org.plumelib.bcelutil

Class BcelUtil

java.lang.Object

org.plumelib.bcelutil.BcelUtil

public final class BcelUtil
extends java.lang.Object

Static utility methods for working with BCEL.

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	skipChecks Controls whether the checks in checkMgen are actually performed.

Method Summary

Modifier and Type	Method and Description
static void	addLineNumbers(org.apache.bcel.generic.MethodGen mg, org.apache.bcel.generic.InstructionList il) Builds an array of line numbers for the specified instruction list.
static void	addToStart(org.apache.bcel.generic.MethodGen mg, org.apache.bcel.generic.InstructionList nl) Adds code in nl to start of method mg.
static org.apache.bcel.generic.Type[]	addType(org.apache.bcel.generic.Type[] types, org.apache.bcel.generic.Type newType) Deprecated. use postpendToArray(org.apache.bcel.generic.Type[], org.apache.bcel.generic.Type)
static void	checkMgen(org.apache.bcel.generic.MethodGen mgen) Checks the specific method for consistency.
static void	checkMgens(org.apache.bcel.generic.ClassGen gen) Checks all of the methods in gen for consistency.
static java.lang.Class<?>	classForName(java.lang.String className) Like Class.forName(String), but also works when the string represents a primitive type or a fully-qualified name (as opposed to a binary name).
static org.apache.bcel.generic.Type	classnameToType(java.lang.String classname) Return the type corresponding to a given class name.
static void	dump(org.apache.bcel.classfile.JavaClass jc, java.io.File dumpDir) Dumps the contents of the specified class to the specified directory.
static void	dump(org.apache.bcel.classfile.JavaClass jc, java.lang.String dumpDir) Dumps the contents of the specified class to the specified directory.
static void	emptyMethod(org.apache.bcel.generic.MethodGen mg) Empties the method of all code (except for a return).
static java.lang.String	getAttributeName(org.apache.bcel.classfile.Attribute a) Return the attribute name for the specified attribute.
static java.lang.String	getAttributeName(org.apache.bcel.classfile.Attribute a, org.apache.bcel.generic.ConstantPoolGen pool) Return the attribute name for the specified attribute.
static java.lang.String	getConstantStr(org.apache.bcel.classfile.ConstantPool pool, int index) Returns the constant string at the specified offset.
static java.lang.String	getMethodDeclaration(org.apache.bcel.classfile.Method m) Returns a string describing a method declaration.
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(java.lang.String classname) Returns whether or not the class is part of the JDK (rt.jar).
static boolean	inJdkInternalform(java.lang.String classname) Returns whether or not the class is part of the JDK (rt.jar).
static org.apache.bcel.generic.Type[]	insertType(org.apache.bcel.generic.Type newType, org.apache.bcel.generic.Type[] types) Deprecated. use prependToArray(org.apache.bcel.generic.Type, org.apache.bcel.generic.Type[])
static java.lang.String	instructionDescr(org.apache.bcel.generic.InstructionList il, org.apache.bcel.generic.ConstantPoolGen pool)
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, name is 'main', and one argument of string array).
static java.lang.String	localVarDescr(org.apache.bcel.generic.MethodGen mg) Return a description of the local variables (one per line).
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	setupInitLocals(org.apache.bcel.generic.MethodGen mg) Sets the locals to 'this' and each of the arguments.
static java.lang.Class<?>	typeToClass(org.apache.bcel.generic.Type type) Returns the class that corresponds to type.
static java.lang.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 are actually performed.

Method Detail

getMethodDeclaration

public static java.lang.String getMethodDeclaration(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 arguments.

Parameters:

m - the method

Returns:

a string describing the method declaration

getAttributeName

public static java.lang.String getAttributeName(org.apache.bcel.classfile.Attribute a)

Return the attribute name for the specified attribute.

Parameters:

a - the attribute

Returns:

the attribute name for the specified attribute

getConstantStr

public static java.lang.String getConstantStr(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

isConstructor

public static boolean isConstructor(org.apache.bcel.generic.MethodGen mg)

Returns whether or not the method is a constructor.

Parameters:

mg - the method 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 part of the JDK (rt.jar)

inJdk

public static boolean inJdk(java.lang.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 part of the JDK (rt.jar)

inJdkInternalform

public static boolean inJdkInternalform(java.lang.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)

checkMgen

public static void checkMgen(org.apache.bcel.generic.MethodGen mgen)

Checks the specific method for consistency.

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

addToStart

public static void addToStart(org.apache.bcel.generic.MethodGen mg,
                              org.apache.bcel.generic.InstructionList nl)

Adds code in nl to start of method mg.

Parameters:

mg - method to be augmented

nl - instructions to prepend to the method

dump

public static void dump(org.apache.bcel.classfile.JavaClass jc,
                        java.lang.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,
                        java.io.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

instructionDescr

public static java.lang.String instructionDescr(org.apache.bcel.generic.InstructionList il,
                                                org.apache.bcel.generic.ConstantPoolGen pool)

localVarDescr

public static java.lang.String localVarDescr(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)

addLineNumbers

public static void addLineNumbers(org.apache.bcel.generic.MethodGen mg,
                                  org.apache.bcel.generic.InstructionList il)

Builds an array of line numbers for the specified instruction list. Each opcode is assigned the next source line number starting at 1000.

Parameters:

mg - the method whose line numbers to extract

il - the instruction list to augment with line numbers

setupInitLocals

public static void setupInitLocals(org.apache.bcel.generic.MethodGen mg)

Sets the locals to 'this' and each of the arguments. Any other locals are removed. An instruction list with at least one instruction must exist.

Parameters:

mg - the method whose locals to set

emptyMethod

public static void emptyMethod(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

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

getAttributeName

public static java.lang.String getAttributeName(org.apache.bcel.classfile.Attribute a,
                                                org.apache.bcel.generic.ConstantPoolGen pool)

Return the attribute name for the specified attribute.

Parameters:

a - the attribute

pool - the constant pool

Returns:

the attribute name for the specified attribute

isMain

public static boolean isMain(org.apache.bcel.generic.MethodGen mg)

Returns whether or not this is a standard main method (static, name is 'main', and one argument of string array).

Parameters:

mg - the method to check

Returns:

true iff the method is a main method

typeToClassgetname

public static java.lang.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 java.lang.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

addType

@Deprecated
public static org.apache.bcel.generic.Type[] addType(org.apache.bcel.generic.Type[] types,
                                                                 org.apache.bcel.generic.Type newType)

Deprecated. use postpendToArray(org.apache.bcel.generic.Type[], org.apache.bcel.generic.Type)

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

insertType

@Deprecated
public static org.apache.bcel.generic.Type[] insertType(org.apache.bcel.generic.Type newType,
                                                                    org.apache.bcel.generic.Type[] types)

Deprecated. use prependToArray(org.apache.bcel.generic.Type, org.apache.bcel.generic.Type[])

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

public static org.apache.bcel.generic.Type classnameToType(java.lang.String classname)

Return the type corresponding to a given class name.

Parameters:

classname - the binary name of a class (= fully-qualified name, except for inner classes)

Returns:

the type corresponding to the given class name

classForName

public static java.lang.Class<?> classForName(java.lang.String className)
                                       throws java.lang.ClassNotFoundException

Like Class.forName(String), but also works when the string represents a primitive type or a fully-qualified name (as opposed to a binary name).

If the given name can't be found, this method changes the last '.' to a dollar sign ($) and tries again. This accounts for inner classes that are incorrectly passed in in fully-qualified format instead of binary format. (It should try multiple dollar signs, not just at the last position.)

Recall the rather odd specification for Class.forName(String): the argument is a binary name for non-arrays, but a field descriptor for arrays. This method uses the same rules, but additionally handles primitive types and, for non-arrays, fully-qualified names.

Parameters:

className - name of the class

Returns:

the Class corresponding to className

Throws:

java.lang.ClassNotFoundException - if the class is not found