org.hotswap.agent.javassist.compiler

Class Javac

java.lang.Object

org.hotswap.agent.javassist.compiler.Javac

public class Javac
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Javac.CtFieldWithInit

Field Summary

Fields

Modifier and Type	Field and Description
static String	param0Name
static String	proceedName
static String	resultVarName

Constructor Summary

Constructors

Constructor and Description
Javac(Bytecode b, CtClass thisClass) Constructs a compiler.
Javac(CtClass thisClass) Constructs a compiler.

Method Summary

Modifier and Type	Method and Description
CtMember	compile(String src) Compiles a method, constructor, or field declaration to a class.
Bytecode	compileBody(CtBehavior method, String src) Compiles a method (or constructor) body.
void	compileExpr(ASTree e) Compiles an exression.
void	compileExpr(String src) Compiles an exression.
void	compileStmnt(String src) Compiles a statement (or a block).
Bytecode	getBytecode() Returns the produced bytecode.
static ASTree	parseExpr(String src, SymbolTable st) Parsers an expression.
boolean	recordLocalVariables(CodeAttribute ca, int pc) Records local variables available at the specified program counter.
boolean	recordParamNames(CodeAttribute ca, int numOfLocalVars) Records parameter names if the LocalVariableAttribute is available.
int	recordParams(CtClass[] params, boolean isStatic) Makes variables $0 (this), $1, $2, ..., and $args represent method parameters.
int	recordParams(String target, CtClass[] params, boolean use0, int varNo, boolean isStatic) Makes variables $0, $1, $2, ..., and $args represent method parameters.
void	recordProceed(ProceedHandler h) Prepares to use $proceed().
void	recordProceed(String target, String method) Prepares to use $proceed().
int	recordReturnType(CtClass type, boolean useResultVar) Prepares to use cast $r, $w, $_, and $type.
void	recordSpecialProceed(String target, String classname, String methodname, String descriptor, int methodIndex) Prepares to use $proceed() representing a private/super's method.
void	recordStaticProceed(String targetClass, String method) Prepares to use $proceed() representing a static method.
void	recordType(CtClass t) Prepares to use $type.
int	recordVariable(CtClass type, String name) Makes the given variable available.
void	setMaxLocals(int max) Sets maxLocals to max.

Methods inherited from class java.lang.Object

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

Field Detail

param0Name

public static final String param0Name

See Also:

Constant Field Values

resultVarName

public static final String resultVarName

See Also:

Constant Field Values

proceedName

public static final String proceedName

See Also:

Constant Field Values

Constructor Detail

Javac

public Javac(CtClass thisClass)

Constructs a compiler.

Parameters:

thisClass - the class that a compiled method/field belongs to.

Javac

public Javac(Bytecode b,
             CtClass thisClass)

Constructs a compiler. The produced bytecode is stored in the Bytecode object specified by b.

Parameters:

thisClass - the class that a compiled method/field belongs to.

Method Detail

getBytecode

public Bytecode getBytecode()

Returns the produced bytecode.

compile

public CtMember compile(String src)
                 throws CompileError

Compiles a method, constructor, or field declaration to a class. A field declaration can declare only one field.

In a method or constructor body, $0, $1, ... and $_ are not available.

Returns:

a CtMethod, CtConstructor, or CtField object.

Throws:

CompileError

See Also:

recordProceed(String,String)

compileBody

public Bytecode compileBody(CtBehavior method,
                            String src)
                     throws CompileError

Compiles a method (or constructor) body.

Parameters:

src - a single statement or a block. If null, this method produces a body returning zero or null.

Throws:

CompileError

recordLocalVariables

public boolean recordLocalVariables(CodeAttribute ca,
                                    int pc)
                             throws CompileError

Records local variables available at the specified program counter. If the LocalVariableAttribute is not available, this method does not record any local variable. It only returns false.

Parameters:

pc - program counter (>= 0)

Returns:

false if the CodeAttribute does not include a LocalVariableAttribute.

Throws:

CompileError

recordParamNames

public boolean recordParamNames(CodeAttribute ca,
                                int numOfLocalVars)
                         throws CompileError

Records parameter names if the LocalVariableAttribute is available. It returns false unless the LocalVariableAttribute is available.

Parameters:

numOfLocalVars - the number of local variables used for storing the parameters.

Returns:

false if the CodeAttribute does not include a LocalVariableAttribute.

Throws:

CompileError

recordParams

public int recordParams(CtClass[] params,
                        boolean isStatic)
                 throws CompileError

Makes variables $0 (this), $1, $2, ..., and $args represent method parameters. $args represents an array of all the parameters. It also makes $$ available as a parameter list of method call.

This must be called before calling compileStmnt() and compileExpr(). The correct value of isStatic must be recorded before compilation. maxLocals is updated to include $0,...

Throws:

CompileError

recordParams

public int recordParams(String target,
                        CtClass[] params,
                        boolean use0,
                        int varNo,
                        boolean isStatic)
                 throws CompileError

Makes variables $0, $1, $2, ..., and $args represent method parameters. $args represents an array of all the parameters. It also makes $$ available as a parameter list of method call. $0 can represent a local variable other than THIS (variable 0). $class is also made available.

This must be called before calling compileStmnt() and compileExpr(). The correct value of isStatic must be recorded before compilation. maxLocals is updated to include $0,...

Parameters:

use0 - true if $0 is used.

varNo - the register number of $0 (use0 is true) or $1 (otherwise).

target - the type of $0 (it can be null if use0 is false). It is used as the name of the type represented by $class.

isStatic - true if the method in which the compiled bytecode is embedded is static.

Throws:

CompileError

setMaxLocals

public void setMaxLocals(int max)

Sets maxLocals to max. This method tells the compiler the local variables that have been allocated for the rest of the code. When the compiler needs new local variables, the local variables at the index max, max + 1, ... are assigned.

This method is indirectly called by recordParams.

recordReturnType

public int recordReturnType(CtClass type,
                            boolean useResultVar)
                     throws CompileError

Prepares to use cast $r, $w, $_, and $type. $type is made to represent the specified return type. It also enables to write a return statement with a return value for void method.

If the return type is void, ($r) does nothing. The type of $_ is java.lang.Object.

Parameters:

type - the return type.

useResultVar - true if $_ is used.

Returns:

-1 or the variable index assigned to $_.

Throws:

CompileError

See Also:

recordType(CtClass)

recordType

public void recordType(CtClass t)

Prepares to use $type. Note that recordReturnType() overwrites the value of $type.

Parameters:

t - the type represented by $type.

recordVariable

public int recordVariable(CtClass type,
                          String name)
                   throws CompileError

Makes the given variable available.

Parameters:

type - variable type

name - variable name

Throws:

CompileError

recordProceed

public void recordProceed(String target,
                          String method)
                   throws CompileError

Prepares to use $proceed(). If the return type of $proceed() is void, null is pushed on the stack.

Parameters:

target - an expression specifying the target object. if null, "this" is the target.

method - the method name.

Throws:

CompileError

recordStaticProceed

public void recordStaticProceed(String targetClass,
                                String method)
                         throws CompileError

Prepares to use $proceed() representing a static method. If the return type of $proceed() is void, null is pushed on the stack.

Parameters:

targetClass - the fully-qualified dot-separated name of the class declaring the method.

method - the method name.

Throws:

CompileError

recordSpecialProceed

public void recordSpecialProceed(String target,
                                 String classname,
                                 String methodname,
                                 String descriptor,
                                 int methodIndex)
                          throws CompileError

Prepares to use $proceed() representing a private/super's method. If the return type of $proceed() is void, null is pushed on the stack. This method is for methods invoked by INVOKESPECIAL.

Parameters:

target - an expression specifying the target object. if null, "this" is the target.

classname - the class name declaring the method.

methodname - the method name.

descriptor - the method descriptor.

Throws:

CompileError

recordProceed

public void recordProceed(ProceedHandler h)

Prepares to use $proceed().

compileStmnt

public void compileStmnt(String src)
                  throws CompileError

Compiles a statement (or a block). recordParams() must be called before invoking this method.

Local variables that are not declared in the compiled source text might not be accessible within that source text. Fields and method parameters ($0, $1, ..) are available.

Throws:

CompileError

compileExpr

public void compileExpr(String src)
                 throws CompileError

Compiles an exression. recordParams() must be called before invoking this method.

Local variables are not accessible within the compiled source text. Fields and method parameters ($0, $1, ..) are available if recordParams() have been invoked.

Throws:

CompileError

parseExpr

public static ASTree parseExpr(String src,
                               SymbolTable st)
                        throws CompileError

Parsers an expression.

Throws:

CompileError

compileExpr

public void compileExpr(ASTree e)
                 throws CompileError

Compiles an exression. recordParams() must be called before invoking this method.

Local variables are not accessible within the compiled source text. Fields and method parameters ($0, $1, ..) are available if recordParams() have been invoked.

Throws:

CompileError