org.sfm.reflect.asm.InstantiatorBuilder Maven / Gradle / Ivy
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Java library to map flat record - ResultSet, csv - to java object with minimum configuration and low footprint.
package org.sfm.reflect.asm;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.sfm.reflect.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.Map.Entry;
import static org.objectweb.asm.Opcodes.*;
public class InstantiatorBuilder {
public static byte[] createInstantiator(final String className, final Class sourceClass,
final InstantiatorDefinition instantiatorDefinition,final Map> injections) throws Exception {
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
MethodVisitor mv;
FieldVisitor fv;
Class targetClass= instantiatorDefinition.getExecutable().getDeclaringClass();
String targetType = AsmUtils.toType(targetClass);
String sourceType = AsmUtils.toType(sourceClass);
String classType = AsmUtils.toType(className);
String instantiatorType = AsmUtils.toType(Instantiator.class);
cw.visit(V1_6, ACC_PUBLIC + ACC_FINAL + ACC_SUPER, classType, "Ljava/lang/Object;L" + instantiatorType + ";", "java/lang/Object",
new String[] { instantiatorType });
Parameter[] parameters = instantiatorDefinition.getParameters();
for(Entry> entry : injections.entrySet()) {
fv = cw.visitField(ACC_FINAL, "getter_" + entry.getKey().getName(), "L" + AsmUtils.toType(entry.getValue().getClass()) +";", null, null);
fv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "", "(Ljava/util/Map;)V", "(Ljava/util/Map;>;)V", null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "", "()V", false);
for(Entry> entry : injections.entrySet()) {
String name = entry.getKey().getName();
String getterType = AsmUtils.toType(entry.getValue().getClass());
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitLdcInsn(name);
mv.visitMethodInsn(INVOKEINTERFACE, "java/util/Map", "get", "(Ljava/lang/Object;)Ljava/lang/Object;", true);
mv.visitTypeInsn(CHECKCAST, getterType);
mv.visitFieldInsn(PUTFIELD, classType, "getter_" + name, "L" + getterType +";");
}
mv.visitInsn(RETURN);
mv.visitMaxs(3, 2);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "newInstance", "(" + AsmUtils.toDeclaredLType(sourceType) + ")L" + targetType + ";", null, new String[] { "java/lang/Exception" });
mv.visitCode();
mv.visitTypeInsn(NEW, targetType);
mv.visitInsn(DUP);
StringBuilder sb = new StringBuilder();
for (Parameter p : parameters) {
Getter getter = injections.get(p);
String propertyType = AsmUtils.toType(p.getType());
if (TypeHelper.isPrimitive(p.getType())) {
sb.append(propertyType);
} else if (TypeHelper.isArray(p.getType())) {
sb.append(propertyType);
} else {
sb.append("L").append(propertyType).append(";");
}
if (getter == null) {
if (TypeHelper.isPrimitive(p.getType())) {
mv.visitInsn(AsmUtils.defaultValue.get(p.getType()));
} else {
mv.visitInsn(ACONST_NULL);
}
} else {
Class getterPublicType = AsmUtils.getPublicOrInterfaceClass(getter.getClass());
String getterType = AsmUtils.toType(getterPublicType);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, classType, "getter_" + p.getName(), "L" + getterType + ";");
mv.visitVarInsn(ALOAD, 1);
if (TypeHelper.isPrimitive(p.getType())) {
String methodSuffix = AsmUtils.wrappers.get(p.getType()).getSimpleName();
if ("Integer".equals(methodSuffix)) {
methodSuffix = "Int";
}
String methodName = "get" + methodSuffix;
try {
getterPublicType.getMethod(methodName);
AsmUtils.invoke(mv, getterPublicType, "get" + methodSuffix, "(" + AsmUtils.toDeclaredLType(sourceType) + ")" + propertyType);
} catch (NoSuchMethodException e) {
if (AsmUtils.isStillGeneric(getter.getClass())) {
AsmUtils.invoke(mv, getterPublicType, "get", "(Ljava/lang/Object;)Ljava/lang/Object;");
mv.visitTypeInsn(CHECKCAST, AsmUtils.toWrapperType(p.getType()));
} else {
AsmUtils.invoke(mv, getterPublicType, "get", "(" + AsmUtils.toDeclaredLType(sourceType) + ")L" + AsmUtils.toType(getter.getClass().getMethod("get", sourceClass).getReturnType()) + ";");
}
//mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Long", "longValue", "()J", false);
String valueMethodPrefix = methodSuffix.toLowerCase();
if ("character".equals(valueMethodPrefix)) {
valueMethodPrefix = "char";
}
String valueMethod = valueMethodPrefix + "Value";
//mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Long", "longValue", "()J", false);
AsmUtils.invoke(mv, AsmUtils.toWrapperClass(p.getType()), valueMethod, "()" + AsmUtils.toType(p.getType()));
}
} else {
if (AsmUtils.isStillGeneric(getter.getClass())) {
AsmUtils.invoke(mv, getterPublicType, "get", "(Ljava/lang/Object;)Ljava/lang/Object;");
mv.visitTypeInsn(CHECKCAST, propertyType);
} else {
AsmUtils.invoke(mv, getterPublicType, "get", "(" + AsmUtils.toDeclaredLType(sourceType) + ")L" + AsmUtils.toType(getter.getClass().getMethod("get", sourceClass).getReturnType()) + ";");
}
}
}
}
Member exec = instantiatorDefinition.getExecutable();
if (exec instanceof Constructor) {
mv.visitMethodInsn(INVOKESPECIAL, targetType, "", "(" + sb.toString() + ")V", false);
} else {
mv.visitMethodInsn(INVOKESTATIC, targetType, exec.getName(),
AsmUtils.toSignature((Method)exec)
, false);
}
mv.visitInsn(ARETURN);
mv.visitMaxs(3 , 2);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC + ACC_BRIDGE + ACC_SYNTHETIC,
"newInstance", "(Ljava/lang/Object;)Ljava/lang/Object;", null,
new String[] { "java/lang/Exception" });
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, sourceType);
mv.visitMethodInsn(INVOKEVIRTUAL, classType, "newInstance", "(" + AsmUtils.toDeclaredLType(sourceType) + ")L"
+ targetType + ";", false);
mv.visitInsn(ARETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "toString", "()Ljava/lang/String;", null, null);
mv.visitCode();
mv.visitTypeInsn(NEW, "java/lang/StringBuilder");
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "", "()V", false);
mv.visitVarInsn(ASTORE, 1);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Class", "getSimpleName", "()Ljava/lang/String;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
mv.visitLdcInsn("{");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
for(int i = 0; i < parameters.length; i++) {
String paramName = (i > 0 ? ", " : "") + "parameter" + i + "=";
String parameter = String.valueOf(parameters[i]);
mv.visitLdcInsn(paramName);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
mv.visitLdcInsn(parameter);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
Getter getter = injections.get(parameters[i]);
String getterName = ", parameter" + i + "=";
String getterString = String.valueOf(getter);
mv.visitLdcInsn(getterName);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
mv.visitLdcInsn(getterString);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
}
mv.visitLdcInsn("}");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;", false);
mv.visitInsn(ARETURN);
mv.visitMaxs(2, 1);
mv.visitEnd();
}
cw.visitEnd();
return AsmUtils.writeClassToFile(className, cw.toByteArray());
}
}
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