVisitor visitTypeAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible)

Overridden from: ClassVisitor

Visits an annotation on a type in the class signature.

typeRefa reference to the annotated type. The sort of this type reference must be TypeReference.CLASS_TYPE_PARAMETER, TypeReference.CLASS_TYPE_PARAMETER_BOUND or TypeReference.CLASS_EXTENDS. See TypeReference.

typePaththe path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.

descriptorthe class descriptor of the annotation class.

visibletrue if the annotation is visible at runtime.

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