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 and Description
static int	javaVersion The major version number of the Java runtime.
static boolean	skipChecks Controls whether the checks in checkMgen(org.apache.bcel.generic.MethodGen) are performed.
private static org.apache.bcel.generic.Type	stringArray The type that represents String[].

Constructor Summary

Constructors

Modifier	Constructor and Description
private	BcelUtil() This class is a collection of methods; it does not represent anything.

Method Summary

Modifier and Type	Method and Description
(package private) static String	accessFlagsToString(org.apache.bcel.classfile.Method m) Return a string representation of the access flags of method m.
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 org.apache.bcel.generic.Type	classnameToType(@BinaryNameOrPrimitiveType String classname) Deprecated. use binaryNameToType(java.lang.String)
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.
(package private) static void	dumpMethods(org.apache.bcel.generic.ClassGen gen) Print the methods in the class, to standard output.
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.
private static int	getJavaVersion() Extract the major version number from the "java.version" system property.
static boolean	inJdk(org.apache.bcel.generic.ClassGen gen) Returns whether or not the class is part of the JDK (rt.jar).
static boolean	inJdk(@ClassGetName String classname) 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 Detail

skipChecks

public static boolean skipChecks

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

stringArray

private static final org.apache.bcel.generic.Type stringArray

The type that represents String[].

javaVersion

public static final int javaVersion

The major version number of the Java runtime.

Constructor Detail

BcelUtil

private BcelUtil()

This class is a collection of methods; it does not represent anything.

Method Detail

getJavaVersion

private static int getJavaVersion()

Extract the major version number from the "java.version" system property.

Returns:

the major version of the Java runtime

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 orignal Java source declarationwas: 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

accessFlagsToString

static String accessFlagsToString(org.apache.bcel.classfile.Method m)

Return a string representation of the access flags of method m. In the string, the flags are space-separated and in a canonical order.

Parameters:

m - the method whose access flags to retrieve

Returns:

a string representation of the access flags of method m

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.

dumpMethods

static void dumpMethods(org.apache.bcel.generic.ClassGen gen)

Print the methods in the class, to standard output.

Parameters:

gen - the class whose methods to print

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(JavaClass, File)

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:

types - the array to extend

newType - the element to add to the beginning of the array

Returns:

a new array, with newType at the beginning

classnameToType

@Deprecated
public static org.apache.bcel.generic.Type classnameToType(@BinaryNameOrPrimitiveType String classname)

Deprecated. use binaryNameToType(java.lang.String)

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(java.lang.String)

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(java.lang.String)

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 uses "$" rather than "." for nested classes

Returns:

the type corresponding to the given name