Package org.mozilla.classfile

Class ClassFileWriter

  • public class ClassFileWriter
extends Object
    ClassFileWriter A ClassFileWriter is used to write a Java class file. Methods are provided to create fields and methods, and within methods to write Java bytecodes.

    • Constructor Detail

      • ClassFileWriter

        public ClassFileWriter​(String className,
                       String superClassName,
                       String sourceFileName)
        Construct a ClassFileWriter for a class.
        Parameters:
        className - the name of the class to write, including full package qualification.
        superClassName - the name of the superclass of the class to write, including full package qualification.
        sourceFileName - the name of the source file to use for producing debug information, or null if debug information is not desired

    • Method Detail

      • getClassName

        public final String getClassName()

      • addInterface

        public void addInterface​(String interfaceName)
        Add an interface implemented by this class. This method may be called multiple times for classes that implement multiple interfaces.
        Parameters:
        interfaceName - a name of an interface implemented by the class being written, including full package qualification.

      • setFlags

        public void setFlags​(short flags)
        Set the class's flags. Flags must be a set of the following flags, bitwise or'd together: ACC_PUBLIC ACC_PRIVATE ACC_PROTECTED ACC_FINAL ACC_ABSTRACT TODO: check that this is the appropriate set
        Parameters:
        flags - the set of class flags to set

      • classNameToSignature

        public static String classNameToSignature​(String name)
        Convert Java class name in dot notation into "Lname-with-dots-replaced-by-slashes;" form suitable for use as JVM type signatures.

      • addField

        public void addField​(String fieldName,
                     String type,
                     short flags)
        Add a field to the class.
        Parameters:
        fieldName - the name of the field
        type - the type of the field using ...
        flags - the attributes of the field, such as ACC_PUBLIC, etc. bitwise or'd together

      • addField

        public void addField​(String fieldName,
                     String type,
                     short flags,
                     int value)
        Add a field to the class.
        Parameters:
        fieldName - the name of the field
        type - the type of the field using ...
        flags - the attributes of the field, such as ACC_PUBLIC, etc. bitwise or'd together
        value - an initial integral value

      • addField

        public void addField​(String fieldName,
                     String type,
                     short flags,
                     long value)
        Add a field to the class.
        Parameters:
        fieldName - the name of the field
        type - the type of the field using ...
        flags - the attributes of the field, such as ACC_PUBLIC, etc. bitwise or'd together
        value - an initial long value

      • addField

        public void addField​(String fieldName,
                     String type,
                     short flags,
                     double value)
        Add a field to the class.
        Parameters:
        fieldName - the name of the field
        type - the type of the field using ...
        flags - the attributes of the field, such as ACC_PUBLIC, etc. bitwise or'd together
        value - an initial double value

      • addVariableDescriptor

        public void addVariableDescriptor​(String name,
                                  String type,
                                  int startPC,
                                  int register)
        Add Information about java variable to use when generating the local variable table.
        Parameters:
        name - variable name.
        type - variable type as bytecode descriptor string.
        startPC - the starting bytecode PC where this variable is live, or -1 if it does not have a Java register.
        register - the Java register number of variable or -1 if it does not have a Java register.

      • startMethod

        public void startMethod​(String methodName,
                        String type,
                        short flags)
        Add a method and begin adding code. This method must be called before other methods for adding code, exception tables, etc. can be invoked.
        Parameters:
        methodName - the name of the method
        type - a string representing the type
        flags - the attributes of the field, such as ACC_PUBLIC, etc. bitwise or'd together

      • stopMethod

        public void stopMethod​(short maxLocals)
        Complete generation of the method. After this method is called, no more code can be added to the method begun with startMethod.
        Parameters:
        maxLocals - the maximum number of local variable slots (a.k.a. Java registers) used by the method

      • add

        public void add​(int theOpCode)
        Add the single-byte opcode to the current method.
        Parameters:
        theOpCode - the opcode of the bytecode

      • add

        public void add​(int theOpCode,
                int theOperand)
        Add a single-operand opcode to the current method.
        Parameters:
        theOpCode - the opcode of the bytecode
        theOperand - the operand of the bytecode

      • addLoadConstant

        public void addLoadConstant​(int k)
        Generate the load constant bytecode for the given integer.
        Parameters:
        k - the constant

      • addLoadConstant

        public void addLoadConstant​(long k)
        Generate the load constant bytecode for the given long.
        Parameters:
        k - the constant

      • addLoadConstant

        public void addLoadConstant​(float k)
        Generate the load constant bytecode for the given float.
        Parameters:
        k - the constant

      • addLoadConstant

        public void addLoadConstant​(double k)
        Generate the load constant bytecode for the given double.
        Parameters:
        k - the constant

      • addLoadConstant

        public void addLoadConstant​(String k)
        Generate the load constant bytecode for the given string.
        Parameters:
        k - the constant

      • add

        public void add​(int theOpCode,
                int theOperand1,
                int theOperand2)
        Add the given two-operand bytecode to the current method.
        Parameters:
        theOpCode - the opcode of the bytecode
        theOperand1 - the first operand of the bytecode
        theOperand2 - the second operand of the bytecode

      • add

        public void add​(int theOpCode,
                String className)

      • add

        public void add​(int theOpCode,
                String className,
                String fieldName,
                String fieldType)

      • addInvoke

        public void addInvoke​(int theOpCode,
                      String className,
                      String methodName,
                      String methodType)

      • addPush

        public void addPush​(int k)
        Generate code to load the given integer on stack.
        Parameters:
        k - the constant

      • addPush

        public void addPush​(boolean k)

      • addPush

        public void addPush​(long k)
        Generate code to load the given long on stack.
        Parameters:
        k - the constant

      • addPush

        public void addPush​(double k)
        Generate code to load the given double on stack.
        Parameters:
        k - the constant

      • addPush

        public void addPush​(String k)
        Generate the code to leave on stack the given string even if the string encoding exeeds the class file limit for single string constant
        Parameters:
        k - the constant

      • isUnderStringSizeLimit

        public boolean isUnderStringSizeLimit​(String k)
        Check if k fits limit on string constant size imposed by class file format.
        Parameters:
        k - the string constant

      • addIStore

        public void addIStore​(int local)
        Store integer from stack top into the given local.
        Parameters:
        local - number of local register

      • addLStore

        public void addLStore​(int local)
        Store long from stack top into the given local.
        Parameters:
        local - number of local register

      • addFStore

        public void addFStore​(int local)
        Store float from stack top into the given local.
        Parameters:
        local - number of local register

      • addDStore

        public void addDStore​(int local)
        Store double from stack top into the given local.
        Parameters:
        local - number of local register

      • addAStore

        public void addAStore​(int local)
        Store object from stack top into the given local.
        Parameters:
        local - number of local register

      • addILoad

        public void addILoad​(int local)
        Load integer from the given local into stack.
        Parameters:
        local - number of local register

      • addLLoad

        public void addLLoad​(int local)
        Load long from the given local into stack.
        Parameters:
        local - number of local register

      • addFLoad

        public void addFLoad​(int local)
        Load float from the given local into stack.
        Parameters:
        local - number of local register

      • addDLoad

        public void addDLoad​(int local)
        Load double from the given local into stack.
        Parameters:
        local - number of local register

      • addALoad

        public void addALoad​(int local)
        Load object from the given local into stack.
        Parameters:
        local - number of local register

      • addLoadThis

        public void addLoadThis()
        Load "this" into stack.

      • addTableSwitch

        public int addTableSwitch​(int low,
                          int high)

      • markTableSwitchDefault

        public final void markTableSwitchDefault​(int switchStart)

      • markTableSwitchCase

        public final void markTableSwitchCase​(int switchStart,
                                      int caseIndex)

      • markTableSwitchCase

        public final void markTableSwitchCase​(int switchStart,
                                      int caseIndex,
                                      int stackTop)

      • setTableSwitchJump

        public void setTableSwitchJump​(int switchStart,
                               int caseIndex,
                               int jumpTarget)
        Set a jump case for a tableswitch instruction. The jump target should be marked as a super block start for stack map generation.

      • acquireLabel

        public int acquireLabel()

      • markLabel

        public void markLabel​(int label)

      • markLabel

        public void markLabel​(int label,
                      short stackTop)

      • markHandler

        public void markHandler​(int theLabel)

      • getLabelPC

        public int getLabelPC​(int label)

      • getCurrentCodeOffset

        public int getCurrentCodeOffset()
        Get the current offset into the code of the current method.
        Returns:
        an integer representing the offset

      • getStackTop

        public short getStackTop()

      • setStackTop

        public void setStackTop​(short n)

      • adjustStackTop

        public void adjustStackTop​(int delta)

      • addExceptionHandler

        public void addExceptionHandler​(int startLabel,
                                int endLabel,
                                int handlerLabel,
                                String catchClassName)

      • addLineNumberEntry

        public void addLineNumberEntry​(short lineNumber)

      • write

        public void write​(OutputStream oStream)
           throws IOException
        Write the class file to the OutputStream.
        Parameters:
        oStream - the stream to write to
        Throws:
        IOException - if writing to the stream produces an exception

      • toByteArray

        public byte[] toByteArray()
        Get the class file as array of bytesto the OutputStream.