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org.apache.derby.impl.services.bytecode
Class BCMethod  

java.lang.Object
  org.apache.derby.impl.services.bytecode.BCMethod

All Implemented Interfaces:

org.apache.derby.iapi.services.compiler.MethodBuilder

---

public class BCMethod

extends java.lang.Object

implements org.apache.derby.iapi.services.compiler.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.

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Field Summary
(package private)  BCClass	cb
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.
private  int	maxStack
protected  org.apache.derby.iapi.services.classfile.ClassHolder	modClass
(package private)  CodeChunk	myCode
protected  org.apache.derby.iapi.services.classfile.ClassMember	myEntry
private  java.lang.String	myName           The original name of the method, this represents how any user would call this method.
private  java.lang.String	myReturnType
private static byte[]	newArrayElementTypeMap           this array maps the BCExpr vm_* constants 0..6 to the expected VM type constants for the newarray instruction.
protected  BCLocalField[]	parameters
private  int	stackDepth
private  int	stackTypeOffset
private  Type[]	stackTypes
private  int	statementNum
private  int	subMethodCount           How many sub-methods we have overflowed to.
(package private) static byte	T_BOOLEAN
protected  java.util.Vector	thrownExceptions

 

Constructor Summary
(package private)	BCMethod(org.apache.derby.iapi.services.compiler.ClassBuilder cb, java.lang.String returnType, java.lang.String methodName, int modifiers, java.lang.String[] parms, BCJava factory)

 

Method Summary
void	addThrownException(java.lang.String exceptionClass)           a throwable can be added to the end of the list of thrownExceptions.
int	callMethod(java.lang.Object methodDescriptor)           Call a method previously described by describeMethod().
int	callMethod(short opcode, java.lang.String declaringClass, java.lang.String methodName, java.lang.String returnType, int numArgs)           Call a method.
void	callSuper()           Call super().
void	cast(java.lang.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 the a ?: operator which completes the false code path.
void	conditionalIf()           Initiate a sequence that corresponds to the Java language ' value ? ...
private  void	conditionalIf(short opcode)
void	conditionalIfNull()           Initiate a sequence that corresponds to the Java language 'ref == null ? ...
(package private)  org.apache.derby.iapi.services.classfile.ClassHolder	constantPool()           In their giveCode methods, the parts of the method body will want to get to the constant pool to add their constants.
java.lang.Object	describeMethod(short opcode, java.lang.String declaringClass, java.lang.String methodName, java.lang.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.
void	getField(org.apache.derby.iapi.services.compiler.LocalField field)           Push the contents of the local field onto the stack.
private  void	getField(short opcode, java.lang.String declaringClass, java.lang.String fieldName, java.lang.String fieldType)
void	getField(java.lang.String declaringClass, java.lang.String fieldName, java.lang.String fieldType)           Push the contents of the described field onto the stack.
java.lang.String	getName()           Return the logical name of the method.
void	getParameter(int id)           Push a parameter value.
void	getStaticField(java.lang.String declaringClass, java.lang.String fieldName, java.lang.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(java.lang.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)
void	push(long value)           Push a long constant onto the stack
void	push(short value)           Push a short constant onto the stack
void	push(java.lang.String value)           Push a String constant onto the stack
void	pushNewArray(java.lang.String className, int size)           Create an array instance Stack ...
void	pushNewComplete(int numArgs)           Complete the sequence that was started with pushNewStart().
void	pushNewStart(java.lang.String className)           Initiate a sequence that calls a constructor, equivalent to the new operator in Java.
void	pushNull(java.lang.String type)           Push a typed null onto the stack
void	pushThis()           Push this onto the stack.
void	putField(org.apache.derby.iapi.services.compiler.LocalField field)           Upon entry the top word(s) on the stack is the value to be put into the field.
void	putField(java.lang.String fieldName, java.lang.String fieldType)           Pop the top stack value and store it in the instance field of this class.
void	putField(java.lang.String declaringClass, java.lang.String fieldName, java.lang.String fieldType)           Pop the top stack value and store it in 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(org.apache.derby.iapi.services.compiler.LocalField field)           Set the field but don't duplicate its value so nothing is left on the stack after this call.
void	startElseCode()           Complete the true code path of a ?: operator.
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(java.lang.String className)           Upcast the top stack value.
private  Type	vmNameDeclaringClass(java.lang.String declaringClass)
protected  void	writeExceptions()           sets exceptionBytes to the attribute_info needed for a method's Exceptions attribute.

 

Methods inherited from class java.lang.Object

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

 

Field Detail

cb

final BCClass cb

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modClass

protected final org.apache.derby.iapi.services.classfile.ClassHolder modClass

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myReturnType

private final java.lang.String myReturnType

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myName

private final java.lang.String myName

The original name of the method, this represents how any user would call this method.

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parameters

protected BCLocalField[] parameters

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thrownExceptions

protected java.util.Vector thrownExceptions

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myCode

CodeChunk myCode

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myEntry

protected org.apache.derby.iapi.services.classfile.ClassMember myEntry

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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

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stackTypeOffset

private int stackTypeOffset

---

maxStack

private int maxStack

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stackDepth

private int stackDepth

---

condition

private Conditional condition

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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:

Constant Field Values

Constructor Detail

BCMethod

BCMethod(org.apache.derby.iapi.services.compiler.ClassBuilder cb,
         java.lang.String returnType,
         java.lang.String methodName,
         int modifiers,
         java.lang.String[] parms,
         BCJava factory)

Method Detail

getName

public java.lang.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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getParameter

public void getParameter(int id)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a parameter value.

                Stack ...  =>
                      ...,param_value
                

Specified by:

getParameter in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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addThrownException

public void addThrownException(java.lang.String exceptionClass)

a throwable can be added to the end of the list of thrownExceptions.

Specified by:

addThrownException in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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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 org.apache.derby.iapi.services.compiler.MethodBuilder

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constantPool

org.apache.derby.iapi.services.classfile.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.

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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.

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growStack

private void growStack(int size,
                       Type type)

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growStack

private void growStack(Type type)

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popStack

private Type popStack()

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pushThis

public void pushThis()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push this onto the stack.

                Stack ...  =>
                      ...,this_ref
                

Specified by:

pushThis in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(byte value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a byte constant onto the stack

                Stack ...  =>
                      ...,byte_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(boolean value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a boolean constant onto the stack

                Stack ...  =>
                      ...,boolean_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(short value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a short constant onto the stack

                Stack ...  =>
                      ...,short_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(int value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a int constant onto the stack

                Stack ...  =>
                      ...,int_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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dup

public void dup()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Duplicate the top value on the stack.

                Stack ...,value =>
                      ...,value,value
                

Specified by:

dup in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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swap

public void swap()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Swap the top two values on the stack.

                Stack ...,valueA,valueB =>
                      ...,valueB,valueA
                

Specified by:

swap in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

private void push(int value,
                  Type type)

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push

public void push(long value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a long constant onto the stack

                Stack ...  =>
                      ...,long_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(float value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a float constant onto the stack

                Stack ...  =>
                      ...,float_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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push

public void push(double value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a double constant onto the stack

                Stack ...  =>
                      ...,double_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

push

public void push(java.lang.String value)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a String constant onto the stack

                Stack ...  =>
                      ...,String_value
                

Specified by:

push in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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methodReturn

public void methodReturn()

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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describeMethod

public java.lang.Object describeMethod(short opcode,
                                       java.lang.String declaringClass,
                                       java.lang.String methodName,
                                       java.lang.String returnType)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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callMethod

public int callMethod(java.lang.Object methodDescriptor)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

callMethod

public int callMethod(short opcode,
                      java.lang.String declaringClass,
                      java.lang.String methodName,
                      java.lang.String returnType,
                      int numArgs)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

vmNameDeclaringClass

private Type vmNameDeclaringClass(java.lang.String declaringClass)

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callSuper

public void callSuper()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Call super(). Caller must only add this to a constructor.

                Stack ... =>
                      ... 
                

Specified by:

callSuper in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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pushNewStart

public void pushNewStart(java.lang.String className)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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pushNewComplete

public void pushNewComplete(int numArgs)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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upCast

public void upCast(java.lang.String className)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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cast

public void cast(java.lang.String className)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

isInstanceOf

public void isInstanceOf(java.lang.String className)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

pushNull

public void pushNull(java.lang.String type)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Push a typed null onto the stack

                Stack ...  =>
                      ...,null
                

Specified by:

pushNull in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

getField

public void getField(org.apache.derby.iapi.services.compiler.LocalField field)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

getField

public void getField(java.lang.String declaringClass,
                     java.lang.String fieldName,
                     java.lang.String fieldType)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

getStaticField

public void getStaticField(java.lang.String declaringClass,
                           java.lang.String fieldName,
                           java.lang.String fieldType)

Push the contents of the described static field onto the stack.

Specified by:

getStaticField in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

getField

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

---

setField

public void setField(org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

putField

public void putField(org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

putField

public void putField(java.lang.String fieldName,
                     java.lang.String fieldType)

Pop the top stack value and store it in the instance field of this class.

Specified by:

putField in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

putField

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

---

putField

public void putField(java.lang.String declaringClass,
                     java.lang.String fieldName,
                     java.lang.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

conditionalIfNull

public void conditionalIfNull()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Initiate a sequence that corresponds to the Java language 'ref == null ? ... : ...'. 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.

                Stack ...,ref =>
                      ...
                

.

Specified by:

conditionalIfNull in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

conditionalIf

public void conditionalIf()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Initiate a sequence that corresponds to the Java language ' value ? ... : ...'. 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.

                Stack ...,boolean_value =>
                      ...
                

.

Specified by:

conditionalIf in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

conditionalIf

private void conditionalIf(short opcode)

---

startElseCode

public void startElseCode()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Complete the true code path of a ?: operator.

Specified by:

startElseCode in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

completeConditional

public void completeConditional()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Complete the a ?: operator which completes the false code path.

Specified by:

completeConditional in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

pop

public void pop()

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Pop the top value off the stack

                Stack ..., value =>
                      ...
                

.

Specified by:

pop in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

endStatement

public void endStatement()

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

---

getArrayElement

public void getArrayElement(int element)

Description copied from interface: org.apache.derby.iapi.services.compiler.MethodBuilder

Pop an array refrence off the stack and push an element from that array.

                Stack ...,array_ref =>
                      ...,value
                

Specified by:

getArrayElement in interface org.apache.derby.iapi.services.compiler.MethodBuilder

---

setArrayElement

public void setArrayElement(int element)

Description copied from interface: org.apache.derby.iapi.services.compiler.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 org.apache.derby.iapi.services.compiler.MethodBuilder

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pushNewArray

public void pushNewArray(java.lang.String className,
                         int size)

Create an array instance Stack ... => ...,arrayref

Specified by:

pushNewArray in interface org.apache.derby.iapi.services.compiler.MethodBuilder

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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 org.apache.derby.iapi.services.compiler.MethodBuilder

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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

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