CodeFlow (Spring Framework 4.3.29.RELEASE API)

java.lang.Object
- org.springframework.expression.spel.CodeFlow

All Implemented Interfaces:

Opcodes
```
public class CodeFlow
extends Object
implements Opcodes
```
Manages the class being generated by the compilation process.
Records intermediate compilation state as the bytecode is generated. Also includes various bytecode generation helper functions.

Since:

4.1

Author:

Andy Clement, Juergen Hoeller

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`CodeFlow.ClinitAdder` Interface used to generate `clinit` static initializer blocks.
`static interface`	`CodeFlow.FieldAdder` Interface used to generate fields.

Field Summary
- Fields inherited from interface org.springframework.asm.Opcodes
  AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_DEPRECATED, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_MANDATED, ACC_MODULE, ACC_NATIVE, ACC_OPEN, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STATIC_PHASE, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_TRANSITIVE, ACC_VARARGS, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASM4, ASM5, ASM6, ASTORE, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DMUL, DNEG, DOUBLE, DREM, DRETURN, DSTORE, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F_APPEND, F_CHOP, F_FULL, F_NEW, F_SAME, F_SAME1, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAT, FMUL, FNEG, FREM, FRETURN, FSTORE, FSUB, GETFIELD, GETSTATIC, GOTO, H_GETFIELD, H_GETSTATIC, H_INVOKEINTERFACE, H_INVOKESPECIAL, H_INVOKESTATIC, H_INVOKEVIRTUAL, H_NEWINVOKESPECIAL, H_PUTFIELD, H_PUTSTATIC, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, IMUL, INEG, INSTANCEOF, INTEGER, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISUB, IUSHR, IXOR, JSR, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDIV, LLOAD, LMUL, LNEG, LONG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, NULL, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, TOP, UNINITIALIZED_THIS, V1_1, V1_2, V1_3, V1_4, V1_5, V1_6, V1_7, V1_8, V1_9

Constructor Summary

Constructors
Constructor and Description

CodeFlow(String className, ClassWriter classWriter)
Construct a new CodeFlow for the given class.

Constructors
Constructor and Description
`CodeFlow(String className, ClassWriter classWriter)` Construct a new `CodeFlow` for the given class.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static boolean`	`areBoxingCompatible(String desc1, String desc2)` Determine whether boxing/unboxing can get from one type to the other.
`static int`	`arrayCodeFor(String arraytype)` Determine the appropriate T tag to use for the NEWARRAY bytecode.
`static String`	`createSignatureDescriptor(Constructor<?> ctor)` Create the JVM signature descriptor for a constructor.
`static String`	`createSignatureDescriptor(Method method)` Create the JVM signature descriptor for a method.
`void`	`enterCompilationScope()` Enter a new compilation scope, usually due to nested expression evaluation.
`void`	`exitCompilationScope()` Exit a compilation scope, usually after a nested expression has been evaluated.
`void`	`finish()` Called after the main expression evaluation method has been generated, this method will callback any registered FieldAdders or ClinitAdders to add any extra information to the class representing the compiled expression.
`String`	`getClassname()` Deprecated.
`String`	`getClassName()`
`static void`	`insertAnyNecessaryTypeConversionBytecodes(MethodVisitor mv, char targetDescriptor, String stackDescriptor)` Insert any necessary numeric conversion bytecodes based upon what is on the stack and the desired target type.
`static void`	`insertArrayStore(MethodVisitor mv, String arrayElementType)` Produce appropriate bytecode to store a stack item in an array.
`static void`	`insertBoxIfNecessary(MethodVisitor mv, char ch)` Determine the appropriate boxing instruction for a specific type (if it needs boxing) and insert the instruction into the supplied visitor.
`static void`	`insertBoxIfNecessary(MethodVisitor mv, String descriptor)` Determine the appropriate boxing instruction for a specific type (if it needs boxing) and insert the instruction into the supplied visitor.
`static void`	`insertCheckCast(MethodVisitor mv, String descriptor)` Insert the appropriate CHECKCAST instruction for the supplied descriptor.
`static void`	`insertNewArrayCode(MethodVisitor mv, int size, String arraytype)` Produce the correct bytecode to build an array.
`static void`	`insertNumericUnboxOrPrimitiveTypeCoercion(MethodVisitor mv, String stackDescriptor, char targetDescriptor)` For use in mathematical operators, handles converting from a (possibly boxed) number on the stack to a primitive numeric type.
`static void`	`insertOptimalLoad(MethodVisitor mv, int value)` Create the optimal instruction for loading a number on the stack.
`static void`	`insertUnboxInsns(MethodVisitor mv, char ch, String stackDescriptor)` Insert any necessary cast and value call to convert from a boxed type to a primitive value.
`static void`	`insertUnboxNumberInsns(MethodVisitor mv, char targetDescriptor, String stackDescriptor)` For numbers, use the appropriate method on the number to convert it to the primitive type requested.
`static boolean`	`isBooleanCompatible(String descriptor)` Determine whether the descriptor is for a boolean primitive or boolean reference type.
`static boolean`	`isIntegerForNumericOp(Number number)` Determine whether the given number is to be considered as an integer for the purposes of a numeric operation at the bytecode level.
`static boolean`	`isPrimitive(String descriptor)` Determine whether the descriptor is for a primitive type.
`static boolean`	`isPrimitiveArray(String descriptor)` Determine whether the descriptor is for a primitive array (e.g.
`static boolean`	`isPrimitiveOrUnboxableSupportedNumber(String descriptor)` Determine if the supplied descriptor is for a supported number.
`static boolean`	`isPrimitiveOrUnboxableSupportedNumberOrBoolean(String descriptor)` Determine if the supplied descriptor is for a supported number type or boolean.
`static boolean`	`isReferenceTypeArray(String arraytype)` Return if the supplied array type has a core component reference type.
`String`	`lastDescriptor()` Return the descriptor for the item currently on top of the stack (in the current scope).
`void`	`loadEvaluationContext(MethodVisitor mv)` Push the bytecode to load the EvaluationContext (the second parameter passed to the compiled expression method).
`void`	`loadTarget(MethodVisitor mv)` Push the byte code to load the target (i.e.
`int`	`nextFieldId()`
`int`	`nextFreeVariableId()`
`void`	`pushDescriptor(String descriptor)` Record the descriptor for the most recently evaluated expression element.
`void`	`registerNewClinit(CodeFlow.ClinitAdder clinitAdder)` Register a ClinitAdder which will add code to the static initializer in the generated class to support the code produced by an ast nodes primary generateCode() method.
`void`	`registerNewField(CodeFlow.FieldAdder fieldAdder)` Register a FieldAdder which will add a new field to the generated class to support the code produced by an ast nodes primary generateCode() method.
`static String`	`toBoxedDescriptor(String primitiveDescriptor)`
`static String`	`toDescriptor(Class<?> type)` Deduce the descriptor for a type.
`static String`	`toDescriptorFromObject(Object value)` Determine the descriptor for an object instance (or `null`).
`static String[]`	`toDescriptors(Class<?>[] types)` Create an array of descriptors from an array of classes.
`static String`	`toJvmDescriptor(Class<?> clazz)` Determine the JVM descriptor for a specified class.
`static String[]`	`toParamDescriptors(Constructor<?> ctor)` Create an array of descriptors representing the parameter types for the supplied constructor.
`static String[]`	`toParamDescriptors(Method method)` Create an array of descriptors representing the parameter types for the supplied method.
`static char`	`toPrimitiveTargetDesc(String descriptor)` Convert a type descriptor to the single character primitive descriptor.
`void`	`unboxBooleanIfNecessary(MethodVisitor mv)` If the codeflow shows the last expression evaluated to java.lang.Boolean then insert the necessary instructions to unbox that to a boolean primitive.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CodeFlow
```
public CodeFlow(String className,
                ClassWriter classWriter)
```
    Construct a new CodeFlow for the given class.
    
    Parameters:
    
    className - the name of the class
    
    classWriter - the corresponding ASM ClassWriter
- Method Detail
  - loadTarget
```
public void loadTarget(MethodVisitor mv)
```
    Push the byte code to load the target (i.e. what was passed as the first argument to CompiledExpression.getValue(target, context))
    
    Parameters:
    
    mv - the visitor into which the load instruction should be inserted
  - loadEvaluationContext
```
public void loadEvaluationContext(MethodVisitor mv)
```
    Push the bytecode to load the EvaluationContext (the second parameter passed to the compiled expression method).
    
    Parameters:
    
    mv - the visitor into which the load instruction should be inserted
    
    Since:
    
    4.3.4
  - pushDescriptor
```
public void pushDescriptor(String descriptor)
```
    Record the descriptor for the most recently evaluated expression element.
    
    Parameters:
    
    descriptor - type descriptor for most recently evaluated element
  - enterCompilationScope
```
public void enterCompilationScope()
```
    Enter a new compilation scope, usually due to nested expression evaluation. For example when the arguments for a method invocation expression are being evaluated, each argument will be evaluated in a new scope.
  - exitCompilationScope
```
public void exitCompilationScope()
```
    Exit a compilation scope, usually after a nested expression has been evaluated. For example after an argument for a method invocation has been evaluated this method returns us to the previous (outer) scope.
  - lastDescriptor
```
public String lastDescriptor()
```
    Return the descriptor for the item currently on top of the stack (in the current scope).
  - unboxBooleanIfNecessary
```
public void unboxBooleanIfNecessary(MethodVisitor mv)
```
    If the codeflow shows the last expression evaluated to java.lang.Boolean then insert the necessary instructions to unbox that to a boolean primitive.
    
    Parameters:
    
    mv - the visitor into which new instructions should be inserted
  - finish
```
public void finish()
```
    Called after the main expression evaluation method has been generated, this method will callback any registered FieldAdders or ClinitAdders to add any extra information to the class representing the compiled expression.
  - registerNewField
```
public void registerNewField(CodeFlow.FieldAdder fieldAdder)
```
    Register a FieldAdder which will add a new field to the generated class to support the code produced by an ast nodes primary generateCode() method.
  - registerNewClinit
```
public void registerNewClinit(CodeFlow.ClinitAdder clinitAdder)
```
    Register a ClinitAdder which will add code to the static initializer in the generated class to support the code produced by an ast nodes primary generateCode() method.
  - nextFieldId
```
public int nextFieldId()
```
  - nextFreeVariableId
```
public int nextFreeVariableId()
```
  - getClassName
```
public String getClassName()
```
  - getClassname
```
@Deprecated
public String getClassname()
```
    Deprecated.
  - insertUnboxInsns
```
public static void insertUnboxInsns(MethodVisitor mv,
                                    char ch,
                                    String stackDescriptor)
```
    Insert any necessary cast and value call to convert from a boxed type to a primitive value.
    
    Parameters:
    
    mv - the method visitor into which instructions should be inserted
    
    ch - the primitive type desired as output
    
    stackDescriptor - the descriptor of the type on top of the stack
  - insertUnboxNumberInsns
```
public static void insertUnboxNumberInsns(MethodVisitor mv,
                                          char targetDescriptor,
                                          String stackDescriptor)
```
    For numbers, use the appropriate method on the number to convert it to the primitive type requested.
    
    Parameters:
    
    mv - the method visitor into which instructions should be inserted
    
    targetDescriptor - the primitive type desired as output
    
    stackDescriptor - the descriptor of the type on top of the stack
  - insertAnyNecessaryTypeConversionBytecodes
```
public static void insertAnyNecessaryTypeConversionBytecodes(MethodVisitor mv,
                                                             char targetDescriptor,
                                                             String stackDescriptor)
```
    Insert any necessary numeric conversion bytecodes based upon what is on the stack and the desired target type.
    
    Parameters:
    
    mv - the method visitor into which instructions should be placed
    
    targetDescriptor - the (primitive) descriptor of the target type
    
    stackDescriptor - the descriptor of the operand on top of the stack
  - createSignatureDescriptor
```
public static String createSignatureDescriptor(Method method)
```
    Create the JVM signature descriptor for a method. This consists of the descriptors for the method parameters surrounded with parentheses, followed by the descriptor for the return type. Note the descriptors here are JVM descriptors, unlike the other descriptor forms the compiler is using which do not include the trailing semicolon.
    
    Parameters:
    
    method - the method
    
    Returns:
    
    a String signature descriptor (e.g. "(ILjava/lang/String;)V")
  - createSignatureDescriptor
```
public static String createSignatureDescriptor(Constructor<?> ctor)
```
    Create the JVM signature descriptor for a constructor. This consists of the descriptors for the constructor parameters surrounded with parentheses, followed by the descriptor for the return type, which is always "V". Note the descriptors here are JVM descriptors, unlike the other descriptor forms the compiler is using which do not include the trailing semicolon.
    
    Parameters:
    
    ctor - the constructor
    
    Returns:
    
    a String signature descriptor (e.g. "(ILjava/lang/String;)V")
  - toJvmDescriptor
```
public static String toJvmDescriptor(Class<?> clazz)
```
    Determine the JVM descriptor for a specified class. Unlike the other descriptors used in the compilation process, this is the one the JVM wants, so this one includes any necessary trailing semicolon (e.g. Ljava/lang/String; rather than Ljava/lang/String)
    
    Parameters:
    
    clazz - a class
    
    Returns:
    
    the JVM descriptor for the class
  - toDescriptorFromObject
```
public static String toDescriptorFromObject(Object value)
```
    Determine the descriptor for an object instance (or null).
    
    Parameters:
    
    value - an object (possibly null)
    
    Returns:
    
    the type descriptor for the object (descriptor is "Ljava/lang/Object" for null value)
  - isBooleanCompatible
```
public static boolean isBooleanCompatible(String descriptor)
```
    Determine whether the descriptor is for a boolean primitive or boolean reference type.
    
    Parameters:
    
    descriptor - type descriptor
    
    Returns:
    
    true if the descriptor is boolean compatible
  - isPrimitive
```
public static boolean isPrimitive(String descriptor)
```
    Determine whether the descriptor is for a primitive type.
    
    Parameters:
    
    descriptor - type descriptor
    
    Returns:
    
    true if a primitive type
  - isPrimitiveArray
```
public static boolean isPrimitiveArray(String descriptor)
```
    Determine whether the descriptor is for a primitive array (e.g. "[[I").
    
    Parameters:
    
    descriptor - the descriptor for a possible primitive array
    
    Returns:
    
    true if the descriptor a primitive array
  - areBoxingCompatible
```
public static boolean areBoxingCompatible(String desc1,
                                          String desc2)
```
    Determine whether boxing/unboxing can get from one type to the other. Assumes at least one of the types is in boxed form (i.e. single char descriptor).
    
    Returns:
    
    true if it is possible to get (via boxing) from one descriptor to the other
  - isPrimitiveOrUnboxableSupportedNumberOrBoolean
```
public static boolean isPrimitiveOrUnboxableSupportedNumberOrBoolean(String descriptor)
```
    Determine if the supplied descriptor is for a supported number type or boolean. The compilation process only (currently) supports certain number types. These are double, float, long and int.
    
    Parameters:
    
    descriptor - the descriptor for a type
    
    Returns:
    
    true if the descriptor is for a supported numeric type or boolean
  - isPrimitiveOrUnboxableSupportedNumber
```
public static boolean isPrimitiveOrUnboxableSupportedNumber(String descriptor)
```
    Determine if the supplied descriptor is for a supported number. The compilation process only (currently) supports certain number types. These are double, float, long and int.
    
    Parameters:
    
    descriptor - the descriptor for a type
    
    Returns:
    
    true if the descriptor is for a supported numeric type
  - isIntegerForNumericOp
```
public static boolean isIntegerForNumericOp(Number number)
```
    Determine whether the given number is to be considered as an integer for the purposes of a numeric operation at the bytecode level.
    
    Parameters:
    
    number - the number to check
    
    Returns:
    
    true if it is an Integer, Short or Byte
  - toPrimitiveTargetDesc
```
public static char toPrimitiveTargetDesc(String descriptor)
```
    Convert a type descriptor to the single character primitive descriptor.
    
    Parameters:
    
    descriptor - a descriptor for a type that should have a primitive representation
    
    Returns:
    
    the single character descriptor for a primitive input descriptor
  - insertCheckCast
```
public static void insertCheckCast(MethodVisitor mv,
                                   String descriptor)
```
    Insert the appropriate CHECKCAST instruction for the supplied descriptor.
    
    Parameters:
    
    mv - the target visitor into which the instruction should be inserted
    
    descriptor - the descriptor of the type to cast to
  - insertBoxIfNecessary
```
public static void insertBoxIfNecessary(MethodVisitor mv,
                                        String descriptor)
```
    Determine the appropriate boxing instruction for a specific type (if it needs boxing) and insert the instruction into the supplied visitor.
    
    Parameters:
    
    mv - the target visitor for the new instructions
    
    descriptor - the descriptor of a type that may or may not need boxing
  - insertBoxIfNecessary
```
public static void insertBoxIfNecessary(MethodVisitor mv,
                                        char ch)
```
    Determine the appropriate boxing instruction for a specific type (if it needs boxing) and insert the instruction into the supplied visitor.
    
    Parameters:
    
    mv - the target visitor for the new instructions
    
    ch - the descriptor of the type that might need boxing
  - toDescriptor
```
public static String toDescriptor(Class<?> type)
```
    Deduce the descriptor for a type. Descriptors are like JVM type names but missing the trailing ';' so for Object the descriptor is "Ljava/lang/Object" for int it is "I".
    
    Parameters:
    
    type - the type (may be primitive) for which to determine the descriptor
    
    Returns:
    
    the descriptor
  - toParamDescriptors
```
public static String[] toParamDescriptors(Method method)
```
    Create an array of descriptors representing the parameter types for the supplied method. Returns a zero sized array if there are no parameters.
    
    Parameters:
    
    method - a Method
    
    Returns:
    
    a String array of descriptors, one entry for each method parameter
  - toParamDescriptors
```
public static String[] toParamDescriptors(Constructor<?> ctor)
```
    Create an array of descriptors representing the parameter types for the supplied constructor. Returns a zero sized array if there are no parameters.
    
    Parameters:
    
    ctor - a Constructor
    
    Returns:
    
    a String array of descriptors, one entry for each constructor parameter
  - toDescriptors
```
public static String[] toDescriptors(Class<?>[] types)
```
    Create an array of descriptors from an array of classes.
    
    Parameters:
    
    types - the input array of classes
    
    Returns:
    
    an array of descriptors
  - insertOptimalLoad
```
public static void insertOptimalLoad(MethodVisitor mv,
                                     int value)
```
    Create the optimal instruction for loading a number on the stack.
    
    Parameters:
    
    mv - where to insert the bytecode
    
    value - the value to be loaded
  - insertArrayStore
```
public static void insertArrayStore(MethodVisitor mv,
                                    String arrayElementType)
```
    Produce appropriate bytecode to store a stack item in an array. The instruction to use varies depending on whether the type is a primitive or reference type.
    
    Parameters:
    
    mv - where to insert the bytecode
    
    arrayElementType - the type of the array elements
  - arrayCodeFor
```
public static int arrayCodeFor(String arraytype)
```
    Determine the appropriate T tag to use for the NEWARRAY bytecode.
    
    Parameters:
    
    arraytype - the array primitive component type
    
    Returns:
    
    the T tag to use for NEWARRAY
  - isReferenceTypeArray
```
public static boolean isReferenceTypeArray(String arraytype)
```
    Return if the supplied array type has a core component reference type.
  - insertNewArrayCode
```
public static void insertNewArrayCode(MethodVisitor mv,
                                      int size,
                                      String arraytype)
```
    Produce the correct bytecode to build an array. The opcode to use and the signature to pass along with the opcode can vary depending on the signature of the array type.
    
    Parameters:
    
    mv - the methodvisitor into which code should be inserted
    
    size - the size of the array
    
    arraytype - the type of the array
  - insertNumericUnboxOrPrimitiveTypeCoercion
```
public static void insertNumericUnboxOrPrimitiveTypeCoercion(MethodVisitor mv,
                                                             String stackDescriptor,
                                                             char targetDescriptor)
```
    For use in mathematical operators, handles converting from a (possibly boxed) number on the stack to a primitive numeric type.
    For example, from a Integer to a double, just need to call 'Number.doubleValue()' but from an int to a double, need to use the bytecode 'i2d'.
    
    Parameters:
    
    mv - the method visitor when instructions should be appended
    
    stackDescriptor - a descriptor of the operand on the stack
    
    targetDescriptor - a primitive type descriptor
  - toBoxedDescriptor
```
public static String toBoxedDescriptor(String primitiveDescriptor)
```

Class CodeFlow

Nested Class Summary

Field Summary

Fields inherited from interface org.springframework.asm.Opcodes

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CodeFlow

Method Detail

loadTarget

loadEvaluationContext

pushDescriptor

enterCompilationScope

exitCompilationScope

lastDescriptor

unboxBooleanIfNecessary

finish

registerNewField

registerNewClinit

nextFieldId

nextFreeVariableId

getClassName

getClassname

insertUnboxInsns

insertUnboxNumberInsns

insertAnyNecessaryTypeConversionBytecodes

createSignatureDescriptor

createSignatureDescriptor

toJvmDescriptor

toDescriptorFromObject

isBooleanCompatible

isPrimitive

isPrimitiveArray

areBoxingCompatible

isPrimitiveOrUnboxableSupportedNumberOrBoolean

isPrimitiveOrUnboxableSupportedNumber

isIntegerForNumericOp

toPrimitiveTargetDesc

insertCheckCast

insertBoxIfNecessary

insertBoxIfNecessary

toDescriptor

toParamDescriptors

toParamDescriptors

toDescriptors

insertOptimalLoad

insertArrayStore

arrayCodeFor

isReferenceTypeArray

insertNewArrayCode

insertNumericUnboxOrPrimitiveTypeCoercion

toBoxedDescriptor