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Java reflect give poor performance on getter setter an constructor calls, accessors-smart use ASM to speed up those calls.
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package net.minidev.asm;
import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
import static org.objectweb.asm.Opcodes.ACONST_NULL;
import static org.objectweb.asm.Opcodes.ALOAD;
import static org.objectweb.asm.Opcodes.ARETURN;
import static org.objectweb.asm.Opcodes.ASTORE;
import static org.objectweb.asm.Opcodes.ATHROW;
import static org.objectweb.asm.Opcodes.BIPUSH;
import static org.objectweb.asm.Opcodes.CHECKCAST;
import static org.objectweb.asm.Opcodes.DUP;
import static org.objectweb.asm.Opcodes.F_SAME;
import static org.objectweb.asm.Opcodes.GETFIELD;
import static org.objectweb.asm.Opcodes.ICONST_1;
import static org.objectweb.asm.Opcodes.ICONST_2;
import static org.objectweb.asm.Opcodes.ICONST_3;
import static org.objectweb.asm.Opcodes.ICONST_4;
import static org.objectweb.asm.Opcodes.ICONST_5;
import static org.objectweb.asm.Opcodes.IFEQ;
import static org.objectweb.asm.Opcodes.IFNE;
import static org.objectweb.asm.Opcodes.IFNULL;
import static org.objectweb.asm.Opcodes.IF_ICMPNE;
import static org.objectweb.asm.Opcodes.ILOAD;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
import static org.objectweb.asm.Opcodes.INVOKESTATIC;
import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL;
import static org.objectweb.asm.Opcodes.NEW;
import static org.objectweb.asm.Opcodes.PUTFIELD;
import static org.objectweb.asm.Opcodes.RETURN;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
/**
* A builder class for dynamically creating {@link BeansAccess} classes for accessing bean properties efficiently.
* This class utilizes the ASM library to generate bytecode at runtime, thereby bypassing the need for Java reflection.
*/
public class BeansAccessBuilder {
static private String METHOD_ACCESS_NAME = Type.getInternalName(BeansAccess.class);
final Class type;
final Accessor[] accs;
final DynamicClassLoader loader;
final String className;
final String accessClassName;
final String accessClassNameInternal;
final String classNameInternal;
final HashMap, Method> convMtds = new HashMap, Method>();
// Class exceptionClass = net.minidev.asm.ex.NoSuchFieldException.class;
Class exceptionClass = NoSuchFieldException.class;
/**
* Initializes a new builder instance for a given bean class.
*
* @param type
* type to be access
* @param accs
* used accessor
* @param loader
* Loader used to store the generated class
*/
public BeansAccessBuilder(Class type, Accessor[] accs, DynamicClassLoader loader) {
this.type = type;
this.accs = accs;
this.loader = loader;
this.className = type.getName();
if (className.startsWith("java."))
this.accessClassName = "net.minidev.asm." + className + "AccAccess";
else
this.accessClassName = className.concat("AccAccess");
this.accessClassNameInternal = accessClassName.replace('.', '/');
this.classNameInternal = className.replace('.', '/');
}
/**
* register multiple new conversion
* @param conv conv list
*/
public void addConversion(Iterable> conv) {
if (conv == null)
return;
for (Class c : conv)
addConversion(c);
}
/**
* Resister a new conversion
* @param conv the conv
*/
public void addConversion(Class conv) {
if (conv == null)
return;
for (Method mtd : conv.getMethods()) {
if ((mtd.getModifiers() & Modifier.STATIC) == 0)
continue;
Class[] param = mtd.getParameterTypes();
if (param.length != 1)
continue;
if (!param[0].equals(Object.class))
continue;
Class rType = mtd.getReturnType();
if (rType.equals(Void.TYPE))
continue;
convMtds.put(rType, mtd);
}
}
/**
* build the conversion class.
* @return the new Class
*/
public Class bulid() {
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
MethodVisitor mv;
boolean USE_HASH = accs.length > 10;
int HASH_LIMIT = 14;
String signature = "Lnet/minidev/asm/BeansAccess;";
cw.visit(Opcodes.V1_6, ACC_PUBLIC + Opcodes.ACC_SUPER, accessClassNameInternal, signature, METHOD_ACCESS_NAME, null);
// init
{
mv = cw.visitMethod(ACC_PUBLIC, "", "()V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, METHOD_ACCESS_NAME, "", "()V", false);
mv.visitInsn(RETURN);
mv.visitMaxs(1, 1);
mv.visitEnd();
}
////////////
// Build SETter using filed index
//
// public void set(Object object, int fieldId, Object value)
mv = cw.visitMethod(ACC_PUBLIC, "set", "(Ljava/lang/Object;ILjava/lang/Object;)V", null, null);
mv.visitCode();
// if no Field simply return
if (accs.length == 0) {
//
// mv.visitInsn(RETURN);
} else if (accs.length > HASH_LIMIT) {
// lots of field Use Switch Statement
mv.visitVarInsn(ILOAD, 2);
Label[] labels = ASMUtil.newLabels(accs.length);
Label defaultLabel = new Label();
mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels);
int i = 0;
for (Accessor acc : accs) {
mv.visitLabel(labels[i++]);
if (!acc.isWritable()) {
mv.visitInsn(RETURN);
continue;
}
internalSetFiled(mv, acc);
}
mv.visitLabel(defaultLabel);
} else {
Label[] labels = ASMUtil.newLabels(accs.length);
int i = 0;
for (Accessor acc : accs) {
ifNotEqJmp(mv, 2, i, labels[i]);
internalSetFiled(mv, acc);
mv.visitLabel(labels[i]);
mv.visitFrame(F_SAME, 0, null, 0, null);
i++;
}
}
if (exceptionClass != null)
throwExIntParam(mv, exceptionClass);
else
mv.visitInsn(RETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
////////////
// Build GETter using filed index
//
// public Object get(Object object, int fieldId)
mv = cw.visitMethod(ACC_PUBLIC, "get", "(Ljava/lang/Object;I)Ljava/lang/Object;", null, null);
mv.visitCode();
if (accs.length == 0) {
mv.visitFrame(F_SAME, 0, null, 0, null);
} else if (accs.length > HASH_LIMIT) {
mv.visitVarInsn(ILOAD, 2);
Label[] labels = ASMUtil.newLabels(accs.length);
Label defaultLabel = new Label();
mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels);
int i = 0;
for (Accessor acc : accs) {
mv.visitLabel(labels[i++]);
mv.visitFrame(F_SAME, 0, null, 0, null);
if (!acc.isReadable()) {
mv.visitInsn(ACONST_NULL);
mv.visitInsn(ARETURN);
continue;
}
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, classNameInternal);
Type fieldType = Type.getType(acc.getType());
if (acc.isPublic() || acc.getter == null) {
mv.visitFieldInsn(GETFIELD, classNameInternal, acc.getName(), fieldType.getDescriptor());
} else {
String sig = Type.getMethodDescriptor(acc.getter);
mv.visitMethodInsn(INVOKEVIRTUAL, classNameInternal, acc.getter.getName(), sig, false);
}
ASMUtil.autoBoxing(mv, fieldType);
mv.visitInsn(ARETURN);
}
mv.visitLabel(defaultLabel);
mv.visitFrame(F_SAME, 0, null, 0, null);
} else {
Label[] labels = ASMUtil.newLabels(accs.length);
int i = 0;
for (Accessor acc : accs) {
ifNotEqJmp(mv, 2, i, labels[i]);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, classNameInternal);
Type fieldType = Type.getType(acc.getType());
if (acc.isPublic() || acc.getter == null) {
mv.visitFieldInsn(GETFIELD, classNameInternal, acc.getName(), fieldType.getDescriptor());
} else {
if (acc.getter == null)
throw new RuntimeException("no Getter for field " + acc.getName() + " in class " + this.className);
String sig = Type.getMethodDescriptor(acc.getter);
mv.visitMethodInsn(INVOKEVIRTUAL, classNameInternal, acc.getter.getName(), sig, false);
}
ASMUtil.autoBoxing(mv, fieldType);
mv.visitInsn(ARETURN);
mv.visitLabel(labels[i]);
mv.visitFrame(F_SAME, 0, null, 0, null);
i++;
}
}
if (exceptionClass != null)
throwExIntParam(mv, exceptionClass);
else {
mv.visitInsn(ACONST_NULL);
mv.visitInsn(ARETURN);
}
mv.visitMaxs(0, 0);
mv.visitEnd();
////////////
// Build SETter using filed Name
//
// public Object set(Object object, String methodName, Object value)
if (!USE_HASH) {
mv = cw.visitMethod(ACC_PUBLIC, "set", "(Ljava/lang/Object;Ljava/lang/String;Ljava/lang/Object;)V", null, null);
mv.visitCode();
Label[] labels = ASMUtil.newLabels(accs.length);
int i = 0;
for (Accessor acc : accs) {
mv.visitVarInsn(ALOAD, 2);
mv.visitLdcInsn(acc.fieldName);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "equals", "(Ljava/lang/Object;)Z", false);
mv.visitJumpInsn(IFEQ, labels[i]);
internalSetFiled(mv, acc);
mv.visitLabel(labels[i]);
mv.visitFrame(F_SAME, 0, null, 0, null);
i++;
}
if (exceptionClass != null)
throwExStrParam(mv, exceptionClass);
else
mv.visitInsn(RETURN);
mv.visitMaxs(0, 0); // 2,4
mv.visitEnd();
}
////////////
// Build GETter using filed Name
//
// public Object get(Object object, String methodName)
if (!USE_HASH) {
mv = cw.visitMethod(ACC_PUBLIC, "get", "(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object;", null, null);
mv.visitCode();
Label[] labels = ASMUtil.newLabels(accs.length);
int i = 0;
for (Accessor acc : accs) {
mv.visitVarInsn(ALOAD, 2); // methodName
mv.visitLdcInsn(acc.fieldName);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "equals", "(Ljava/lang/Object;)Z", false);
mv.visitJumpInsn(IFEQ, labels[i]);
mv.visitVarInsn(ALOAD, 1); // object
mv.visitTypeInsn(CHECKCAST, classNameInternal);
Type fieldType = Type.getType(acc.getType());
if (acc.isPublic() || acc.getter == null) {
mv.visitFieldInsn(GETFIELD, classNameInternal, acc.getName(), fieldType.getDescriptor());
} else {
String sig = Type.getMethodDescriptor(acc.getter);
mv.visitMethodInsn(INVOKEVIRTUAL, classNameInternal, acc.getter.getName(), sig, false);
}
ASMUtil.autoBoxing(mv, fieldType);
mv.visitInsn(ARETURN);
mv.visitLabel(labels[i]);
mv.visitFrame(F_SAME, 0, null, 0, null);
i++;
}
if (exceptionClass != null)
throwExStrParam(mv, exceptionClass);
else {
mv.visitInsn(ACONST_NULL);
mv.visitInsn(ARETURN);
}
mv.visitMaxs(0, 0);
mv.visitEnd();
}
////////////
// Build constructor
//
{
mv = cw.visitMethod(ACC_PUBLIC, "newInstance", "()Ljava/lang/Object;", null, null);
mv.visitCode();
mv.visitTypeInsn(NEW, classNameInternal);
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL, classNameInternal, "", "()V", false);
mv.visitInsn(ARETURN);
mv.visitMaxs(2, 1);
mv.visitEnd();
}
cw.visitEnd();
byte[] data = cw.toByteArray();
// dumpDebug(data, "/tmp/debug-" + accessClassName + ".txt");
return loader.defineClass(accessClassName, data);
}
/**
* Dump Generate Code
*/
@SuppressWarnings("unused")
private void dumpDebug(byte[] data, String destFile) {
// try {
// File debug = new File(destFile);
// int flags = ClassReader.SKIP_DEBUG;
// ClassReader cr = new ClassReader(new ByteArrayInputStream(data));
// cr.accept(new ASMifierClassVisitor(new PrintWriter(debug)),
// ASMifierClassVisitor.getDefaultAttributes(),
// flags);
// } catch (Exception e) {
// }
}
/**
* Dump Set Field Code
*
* @param mv
* @param acc
*/
private void internalSetFiled(MethodVisitor mv, Accessor acc) {
/**
* FNC params
*
* 1 -> object to alter
*
* 2 -> id of field
*
* 3 -> new value
*/
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, classNameInternal);
// get VALUE
mv.visitVarInsn(ALOAD, 3);
Type fieldType = Type.getType(acc.getType());
Class type = acc.getType();
String destClsName = Type.getInternalName(type);
Method conMtd = convMtds.get(type);
if (conMtd != null) {
// external conversion
String clsSig = Type.getInternalName(conMtd.getDeclaringClass());
String mtdName = conMtd.getName();
String mtdSig = Type.getMethodDescriptor(conMtd);
mv.visitMethodInsn(INVOKESTATIC, clsSig, mtdName, mtdSig, false);
} else if (acc.isEnum()) {
// builtIn Enum Conversion
Label isNull = new Label();
mv.visitJumpInsn(IFNULL, isNull);
mv.visitVarInsn(ALOAD, 3);
// mv.visitTypeInsn(CHECKCAST, "java/lang/String");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "toString", "()Ljava/lang/String;", false);
mv.visitMethodInsn(INVOKESTATIC, destClsName, "valueOf", "(Ljava/lang/String;)L" + destClsName + ";", false);
mv.visitVarInsn(ASTORE, 3);
mv.visitLabel(isNull);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, this.classNameInternal); // "net/minidev/asm/bean/BEnumPriv"
mv.visitVarInsn(ALOAD, 3);
mv.visitTypeInsn(CHECKCAST, destClsName);
} else if (type.equals(String.class)) {
// built In String Conversion
Label isNull = new Label();
mv.visitJumpInsn(IFNULL, isNull);
mv.visitVarInsn(ALOAD, 3);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "toString", "()Ljava/lang/String;", false);
mv.visitVarInsn(ASTORE, 3);
mv.visitLabel(isNull);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, this.classNameInternal);
mv.visitVarInsn(ALOAD, 3);
mv.visitTypeInsn(CHECKCAST, destClsName);
} else {
// just check Cast
mv.visitTypeInsn(CHECKCAST, destClsName);
}
if (acc.isPublic() || acc.setter == null) {
mv.visitFieldInsn(PUTFIELD, classNameInternal, acc.getName(), fieldType.getDescriptor());
} else {
String sig = Type.getMethodDescriptor(acc.setter);
mv.visitMethodInsn(INVOKEVIRTUAL, classNameInternal, acc.setter.getName(), sig, false);
}
mv.visitInsn(RETURN);
}
/**
* add Throws statement with int param 2
*/
private void throwExIntParam(MethodVisitor mv, Class exCls) {
String exSig = Type.getInternalName(exCls);
mv.visitTypeInsn(NEW, exSig);
mv.visitInsn(DUP);
mv.visitLdcInsn("mapping " + this.className + " failed to map field:");
mv.visitVarInsn(ILOAD, 2);
mv.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "toString", "(I)Ljava/lang/String;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "concat", "(Ljava/lang/String;)Ljava/lang/String;", false);
mv.visitMethodInsn(INVOKESPECIAL, exSig, "", "(Ljava/lang/String;)V", false);
mv.visitInsn(ATHROW);
}
/**
* add Throws statement with String param 2
*/
private void throwExStrParam(MethodVisitor mv, Class exCls) {
String exSig = Type.getInternalName(exCls);
mv.visitTypeInsn(NEW, exSig);
mv.visitInsn(DUP);
mv.visitLdcInsn("mapping " + this.className + " failed to map field:");
mv.visitVarInsn(ALOAD, 2);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "concat", "(Ljava/lang/String;)Ljava/lang/String;", false);
mv.visitMethodInsn(INVOKESPECIAL, exSig, "", "(Ljava/lang/String;)V", false);
mv.visitInsn(ATHROW);
}
/**
* dump a Jump if not EQ
*/
private void ifNotEqJmp(MethodVisitor mv, int param, int value, Label label) {
mv.visitVarInsn(ILOAD, param);
if (value == 0) {
/* notest for value 0 */
mv.visitJumpInsn(IFNE, label);
} else if (value == 1) {
mv.visitInsn(ICONST_1);
mv.visitJumpInsn(IF_ICMPNE, label);
} else if (value == 2) {
mv.visitInsn(ICONST_2);
mv.visitJumpInsn(IF_ICMPNE, label);
} else if (value == 3) {
mv.visitInsn(ICONST_3);
mv.visitJumpInsn(IF_ICMPNE, label);
} else if (value == 4) {
mv.visitInsn(ICONST_4);
mv.visitJumpInsn(IF_ICMPNE, label);
} else if (value == 5) {
mv.visitInsn(ICONST_5);
mv.visitJumpInsn(IF_ICMPNE, label);
} else if (value >= 6) {
mv.visitIntInsn(BIPUSH, value);
mv.visitJumpInsn(IF_ICMPNE, label);
} else {
throw new RuntimeException("non supported negative values");
}
}
}