Package org.plumelib.bcelutil

Class BcelUtil

java.lang.Object
org.plumelib.bcelutil.BcelUtil
public final class BcelUtil extends Object
Static utility methods for working with BCEL.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    javaVersion
    The major version number of the Java runtime (JRE), such as 8, 11, or 17.
    static boolean
    skipChecks
    Controls whether the checks in checkMgen(org.apache.bcel.generic.MethodGen) are performed.

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    addToStart(org.apache.bcel.generic.MethodGen mg, org.apache.bcel.generic.InstructionList newList)
    Adds instructions to the start of a method.
    static String
    attributeNameToString(org.apache.bcel.classfile.Attribute a)
    Return the attribute name for the specified attribute, looked up in the original class file ConstantPool.
    static String
    attributeNameToString(org.apache.bcel.classfile.Attribute a, org.apache.bcel.generic.ConstantPoolGen pool)
    Return the attribute name for the specified attribute, looked up in the given ConstantPoolGen.
    static org.apache.bcel.generic.Type
    binaryNameToType(@BinaryNameOrPrimitiveType String classname)
    Return the type corresponding to a given binary name or primitive type name.
    static void
    checkMgen(org.apache.bcel.generic.MethodGen mgen)
    Checks the specified method for consistency.
    static void
    checkMgens(org.apache.bcel.generic.ClassGen gen)
    Checks all of the methods in gen for consistency.
    static void
    dump(org.apache.bcel.classfile.JavaClass jc, File dumpDir)
    Dumps the contents of the specified class to the specified directory.
    static void
    dump(org.apache.bcel.classfile.JavaClass jc, String dumpDir)
    Dumps the contents of the specified class to the specified directory.
    static void
    dumpStackTrace()
    Print the current java call stack.
    static org.apache.bcel.generic.Type
    fqBinaryNameToType(@FqBinaryName String classname)
    Return the type corresponding to a given fully-qualified binary name.
    static String
    getConstantString(org.apache.bcel.classfile.ConstantPool pool, int index)
    Returns the constant string at the specified offset.
    static boolean
    inJdk(@ClassGetName String classname)
    Returns whether or not the class is part of the JDK (rt.jar).
    static boolean
    inJdk(org.apache.bcel.generic.ClassGen gen)
    Returns whether or not the class is part of the JDK (rt.jar).
    static boolean
    inJdkInternalform(@InternalForm String classname)
    Returns whether or not the class is part of the JDK (rt.jar).
    static String
    instructionListToString(org.apache.bcel.generic.InstructionList il, org.apache.bcel.generic.ConstantPoolGen pool)
    Return a printed description of the given instructions.
    static boolean
    isClinit(org.apache.bcel.classfile.Method m)
    Returns whether or not the method is a class initializer.
    static boolean
    isClinit(org.apache.bcel.generic.MethodGen mg)
    Returns whether or not the method is a class initializer.
    static boolean
    isConstructor(org.apache.bcel.classfile.Method m)
    Returns whether or not the method is a constructor.
    static boolean
    isConstructor(org.apache.bcel.generic.MethodGen mg)
    Returns whether or not the method is a constructor.
    static boolean
    isLocalVariableTypeTable(org.apache.bcel.classfile.Attribute a, org.apache.bcel.generic.ConstantPoolGen pool)
    Returns whether or not the specified attribute is a local variable type table.
    static boolean
    isMain(org.apache.bcel.generic.MethodGen mg)
    Returns whether or not this is a standard main method (static, void, name is 'main', and one formal parameter: a string array).
    static String
    localVariablesToString(org.apache.bcel.generic.MethodGen mg)
    Return a description of the local variables (one per line).
    static void
    makeMethodBodyEmpty(org.apache.bcel.generic.MethodGen mg)
    Empties the method of all code (except for a return).
    static String
    methodDeclarationToString(org.apache.bcel.classfile.Method m)
    Returns a string describing a method declaration.
    static org.apache.bcel.generic.Type[]
    postpendToArray(org.apache.bcel.generic.Type[] types, org.apache.bcel.generic.Type newType)
    Returns a copy of the given type array, with newType added to the end.
    static org.apache.bcel.generic.Type[]
    prependToArray(org.apache.bcel.generic.Type newType, org.apache.bcel.generic.Type[] types)
    Returns a copy of the given type array, with newType inserted at the beginning.
    static void
    removeLocalVariableTypeTables(org.apache.bcel.generic.MethodGen mg)
    Remove the local variable type table attribute (LVTT) from mg.
    static void
    resetLocalsToFormals(org.apache.bcel.generic.MethodGen mg)
    Sets the locals to be the formal parameters.
    static Class<?>
    typeToClass(org.apache.bcel.generic.Type type)
    Returns the class that corresponds to type.
    static @ClassGetName String
    typeToClassgetname(org.apache.bcel.generic.Type type)
    Returns the Java class name, in the format of Class.getName(), that corresponds to type.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • skipChecks

      public static boolean skipChecks
      Controls whether the checks in checkMgen(org.apache.bcel.generic.MethodGen) are performed.

    • javaVersion

      public static final int javaVersion
      The major version number of the Java runtime (JRE), such as 8, 11, or 17.

  • Method Details

    • methodDeclarationToString

      public static String methodDeclarationToString(org.apache.bcel.classfile.Method m)
      Returns a string describing a method declaration. It contains the access flags (public, private, static, etc), the return type, the method name, and the types of each of its parameters.

      For example, if the original Java source declaration was: private final String constantToString (int index) Then the output of methodDeclarationToString would be: private final java.lang.String constantToString (int)

      Parameters:
      m - the method
      Returns:
      a string describing the method declaration

    • instructionListToString

      public static String instructionListToString(org.apache.bcel.generic.InstructionList il, org.apache.bcel.generic.ConstantPoolGen pool)
      Return a printed description of the given instructions.
      Parameters:
      il - the instructions to describe
      pool - the constant pool the instructions refer to
      Returns:
      a printed representation of the instructions in il

    • localVariablesToString

      public static String localVariablesToString(org.apache.bcel.generic.MethodGen mg)
      Return a description of the local variables (one per line).
      Parameters:
      mg - the method whose local variables to describe
      Returns:
      a description of the local variables (one per line)

    • attributeNameToString

      public static String attributeNameToString(org.apache.bcel.classfile.Attribute a)
      Return the attribute name for the specified attribute, looked up in the original class file ConstantPool.
      Parameters:
      a - the attribute
      Returns:
      the attribute name for the specified attribute

    • attributeNameToString

      public static String attributeNameToString(org.apache.bcel.classfile.Attribute a, org.apache.bcel.generic.ConstantPoolGen pool)
      Return the attribute name for the specified attribute, looked up in the given ConstantPoolGen.
      Parameters:
      a - the attribute
      pool - the constant pool
      Returns:
      the attribute name for the specified attribute

    • isConstructor

      public static boolean isConstructor(org.apache.bcel.generic.MethodGen mg)
      Returns whether or not the method is a constructor.
      Parameters:
      mg - the MethodGen to test
      Returns:
      true iff the method is a constructor

    • isConstructor

      public static boolean isConstructor(org.apache.bcel.classfile.Method m)
      Returns whether or not the method is a constructor.
      Parameters:
      m - the Method to test
      Returns:
      true iff the method is a constructor

    • isClinit

      public static boolean isClinit(org.apache.bcel.generic.MethodGen mg)
      Returns whether or not the method is a class initializer.
      Parameters:
      mg - the method to test
      Returns:
      true iff the method is a class initializer

    • isClinit

      public static boolean isClinit(org.apache.bcel.classfile.Method m)
      Returns whether or not the method is a class initializer.
      Parameters:
      m - the method to test
      Returns:
      true iff the method is a class initializer

    • inJdk

      public static boolean inJdk(org.apache.bcel.generic.ClassGen gen)
      Returns whether or not the class is part of the JDK (rt.jar).
      Parameters:
      gen - the class to test
      Returns:
      true iff the class is in a package that is in the JDK (rt.jar)

    • inJdk

      public static boolean inJdk(@ClassGetName String classname)
      Returns whether or not the class is part of the JDK (rt.jar).
      Parameters:
      classname - the class to test, in the format of Class.getName(); the class should not be an array
      Returns:
      true iff the class is in a package that is in the JDK (rt.jar)

    • inJdkInternalform

      public static boolean inJdkInternalform(@InternalForm String classname)
      Returns whether or not the class is part of the JDK (rt.jar).
      Parameters:
      classname - the class to test, in internal form
      Returns:
      true iff the class is part of the JDK (rt.jar)

    • isLocalVariableTypeTable

      public static boolean isLocalVariableTypeTable(org.apache.bcel.classfile.Attribute a, org.apache.bcel.generic.ConstantPoolGen pool)
      Returns whether or not the specified attribute is a local variable type table.
      Parameters:
      a - the attribute
      pool - the constant pool
      Returns:
      true iff the attribute is a local variable type table

    • isMain

      public static boolean isMain(org.apache.bcel.generic.MethodGen mg)
      Returns whether or not this is a standard main method (static, void, name is 'main', and one formal parameter: a string array).
      Parameters:
      mg - the method to check
      Returns:
      true iff the method is a main method

    • checkMgen

      public static void checkMgen(org.apache.bcel.generic.MethodGen mgen)
      Checks the specified method for consistency.

      Does nothing if skipChecks is false.

      Parameters:
      mgen - the class to check

    • checkMgens

      public static void checkMgens(org.apache.bcel.generic.ClassGen gen)
      Checks all of the methods in gen for consistency.
      Parameters:
      gen - the class to check

    • dumpStackTrace

      public static void dumpStackTrace()
      Print the current java call stack.

    • dump

      public static void dump(org.apache.bcel.classfile.JavaClass jc, String dumpDir)
      Dumps the contents of the specified class to the specified directory. The file is named dumpDir/[class].bcel. It contains a synopsis of the fields and methods followed by the JVM code for each method.
      Parameters:
      jc - JavaClass to dump
      dumpDir - directory in which to write the file
      See Also:

    • dump

      public static void dump(org.apache.bcel.classfile.JavaClass jc, File dumpDir)
      Dumps the contents of the specified class to the specified directory. The file is named dumpDir/[class].bcel. It contains a synopsis of the fields and methods followed by the JVM code for each method.
      Parameters:
      jc - JavaClass to dump
      dumpDir - directory in which to write the file

    • addToStart

      public static void addToStart(org.apache.bcel.generic.MethodGen mg, org.apache.bcel.generic.InstructionList newList)
      Adds instructions to the start of a method.
      Parameters:
      mg - method to be augmented
      newList - instructions to prepend to the method

    • getConstantString

      public static String getConstantString(org.apache.bcel.classfile.ConstantPool pool, int index)
      Returns the constant string at the specified offset.
      Parameters:
      pool - the constant pool
      index - the index in the constant pool
      Returns:
      the constant string at the specified offset in the constant pool

    • resetLocalsToFormals

      public static void resetLocalsToFormals(org.apache.bcel.generic.MethodGen mg)
      Sets the locals to be the formal parameters. Any other locals are removed. An instruction list with at least one instruction must exist.
      Parameters:
      mg - the method whose locals to set

    • makeMethodBodyEmpty

      public static void makeMethodBodyEmpty(org.apache.bcel.generic.MethodGen mg)
      Empties the method of all code (except for a return). This includes line numbers, exceptions, local variables, etc.
      Parameters:
      mg - the method to clear out

    • removeLocalVariableTypeTables

      public static void removeLocalVariableTypeTables(org.apache.bcel.generic.MethodGen mg)
      Remove the local variable type table attribute (LVTT) from mg. Evidently some changes require this to be updated, but without BCEL support that would be hard to do. It should be safe to just delete it since it is optional and really only of use to a debugger.
      Parameters:
      mg - the method to clear out

    • typeToClassgetname

      public static @ClassGetName String typeToClassgetname(org.apache.bcel.generic.Type type)
      Returns the Java class name, in the format of Class.getName(), that corresponds to type.
      Parameters:
      type - the type
      Returns:
      the Java classname that corresponds to type

    • typeToClass

      public static Class<?> typeToClass(org.apache.bcel.generic.Type type)
      Returns the class that corresponds to type.
      Parameters:
      type - the type
      Returns:
      the Java class that corresponds to type

    • postpendToArray

      public static org.apache.bcel.generic.Type[] postpendToArray(org.apache.bcel.generic.Type[] types, org.apache.bcel.generic.Type newType)
      Returns a copy of the given type array, with newType added to the end.
      Parameters:
      types - the array to extend
      newType - the element to add to the end of the array
      Returns:
      a new array, with newType at the end

    • prependToArray

      public static org.apache.bcel.generic.Type[] prependToArray(org.apache.bcel.generic.Type newType, org.apache.bcel.generic.Type[] types)
      Returns a copy of the given type array, with newType inserted at the beginning.
      Parameters:
      newType - the element to add to the beginning of the array
      types - the array to extend
      Returns:
      a new array, with newType at the beginning

    • binaryNameToType

      public static org.apache.bcel.generic.Type binaryNameToType(@BinaryNameOrPrimitiveType String classname)
      Return the type corresponding to a given binary name or primitive type name.
      Parameters:
      classname - the binary name of a class (= fully-qualified name, except for inner classes), or a primitive type name, but not an array
      Returns:
      the type corresponding to the given class name
      See Also:

    • fqBinaryNameToType

      public static org.apache.bcel.generic.Type fqBinaryNameToType(@FqBinaryName String classname)
      Return the type corresponding to a given fully-qualified binary name.
      Parameters:
      classname - the fully-qualified binary name of a type, which is like a fully-qualified-name but uses "$" rather than "." for nested classes
      Returns:
      the type corresponding to the given name