package org.drools.factmodel;
/*
* Copyright 2008 JBoss Inc
*
* Licensed 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.
*/
import java.beans.IntrospectionException;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import org.drools.asm.ClassWriter;
import org.drools.asm.FieldVisitor;
import org.drools.asm.Label;
import org.drools.asm.MethodVisitor;
import org.drools.asm.Opcodes;
import org.drools.asm.Type;
/**
* A builder to dynamically build simple Javabean(TM) classes
*
* @author etirelli
*/
public class ClassBuilder {
private boolean debug = false;
private ClassLoader loader = null;
public ClassBuilder() {
this( null,
"true".equalsIgnoreCase( System.getProperty( "org.drools.classbuilder.debug" ) ) );
}
public ClassBuilder(final boolean debug) {
this( null,
debug );
}
public ClassBuilder(final ClassLoader loader) {
this( loader,
false );
}
public ClassBuilder(final ClassLoader loader,
final boolean debug) {
this.loader = loader;
if ( this.loader == null ) {
this.loader = Thread.currentThread().getContextClassLoader();
if ( this.loader == null ) {
this.loader = getClass().getClassLoader();
}
}
this.debug = debug;
}
/**
* Dynamically builds, defines and loads a class based on the given class definition
*
* @param classDef the class definition object structure
*
* @return the Class instance for the given class definition
*
* @throws IOException
* @throws IntrospectionException
* @throws InvocationTargetException
* @throws IllegalAccessException
* @throws NoSuchMethodException
* @throws ClassNotFoundException
* @throws IllegalArgumentException
* @throws SecurityException
* @throws NoSuchFieldException
* @throws InstantiationException
*/
public Class< ? > buildAndLoadClass(ClassDefinition classDef) throws IOException,
IntrospectionException,
SecurityException,
IllegalArgumentException,
ClassNotFoundException,
NoSuchMethodException,
IllegalAccessException,
InvocationTargetException,
InstantiationException,
NoSuchFieldException {
try {
Class< ? > clazz = Class.forName( classDef.getClassName() );
classDef.setDefinedClass( clazz );
return clazz;
} catch ( ClassNotFoundException e ) {
// class not loaded, so create and load it
byte[] serializedClazz = this.buildClass( classDef );
Class< ? > clazz = this.loadClass( classDef.getClassName(),
serializedClazz );
classDef.setDefinedClass( clazz );
return clazz;
}
}
/**
* Dynamically builds, defines and loads a class based on the given class definition
*
* @param classDef the class definition object structure
*
* @return the Class instance for the given class definition
*
* @throws IOException
* @throws IntrospectionException
* @throws InvocationTargetException
* @throws IllegalAccessException
* @throws NoSuchMethodException
* @throws ClassNotFoundException
* @throws IllegalArgumentException
* @throws SecurityException
* @throws NoSuchFieldException
* @throws InstantiationException
*/
public byte[] buildClass(ClassDefinition classDef) throws IOException,
IntrospectionException,
SecurityException,
IllegalArgumentException,
ClassNotFoundException,
NoSuchMethodException,
IllegalAccessException,
InvocationTargetException,
InstantiationException,
NoSuchFieldException {
ClassWriter cw = new ClassWriter( true );
this.buildClassHeader( cw,
classDef );
// Building fields
for ( FieldDefinition fieldDef : classDef.getFieldsDefinitions() ) {
this.buildField( cw,
fieldDef );
}
// Building default constructor
this.buildDefaultConstructor( cw,
classDef );
// Building methods
for ( FieldDefinition fieldDef : classDef.getFieldsDefinitions() ) {
this.buildGetMethod( cw,
classDef,
fieldDef );
this.buildSetMethod( cw,
classDef,
fieldDef );
}
this.buildEquals( cw,
classDef );
this.buildHashCode( cw,
classDef );
this.buildToString( cw,
classDef );
cw.visitEnd();
return cw.toByteArray();
}
/**
* Defines the class header for the given class definition
*
* @param cw
* @param dimDef
*/
private void buildClassHeader(ClassWriter cw,
ClassDefinition classDef) {
String[] original = classDef.getInterfaces();
String[] interfaces = new String[ original.length ];
for( int i = 0; i < original.length; i++ ) {
interfaces[i] = getInternalType( original[i] );
}
// Building class header
cw.visit( Opcodes.V1_4,
Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER,
getInternalType( classDef.getClassName() ),
null,
getInternalType( classDef.getSuperClass() ),
interfaces );
cw.visitSource( classDef.getClassName() + ".java",
null );
}
/**
* Creates the field defined by the given FieldDefinition
*
* @param cw
* @param fieldDef
*/
private void buildField(ClassWriter cw,
FieldDefinition fieldDef) {
FieldVisitor fv;
fv = cw.visitField( Opcodes.ACC_PRIVATE,
fieldDef.getName(),
getTypeDescriptor( fieldDef.getTypeName() ),
null,
null );
fv.visitEnd();
}
/**
* Creates a default constructor for the class
*
* @param cw
*/
private void buildDefaultConstructor(ClassWriter cw,
ClassDefinition classDef) {
MethodVisitor mv;
// Building default constructor
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
"<init>",
Type.getMethodDescriptor( Type.VOID_TYPE,
new Type[]{} ),
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitMethodInsn( Opcodes.INVOKESPECIAL,
Type.getInternalName( Object.class ),
"<init>",
Type.getMethodDescriptor( Type.VOID_TYPE,
new Type[]{} ) );
mv.visitInsn( Opcodes.RETURN );
Label l1 = null;
if ( this.debug ) {
l1 = new Label();
mv.visitLabel( l1 );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
l1,
0 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
/**
* Creates the set method for the given field definition
*
* @param cw
* @param classDef
* @param fieldDef
*/
private void buildSetMethod(ClassWriter cw,
ClassDefinition classDef,
FieldDefinition fieldDef) {
MethodVisitor mv;
// set method
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
fieldDef.getWriteMethod(),
Type.getMethodDescriptor( Type.VOID_TYPE,
new Type[]{Type.getType( getTypeDescriptor( fieldDef.getTypeName() ) )} ),
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitVarInsn( Type.getType( getTypeDescriptor( fieldDef.getTypeName() ) ).getOpcode( Opcodes.ILOAD ),
1 );
mv.visitFieldInsn( Opcodes.PUTFIELD,
getInternalType( classDef.getClassName() ),
fieldDef.getName(),
getTypeDescriptor( fieldDef.getTypeName() ) );
mv.visitInsn( Opcodes.RETURN );
Label l1 = null;
if ( this.debug ) {
l1 = new Label();
mv.visitLabel( l1 );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
l1,
0 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
/**
* Creates the get method for the given field definition
*
* @param cw
* @param classDef
* @param fieldDef
*/
private void buildGetMethod(ClassWriter cw,
ClassDefinition classDef,
FieldDefinition fieldDef) {
MethodVisitor mv;
// Get method
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
fieldDef.getReadMethod(),
Type.getMethodDescriptor( Type.getType( getTypeDescriptor( fieldDef.getTypeName() ) ),
new Type[]{} ),
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
fieldDef.getName(),
getTypeDescriptor( fieldDef.getTypeName() ) );
mv.visitInsn( Type.getType( getTypeDescriptor( fieldDef.getTypeName() ) ).getOpcode( Opcodes.IRETURN ) );
Label l1 = null;
if ( this.debug ) {
l1 = new Label();
mv.visitLabel( l1 );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
l1,
0 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
private void buildEquals(ClassWriter cw,
ClassDefinition classDef) {
MethodVisitor mv;
// Building equals method
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
"equals",
"(Ljava/lang/Object;)Z",
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
// if ( this == obj ) return true;
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitVarInsn( Opcodes.ALOAD,
1 );
Label l1 = new Label();
mv.visitJumpInsn( Opcodes.IF_ACMPNE,
l1 );
mv.visitInsn( Opcodes.ICONST_1 );
mv.visitInsn( Opcodes.IRETURN );
// if ( obj == null ) return false;
mv.visitLabel( l1 );
mv.visitVarInsn( Opcodes.ALOAD,
1 );
Label l2 = new Label();
mv.visitJumpInsn( Opcodes.IFNONNULL,
l2 );
mv.visitInsn( Opcodes.ICONST_0 );
mv.visitInsn( Opcodes.IRETURN );
// if ( getClass() != obj.getClass() ) return false;
mv.visitLabel( l2 );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( Object.class ),
"getClass",
Type.getMethodDescriptor( Type.getType( Class.class ),
new Type[]{} ) );
mv.visitVarInsn( Opcodes.ALOAD,
1 );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( Object.class ),
"getClass",
Type.getMethodDescriptor( Type.getType( Class.class ),
new Type[]{} ) );
Label l3 = new Label();
mv.visitJumpInsn( Opcodes.IF_ACMPEQ,
l3 );
mv.visitInsn( Opcodes.ICONST_0 );
mv.visitInsn( Opcodes.IRETURN );
// final <classname> other = (<classname>) obj;
mv.visitLabel( l3 );
mv.visitVarInsn( Opcodes.ALOAD,
1 );
mv.visitTypeInsn( Opcodes.CHECKCAST,
getInternalType( classDef.getClassName() ) );
mv.visitVarInsn( Opcodes.ASTORE,
2 );
// for each key field
int count = 0;
for ( FieldDefinition field : classDef.getFieldsDefinitions() ) {
if ( field.isKey() ) {
count++;
Label goNext = new Label();
if ( isPrimitive( field.getTypeName() ) ) {
// if attr is primitive
// if ( this.<attr> != other.<booleanAttr> ) return false;
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitVarInsn( Opcodes.ALOAD,
2 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
if ( field.getTypeName().equals( "long" ) ) {
mv.visitInsn( Opcodes.LCMP );
mv.visitJumpInsn( Opcodes.IFEQ,
goNext );
} else if ( field.getTypeName().equals( "double" ) ) {
mv.visitInsn( Opcodes.DCMPL );
mv.visitJumpInsn( Opcodes.IFEQ,
goNext );
} else if ( field.getTypeName().equals( "float" ) ) {
mv.visitInsn( Opcodes.FCMPL );
mv.visitJumpInsn( Opcodes.IFEQ,
goNext );
} else {
// boolean, byte, char, short, int
mv.visitJumpInsn( Opcodes.IF_ICMPEQ,
goNext );
}
mv.visitInsn( Opcodes.ICONST_0 );
mv.visitInsn( Opcodes.IRETURN );
} else {
// if attr is not a primitive
// if ( this.<attr> == null && other.<attr> != null ||
// this.<attr> != null && ! this.<attr>.equals( other.<attr> ) ) return false;
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
Label secondIfPart = new Label();
mv.visitJumpInsn( Opcodes.IFNONNULL,
secondIfPart );
// if ( other.objAttr != null ) return false;
mv.visitVarInsn( Opcodes.ALOAD,
2 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
Label returnFalse = new Label();
mv.visitJumpInsn( Opcodes.IFNONNULL,
returnFalse );
mv.visitLabel( secondIfPart );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitJumpInsn( Opcodes.IFNULL,
goNext );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitVarInsn( Opcodes.ALOAD,
2 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
getInternalType( field.getTypeName() ),
"equals",
"(Ljava/lang/Object;)Z" );
mv.visitJumpInsn( Opcodes.IFNE,
goNext );
mv.visitLabel( returnFalse );
mv.visitInsn( Opcodes.ICONST_0 );
mv.visitInsn( Opcodes.IRETURN );
}
mv.visitLabel( goNext );
}
}
if ( count > 0 ) {
mv.visitInsn( Opcodes.ICONST_1 );
} else {
mv.visitInsn( Opcodes.ICONST_0 );
}
mv.visitInsn( Opcodes.IRETURN );
Label lastLabel = null;
if ( this.debug ) {
lastLabel = new Label();
mv.visitLabel( lastLabel );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
lastLabel,
0 );
mv.visitLocalVariable( "obj",
Type.getDescriptor( Object.class ),
null,
l0,
lastLabel,
1 );
mv.visitLocalVariable( "other",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
lastLabel,
2 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
private void buildHashCode(ClassWriter cw,
ClassDefinition classDef) {
MethodVisitor mv;
// Building hashCode() method
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
"hashCode",
"()I",
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
// int result = 1;
mv.visitInsn( Opcodes.ICONST_1 );
mv.visitVarInsn( Opcodes.ISTORE,
1 );
// for each key field
for ( FieldDefinition field : classDef.getFieldsDefinitions() ) {
if ( field.isKey() ) {
// result = result * 31 + <attr_hash>
mv.visitVarInsn( Opcodes.ILOAD,
1 );
mv.visitIntInsn( Opcodes.BIPUSH,
31 );
mv.visitVarInsn( Opcodes.ILOAD,
1 );
mv.visitInsn( Opcodes.IMUL );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
if ( "boolean".equals( field.getTypeName() ) ) {
// attr_hash ::== <boolean_attr> ? 1231 : 1237;
Label blabel1 = new Label();
mv.visitJumpInsn( Opcodes.IFEQ,
blabel1 );
mv.visitIntInsn( Opcodes.SIPUSH,
1231 );
Label blabel2 = new Label();
mv.visitJumpInsn( Opcodes.GOTO,
blabel2 );
mv.visitLabel( blabel1 );
mv.visitIntInsn( Opcodes.SIPUSH,
1237 );
mv.visitLabel( blabel2 );
} else if ( "long".equals( field.getTypeName() ) ) {
// attr_hash ::== (int) (longAttr ^ (longAttr >>> 32))
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitIntInsn( Opcodes.BIPUSH,
32 );
mv.visitInsn( Opcodes.LUSHR );
mv.visitInsn( Opcodes.LXOR );
mv.visitInsn( Opcodes.L2I );
} else if ( "float".equals( field.getTypeName() ) ) {
// attr_hash ::== Float.floatToIntBits( floatAttr );
mv.visitMethodInsn( Opcodes.INVOKESTATIC,
Type.getInternalName( Float.class ),
"floatToIntBits",
"(F)I" );
} else if ( "double".equals( field.getTypeName() ) ) {
// attr_hash ::== (int) (Double.doubleToLongBits( doubleAttr ) ^ (Double.doubleToLongBits( doubleAttr ) >>> 32));
mv.visitMethodInsn( Opcodes.INVOKESTATIC,
Type.getInternalName( Double.class ),
"doubleToLongBits",
"(D)J" );
mv.visitInsn( Opcodes.DUP2 );
mv.visitIntInsn( Opcodes.BIPUSH,
32 );
mv.visitInsn( Opcodes.LUSHR );
mv.visitInsn( Opcodes.LXOR );
mv.visitInsn( Opcodes.L2I );
} else if ( !isPrimitive( field.getTypeName() ) ) {
// attr_hash ::== ((objAttr == null) ? 0 : objAttr.hashCode());
Label olabel1 = new Label();
mv.visitJumpInsn( Opcodes.IFNONNULL,
olabel1 );
mv.visitInsn( Opcodes.ICONST_0 );
Label olabel2 = new Label();
mv.visitJumpInsn( Opcodes.GOTO,
olabel2 );
mv.visitLabel( olabel1 );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
getInternalType( field.getTypeName() ),
"hashCode",
"()I" );
mv.visitLabel( olabel2 );
}
mv.visitInsn( Opcodes.IADD );
mv.visitVarInsn( Opcodes.ISTORE,
1 );
}
}
mv.visitVarInsn( Opcodes.ILOAD,
1 );
mv.visitInsn( Opcodes.IRETURN );
Label lastLabel = null;
if ( this.debug ) {
lastLabel = new Label();
mv.visitLabel( lastLabel );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
lastLabel,
0 );
mv.visitLocalVariable( "hash",
Type.getDescriptor( int.class ),
null,
l0,
lastLabel,
1 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
private void buildToString(ClassWriter cw,
ClassDefinition classDef) {
MethodVisitor mv;
{
mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
"toString",
"()Ljava/lang/String;",
null,
null );
mv.visitCode();
Label l0 = null;
if ( this.debug ) {
l0 = new Label();
mv.visitLabel( l0 );
}
// StringBuffer buf = new StringBuffer();
mv.visitTypeInsn( Opcodes.NEW,
Type.getInternalName( StringBuffer.class ) );
mv.visitInsn( Opcodes.DUP );
mv.visitMethodInsn( Opcodes.INVOKESPECIAL,
Type.getInternalName( StringBuffer.class ),
"<init>",
"()V" );
mv.visitVarInsn( Opcodes.ASTORE,
1 );
// buf.append(this.getClass().getSimpleName())
mv.visitVarInsn( Opcodes.ALOAD,
1 );
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
getInternalType( classDef.getClassName() ),
"getClass",
"()Ljava/lang/Class;" );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( Class.class ),
"getSimpleName",
"()Ljava/lang/String;" );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
// buf.append("( ");
mv.visitLdcInsn( "( " );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
boolean previous = false;
for ( FieldDefinition field : classDef.getFieldsDefinitions() ) {
if ( previous ) {
// buf.append(", ");
mv.visitLdcInsn( ", " );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
}
// buf.append(attrName)
mv.visitLdcInsn( field.getName() );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
// buf.append("=");
mv.visitLdcInsn( "=" );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
// buf.append(attrValue)
mv.visitVarInsn( Opcodes.ALOAD,
0 );
mv.visitFieldInsn( Opcodes.GETFIELD,
getInternalType( classDef.getClassName() ),
field.getName(),
getTypeDescriptor( field.getTypeName() ) );
if ( isPrimitive( field.getTypeName() ) ) {
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
Type.getMethodDescriptor( Type.getType( StringBuffer.class ),
new Type[]{Type.getType( getTypeDescriptor( field.getTypeName() ) )} ) );
} else {
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
Type.getMethodDescriptor( Type.getType( StringBuffer.class ),
new Type[]{Type.getType( Object.class )} ) );
}
previous = true;
}
mv.visitLdcInsn( " )" );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"append",
"(Ljava/lang/String;)Ljava/lang/StringBuffer;" );
mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
Type.getInternalName( StringBuffer.class ),
"toString",
"()Ljava/lang/String;" );
mv.visitInsn( Opcodes.ARETURN );
Label lastLabel = null;
if ( this.debug ) {
lastLabel = new Label();
mv.visitLabel( lastLabel );
mv.visitLocalVariable( "this",
getTypeDescriptor( classDef.getClassName() ),
null,
l0,
lastLabel,
0 );
mv.visitLocalVariable( "buf",
Type.getDescriptor( StringBuffer.class ),
null,
l0,
lastLabel,
1 );
}
mv.visitMaxs( 0,
0 );
mv.visitEnd();
}
}
private Class< ? > loadClass(String classname,
byte[] b) throws ClassNotFoundException,
SecurityException,
NoSuchMethodException,
IllegalArgumentException,
IllegalAccessException,
InvocationTargetException {
//override classDefine (as it is protected) and define the class.
Class< ? > clazz = null;
ClassLoader loader = ClassBuilder.class.getClassLoader();
Class< ? > cls = Class.forName( "java.lang.ClassLoader" );
java.lang.reflect.Method method = cls.getDeclaredMethod( "defineClass",
new Class[]{String.class, byte[].class, int.class, int.class} );
// protected method invocaton
method.setAccessible( true );
try {
Object[] args = new Object[]{classname, b, new Integer( 0 ), new Integer( b.length )};
clazz = (Class< ? >) method.invoke( loader,
args );
} finally {
method.setAccessible( false );
}
return clazz;
}
/**
* Returns the corresponding internal type representation for the
* given type.
*
* I decided to not use the ASM Type class methods because they require
* resolving the actual type into a Class instance and at this point,
* I think it is best to delay type resolution until it is really needed.
*
* @param type
* @return
*/
private String getInternalType(String type) {
String internalType = null;
if ( "byte".equals( type ) ) {
internalType = "B";
} else if ( "char".equals( type ) ) {
internalType = "C";
} else if ( "double".equals( type ) ) {
internalType = "D";
} else if ( "float".equals( type ) ) {
internalType = "F";
} else if ( "int".equals( type ) ) {
internalType = "I";
} else if ( "long".equals( type ) ) {
internalType = "J";
} else if ( "short".equals( type ) ) {
internalType = "S";
} else if ( "boolean".equals( type ) ) {
internalType = "Z";
} else if ( "void".equals( type ) ) {
internalType = "V";
} else if ( type != null ) {
// I think this will fail for inner classes, but we don't really
// support inner class generation at the moment
internalType = type.replace( '.',
'/' );
}
return internalType;
}
/**
* Returns the corresponding type descriptor for the
* given type.
*
* I decided to not use the ASM Type class methods because they require
* resolving the actual type into a Class instance and at this point,
* I think it is best to delay type resolution until it is really needed.
*
* @param type
* @return
*/
private String getTypeDescriptor(String type) {
String internalType = null;
if ( "byte".equals( type ) ) {
internalType = "B";
} else if ( "char".equals( type ) ) {
internalType = "C";
} else if ( "double".equals( type ) ) {
internalType = "D";
} else if ( "float".equals( type ) ) {
internalType = "F";
} else if ( "int".equals( type ) ) {
internalType = "I";
} else if ( "long".equals( type ) ) {
internalType = "J";
} else if ( "short".equals( type ) ) {
internalType = "S";
} else if ( "boolean".equals( type ) ) {
internalType = "Z";
} else if ( "void".equals( type ) ) {
internalType = "V";
} else if ( type != null ) {
// I think this will fail for inner classes, but we don't really
// support inner class generation at the moment
internalType = "L" + type.replace( '.',
'/' ) + ";";
}
return internalType;
}
/**
* Returns true if the provided type is a primitive type
*
* @param type
* @return
*/
private boolean isPrimitive(String type) {
boolean isPrimitive = false;
if ( "byte".equals( type ) || "char".equals( type ) || "double".equals( type ) || "float".equals( type ) || "int".equals( type ) || "long".equals( type ) || "short".equals( type ) || "boolean".equals( type ) || "void".equals( type ) ) {
isPrimitive = true;
}
return isPrimitive;
}
}