ClassInvestigator.java
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org.apache.derby.iapi.services.classfile |
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Apache Derby |
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These are the metrics that contribute to the Enerjy Score for this file, ranked by impact. So the metrics listed at the top influence the score to a greater extent that the metrics listed at the bottom.
/*
Derby - Class org.apache.derby.iapi.services.classfile.ClassInvestigator
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to you under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.derby.iapi.services.classfile;
import java.io.InputStream;
import java.util.Enumeration;
import java.io.IOException;
import java.util.Vector;
import org.apache.derby.iapi.services.classfile.VMDescriptor;
import org.apache.derby.iapi.services.classfile.VMDescriptor;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Vector;
import java.util.Enumeration;
import java.util.Collections;
/**
*/
public class ClassInvestigator extends ClassHolder {
public static ClassInvestigator load(InputStream is)
throws IOException {
ClassInput classInput = new ClassInput(is);
// Check the header
int magic = classInput.getU4();
int minor_version = classInput.getU2();
int major_version = classInput.getU2();
if (magic != VMDescriptor.JAVA_CLASS_FORMAT_MAGIC)
throw new ClassFormatError();
// Read in the Constant Pool
int constantPoolCount = classInput.getU2();
ClassInvestigator ci = new ClassInvestigator(constantPoolCount);
ci.minor_version = minor_version;
ci.major_version = major_version;
// Yes, index starts at 1, The '0'th constant pool entry
// is reserved for the JVM and is not present in the class file.
for (int i = 1; i < constantPoolCount; ) {
ConstantPoolEntry item = ClassInvestigator.getConstant(classInput);
i += ci.addEntry(item.getKey(), item);
}
// Read in access_flags and class indexes
ci.access_flags = classInput.getU2();
ci.this_class = classInput.getU2();
ci.super_class = classInput.getU2();
// interfaces is a simple int array
int interfaceCount = classInput.getU2();
if (interfaceCount != 0) {
ci.interfaces = new int[interfaceCount];
for (int i = 0; i < interfaceCount; i++)
ci.interfaces[i] = classInput.getU2();
}
int fieldCount = classInput.getU2();
if (fieldCount != 0) {
ci.field_info = new MemberTable(fieldCount);
for (int i = 0; i < fieldCount; i++)
{
ci.field_info.addEntry(readClassMember(ci, classInput));
}
}
int methodCount = classInput.getU2();
if (methodCount != 0) {
ci.method_info = new MemberTable(methodCount);
for (int i = 0; i < methodCount; i++)
{
ci.method_info.addEntry(readClassMember(ci, classInput));
}
}
int attributeCount = classInput.getU2();
if (attributeCount != 0) {
ci.attribute_info = new Attributes(attributeCount);
for (int i = 0; i < attributeCount; i++)
ci.attribute_info.addEntry(new AttributeEntry(classInput));
}
return ci;
}
private static ClassMember readClassMember(ClassInvestigator ci, ClassInput in)
throws IOException {
ClassMember member = new ClassMember(ci, in.getU2(), in.getU2(), in.getU2());
int attributeCount = in.getU2();
if (attributeCount != 0) {
member.attribute_info = new Attributes(attributeCount);
for (int i = 0; i < attributeCount; i++)
member.attribute_info.addEntry(new AttributeEntry(in));
}
return member;
}
/*
** Constructors.
*/
private ClassInvestigator(int constantPoolCount) {
super(constantPoolCount);
}
/*
** Methods to investigate this class
*/
public Enumeration implementedInterfaces()
{
int interfaceCount = interfaces == null ? 0 : interfaces.length;
Vector implemented = new Vector(interfaceCount);
for (int i = 0; i < interfaceCount; i++)
{
implemented.addElement(className(interfaces[i]));
}
return implemented.elements();
}
public Enumeration getFields() {
if (field_info == null)
return Collections.enumeration(Collections.EMPTY_LIST);
return field_info.entries.elements();
}
public Enumeration getMethods() {
if (method_info == null)
return Collections.enumeration(Collections.EMPTY_LIST);
return method_info.entries.elements();
}
public Enumeration referencedClasses() {
return getClasses(getMethods(), getFields() );
}
/**
Return an Enumeration of all referenced classes
*/
private Enumeration getClasses(Enumeration methods, Enumeration fields)
{
return new ClassEnumeration(this, cptEntries.elements(), methods, fields);
}
public Enumeration getStrings() {
HashSet strings = new HashSet(30, 0.8f);
int size = cptEntries.size();
for (int i = 1; i < size; i++) {
ConstantPoolEntry cpe = getEntry(i);
if ((cpe == null) || (cpe.getTag() != VMDescriptor.CONSTANT_String))
continue;
CONSTANT_Index_info cii = (CONSTANT_Index_info) cpe;
strings.add(nameIndexToString(cii.getI1()));
}
return java.util.Collections.enumeration(strings);
}
public ClassMember getMember(String simpleName, String descriptor) {
if (descriptor.startsWith("(")) {
if (method_info == null)
return null;
return method_info.find(simpleName, descriptor);
}
else {
if (field_info == null)
return null;
return field_info.find(simpleName, descriptor);
}
}
/**
Return an Enumeration of all Member References
*/
/*
Enumeration getMemberReferences() {
return new ReferenceEnumeration(this, elements());
}
*/
/*
** Methods to modify the class.
*/
// remove all atttributes that are not essential
public void removeAttributes() throws IOException {
// Class level attributes
if (attribute_info != null) {
for (int i = attribute_info.size() - 1; i >= 0 ; i--) {
AttributeEntry ae = (AttributeEntry) attribute_info.elementAt(i);
String name = nameIndexToString(ae.getNameIndex());
if (name.equals("SourceFile"))
attribute_info.removeElementAt(i);
else if (name.equals("InnerClasses"))
; // leave in
else
System.err.println("WARNING - Unknown Class File attribute " + name);
}
if (attribute_info.size() == 0)
attribute_info = null;
}
attribute_info = null;
// fields
for (Enumeration e = getFields(); e.hasMoreElements(); ) {
ClassMember member = (ClassMember) e.nextElement();
Attributes attrs = member.attribute_info;
if (attrs != null) {
for (int i = attrs.size() - 1; i >= 0 ; i--) {
AttributeEntry ae = (AttributeEntry) attrs.elementAt(i);
String name = nameIndexToString(ae.getNameIndex());
if (name.equals("ConstantValue"))
; // leave in
else if (name.equals("Synthetic"))
; // leave in
else
System.err.println("WARNING - Unknown Field attribute " + name);
}
if (attrs.size() == 0)
member.attribute_info = null;
}
}
// methods
for (Enumeration e = getMethods(); e.hasMoreElements(); ) {
ClassMember member = (ClassMember) e.nextElement();
Attributes attrs = member.attribute_info;
if (attrs != null) {
for (int i = attrs.size() - 1; i >= 0 ; i--) {
AttributeEntry ae = (AttributeEntry) attrs.elementAt(i);
String name = nameIndexToString(ae.getNameIndex());
if (name.equals("Code"))
processCodeAttribute(member, ae);
else if (name.equals("Exceptions"))
; // leave in
else if (name.equals("Deprecated"))
; // leave in
else if (name.equals("Synthetic"))
; // leave in
else
System.err.println("WARNING - Unknown method attribute " + name);
}
if (attrs.size() == 0)
member.attribute_info = null;
}
}
}
private void processCodeAttribute(ClassMember member, AttributeEntry ae) throws IOException {
ClassInput ci = new ClassInput(new java.io.ByteArrayInputStream(ae.infoIn));
ci.skipBytes(4); // puts us at code_length
int len = ci.getU4();
ci.skipBytes(len); // puts us at exception_table_length
int count = ci.getU2();
if (count != 0)
ci.skipBytes(8 * count);
int nonAttrLength = 4 + 4 + len + 2 + (8 * count);
// now at attributes
count = ci.getU2();
if (count == 0)
return;
int newCount = count;
for (int i = 0; i < count; i++) {
int nameIndex = ci.getU2();
String name = nameIndexToString(nameIndex);
if (name.equals("LineNumberTable") || name.equals("LocalVariableTable"))
newCount--;
else
System.err.println("ERROR - Unknown code attribute " + name);
len = ci.getU4();
ci.skipBytes(len);
}
if (newCount != 0) {
System.err.println("ERROR - expecting all code attributes to be removed");
System.exit(1);
}
// this is only coded for all attributes within a Code attribute being removed.
byte[] newInfo = new byte[nonAttrLength + 2];
System.arraycopy(ae.infoIn, 0, newInfo, 0, nonAttrLength);
// last two bytes are left at 0 which means 0 attributes
ae.infoIn = newInfo;
}
public void renameClassElements(Hashtable classNameMap, Hashtable memberNameMap) {
// this & super class
renameString(classNameMap, (CONSTANT_Index_info) getEntry(this_class));
renameString(classNameMap, (CONSTANT_Index_info) getEntry(super_class));
// implemented interfaces
// handled by Class entries below
// classes & Strings
// descriptors
int size = cptEntries.size();
for (int i = 1; i < size; i++) {
ConstantPoolEntry cpe = getEntry(i);
if (cpe == null)
continue;
switch (cpe.getTag()) {
case VMDescriptor.CONSTANT_String:
case VMDescriptor.CONSTANT_Class:
{
CONSTANT_Index_info cii = (CONSTANT_Index_info) cpe;
renameString(classNameMap, cii);
break;
}
case VMDescriptor.CONSTANT_NameAndType:
{
CONSTANT_Index_info cii = (CONSTANT_Index_info) cpe;
String newDescriptor = newDescriptor(classNameMap, nameIndexToString(cii.getI2()));
if (newDescriptor != null) {
doRenameString(cii.getI2(), newDescriptor);
}
break;
}
default:
continue;
}
}
//System.out.println("Starting Fields");
// now the methods & fields, only descriptors at this time
renameMembers(getFields(), classNameMap, memberNameMap);
renameMembers(getMethods(), classNameMap, memberNameMap);
}
private void renameMembers(Enumeration e, Hashtable classNameMap, Hashtable memberNameMap) {
for (; e.hasMoreElements(); ) {
ClassMember member = (ClassMember) e.nextElement();
String oldMemberName = nameIndexToString(member.name_index);
String newMemberName = (String) memberNameMap.get(oldMemberName);
if (newMemberName != null)
doRenameString(member.name_index, newMemberName);
String newDescriptor = newDescriptor(classNameMap, nameIndexToString(member.descriptor_index));
if (newDescriptor != null) {
doRenameString(member.descriptor_index, newDescriptor);
}
}
}
private void renameString(Hashtable classNameMap, CONSTANT_Index_info cii) {
int index = cii.getI1();
String name = nameIndexToString(index);
String newName = (String) classNameMap.get(name);
if (newName != null) {
doRenameString(index, newName);
return;
}
// have to look for arrays
if (cii.getTag() == VMDescriptor.CONSTANT_Class) {
if (name.charAt(0) == '[') {
int classOffset = name.indexOf('L') + 1;
String baseClassName = name.substring(classOffset, name.length() - 1);
newName = (String) classNameMap.get(baseClassName);
if (newName != null) {
String newArrayClassName = name.substring(0, classOffset) + newName + ";";
doRenameString(index, newArrayClassName);
}
}
}
}
private void doRenameString(int index, String newName) {
ConstantPoolEntry cpe = getEntry(index);
if (cpe.getTag() != VMDescriptor.CONSTANT_Utf8)
throw new RuntimeException("unexpected type " + cpe);
CONSTANT_Utf8_info newCpe = new CONSTANT_Utf8_info(newName);
cptHashTable.remove(cpe.getKey());
cptHashTable.put(newCpe.getKey(), newCpe);
newCpe.index = index;
cptEntries.setElementAt(newCpe, index);
}
private static ConstantPoolEntry getConstant(ClassInput in)
throws IOException {
ConstantPoolEntry item;
int tag;
tag = in.readUnsignedByte();
switch (tag) {
case VMDescriptor.CONSTANT_Class:
case VMDescriptor.CONSTANT_String:
item = new CONSTANT_Index_info(tag, in.getU2(), 0);
break;
case VMDescriptor.CONSTANT_NameAndType:
case VMDescriptor.CONSTANT_Fieldref:
case VMDescriptor.CONSTANT_Methodref:
case VMDescriptor.CONSTANT_InterfaceMethodref:
item = new CONSTANT_Index_info(tag, in.getU2(), in.getU2());
break;
case VMDescriptor.CONSTANT_Integer:
item = new CONSTANT_Integer_info(in.getU4());
break;
case VMDescriptor.CONSTANT_Float:
item = new CONSTANT_Float_info(in.readFloat());
break;
case VMDescriptor.CONSTANT_Long:
item = new CONSTANT_Long_info(in.readLong());
break;
case VMDescriptor.CONSTANT_Double:
item = new CONSTANT_Double_info(in.readDouble());
break;
case VMDescriptor.CONSTANT_Utf8:
item = new CONSTANT_Utf8_info(in.readUTF());
break;
default:
throw new ClassFormatError();
}
return item;
}
public static String newDescriptor(Hashtable classNameMap, String descriptor) {
String newDescriptor = null;
int dlen = descriptor.length();
for (int offset = 0; offset < dlen; ) {
char c = descriptor.charAt(offset);
switch (c) {
case VMDescriptor.C_VOID :
case VMDescriptor.C_BOOLEAN:
case VMDescriptor.C_BYTE:
case VMDescriptor.C_CHAR:
case VMDescriptor.C_SHORT:
case VMDescriptor.C_INT:
case VMDescriptor.C_LONG:
case VMDescriptor.C_FLOAT:
case VMDescriptor.C_DOUBLE:
case VMDescriptor.C_ARRAY:
case VMDescriptor.C_METHOD:
case VMDescriptor.C_ENDMETHOD:
default:
offset++;
continue;
case VMDescriptor.C_CLASS:
{
int startOffset = offset;
while (descriptor.charAt(offset++) != VMDescriptor.C_ENDCLASS)
;
int endOffset = offset;
// name includes L and ;
String name = descriptor.substring(startOffset, endOffset);
String newName = (String) classNameMap.get(name);
if (newName != null) {
if (newDescriptor == null)
newDescriptor = descriptor;
// we just replace the first occurance of it,
// the loop will hit any next occurance.
int startPos = newDescriptor.indexOf(name);
String tmp;
if (startPos == 0)
tmp = newName;
else
tmp = newDescriptor.substring(0, startPos) +
newName;
int endPos = startPos + name.length();
if (endPos < newDescriptor.length()) {
tmp += newDescriptor.substring(endPos , newDescriptor.length());
}
newDescriptor = tmp;
}
}
}
}
//if (newDescriptor != null) {
// System.out.println("O - " + descriptor);
// System.out.println("N - " + newDescriptor);
//}
return newDescriptor;
}
}
The table below shows all metrics for ClassInvestigator.java.




