Class ClassHolder

java.lang.Object

org.apache.derby.iapi.services.classfile.ClassHolder

Direct Known Subclasses:

ClassInvestigator

public class ClassHolder
extends Object

Based upon "THE class FILE FORMAT" chapter of "The Java Virtual Machine Specification" corresponding to version 1.0.2 of the Java Virtual Machine and 1.0.2 of the Java Language Specification. ISBN 0-201-63452-X, September 1996.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	access_flags
protected Attributes	attribute_info
protected Vector<ConstantPoolEntry>	cptEntries
private int	cptEstimatedSize
protected Hashtable<Object, ConstantPoolEntry>	cptHashTable
protected MemberTable	field_info
protected int[]	interfaces
protected int	major_version	Minor class format number defaults to VMDescriptor.JAVA_CLASS_FORMAT_MAJOR_VERSION
protected MemberTable	method_info
protected int	minor_version	Minor class format number defaults to VMDescriptor.JAVA_CLASS_FORMAT_MINOR_VERSION which currently corresponds to a really old (JDK 1.0.2) setting.
private final CONSTANT_Index_info	searchIndex	Used to search for index entries to avoid object allocation in the case a referecne already exists.
protected int	super_class
protected int	this_class

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ClassHolder(int estimatedConstantPoolCount)
	ClassHolder(String fullyQualifiedName, String superClassName, int modifiers)	This will not define a constructor -- it is up to the caller to add at least one.

Method Summary

Modifier and Type	Method	Description
void	addAttribute(String attributeName, ClassFormatOutput info)
int	addClassReference(String fullyQualifiedName)	Add a class entry to the pool.
int	addConstant(double value)
int	addConstant(float value)
int	addConstant(int value)
int	addConstant(long value)
int	addConstant(String value)
private int	addDirectEntry(ConstantPoolEntry item)	Add an entry, but only if it doesn't exist.
protected int	addEntry(Object key, ConstantPoolEntry item)	Generic add entry to constant pool.
private CONSTANT_Utf8_info	addExtraUtf8(String value)	Add an extra UTF8 into the pool
int	addFieldReference(String className, String simpleName, String descriptor)
int	addFieldReference(ClassMember field)
private int	addIndexReference(int tag, int i1, int i2)	Add an index reference.
ClassMember	addMember(String simpleName, String descriptor, int modifier)
int	addMethodReference(String className, String simpleName, String descriptor, boolean isInterface)
private int	addNameAndType(String name, String descriptor)	Add a name and type entry
private int	addReference(int tag, String className, String simpleName, String descriptor)
private int	addReference(int tag, ClassMember member)
private int	addString(String value)	Add a string entry
int	addUtf8(String value)
private CONSTANT_Utf8_info	addUtf8Entry(String value)	Add a UTF8 into the pool and return the index to it.
protected String	className(int classIndex)	Return the class name for an index to a CONSTANT_Class_info.
private static String	convertToInternal(String externalName, boolean descriptor)
static String	convertToInternalClassName(String externalName)
static String	convertToInternalDescriptor(String externalName)
protected void	cptPut(ClassFormatOutput out)
int	findClass(String fullyQualifiedName)	Find a class descriptor (section 4.4.1) and return its index, returns -1 if not found.
protected CONSTANT_Index_info	findIndexEntry(int tag, int i1, int i2)
protected int	findIndexIndex(int tag, int i1, int i2)
protected ConstantPoolEntry	findMatchingEntry(Object key)
int	findNameAndType(String name, String descriptor)	Find a name and type descriptor (section 4.4.6) and return it's index.
(package private) int	findUtf8(String value)	Return the index of a UTF entry or -1 if it doesn't exist.
protected String	getClassName(int index)	get the class name of a Class given the index of its CONSTANT_Class_info entry in the Constant Pool.
int	getConstantPoolIndex()
ConstantPoolEntry	getEntry(int index)
ByteArray	getFileFormat()	Convert the object representation of the class into its class file format.
int	getModifier()
String	getName()
String	getSuperClassName()
static boolean	isExternalClassName(String className)
private static String	makeDesc(char builtin, int arity)	A helper to build a type description based on a built-in type and an array arity.
private static String	makeDesc(String className, int arity, boolean descriptor)	A helper to build a type description based on a Java class and an array arity.
(package private) String	nameIndexToString(int index)	get a string (UTF) given a name_index into the constant pool
private void	put(ClassFormatOutput out)

Methods inherited from class Object

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

Field Details

minor_version

protected int minor_version

Minor class format number defaults to VMDescriptor.JAVA_CLASS_FORMAT_MINOR_VERSION which currently corresponds to a really old (JDK 1.0.2) setting. The default major and minor value is used by the generated code for Derby's SQL statements. Currently there is no need to bump the version number as the generated code does not take advantage of any of the new elements in the class file format. If such a need exists then this can be bumped. One issue is that the change in format numbers is not well documented.

major_version

protected int major_version

Minor class format number defaults to VMDescriptor.JAVA_CLASS_FORMAT_MAJOR_VERSION

access_flags

protected int access_flags

this_class

protected int this_class

super_class

protected int super_class

interfaces

protected int[] interfaces

field_info

protected MemberTable field_info

method_info

protected MemberTable method_info

attribute_info

protected Attributes attribute_info

cptHashTable

protected Hashtable<Object, ConstantPoolEntry> cptHashTable

cptEntries

protected Vector<ConstantPoolEntry> cptEntries

cptEstimatedSize

private int cptEstimatedSize

searchIndex

private final CONSTANT_Index_info searchIndex

Used to search for index entries to avoid object allocation in the case a referecne already exists.

Constructor Details

ClassHolder

protected ClassHolder(int estimatedConstantPoolCount)

ClassHolder

public ClassHolder(String fullyQualifiedName,
 String superClassName,
 int modifiers)

This will not define a constructor -- it is up to the caller to add at least one.

Method Details

put

private void put(ClassFormatOutput out)
          throws IOException

Throws:

IOException

getFileFormat

public ByteArray getFileFormat()
                        throws IOException

Convert the object representation of the class into its class file format.

Throws:

IOException - error writing the class

getModifier

public int getModifier()

See Also:

• ClassMember

getName

public String getName()

See Also:

• ClassMember

addMember

public ClassMember addMember(String simpleName,
 String descriptor,
 int modifier)

See Also:

• addMember(String, String, int)

addFieldReference

public int addFieldReference(String className,
 String simpleName,
 String descriptor)

See Also:

• addFieldReference(String, String, String)

addFieldReference

public int addFieldReference(ClassMember field)

addMethodReference

public int addMethodReference(String className,
 String simpleName,
 String descriptor,
 boolean isInterface)

See Also:

• addMethodReference(String, String, String, boolean)

addReference

private int addReference(int tag,
 String className,
 String simpleName,
 String descriptor)

addReference

private int addReference(int tag,
 ClassMember member)

addConstant

public int addConstant(String value)

See Also:

• addConstant(String)

addUtf8

public int addUtf8(String value)

See Also:

• addUtf8(String)

addConstant

public int addConstant(int value)

See Also:

• addConstant(String)

addConstant

public int addConstant(float value)

See Also:

• addConstant(String)

addConstant

public int addConstant(long value)

See Also:

• addConstant(String)

addConstant

public int addConstant(double value)

See Also:

• addConstant(String)

getConstantPoolIndex

public int getConstantPoolIndex()

See Also:

• ClassMember

addAttribute

public void addAttribute(String attributeName,
 ClassFormatOutput info)

getSuperClassName

public String getSuperClassName()

addEntry

protected int addEntry(Object key,
 ConstantPoolEntry item)

Generic add entry to constant pool. Includes the logic for an entry to occupy more than one slot (e.g. long).

Returns:

The number of slots occupied by the entry. .

addDirectEntry

private int addDirectEntry(ConstantPoolEntry item)

Add an entry, but only if it doesn't exist.

Returns:

the constant pool index of the added or existing item.

addIndexReference

private int addIndexReference(int tag,
 int i1,
 int i2)

Add an index reference.

addClassReference

public int addClassReference(String fullyQualifiedName)

Add a class entry to the pool.

addNameAndType

private int addNameAndType(String name,
 String descriptor)

Add a name and type entry

addUtf8Entry

private CONSTANT_Utf8_info addUtf8Entry(String value)

Add a UTF8 into the pool and return the index to it.

addExtraUtf8

private CONSTANT_Utf8_info addExtraUtf8(String value)

Add an extra UTF8 into the pool

addString

private int addString(String value)

Add a string entry

cptPut

protected void cptPut(ClassFormatOutput out)
               throws IOException

Throws:

IOException

getEntry

public ConstantPoolEntry getEntry(int index)

className

protected String className(int classIndex)

Return the class name for an index to a CONSTANT_Class_info.

findUtf8

int findUtf8(String value)

Return the index of a UTF entry or -1 if it doesn't exist.

findClass

public int findClass(String fullyQualifiedName)

Find a class descriptor (section 4.4.1) and return its index, returns -1 if not found.

findNameAndType

public int findNameAndType(String name,
 String descriptor)

Find a name and type descriptor (section 4.4.6) and return it's index.

returns -1 if not found.

findIndexEntry

protected CONSTANT_Index_info findIndexEntry(int tag,
 int i1,
 int i2)

findIndexIndex

protected int findIndexIndex(int tag,
 int i1,
 int i2)

findMatchingEntry

protected ConstantPoolEntry findMatchingEntry(Object key)

nameIndexToString

String nameIndexToString(int index)

get a string (UTF) given a name_index into the constant pool

getClassName

protected String getClassName(int index)

get the class name of a Class given the index of its CONSTANT_Class_info entry in the Constant Pool.

isExternalClassName

public static boolean isExternalClassName(String className)

convertToInternalClassName

public static String convertToInternalClassName(String externalName)

convertToInternalDescriptor

public static String convertToInternalDescriptor(String externalName)

convertToInternal

private static String convertToInternal(String externalName,
 boolean descriptor)

makeDesc

private static String makeDesc(char builtin,
 int arity)

A helper to build a type description based on a built-in type and an array arity.

makeDesc

private static String makeDesc(String className,
 int arity,
 boolean descriptor)

A helper to build a type description based on a Java class and an array arity. If descriptor is true create a descriptor according to section 4.3.2 of the vm spec. If false create a class name according to sections 4.3.2 and 4.4.1 of the vm spec.