Class BCMethod

java.lang.Object
org.apache.derby.impl.services.bytecode.BCMethod
All Implemented Interfaces:
MethodBuilder
class BCMethod extends Object implements MethodBuilder
MethodBuilder is used to piece together a method when building a java class definition.

When a method is first created, it has:

  • a return type
  • modifiers
  • a name
  • an empty parameter list
  • an empty throws list
  • an empty statement block

MethodBuilder implementations are required to supply a way for Statements and Expressions to give them code. Most typically, they may have a stream to which their contents writes the code that is of the type to satisfy what the contents represent. MethodBuilder implementations also have to have a way to supply ClassBuilders with their code, that satisfies the type of class builder they are implemented with. This is implementation-dependent, so ClassBuilders, MethodBuilders, Statements, and Expressions all have to be of the same implementation in order to interact to generate a class.

Method Builder implementation for generating bytecode.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    (package private) final BCClass
    cb
     
    (package private) static final int
    CODE_SPLIT_LENGTH
    Code length at which to split into sub-methods.
    private Conditional
    condition
     
    private int
    currentVarNum
     
    private boolean
    handlingOverflow
    True if we are currently switching control over to a sub method to avoid hitting the code generation limit of 65535 bytes per method.
    (package private) int
    maxStack
    Maximum stack depth seen in this method, measured in words.
    protected final ClassHolder
    modClass
     
    (package private) CodeChunk
    myCode
     
    protected ClassMember
    myEntry
     
    private final String
    myName
    The original name of the method, this represents how any user would call this method.
    (package private) final String
    myReturnType
     
    private static final byte[]
    newArrayElementTypeMap
    this array maps the BCExpr vm_* constants 0..6 to the expected VM type constants for the newarray instruction.
    (package private) BCLocalField[]
    parameters
    Fast access for the parametes, will be null if the method has no parameters.
    private final String[]
    parameterTypes
    List of parameter types with java language class names.
    private int
    stackDepth
    Current stack depth in this method, measured in words.
    private int
    stackTypeOffset
    Points to the next array offset in stackTypes to be used.
    private Type[]
    stackTypes
    Array of the current types of the values on the stack.
    private int
    statementNum
     
    private int
    subMethodCount
    How many sub-methods we have overflowed to.
    (package private) static final byte
    T_BOOLEAN
     
    (package private) Vector<String>
    thrownExceptions
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    BCMethod(ClassBuilder cb, String returnType, String methodName, int modifiers, String[] parms, BCJava factory)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    private void
    addInstrCPE(short opcode, int cpe)
    Write a instruction that uses a constant pool entry as an operand, add a limit exceeded message if the number of constant pool entries has exceeded the limit.
    void
    addThrownException(String exceptionClass)
    a throwable can be added to the end of the list of thrownExceptions.
    int
    callMethod(short opcode, String declaringClass, String methodName, String returnType, int numArgs)
    Call a method.
    int
    callMethod(Object methodDescriptor)
    Call a method previously described by describeMethod().
    (package private) final void
    callSubMethod(BCMethod subMethod)
    Call a sub-method created by getNewSubMethod handling parameters correctly.
    void
    callSuper()
    Call super().
    void
    cast(String className)
    Cast the top stack value.
    void
    complete()
    when the method has had all of its parameters and thrown exceptions defined, and its statement block has been completed, it can be completed and its class file information generated.
    void
    completeConditional()
    Complete a conditional which completes the false code path.
    void
    conditionalIf()
    Initiate a conditional sequence.
    private void
    conditionalIf(short opcode)
     
    void
    conditionalIfNull()
    Initiate a conditional sequence.
    (package private) ClassHolder
    constantPool()
    In their giveCode methods, the parts of the method body will want to get to the constant pool to add their constants.
    private Type[]
    copyStack()
     
    Object
    describeMethod(short opcode, String declaringClass, String methodName, String returnType)
    Return an object that efficiently (to the implementation) describes a zero-argument method and can be used with the single argument callMethod().
    void
    dup()
    Duplicate the top value on the stack.
    void
    endStatement()
    End a statement.
    void
    getArrayElement(int element)
    Pop an array refrence off the stack and push an element from that array.
    private void
    getField(short opcode, String declaringClass, String fieldName, String fieldType)
     
    void
    getField(String declaringClass, String fieldName, String fieldType)
    Push the contents of the described field onto the stack.
    void
    getField(LocalField field)
    Push the contents of the local field onto the stack.
    String
    getName()
    Return the logical name of the method.
    (package private) final BCMethod
    getNewSubMethod(String returnType, boolean withParameters)
    Create a sub-method from this method to allow the code builder to split a single logical method into multiple methods to avoid the 64k per-method code size limit.
    void
    getParameter(int id)
    Push a parameter value.
    void
    getStaticField(String declaringClass, String fieldName, String fieldType)
    Push the contents of the described static field onto the stack.
    private void
    growStack(int size, Type type)
     
    private void
    growStack(Type type)
     
    void
    isInstanceOf(String className)
    Pop the top stack value and push a boolean that is the result of an instanceof check on the popped reference.
    void
    methodReturn()
    Return from a method, optionally with a value.
    private void
    overflowMethodCheck()
    Check to see if the current method byte code is nearing the limit of 65535.
    void
    pop()
    Pop the top value off the stack
    private Type
    popStack()
     
    void
    push(boolean value)
    Push a boolean constant onto the stack
    void
    push(byte value)
    Push a byte constant onto the stack
    void
    push(double value)
    Push a double constant onto the stack
    void
    push(float value)
    Push a float constant onto the stack
    void
    push(int value)
    Push a int constant onto the stack
    private void
    push(int value, Type type)
    Push an integer value.
    void
    push(long value)
    Push a long value onto the stack.
    void
    push(short value)
    Push a short constant onto the stack
    void
    push(String value)
    Push a String constant onto the stack
    void
    pushNewArray(String className, int size)
    Create an array instance Stack
    void
    pushNewComplete(int numArgs)
    Complete the sequence that was started with pushNewStart().
    void
    pushNewStart(String className)
    Initiate a sequence that calls a constructor, equivalent to the new operator in Java.
    void
    pushNull(String type)
    Push a typed null onto the stack
    void
    pushThis()
    Push this onto the stack.
    void
    putField(String fieldName, String fieldType)
    Pop the top stack value and store it in the instance field of this class.
    void
    putField(String declaringClass, String fieldName, String fieldType)
    Pop the top stack value and store it in the field.
    void
    putField(LocalField field)
    Upon entry the top word(s) on the stack is the value to be put into the field.
    private void
    putField(Type fieldType, int cpi, boolean dup)
     
    void
    setArrayElement(int element)
    Pop an array reference off the stack, store a value in the array at the passed in offset.
    void
    setField(LocalField field)
    Set the field but don't duplicate its value so nothing is left on the stack after this call.
    private void
    splitMethod()
    Attempt to split a large method by pushing code out to several sub-methods.
    void
    startElseCode()
    Complete the true code path of a conditional.
    boolean
    statementNumHitLimit(int noStatementsAdded)
    Tell if statement number in this method builder hits limit.
    void
    swap()
    Swap the top two values on the stack.
    void
    upCast(String className)
    Upcast the top stack value.
    private Type
    vmNameDeclaringClass(String declaringClass)
     
    protected void
    writeExceptions()
    sets exceptionBytes to the attribute_info needed for a method's Exceptions attribute.

    Methods inherited from class Object

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

  • Field Details

    • CODE_SPLIT_LENGTH

      static final int CODE_SPLIT_LENGTH
      Code length at which to split into sub-methods. Normally set to the maximim code length the JVM can support, but for testing the split code it can be reduced so that the standard tests cause some splitting. Tested with value set to 2000.
      See Also:

    • cb

      final BCClass cb

    • modClass

      protected final ClassHolder modClass

    • myReturnType

      final String myReturnType

    • myName

      private final String myName
      The original name of the method, this represents how any user would call this method.

    • parameters

      BCLocalField[] parameters
      Fast access for the parametes, will be null if the method has no parameters.

    • parameterTypes

      private final String[] parameterTypes
      List of parameter types with java language class names. Can be null or zero length for no parameters.

    • thrownExceptions

      Vector<String> thrownExceptions

    • myCode

      CodeChunk myCode

    • myEntry

      protected ClassMember myEntry

    • currentVarNum

      private int currentVarNum

    • statementNum

      private int statementNum

    • handlingOverflow

      private boolean handlingOverflow
      True if we are currently switching control over to a sub method to avoid hitting the code generation limit of 65535 bytes per method.

    • subMethodCount

      private int subMethodCount
      How many sub-methods we have overflowed to.

    • stackTypes

      private Type[] stackTypes
      Array of the current types of the values on the stack. A type that types up two words on the stack, e.g. double will only occupy one element in this array. This array is dynamically re-sized as needed.

    • stackTypeOffset

      private int stackTypeOffset
      Points to the next array offset in stackTypes to be used. Really it's the number of valid entries in stackTypes.

    • maxStack

      int maxStack
      Maximum stack depth seen in this method, measured in words. Corresponds to max_stack in the Code attribute of section 4.7.3 of the vm spec.

    • stackDepth

      private int stackDepth
      Current stack depth in this method, measured in words.

    • condition

      private Conditional condition

    • newArrayElementTypeMap

      private static final byte[] newArrayElementTypeMap
      this array maps the BCExpr vm_* constants 0..6 to the expected VM type constants for the newarray instruction.

      Because boolean was mapped to integer for general instructions, it will have to be specially matched and mapped to its value directly (4).

    • T_BOOLEAN

      static final byte T_BOOLEAN
      See Also:

  • Constructor Details

  • Method Details

    • getName

      public String getName()
      Return the logical name of the method. The current myEntry refers to the sub method we are currently overflowing to. Those sub-methods are hidden from any caller.
      Specified by:
      getName in interface MethodBuilder

    • getParameter

      public void getParameter(int id)
      Description copied from interface: MethodBuilder
      Push a parameter value. 
      Stack ...  =>
      ...,param_value
      Specified by:
      getParameter in interface MethodBuilder
      Parameters:
      id - position of the parameter (zero based).

    • addThrownException

      public void addThrownException(String exceptionClass)
      a throwable can be added to the end of the list of thrownExceptions.
      Specified by:
      addThrownException in interface MethodBuilder

    • complete

      public void complete()
      when the method has had all of its parameters and thrown exceptions defined, and its statement block has been completed, it can be completed and its class file information generated.

      further alterations of the method will not be reflected in the code generated for it.

      Specified by:
      complete in interface MethodBuilder

    • splitMethod

      private void splitMethod()
      Attempt to split a large method by pushing code out to several sub-methods. Performs a number of steps.
      1. Split at zero stack depth.
      2. Split at non-zero stack depth (FUTURE)
      If the class has already exceeded some limit in building the class file format structures then don't attempt to split. Most likely the number of constant pool entries has been exceeded and thus the built class file no longer has integrity. The split code relies on being able to read the in-memory version of the class file in order to determine descriptors for methods and fields.

    • constantPool

      ClassHolder constantPool()
      In their giveCode methods, the parts of the method body will want to get to the constant pool to add their constants. We really only want them treating it like a constant pool inclusion mechanism, we could write a wrapper to limit it to that.

    • writeExceptions

      protected void writeExceptions()
      sets exceptionBytes to the attribute_info needed for a method's Exceptions attribute. The ClassUtilities take care of the header 6 bytes for us, so they are not included here. See The Java Virtual Machine Specification Section 4.7.5, Exceptions attribute.

    • growStack

      private void growStack(int size, Type type)

    • growStack

      private void growStack(Type type)

    • popStack

      private Type popStack()

    • copyStack

      private Type[] copyStack()

    • pushThis

      public void pushThis()
      Description copied from interface: MethodBuilder
      Push this onto the stack. 
      Stack ...  =>
      ...,this_ref
      Specified by:
      pushThis in interface MethodBuilder

    • push

      public void push(byte value)
      Description copied from interface: MethodBuilder
      Push a byte constant onto the stack 
      Stack ...  =>
      ...,byte_value
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(boolean value)
      Description copied from interface: MethodBuilder
      Push a boolean constant onto the stack 
      Stack ...  =>
      ...,boolean_value
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(short value)
      Description copied from interface: MethodBuilder
      Push a short constant onto the stack 
      Stack ...  =>
      ...,short_value
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(int value)
      Description copied from interface: MethodBuilder
      Push a int constant onto the stack 
      Stack ...  =>
      ...,int_value
      Specified by:
      push in interface MethodBuilder

    • dup

      public void dup()
      Description copied from interface: MethodBuilder
      Duplicate the top value on the stack. 
      Stack ...,value =>
      ...,value,value
      Specified by:
      dup in interface MethodBuilder

    • swap

      public void swap()
      Description copied from interface: MethodBuilder
      Swap the top two values on the stack. 
      Stack ...,valueA,valueB =>
      ...,valueB,valueA
      Specified by:
      swap in interface MethodBuilder

    • push

      private void push(int value, Type type)
      Push an integer value. Uses the special integer opcodes for the constants -1 to 5, BIPUSH for values that fit in a byte and SIPUSH for values that fit in a short. Otherwise uses LDC with a constant pool entry.
      Parameters:
      value - Value to be pushed
      type - Final type of the value.

    • push

      public void push(long value)
      Push a long value onto the stack. For the values zero and one the LCONST_0 and LCONST_1 instructions are used. For values betwee Short.MIN_VALUE and Short.MAX_VALUE inclusive an byte/short/int value is pushed using push(int, Type) followed by an I2L instruction. This saves using a constant pool entry for such values. All other values use a constant pool entry. For values in the range of an Integer an integer constant pool entry is created to allow sharing with integer constants and to reduce constant pool slot entries.
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(float value)
      Description copied from interface: MethodBuilder
      Push a float constant onto the stack 
      Stack ...  =>
      ...,float_value
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(double value)
      Description copied from interface: MethodBuilder
      Push a double constant onto the stack 
      Stack ...  =>
      ...,double_value
      Specified by:
      push in interface MethodBuilder

    • push

      public void push(String value)
      Description copied from interface: MethodBuilder
      Push a String constant onto the stack 
      Stack ...  =>
      ...,String_value
      Specified by:
      push in interface MethodBuilder

    • methodReturn

      public void methodReturn()
      Description copied from interface: MethodBuilder
      Return from a method, optionally with a value. Must only be called if zero or one item exists on the stack. If the stack contains a single value then that is popped and used as the returned value. 
      Stack value =>
      :empty:
or

Stack :empty: =>
      :empty:
      .
      Specified by:
      methodReturn in interface MethodBuilder

    • describeMethod

      public Object describeMethod(short opcode, String declaringClass, String methodName, String returnType)
      Description copied from interface: MethodBuilder
      Return an object that efficiently (to the implementation) describes a zero-argument method and can be used with the single argument callMethod(). Descriptions for the parameters to this method are the same as the five argument callMethod(). This allows the caller to cache frequently used methods. The returned object is only valid for use by this MethodBuilder.
      This call does not affect the Stack.
      Specified by:
      describeMethod in interface MethodBuilder

    • callMethod

      public int callMethod(Object methodDescriptor)
      Description copied from interface: MethodBuilder
      Call a method previously described by describeMethod(). 
      static methods

Stack ...,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

non-static methods

Stack ...,ref,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]
      Specified by:
      callMethod in interface MethodBuilder

    • callMethod

      public int callMethod(short opcode, String declaringClass, String methodName, String returnType, int numArgs)
      Description copied from interface: MethodBuilder
      Call a method. The instance (receiver or reference) for non-static methods must be pushed by the caller. The instance (for non-static) and the arguments are popped of the stack, and the return value (if any) is pushed onto the stack.
      The type needs to be one of:
      • VMOpcode.INVOKESTATIC - call a static method
      • VMOpcode.INVOKEVIRTUAL - call method declared in the class or super-class.
      • VMOpcode.INVOKEINTERFACE - call a method declared in an interface 
      static methods

Stack ...,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

non-static methods

Stack ...,ref,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

      The type of the arguments to the methods must exactly match the declared types of the parameters to the methods. If a argument is of the incorrect type the caller must up cast it or down cast it.
      Specified by:
      callMethod in interface MethodBuilder
      Parameters:
      opcode - type of method invocation
      declaringClass - Class or interface the method is declared in. If it is a non-static method call then if declaringClass is null, the declared type is taken to be the type of the reference that will be popped.
      methodName - name of the method
      returnType - class name or primitive type (including "void") of the return type of the method, can not be null.
      numArgs - number of arguments to the method (can be 0).

    • vmNameDeclaringClass

      private Type vmNameDeclaringClass(String declaringClass)

    • callSuper

      public void callSuper()
      Description copied from interface: MethodBuilder
      Call super(). Caller must only add this to a constructor. 
      
Stack ... =>
      ...
      Specified by:
      callSuper in interface MethodBuilder

    • pushNewStart

      public void pushNewStart(String className)
      Description copied from interface: MethodBuilder
      Initiate a sequence that calls a constructor, equivalent to the new operator in Java. After this call, the caller must push any arguments and then complete the construction with a call to pushNewComplete(). Only arguments to the constructor can be pushed onto the stack between the pushNewStart() and pushNewComplete() method calls. 
      Stack ... => [unchanged]
      ...
      Specified by:
      pushNewStart in interface MethodBuilder
      Parameters:
      className - class name of object to be created.

    • pushNewComplete

      public void pushNewComplete(int numArgs)
      Description copied from interface: MethodBuilder
      Complete the sequence that was started with pushNewStart(). Pop the arguments to the constructor and push the reference to the newly created object. 
      Stack ...,value* => [numArgs number of values will be popped]
      ...,new_ref
      Specified by:
      pushNewComplete in interface MethodBuilder
      Parameters:
      numArgs - number of arguments to the constructor (can be 0).

    • upCast

      public void upCast(String className)
      Description copied from interface: MethodBuilder
      Upcast the top stack value. This is used for correct method resolution by upcasting method parameters. It does not put any casting code into the byte code stream. Can only be used for refrences. 
      Stack ...,ref =>
      ...,ref
      Specified by:
      upCast in interface MethodBuilder

    • cast

      public void cast(String className)
      Description copied from interface: MethodBuilder
      Cast the top stack value. Correctly down-casts a reference or casts a primitive type (e.g. int to short). 
      Stack ...,value =>
      ...,cast_value
      Specified by:
      cast in interface MethodBuilder
      Parameters:
      className - type (primitive, interface or class) to cast to.

    • isInstanceOf

      public void isInstanceOf(String className)
      Description copied from interface: MethodBuilder
      Pop the top stack value and push a boolean that is the result of an instanceof check on the popped reference. 
      Stack ...,ref =>
      ...,boolean_value
      .
      Specified by:
      isInstanceOf in interface MethodBuilder

    • pushNull

      public void pushNull(String type)
      Description copied from interface: MethodBuilder
      Push a typed null onto the stack 
      Stack ...  =>
      ...,null
      Specified by:
      pushNull in interface MethodBuilder

    • getField

      public void getField(LocalField field)
      Description copied from interface: MethodBuilder
      Push the contents of the local field onto the stack. This call pushes the this instance required to access the field itself. 
      Stack ...  =>
      ...,field_value
      Specified by:
      getField in interface MethodBuilder

    • getField

      public void getField(String declaringClass, String fieldName, String fieldType)
      Description copied from interface: MethodBuilder
      Push the contents of the described field onto the stack. This call requires the instance (reference) to be pushed by the caller. 
      Stack ...,field_ref  =>
      ...,field_value
      Specified by:
      getField in interface MethodBuilder

    • getStaticField

      public void getStaticField(String declaringClass, String fieldName, String fieldType)
      Push the contents of the described static field onto the stack.
      Specified by:
      getStaticField in interface MethodBuilder

    • getField

      private void getField(short opcode, String declaringClass, String fieldName, String fieldType)

    • setField

      public void setField(LocalField field)
      Set the field but don't duplicate its value so nothing is left on the stack after this call.
      Specified by:
      setField in interface MethodBuilder

    • putField

      public void putField(LocalField field)
      Upon entry the top word(s) on the stack is the value to be put into the field. Ie. we have 
      word
      Before the call we need 
      word
this
word
      word2,word1 -> word2, word1, word2 So that we are left with word after the put.
      Specified by:
      putField in interface MethodBuilder

    • putField

      public void putField(String fieldName, String fieldType)
      Pop the top stack value and store it in the instance field of this class.
      Specified by:
      putField in interface MethodBuilder

    • putField

      private void putField(Type fieldType, int cpi, boolean dup)

    • putField

      public void putField(String declaringClass, String fieldName, String fieldType)
      Pop the top stack value and store it in the field. This call requires the instance to be pushed by the caller.
      Specified by:
      putField in interface MethodBuilder

    • conditionalIfNull

      public void conditionalIfNull()
      Description copied from interface: MethodBuilder
      Initiate a conditional sequence. The top value on the stack (a reference) is popped and compared to 'null'. If the value is null then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called.
      E.g. 
      mb.callMethod(...); // pushes an object onto the stack
mb.conditionalIfNull();
  mb.push(3);
mb.startElseCode();
  mb.push(5);
mb.completeConditional();
// at this point 3 or 5 will be on the stack
      Each path through the ?: statement must leave the stack at the same depth as the other.
      If the if or else code pops values from the stack that were before the conditional value, then they must use the same number of values from the stack. 
      Stack ...,ref =>
      ...
      .
      Specified by:
      conditionalIfNull in interface MethodBuilder

    • conditionalIf

      public void conditionalIf()
      Description copied from interface: MethodBuilder
      Initiate a conditional sequence. The top value on the stack must be a boolean and will be popped. If it is true then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called. See conditionalIfNull() for example and restrictions. 
      Stack ...,boolean_value =>
      ...
      .
      Specified by:
      conditionalIf in interface MethodBuilder

    • conditionalIf

      private void conditionalIf(short opcode)

    • startElseCode

      public void startElseCode()
      Description copied from interface: MethodBuilder
      Complete the true code path of a conditional.
      Specified by:
      startElseCode in interface MethodBuilder

    • completeConditional

      public void completeConditional()
      Description copied from interface: MethodBuilder
      Complete a conditional which completes the false code path.
      Specified by:
      completeConditional in interface MethodBuilder

    • pop

      public void pop()
      Description copied from interface: MethodBuilder
      Pop the top value off the stack 
              Stack ..., value =>
              ...
      .
      Specified by:
      pop in interface MethodBuilder

    • endStatement

      public void endStatement()
      Description copied from interface: MethodBuilder
      End a statement. Pops the top-word of the stack, if any. Must only be called if zero or one item exists on the stack. 
      Stack value =>
      :empty:
or

Stack :empty: =>
      :empty:
      .
      Specified by:
      endStatement in interface MethodBuilder

    • getArrayElement

      public void getArrayElement(int element)
      Description copied from interface: MethodBuilder
      Pop an array refrence off the stack and push an element from that array. 
      Stack ...,array_ref =>
      ...,value
      Specified by:
      getArrayElement in interface MethodBuilder
      Parameters:
      element - Offset into the array (zero based)

    • setArrayElement

      public void setArrayElement(int element)
      Description copied from interface: MethodBuilder
      Pop an array reference off the stack, store a value in the array at the passed in offset. 
      Stack ...,array_ref, value =>
      ...
      Specified by:
      setArrayElement in interface MethodBuilder
      Parameters:
      element - Offset into the array (zero based)

    • pushNewArray

      public void pushNewArray(String className, int size)
      Create an array instance Stack ... => ...,arrayref
      Specified by:
      pushNewArray in interface MethodBuilder
      Parameters:
      className - - type of array.
      size - - number of elements in the array

    • addInstrCPE

      private void addInstrCPE(short opcode, int cpe)
      Write a instruction that uses a constant pool entry as an operand, add a limit exceeded message if the number of constant pool entries has exceeded the limit.

    • statementNumHitLimit

      public boolean statementNumHitLimit(int noStatementsAdded)
      Tell if statement number in this method builder hits limit. This method builder keeps a counter of how many statements are added to it. Caller should call this function every time it tries to add a statement to this method builder (counter is increased by 1), then the function returns whether the accumulated statement number hits a limit. The reason of doing this is that Java compiler has a limit of 64K code size for each method. We might hit this limit if an extremely long insert statement is issued, for example (see beetle 4293). Counting statement number is an approximation without too much overhead.
      Specified by:
      statementNumHitLimit in interface MethodBuilder

    • overflowMethodCheck

      private void overflowMethodCheck()
      Check to see if the current method byte code is nearing the limit of 65535. If it is start overflowing to a new method.

      Overflow is handled for a method named e23 as: public Object e23() { ... existing code // split point return e23_0(); } private Object e23_0() { ... first set overflowed code // split point return e23_1(); } private Object e23_1() { ... second set overflowed code // method complete return result; }

      These overflow methods are hidden from the code using this MethodBuilder, it continues to think that it is building a single method with the original name.
      Restrictions:

      • Only handles methods with no arguments
      • Stack depth must be zero

    • getNewSubMethod

      final BCMethod getNewSubMethod(String returnType, boolean withParameters)
      Create a sub-method from this method to allow the code builder to split a single logical method into multiple methods to avoid the 64k per-method code size limit. The sub method with inherit the thrown exceptions of this method.
      Parameters:
      returnType - Return type of the new method
      withParameters - True to define the method with matching parameters false to define it with no parameters.
      Returns:
      A valid empty sub method.

    • callSubMethod

      final void callSubMethod(BCMethod subMethod)
      Call a sub-method created by getNewSubMethod handling parameters correctly.