程序包 cn.taketoday.bytecode

类 Attribute

java.lang.Object
cn.taketoday.bytecode.Attribute
直接已知子类:
ModuleHashesAttribute, ModuleResolutionAttribute, ModuleTargetAttribute
public class Attribute extends Object
A non standard class, field, method or Code attribute, as defined in the Java Virtual Machine Specification (JVMS).
作者:
Eric Bruneton, Eugene Kuleshov, Harry Yang
另请参阅:

  • 嵌套类概要

    嵌套类
    修饰符和类型
    类
    说明
    (专用程序包) static final class 
    Attribute.Set
    A set of attribute prototypes (attributes with the same type are considered equal).

  • 字段概要

    字段
    修饰符和类型
    字段
    说明
    private byte[]
    content
    The raw content of this attribute, only used for unknown attributes (see isUnknown()).
    (专用程序包) Attribute
    nextAttribute
    The next attribute in this attribute list (Attribute instances can be linked via this field to store a list of class, field, method or Code attributes).
    final String
    type
    The type of this attribute, also called its name in the JVMS.

  • 构造器概要

    构造器
    限定符
    构造器
    说明
    protected
    Attribute(String type)
    Constructs a new empty attribute.

  • 方法概要

    修饰符和类型
    方法
    说明
    (专用程序包) final int
    computeAttributesSize(SymbolTable symbolTable)
    Returns the total size in bytes of all the attributes in the attribute list that begins with this attribute.
    (专用程序包) final int
    computeAttributesSize(SymbolTable symbolTable, byte[] code, int codeLength, int maxStack, int maxLocals)
    Returns the total size in bytes of all the attributes in the attribute list that begins with this attribute.
    (专用程序包) static int
    computeAttributesSize(SymbolTable symbolTable, int accessFlags, int signatureIndex)
    Returns the total size in bytes of all the attributes that correspond to the given field, method or class access flags and signature.
    (专用程序包) final int
    getAttributeCount()
    Returns the number of attributes of the attribute list that begins with this attribute.
    protected Label[]
    getLabels()
    Returns the labels corresponding to this attribute.
    boolean
    isCodeAttribute()
    Returns true if this type of attribute is a Code attribute.
    boolean
    isUnknown()
    Returns true if this type of attribute is unknown.
    (专用程序包) final void
    putAttributes(SymbolTable symbolTable, byte[] code, int codeLength, int maxStack, int maxLocals, ByteVector output)
    Puts all the attributes of the attribute list that begins with this attribute, in the given byte vector.
    (专用程序包) static void
    putAttributes(SymbolTable symbolTable, int accessFlags, int signatureIndex, ByteVector output)
    Puts all the attributes that correspond to the given field, method or class access flags and signature, in the given byte vector.
    (专用程序包) final void
    putAttributes(SymbolTable symbolTable, ByteVector output)
    Puts all the attributes of the attribute list that begins with this attribute, in the given byte vector.
    protected Attribute
    read(ClassReader classReader, int offset, int length, char[] charBuffer, int codeAttributeOffset, Label[] labels)
    Reads a type attribute.
    protected ByteVector
    write(ClassWriter classWriter, byte[] code, int codeLength, int maxStack, int maxLocals)
    Returns the byte array form of the content of this attribute.

    从类继承的方法 java.lang.Object

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

  • 字段详细资料

    • type

      public final String type
      The type of this attribute, also called its name in the JVMS.

    • content

      private byte[] content
      The raw content of this attribute, only used for unknown attributes (see isUnknown()). The 6 header bytes of the attribute (attribute_name_index and attribute_length) are not included.

    • nextAttribute

      Attribute nextAttribute
      The next attribute in this attribute list (Attribute instances can be linked via this field to store a list of class, field, method or Code attributes). May be null.

  • 构造器详细资料

    • Attribute

      protected Attribute(String type)
      Constructs a new empty attribute.
      参数:
      type - the type of the attribute.

  • 方法详细资料

    • isUnknown

      public boolean isUnknown()
      Returns true if this type of attribute is unknown. This means that the attribute content can't be parsed to extract constant pool references, labels, etc. Instead, the attribute content is read as an opaque byte array, and written back as is. This can lead to invalid attributes, if the content actually contains constant pool references, labels, or other symbolic references that need to be updated when there are changes to the constant pool, the method bytecode, etc. The default implementation of this method always returns true.
      返回:
      true if this type of attribute is unknown.

    • isCodeAttribute

      public boolean isCodeAttribute()
      Returns true if this type of attribute is a Code attribute.
      返回:
      true if this type of attribute is a Code attribute.

    • getLabels

      protected Label[] getLabels()
      Returns the labels corresponding to this attribute.
      返回:
      the labels corresponding to this attribute, or null if this attribute is not a Code attribute that contains labels.

    • read

      protected Attribute read(ClassReader classReader, int offset, int length, char[] charBuffer, int codeAttributeOffset, Label[] labels)
      Reads a type attribute. This method must return a new Attribute object, of type type, corresponding to the 'length' bytes starting at 'offset', in the given ClassReader.
      参数:
      classReader - the class that contains the attribute to be read.
      offset - index of the first byte of the attribute's content in ClassReader. The 6 attribute header bytes (attribute_name_index and attribute_length) are not taken into account here.
      length - the length of the attribute's content (excluding the 6 attribute header bytes).
      charBuffer - the buffer to be used to call the ClassReader methods requiring a 'charBuffer' parameter.
      codeAttributeOffset - index of the first byte of content of the enclosing Code attribute in ClassReader, or -1 if the attribute to be read is not a Code attribute. The 6 attribute header bytes (attribute_name_index and attribute_length) are not taken into account here.
      labels - the labels of the method's code, or null if the attribute to be read is not a Code attribute.
      返回:
      a new Attribute object corresponding to the specified bytes.

    • write

      protected ByteVector write(ClassWriter classWriter, byte[] code, int codeLength, int maxStack, int maxLocals)
      Returns the byte array form of the content of this attribute. The 6 header bytes (attribute_name_index and attribute_length) must not be added in the returned ByteVector.
      参数:
      classWriter - the class to which this attribute must be added. This parameter can be used to add the items that corresponds to this attribute to the constant pool of this class.
      code - the bytecode of the method corresponding to this Code attribute, or null if this attribute is not a Code attribute. Corresponds to the 'code' field of the Code attribute.
      codeLength - the length of the bytecode of the method corresponding to this code attribute, or 0 if this attribute is not a Code attribute. Corresponds to the 'code_length' field of the Code attribute.
      maxStack - the maximum stack size of the method corresponding to this Code attribute, or -1 if this attribute is not a Code attribute.
      maxLocals - the maximum number of local variables of the method corresponding to this code attribute, or -1 if this attribute is not a Code attribute.
      返回:
      the byte array form of this attribute.

    • getAttributeCount

      final int getAttributeCount()
      Returns the number of attributes of the attribute list that begins with this attribute.
      返回:
      the number of attributes of the attribute list that begins with this attribute.

    • computeAttributesSize

      final int computeAttributesSize(SymbolTable symbolTable)
      Returns the total size in bytes of all the attributes in the attribute list that begins with this attribute. This size includes the 6 header bytes (attribute_name_index and attribute_length) per attribute. Also adds the attribute type names to the constant pool.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      返回:
      the size of all the attributes in this attribute list. This size includes the size of the attribute headers.

    • computeAttributesSize

      final int computeAttributesSize(SymbolTable symbolTable, byte[] code, int codeLength, int maxStack, int maxLocals)
      Returns the total size in bytes of all the attributes in the attribute list that begins with this attribute. This size includes the 6 header bytes (attribute_name_index and attribute_length) per attribute. Also adds the attribute type names to the constant pool.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      code - the bytecode of the method corresponding to these Code attributes, or null if they are not Code attributes. Corresponds to the 'code' field of the Code attribute.
      codeLength - the length of the bytecode of the method corresponding to these code attributes, or 0 if they are not Code attributes. Corresponds to the 'code_length' field of the Code attribute.
      maxStack - the maximum stack size of the method corresponding to these Code attributes, or -1 if they are not Code attributes.
      maxLocals - the maximum number of local variables of the method corresponding to these Code attributes, or -1 if they are not Code attribute.
      返回:
      the size of all the attributes in this attribute list. This size includes the size of the attribute headers.

    • computeAttributesSize

      static int computeAttributesSize(SymbolTable symbolTable, int accessFlags, int signatureIndex)
      Returns the total size in bytes of all the attributes that correspond to the given field, method or class access flags and signature. This size includes the 6 header bytes (attribute_name_index and attribute_length) per attribute. Also adds the attribute type names to the constant pool.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      accessFlags - some field, method or class access flags.
      signatureIndex - the constant pool index of a field, method of class signature.
      返回:
      the size of all the attributes in bytes. This size includes the size of the attribute headers.

    • putAttributes

      final void putAttributes(SymbolTable symbolTable, ByteVector output)
      Puts all the attributes of the attribute list that begins with this attribute, in the given byte vector. This includes the 6 header bytes (attribute_name_index and attribute_length) per attribute.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      output - where the attributes must be written.

    • putAttributes

      final void putAttributes(SymbolTable symbolTable, byte[] code, int codeLength, int maxStack, int maxLocals, ByteVector output)
      Puts all the attributes of the attribute list that begins with this attribute, in the given byte vector. This includes the 6 header bytes (attribute_name_index and attribute_length) per attribute.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      code - the bytecode of the method corresponding to these Code attributes, or null if they are not Code attributes. Corresponds to the 'code' field of the Code attribute.
      codeLength - the length of the bytecode of the method corresponding to these code attributes, or 0 if they are not Code attributes. Corresponds to the 'code_length' field of the Code attribute.
      maxStack - the maximum stack size of the method corresponding to these Code attributes, or -1 if they are not Code attributes.
      maxLocals - the maximum number of local variables of the method corresponding to these Code attributes, or -1 if they are not Code attribute.
      output - where the attributes must be written.

    • putAttributes

      static void putAttributes(SymbolTable symbolTable, int accessFlags, int signatureIndex, ByteVector output)
      Puts all the attributes that correspond to the given field, method or class access flags and signature, in the given byte vector. This includes the 6 header bytes (attribute_name_index and attribute_length) per attribute.
      参数:
      symbolTable - where the constants used in the attributes must be stored.
      accessFlags - some field, method or class access flags.
      signatureIndex - the constant pool index of a field, method of class signature.
      output - where the attributes must be written.