org.apache.tapestry5.plastic

Interface InstructionBuilder

All Known Implementing Classes:

InstructionBuilderImpl

public interface InstructionBuilder

Simplifies the generation of method instructions for a particular method (or constructor), allowing bytecode to be created with a friendlier API that focuses on Java type names (names as they would appear in Java source) rather than JVM descriptors or internal names. In some limited cases, types may be specified as Java Class instances as well. In addition, there is good support for primitive type boxing and unboxing. Most methods return the same instance of InstructionBuilder, allowing for a "fluid" API. More complex functionality, such as try/catch blocks, is more like a DSL (domain specific language), and is based on callbacks. This looks better in Groovy and will be more reasonable once JDK 1.8 closures are available; in the meantime, it means some deeply nested inner classes, but helps ensure that correct bytecode is generated and helps to limit the amount of bookkeeping is necessary on the part of code using InstructionBuilder.

Method Summary

Modifier and Type	Method and Description
InstructionBuilder	arrayLength() Expects the top object on the stack to be an array.
InstructionBuilder	boxPrimitive(String typeName) If the type name is a primitive type, adds code to box the type into the equivalent wrapper type, using static methods on the wrapper type.
InstructionBuilder	castOrUnbox(String typeName) Casts the object on top of the stack to the indicated type.
InstructionBuilder	checkcast(Class clazz)
InstructionBuilder	checkcast(String className) Adds a check that the object on top of the stack is assignable to the indicated class.
InstructionBuilder	compareSpecial(String typeName) Special comparison logic for primitive float, double and long.
InstructionBuilder	doWhile(Condition condition, WhileCallback callback) Implements a simple loop based on a condition.
InstructionBuilder	dupe() Duplicates the top object on the stack.
InstructionBuilder	dupe(int depth) Duplicates the top object on the stack, placing the result at some depth.
InstructionBuilder	dupeWide() Duplicates a wide value (a primitive long or double).
InstructionBuilder	getField(PlasticField field) Loads an instance or static field onto the stack.
InstructionBuilder	getField(String className, String fieldName, Class fieldType) Loads a field onto the stack.
InstructionBuilder	getField(String className, String fieldName, String typeName) Loads an instance field onto the stack.
InstructionBuilder	getStaticField(String className, String fieldName, Class fieldType) Gets a static field; does not consume a value from the stack, but pushes the fields' value onto the stack.
InstructionBuilder	getStaticField(String className, String fieldName, String typeName) Gets a static field; does not consume a value from the stack, but pushes the fields' value onto the stack.
InstructionBuilder	increment(LocalVariable variable) Increments a local integer variable.
InstructionBuilder	invoke(Class clazz, Class returnType, String methodName, Class... argumentTypes) Automatically invokes an interface or virtual method.
InstructionBuilder	invoke(Method method) Automatically invokes an interface or virtual method.
InstructionBuilder	invokeConstructor(Class clazz, Class... argumentTypes)
InstructionBuilder	invokeConstructor(String className, String... argumentTypes) Invokes a constructor on a class.
InstructionBuilder	invokeInterface(String interfaceName, String returnType, String methodName, String... argumentTypes) Invokes a standard virtual method.
InstructionBuilder	invokeSpecial(String containingClassName, MethodDescription description) Invokes an instance method of a base class, or a private method of a class, using the target object and parameters already on the stack.
InstructionBuilder	invokeStatic(Class clazz, Class returnType, String methodName, Class... argumentTypes) Invokes a static method of a class.
InstructionBuilder	invokeVirtual(PlasticMethod method)
InstructionBuilder	invokeVirtual(String className, String returnType, String methodName, String... argumentTypes) Invokes a standard virtual method.
InstructionBuilder	iterateArray(InstructionBuilderCallback callback) Expects an array to be the top value on the stack.
InstructionBuilder	loadArgument(int index) Loads an argument onto the stack, using the opcode appropriate to the argument's type.
InstructionBuilder	loadArguments() Loads all arguments for the current method onto the stack; this is used when invoking a method that takes the exact same parameters (often, a super-class implementation).
InstructionBuilder	loadArrayElement() Loads a value from an array object.
InstructionBuilder	loadArrayElement(int index, String elementType) Loads a value from an array object, which must be the top element of the stack.
InstructionBuilder	loadConstant(Object constant) Loads a constant value
InstructionBuilder	loadNull() Loads the null constant onto the stack.
InstructionBuilder	loadThis() Loads this onto the stack.
InstructionBuilder	loadTypeConstant(Class type) Loads a Java type (a Class instance) as a constant.
InstructionBuilder	loadTypeConstant(String typeName) Loads a Java type (a Class instance) as a constant.
InstructionBuilder	loadVariable(LocalVariable variable) Loads a value from a local variable and pushes it onto the stack.
InstructionBuilder	newInstance(Class clazz) A convenience version of newInstance(String) used when the class is known at build time.
InstructionBuilder	newInstance(String className) Creates a new, uninitialized instance of the indicated class.
InstructionBuilder	pop() Discards the top value on the stack.
InstructionBuilder	popWide() Pops a wide value (a primitive long or double).
InstructionBuilder	putField(String className, String fieldName, Class fieldType)
InstructionBuilder	putField(String className, String fieldName, String typeName) Expects the stack to contain the instance to update, and the value to store into the field.
InstructionBuilder	putStaticField(String className, String fieldName, Class fieldType) Sets a static field; the new field value should be on top of the stack.
InstructionBuilder	putStaticField(String className, String fieldName, String typeName) Sets a static field; the new field value should be on top of the stack.
InstructionBuilder	returnDefaultValue() Returns the default value for the method, which may be null, or a specific primitive value.
InstructionBuilder	returnResult() Returns the top value on the stack.
InstructionBuilder	startSwitch(int min, int max, SwitchCallback callback) Starts a switch statement.
InstructionBuilder	startTryCatch(TryCatchCallback tryCatchCallback) Defines the start of a block that can have exception handlers and finally blocks applied.
InstructionBuilder	startVariable(String type, LocalVariableCallback callback) Starts a block where the given name is active.
InstructionBuilder	storeVariable(LocalVariable variable) Stores the value on top of the stack to a local variable (previously defined by startVariable(String, LocalVariableCallback).
InstructionBuilder	swap() Swaps the top element of the stack with the next element down.
InstructionBuilder	throwException() Throws the exception on the top of the stack.
InstructionBuilder	throwException(Class<? extends Throwable> exceptionType, String message)
InstructionBuilder	throwException(String className, String message) Throws an exception with a fixed message.
InstructionBuilder	unboxPrimitive(String typeName) Unboxes a wrapper type to a primitive type if typeName is a primitive type name (the value on the stack should be the corresponding wrapper type instance).
InstructionBuilder	when(Condition condition, InstructionBuilderCallback ifTrue) Simplified version of when(Condition, WhenCallback) that simply executes the callback code when the condition is true and does nothing if the condition is false (the more general case).
InstructionBuilder	when(Condition condition, WhenCallback callback) Executes conditional code based on a Condition.

Method Detail

returnDefaultValue

@Opcodes(value="ACONST_NULL, LCONST_0, FCONST_0, DCONST_0, ICONST_0, RETURN, ARETURN, IRETURN, FRETURN, LRETURN, DRETURN")
InstructionBuilder returnDefaultValue()

Returns the default value for the method, which may be null, or a specific primitive value.

loadThis

@Opcodes(value="ALOAD")
InstructionBuilder loadThis()

Loads this onto the stack.

loadNull

@Opcodes(value="ACONST_NULL")
InstructionBuilder loadNull()

Loads the null constant onto the stack.

loadArgument

@Opcodes(value="ALOAD, ILOAD, LLOAD, FLOAD, DLOAD")
InstructionBuilder loadArgument(int index)

Loads an argument onto the stack, using the opcode appropriate to the argument's type. In addition this automatically adjusts for arguments of primitive type long or double (which take up two local variable indexes, rather than one as for all other types)

Parameters:

index - to argument (0 is the first argument, not this)

loadArguments

@Opcodes(value="ALOAD, ILOAD, LLOAD, FLOAD, DLOAD")
InstructionBuilder loadArguments()

Loads all arguments for the current method onto the stack; this is used when invoking a method that takes the exact same parameters (often, a super-class implementation). A call to loadThis() (or some other way of identifying the target method) should precede this call.

invokeSpecial

@Opcodes(value="INVOKESPECIAL")
InstructionBuilder invokeSpecial(String containingClassName,
                                                                 MethodDescription description)

Invokes an instance method of a base class, or a private method of a class, using the target object and parameters already on the stack. Leaves the result on the stack (unless its a void method).

Parameters:

containingClassName - class name containing the method

description - describes the method name, parameters and return type

invokeVirtual

@Opcodes(value="INVOKEVIRTUAL")
InstructionBuilder invokeVirtual(String className,
                                                                 String returnType,
                                                                 String methodName,
                                                                 String... argumentTypes)

Invokes a standard virtual method.

invokeVirtual

@Opcodes(value="INVOKEVIRTUAL")
InstructionBuilder invokeVirtual(PlasticMethod method)

invokeInterface

@Opcodes(value="INVOKEINTERFACE")
InstructionBuilder invokeInterface(String interfaceName,
                                                                     String returnType,
                                                                     String methodName,
                                                                     String... argumentTypes)

Invokes a standard virtual method.

invoke

@Opcodes(value="INVOKEVIRTUAL, INVOKEINTERFACE")
InstructionBuilder invoke(Class clazz,
                                                                           Class returnType,
                                                                           String methodName,
                                                                           Class... argumentTypes)

Automatically invokes an interface or virtual method. Remember to use invokeConstructor(Class, Class...) for constructors and invokeSpecial(String, MethodDescription) for private methods.

invoke

InstructionBuilder invoke(Method method)

Automatically invokes an interface or virtual method. Remember to use invokeConstructor(Class, Class...) for constructors and invokeSpecial(String, MethodDescription) for private methods.

invokeStatic

@Opcodes(value="INVOKESTATIC")
InstructionBuilder invokeStatic(Class clazz,
                                                               Class returnType,
                                                               String methodName,
                                                               Class... argumentTypes)

Invokes a static method of a class.

returnResult

@Opcodes(value="ARETURN, IRETURN, LRETURN, FRETURN, DRETURN")
InstructionBuilder returnResult()

Returns the top value on the stack. For void methods, no value should be on the stack and the method will simply return.

boxPrimitive

@Opcodes(value="INVOKESTATIC")
InstructionBuilder boxPrimitive(String typeName)

If the type name is a primitive type, adds code to box the type into the equivalent wrapper type, using static methods on the wrapper type. Does nothing if the type is not primitive, or type void.

unboxPrimitive

@Opcodes(value="INVOKEVIRTUAL")
InstructionBuilder unboxPrimitive(String typeName)

Unboxes a wrapper type to a primitive type if typeName is a primitive type name (the value on the stack should be the corresponding wrapper type instance). Does nothing for non-primitive types.

Parameters:

typeName - possibly primitive type name

getField

@Opcodes(value="GETFIELD")
InstructionBuilder getField(String className,
                                                       String fieldName,
                                                       String typeName)

Loads an instance field onto the stack. The object containing the field should already be loaded onto the stack (usually, via loadThis()).

Parameters:

className - name of class containing the field

fieldName - name of the field

typeName - type of field

getField

@Opcodes(value="GETFIELD")
InstructionBuilder getField(PlasticField field)

Loads an instance or static field onto the stack. The plastic class instance containing the field should already be loaded onto the stack (usually, via loadThis()).

Parameters:

field - identifies name, type and container of field to load

getField

@Opcodes(value="GETFIELD")
InstructionBuilder getField(String className,
                                                       String fieldName,
                                                       Class fieldType)

Loads a field onto the stack. This version is used when the field type is known at build time, rather than discovered at runtime.

Parameters:

className - name of class containing the field

fieldName - name of the field

fieldType - type of field

getStaticField

@Opcodes(value="GETSTATIC")
InstructionBuilder getStaticField(String className,
                                                              String fieldName,
                                                              Class fieldType)

Gets a static field; does not consume a value from the stack, but pushes the fields' value onto the stack.

Parameters:

className - name of class containing the field

fieldName - name of the field

fieldType - type of field

getStaticField

@Opcodes(value="GETSTATIC")
InstructionBuilder getStaticField(String className,
                                                              String fieldName,
                                                              String typeName)

Gets a static field; does not consume a value from the stack, but pushes the fields' value onto the stack.

Parameters:

className - name of class containing the field

fieldName - name of the field

typeName - type of field

putStaticField

@Opcodes(value="PUTSTATIC")
InstructionBuilder putStaticField(String className,
                                                              String fieldName,
                                                              Class fieldType)

Sets a static field; the new field value should be on top of the stack.

Parameters:

className - name of class containing the field

fieldName - name of the field

fieldType - type of field

putStaticField

@Opcodes(value="PUTSTATIC")
InstructionBuilder putStaticField(String className,
                                                              String fieldName,
                                                              String typeName)

Sets a static field; the new field value should be on top of the stack.

Parameters:

className - name of class containing the field

fieldName - name of the field

typeName - type of field

putField

@Opcodes(value="PUTFIELD")
InstructionBuilder putField(String className,
                                                       String fieldName,
                                                       String typeName)

Expects the stack to contain the instance to update, and the value to store into the field.

putField

@Opcodes(value="PUTFIELD")
InstructionBuilder putField(String className,
                                                       String fieldName,
                                                       Class fieldType)

loadArrayElement

@Opcodes(value="LDC, AALOAD")
InstructionBuilder loadArrayElement(int index,
                                                                  String elementType)

Loads a value from an array object, which must be the top element of the stack.

Parameters:

index - constant index into the array

elementType - the type name of the elements of the array Note: currently only reference types (objects and arrays) are supported, not primitives

loadArrayElement

@Opcodes(value="AALOAD")
InstructionBuilder loadArrayElement()

Loads a value from an array object. The stack should have the array at depth 1, and an array index on top. Only object arrays (not arrays of primitives) are supported.

checkcast

@Opcodes(value="CHECKCAST")
InstructionBuilder checkcast(String className)

Adds a check that the object on top of the stack is assignable to the indicated class.

Parameters:

className - class to cast to

checkcast

@Opcodes(value="CHECKCAST")
InstructionBuilder checkcast(Class clazz)

startTryCatch

InstructionBuilder startTryCatch(TryCatchCallback tryCatchCallback)

Defines the start of a block that can have exception handlers and finally blocks applied. Continue using this InstructionBuilder to define code inside the block, then call methods on the InstructionBlock to define the end of the block and set up handlers.

Parameters:

tryCatchCallback - allows generation of try, catch, and finally clauses

newInstance

@Opcodes(value="NEW")
InstructionBuilder newInstance(String className)

Creates a new, uninitialized instance of the indicated class. This should be followed by code to call the new instance's constructor.

Parameters:

className - of class to instantiate

newInstance

@Opcodes(value="NEW")
InstructionBuilder newInstance(Class clazz)

A convenience version of newInstance(String) used when the class is known at build time.

Parameters:

clazz - to instantiate

invokeConstructor

@Opcodes(value="INVOKESPECIAL")
InstructionBuilder invokeConstructor(String className,
                                                                     String... argumentTypes)

Invokes a constructor on a class. The instance should already be on the stack, followed by the right number and type of parameters. Note that a constructor acts like a void method, so you will often follow the sequence: newInstance(), dupe(0), invokeConstructor() so that a reference to the instance is left on the stack.F

Parameters:

className - the class containing the constructor

argumentTypes - java type names for each argument of the constructor

invokeConstructor

@Opcodes(value="INVOKESPECIAL")
InstructionBuilder invokeConstructor(Class clazz,
                                                                     Class... argumentTypes)

dupe

@Opcodes(value="DUP, DUP_X1, DUP_X2")
InstructionBuilder dupe(int depth)

Duplicates the top object on the stack, placing the result at some depth.

Parameters:

depth - 0 (DUP), 1 (DUP_X1) or 2 (DUP_X2)

dupeWide

@Opcodes(value="DUP2")
InstructionBuilder dupeWide()

Duplicates a wide value (a primitive long or double).

popWide

@Opcodes(value="POP2")
InstructionBuilder popWide()

Pops a wide value (a primitive long or double).

dupe

@Opcodes(value="DUP")
InstructionBuilder dupe()

Duplicates the top object on the stack. Commonly used with when(Condition, WhenCallback).

See Also:

dupe(int)

pop

InstructionBuilder pop()

Discards the top value on the stack. Assumes the value is a single word value: an object reference, or a small primitive) and not a double or long.

swap

@Opcodes(value="SWAP")
InstructionBuilder swap()

Swaps the top element of the stack with the next element down. Note that this can cause problems if the top element on the stack is a long or double.

loadConstant

@Opcodes(value="LDC, ICONST_*, LCONST_*, FCONST_*, DCONST_*, ACONST_NULL")
InstructionBuilder loadConstant(Object constant)

Loads a constant value

Parameters:

constant - Integer, Float, Double, Long, String or null

loadTypeConstant

@Opcodes(value="LDC")
InstructionBuilder loadTypeConstant(String typeName)

Loads a Java type (a Class instance) as a constant. This assumes the type name is the name of class (or array) but not a primitive type.

Parameters:

typeName - Java class name

loadTypeConstant

@Opcodes(value="LDC")
InstructionBuilder loadTypeConstant(Class type)

Loads a Java type (a Class instance) as a constant. This assumes the type name is the name of class (or array) but not a primitive type.

Parameters:

type - Java type to load as a constant

castOrUnbox

@Opcodes(value="CHECKCAST, INVOKEVIRTUAL")
InstructionBuilder castOrUnbox(String typeName)

Casts the object on top of the stack to the indicated type. For primitive types, casts to the wrapper type and invokes the appropriate unboxing static method call, leaving a primitive type value on the stack.

Parameters:

typeName - to cast or unbox to

throwException

@Opcodes(value="NEW, DUP, LDC, INVOKESPECIAL, ATHROW")
InstructionBuilder throwException(String className,
                                                                                         String message)

Throws an exception with a fixed message. Assumes the exception class includes a constructor that takes a single string.

Parameters:

className - name of exception class to instantiate

message - message (passed as first and only parameter to constructor)

throwException

@Opcodes(value="NEW, DUP, LDC, INVOKESPECIAL, ATHROW")
InstructionBuilder throwException(Class<? extends Throwable> exceptionType,
                                                                                         String message)

throwException

@Opcodes(value="ATHROW")
InstructionBuilder throwException()

Throws the exception on the top of the stack.

startSwitch

@Opcodes(value="TABLESWITCH")
InstructionBuilder startSwitch(int min,
                                                             int max,
                                                             SwitchCallback callback)

Starts a switch statement.

Parameters:

min - the minimum value to match against

max - the maximum value to match against

startVariable

InstructionBuilder startVariable(String type,
                                 LocalVariableCallback callback)

Starts a block where the given name is active.

Parameters:

type - type of local variable

callback - generates code used when variable is in effect

storeVariable

@Opcodes(value="ASTORE, ISTORE, LSTORE, FSTORE, DSTORE")
InstructionBuilder storeVariable(LocalVariable variable)

Stores the value on top of the stack to a local variable (previously defined by startVariable(String, LocalVariableCallback).

loadVariable

@Opcodes(value="ALOAD, ILOAD, LLOAD, FLOAD, DLOAD")
InstructionBuilder loadVariable(LocalVariable variable)

Loads a value from a local variable and pushes it onto the stack. The variable is defined by startVariable(String, LocalVariableCallback).

when

@Opcodes(value="IFEQ, etc., GOTO")
InstructionBuilder when(Condition condition,
                                                           WhenCallback callback)

Executes conditional code based on a Condition. The testing opcodes all pop the value off the stack, so this is usually preceded by dupe(0).

Parameters:

condition - defines true and false cases

callback - provides code for true and false blocks

Returns:

this builder

when

@Opcodes(value="IFEQ, etc., GOTO")
InstructionBuilder when(Condition condition,
                                                           InstructionBuilderCallback ifTrue)

Simplified version of when(Condition, WhenCallback) that simply executes the callback code when the condition is true and does nothing if the condition is false (the more general case). The testing opcodes all pop the value off the stack, so this is usually preceded by dupe(0).

Parameters:

condition - to evaluate

ifTrue - generates code for when condition is true

Returns:

this builder

doWhile

@Opcodes(value="IFEQ, etc., GOTO")
InstructionBuilder doWhile(Condition condition,
                                                              WhileCallback callback)

Implements a simple loop based on a condition. First the WhileCallback.buildTest(InstructionBuilder) code is executed, then the condition is evaluated (which will consume at least the top value on the stack). When the condition is false, the loop is exited. When the condition is true, the code defined by WhileCallback.buildBody(InstructionBuilder) is executed, and then a GOTO back to the test code.

Parameters:

condition -

callback -

Returns:

this builder

iterateArray

@Opcodes(value="IINC, ARRAYLENGTH, IFEQ, etc., GOTO")
InstructionBuilder iterateArray(InstructionBuilderCallback callback)

Expects an array to be the top value on the stack. Iterates the array. The callback generates code that will have each successive value from the array as the top value on the stack. Creates a variable to store the loop index.

Parameters:

callback - to invoke. The element will be the top value on the stack. The callback is responsible for removing it from the stack.

Returns:

this builder

increment

@Opcodes(value="IINC")
InstructionBuilder increment(LocalVariable variable)

Increments a local integer variable.

Returns:

this builder

arrayLength

@Opcodes(value="ARRAYLENGTH")
InstructionBuilder arrayLength()

Expects the top object on the stack to be an array. Replaces it with the length of that array.

compareSpecial

@Opcodes(value="LCMP, FCMPL, DCMPL")
InstructionBuilder compareSpecial(String typeName)

Special comparison logic for primitive float, double and long. Expect two matching wide values on the stack. Reduces the two wide values to a single int value: -1, 0, or 1 depending on whether the deeper value is less than, equal to, or greater than the top value on the stack.

Parameters:

typeName -