Package org.apache.bcel.classfile

Class Code

  • All Implemented Interfaces:
    java.lang.Cloneable, Node
    public final class Code
extends Attribute
    This class represents a chunk of Java byte code contained in a method. It is instantiated by the Attribute.readAttribute() method. A Code attribute contains informations about operand stack, local variables, byte code and the exceptions handled within this method. This attribute has attributes itself, namely LineNumberTable which is used for debugging purposes and LocalVariableTable which contains information about the local variables. 
     Code_attribute {
   u2 attribute_name_index;
   u4 attribute_length;
   u2 max_stack;
   u2 max_locals;
   u4 code_length;
   u1 code[code_length];
   u2 exception_table_length;
   {
     u2 start_pc;
     u2 end_pc;
     u2 handler_pc;
     u2 catch_type;
   } exception_table[exception_table_length];
   u2 attributes_count;
   attribute_info attributes[attributes_count];
 }
    See Also:
    Attribute, CodeException, LineNumberTable, LocalVariableTable

    • Constructor Detail

      • Code

        public Code​(Code code)
        Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a physical copy.
        Parameters:
        code - The source Code.

      • Code

        public Code​(int nameIndex,
            int length,
            int maxStack,
            int maxLocals,
            byte[] code,
            CodeException[] exceptionTable,
            Attribute[] attributes,
            ConstantPool constantPool)
        Constructs a Code attribute.
        Parameters:
        nameIndex - Index pointing to the name Code.
        length - Content length in bytes.
        maxStack - Maximum size of stack.
        maxLocals - Number of local variables.
        code - Actual byte code.
        exceptionTable - of handled exceptions.
        attributes - Attributes of code: LineNumber or LocalVariable.
        constantPool - Array of constants.
        Throws:
        ClassFormatException - Thrown if the code array is greater than Const.MAX_CODE_SIZE.

    • Method Detail

      • accept

        public void accept​(Visitor v)
        Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. That is, the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
        Specified by:
        accept in interface Node
        Specified by:
        accept in class Attribute
        Parameters:
        v - Visitor object.

      • copy

        public Attribute copy​(ConstantPool constantPool)
        Creates a deep copy of this attribute.
        Specified by:
        copy in class Attribute
        Parameters:
        constantPool - The constant pool to duplicate.
        Returns:
        deep copy of this attribute.

      • dump

        public void dump​(java.io.DataOutputStream file)
          throws java.io.IOException
        Dumps code attribute to file stream in binary format.
        Overrides:
        dump in class Attribute
        Parameters:
        file - Output file stream.
        Throws:
        java.io.IOException - Thrown if an I/O error occurs.

      • getCode

        public byte[] getCode()
        Gets the actual byte code of the method.
        Returns:
        Actual byte code of the method.

      • getMaxLocals

        public int getMaxLocals()
        Gets the number of local variables.
        Returns:
        Number of local variables.

      • getMaxStack

        public int getMaxStack()
        Gets the maximum size of stack used by this method.
        Returns:
        Maximum size of stack used by this method.

      • getStackMap

        public StackMap getStackMap()
        Finds the attribute of StackMap instance.
        Returns:
        StackMap of Code, if it has one, else null.
        Since:
        6.8.0

      • setAttributes

        public void setAttributes​(Attribute[] attributes)
        Sets the attributes for this Code.
        Parameters:
        attributes - The attributes to set for this Code.

      • setExceptionTable

        public void setExceptionTable​(CodeException[] exceptionTable)
        Sets the exception table.
        Parameters:
        exceptionTable - exception table.

      • setMaxLocals

        public void setMaxLocals​(int maxLocals)
        Sets the maximum number of local variables.
        Parameters:
        maxLocals - maximum number of local variables.

      • setMaxStack

        public void setMaxStack​(int maxStack)
        Sets the maximum stack size.
        Parameters:
        maxStack - maximum stack size.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class Attribute
        Returns:
        String representation of code chunk.

      • toString

        public java.lang.String toString​(boolean verbose)
        Converts this object to a String.
        Parameters:
        verbose - Provides verbose output when true.
        Returns:
        String representation of code chunk.