Class Javac

java.lang.Object
javassist.compiler.Javac

public class Javac extends Object
  • Field Details

  • Constructor Details

    • 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 Details

    • 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:
    • compileField

      private CtField compileField(FieldDecl fd) throws CompileError, CannotCompileException
      Throws:
      CompileError
      CannotCompileException
    • compileMethod

      private CtBehavior compileMethod(Parser p, MethodDecl md) throws CompileError
      Throws:
      CompileError
    • 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
    • makeDefaultBody

      private static void makeDefaultBody(Bytecode b, CtClass type)
    • 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:
      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.
      use0 - true if $0 is used.
      varNo - the register number of $0 (use0 is true) or $1 (otherwise).
      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

      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