Java tutorial
/* * Copyright 2011-2013 the original author or authors. * * 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. */ package kr.debop4j.core.reflect; import com.google.common.collect.Lists; import kr.debop4j.core.Guard; import lombok.extern.slf4j.Slf4j; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.Label; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Type; import java.lang.reflect.Field; import java.lang.reflect.Modifier; import java.util.Arrays; import java.util.List; import static org.objectweb.asm.Opcodes.*; /** * ?? ?? Accessor . (?? get, set? ) * * @author ? ( sunghyouk.bae@gmail.com ) * @since 13. 1. 21 */ @Slf4j public abstract class FieldAccess { private String[] fieldNames; /** * Gets index. * * @param fieldName the field name * @return the index */ public int getIndex(String fieldName) { for (int i = 0, n = fieldNames.length; i < n; i++) if (fieldNames[i].equals(fieldName)) return i; throw new IllegalArgumentException("Unable to find public field: " + fieldName); } /** * Set void. * * @param instance the instance * @param fieldName the field name * @param value the value */ public void set(Object instance, String fieldName, Object value) { log.trace("?[{}]? ?[{}]? [{}] ? .", instance, fieldName, value); set(instance, getIndex(fieldName), value); } /** * Get object. * * @param instance the instance * @param fieldName the field name * @return the object */ public Object get(Object instance, String fieldName) { log.trace("?[{}]? ?[{}] ? .", instance, fieldName); return get(instance, getIndex(fieldName)); } /** * Get field names. * * @return the string [ ] */ public String[] getFieldNames() { return Arrays.copyOf(fieldNames, fieldNames.length); } /** * Set void. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void set(Object instance, int fieldIndex, Object value); /** * Sets boolean. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setBoolean(Object instance, int fieldIndex, boolean value); /** * Sets byte. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setByte(Object instance, int fieldIndex, byte value); /** * Sets short. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setShort(Object instance, int fieldIndex, short value); /** * Sets int. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setInt(Object instance, int fieldIndex, int value); /** * Sets long. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setLong(Object instance, int fieldIndex, long value); /** * Sets double. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setDouble(Object instance, int fieldIndex, double value); /** * Sets float. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setFloat(Object instance, int fieldIndex, float value); /** * Sets char. * * @param instance the instance * @param fieldIndex the field index * @param value the value */ abstract public void setChar(Object instance, int fieldIndex, char value); /** * Get object. * * @param instance the instance * @param fieldIndex the field index * @return the object */ abstract public Object get(Object instance, int fieldIndex); /** * Gets string. * * @param instance the instance * @param fieldIndex the field index * @return the string */ abstract public String getString(Object instance, int fieldIndex); /** * Gets char. * * @param instance the instance * @param fieldIndex the field index * @return the char */ abstract public char getChar(Object instance, int fieldIndex); /** * Gets boolean. * * @param instance the instance * @param fieldIndex the field index * @return the boolean */ abstract public boolean getBoolean(Object instance, int fieldIndex); /** * Gets byte. * * @param instance the instance * @param fieldIndex the field index * @return the byte */ abstract public byte getByte(Object instance, int fieldIndex); /** * Gets short. * * @param instance the instance * @param fieldIndex the field index * @return the short */ abstract public short getShort(Object instance, int fieldIndex); /** * Gets int. * * @param instance the instance * @param fieldIndex the field index * @return the int */ abstract public int getInt(Object instance, int fieldIndex); /** * Gets long. * * @param instance the instance * @param fieldIndex the field index * @return the long */ abstract public long getLong(Object instance, int fieldIndex); /** * Gets double. * * @param instance the instance * @param fieldIndex the field index * @return the double */ abstract public double getDouble(Object instance, int fieldIndex); /** * Gets float. * * @param instance the instance * @param fieldIndex the field index * @return the float */ abstract public float getFloat(Object instance, int fieldIndex); /** * Get field access. * * @param type the type * @return the field access */ static public FieldAccess get(Class type) { Guard.shouldNotBeNull(type, "type"); List<Field> fields = Lists.newArrayList(); Class nextClass = type; while (nextClass != Object.class) { Field[] declaredFields = nextClass.getDeclaredFields(); for (Field field : declaredFields) { int modifiers = field.getModifiers(); if (Modifier.isStatic(modifiers)) continue; if (Modifier.isPrivate(modifiers)) continue; fields.add(field); } nextClass = nextClass.getSuperclass(); } String[] fieldNames = new String[fields.size()]; for (int i = 0, n = fieldNames.length; i < n; i++) fieldNames[i] = fields.get(i).getName(); String className = type.getName(); String accessClassName = className + "FieldAccess"; if (accessClassName.startsWith("java.")) accessClassName = ReflectConsts.BASE_PACKAGE + "." + accessClassName; Class accessClass = null; AccessClassLoader loader = AccessClassLoader.get(type); synchronized (loader) { try { accessClass = loader.loadClass(accessClassName); } catch (ClassNotFoundException ignored) { String accessClassNameInternal = accessClassName.replace('.', '/'); String classNameInternal = className.replace('.', '/'); ClassWriter cw = new ClassWriter(0); cw.visit(V1_1, ACC_PUBLIC + ACC_SUPER, accessClassNameInternal, null, ReflectConsts.FIELD_ACCESS_PATH, null); insertConstructor(cw); insertGetObject(cw, classNameInternal, fields); insertSetObject(cw, classNameInternal, fields); insertGetPrimitive(cw, classNameInternal, fields, Type.BOOLEAN_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.BOOLEAN_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.BYTE_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.BYTE_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.SHORT_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.SHORT_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.INT_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.INT_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.LONG_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.LONG_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.DOUBLE_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.DOUBLE_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.FLOAT_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.FLOAT_TYPE); insertGetPrimitive(cw, classNameInternal, fields, Type.CHAR_TYPE); insertSetPrimitive(cw, classNameInternal, fields, Type.CHAR_TYPE); insertGetString(cw, classNameInternal, fields); cw.visitEnd(); accessClass = loader.defineClass(accessClassName, cw.toByteArray()); } } try { FieldAccess access = (FieldAccess) accessClass.newInstance(); access.fieldNames = fieldNames; return access; } catch (Exception ex) { throw new RuntimeException("Error constructing field access class: " + accessClassName, ex); } } static private void insertConstructor(ClassWriter cw) { MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, ReflectConsts.FIELD_ACCESS_PATH, "<init>", "()V"); mv.visitInsn(RETURN); mv.visitMaxs(1, 1); mv.visitEnd(); } static private void insertSetObject(ClassWriter cw, String classNameInternal, List<Field> fields) { int maxStack = 6; MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "set", "(Ljava/lang/Object;ILjava/lang/Object;)V", null, null); mv.visitCode(); mv.visitVarInsn(ILOAD, 2); if (!fields.isEmpty()) { maxStack--; Label[] labels = new Label[fields.size()]; for (int i = 0, n = labels.length; i < n; i++) labels[i] = new Label(); Label defaultLabel = new Label(); mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels); for (int i = 0, n = labels.length; i < n; i++) { Field field = fields.get(i); Type fieldType = Type.getType(field.getType()); mv.visitLabel(labels[i]); mv.visitFrame(F_SAME, 0, null, 0, null); mv.visitVarInsn(ALOAD, 1); mv.visitTypeInsn(CHECKCAST, classNameInternal); mv.visitVarInsn(ALOAD, 3); switch (fieldType.getSort()) { case Type.BOOLEAN: mv.visitTypeInsn(CHECKCAST, "java/lang/Boolean"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Boolean", "booleanValue", "()Z"); break; case Type.BYTE: mv.visitTypeInsn(CHECKCAST, "java/lang/Byte"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Byte", "byteValue", "()B"); break; case Type.CHAR: mv.visitTypeInsn(CHECKCAST, "java/lang/Character"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Character", "charValue", "()C"); break; case Type.SHORT: mv.visitTypeInsn(CHECKCAST, "java/lang/Short"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Short", "shortValue", "()S"); break; case Type.INT: mv.visitTypeInsn(CHECKCAST, "java/lang/Integer"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Integer", "intValue", "()I"); break; case Type.FLOAT: mv.visitTypeInsn(CHECKCAST, "java/lang/Float"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Float", "floatValue", "()F"); break; case Type.LONG: mv.visitTypeInsn(CHECKCAST, "java/lang/Long"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Long", "longValue", "()J"); break; case Type.DOUBLE: mv.visitTypeInsn(CHECKCAST, "java/lang/Double"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Double", "doubleValue", "()D"); break; case Type.ARRAY: mv.visitTypeInsn(CHECKCAST, fieldType.getDescriptor()); break; case Type.OBJECT: mv.visitTypeInsn(CHECKCAST, fieldType.getInternalName()); break; default: } mv.visitFieldInsn(PUTFIELD, classNameInternal, field.getName(), fieldType.getDescriptor()); mv.visitInsn(RETURN); } mv.visitLabel(defaultLabel); mv.visitFrame(F_SAME, 0, null, 0, null); } mv = insertThrowExceptionForFieldNotFound(mv); mv.visitMaxs(maxStack, 4); mv.visitEnd(); } static private void insertGetObject(ClassWriter cw, String classNameInternal, List<Field> fields) { int maxStack = 6; MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "get", "(Ljava/lang/Object;I)Ljava/lang/Object;", null, null); mv.visitCode(); mv.visitVarInsn(ILOAD, 2); if (!fields.isEmpty()) { maxStack--; Label[] labels = new Label[fields.size()]; for (int i = 0, n = labels.length; i < n; i++) labels[i] = new Label(); Label defaultLabel = new Label(); mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels); for (int i = 0, n = labels.length; i < n; i++) { Field field = fields.get(i); mv.visitLabel(labels[i]); mv.visitFrame(F_SAME, 0, null, 0, null); mv.visitVarInsn(ALOAD, 1); mv.visitTypeInsn(CHECKCAST, classNameInternal); mv.visitFieldInsn(GETFIELD, classNameInternal, field.getName(), Type.getDescriptor(field.getType())); Type fieldType = Type.getType(field.getType()); switch (fieldType.getSort()) { case Type.BOOLEAN: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;"); break; case Type.BYTE: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;"); break; case Type.CHAR: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;"); break; case Type.SHORT: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Short", "valueOf", "(S)Ljava/lang/Short;"); break; case Type.INT: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;"); break; case Type.FLOAT: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;"); break; case Type.LONG: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;"); break; case Type.DOUBLE: mv.visitMethodInsn(INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;"); break; default: } mv.visitInsn(ARETURN); } mv.visitLabel(defaultLabel); mv.visitFrame(F_SAME, 0, null, 0, null); } insertThrowExceptionForFieldNotFound(mv); mv.visitMaxs(maxStack, 3); mv.visitEnd(); } static private void insertGetString(ClassWriter cw, String classNameInternal, List<Field> fields) { int maxStack = 6; MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "getString", "(Ljava/lang/Object;I)Ljava/lang/String;", null, null); mv.visitCode(); mv.visitVarInsn(ILOAD, 2); if (!fields.isEmpty()) { maxStack--; Label[] labels = new Label[fields.size()]; Label labelForInvalidTypes = new Label(); boolean hasAnyBadTypeLabel = false; for (int i = 0, n = labels.length; i < n; i++) { if (fields.get(i).getType().equals(String.class)) labels[i] = new Label(); else { labels[i] = labelForInvalidTypes; hasAnyBadTypeLabel = true; } } Label defaultLabel = new Label(); mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels); for (int i = 0, n = labels.length; i < n; i++) { if (!labels[i].equals(labelForInvalidTypes)) { mv.visitLabel(labels[i]); mv.visitFrame(F_SAME, 0, null, 0, null); mv.visitVarInsn(ALOAD, 1); mv.visitTypeInsn(CHECKCAST, classNameInternal); mv.visitFieldInsn(GETFIELD, classNameInternal, fields.get(i).getName(), "Ljava/lang/String;"); mv.visitInsn(ARETURN); } } // Rest of fields: different type if (hasAnyBadTypeLabel) { mv.visitLabel(labelForInvalidTypes); mv.visitFrame(F_SAME, 0, null, 0, null); insertThrowExceptionForFieldType(mv, "String"); } // Default: field not found mv.visitLabel(defaultLabel); mv.visitFrame(F_SAME, 0, null, 0, null); } insertThrowExceptionForFieldNotFound(mv); mv.visitMaxs(maxStack, 3); mv.visitEnd(); } static private void insertSetPrimitive(ClassWriter cw, String classNameInternal, List<Field> fields, Type primitiveType) { int maxStack = 6; int maxLocals = 4; // See correction below for LLOAD and DLOAD final String setterMethodName; final String typeNameInternal = primitiveType.getDescriptor(); final int loadValueInstruction; switch (primitiveType.getSort()) { case Type.BOOLEAN: setterMethodName = "setBoolean"; loadValueInstruction = ILOAD; break; case Type.BYTE: setterMethodName = "setByte"; loadValueInstruction = ILOAD; break; case Type.CHAR: setterMethodName = "setChar"; loadValueInstruction = ILOAD; break; case Type.SHORT: setterMethodName = "setShort"; loadValueInstruction = ILOAD; break; case Type.INT: setterMethodName = "setInt"; loadValueInstruction = ILOAD; break; case Type.FLOAT: setterMethodName = "setFloat"; loadValueInstruction = FLOAD; break; case Type.LONG: setterMethodName = "setLong"; loadValueInstruction = LLOAD; maxLocals++; // (LLOAD and DLOAD actually load two slots) break; case Type.DOUBLE: setterMethodName = "setDouble"; loadValueInstruction = DLOAD; // (LLOAD and DLOAD actually load two slots) maxLocals++; break; default: setterMethodName = "set"; loadValueInstruction = ALOAD; break; } MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, setterMethodName, "(Ljava/lang/Object;I" + typeNameInternal + ")V", null, null); mv.visitCode(); mv.visitVarInsn(ILOAD, 2); if (!fields.isEmpty()) { maxStack--; Label[] labels = new Label[fields.size()]; Label labelForInvalidTypes = new Label(); boolean hasAnyBadTypeLabel = false; for (int i = 0, n = labels.length; i < n; i++) { if (Type.getType(fields.get(i).getType()).equals(primitiveType)) labels[i] = new Label(); else { labels[i] = labelForInvalidTypes; hasAnyBadTypeLabel = true; } } Label defaultLabel = new Label(); mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels); for (int i = 0, n = labels.length; i < n; i++) { if (!labels[i].equals(labelForInvalidTypes)) { mv.visitLabel(labels[i]); mv.visitFrame(F_SAME, 0, null, 0, null); mv.visitVarInsn(ALOAD, 1); mv.visitTypeInsn(CHECKCAST, classNameInternal); mv.visitVarInsn(loadValueInstruction, 3); mv.visitFieldInsn(PUTFIELD, classNameInternal, fields.get(i).getName(), typeNameInternal); mv.visitInsn(RETURN); } } // Rest of fields: different type if (hasAnyBadTypeLabel) { mv.visitLabel(labelForInvalidTypes); mv.visitFrame(F_SAME, 0, null, 0, null); insertThrowExceptionForFieldType(mv, primitiveType.getClassName()); } // Default: field not found mv.visitLabel(defaultLabel); mv.visitFrame(F_SAME, 0, null, 0, null); } mv = insertThrowExceptionForFieldNotFound(mv); mv.visitMaxs(maxStack, maxLocals); mv.visitEnd(); } static private void insertGetPrimitive(ClassWriter cw, String classNameInternal, List<Field> fields, Type primitiveType) { int maxStack = 6; final String getterMethodName; final String typeNameInternal = primitiveType.getDescriptor(); final int returnValueInstruction; switch (primitiveType.getSort()) { case Type.BOOLEAN: getterMethodName = "getBoolean"; returnValueInstruction = IRETURN; break; case Type.BYTE: getterMethodName = "getByte"; returnValueInstruction = IRETURN; break; case Type.CHAR: getterMethodName = "getChar"; returnValueInstruction = IRETURN; break; case Type.SHORT: getterMethodName = "getShort"; returnValueInstruction = IRETURN; break; case Type.INT: getterMethodName = "getInt"; returnValueInstruction = IRETURN; break; case Type.FLOAT: getterMethodName = "getFloat"; returnValueInstruction = FRETURN; break; case Type.LONG: getterMethodName = "getLong"; returnValueInstruction = LRETURN; break; case Type.DOUBLE: getterMethodName = "getDouble"; returnValueInstruction = DRETURN; break; default: getterMethodName = "get"; returnValueInstruction = ARETURN; break; } MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, getterMethodName, "(Ljava/lang/Object;I)" + typeNameInternal, null, null); mv.visitCode(); mv.visitVarInsn(ILOAD, 2); if (!fields.isEmpty()) { maxStack--; Label[] labels = new Label[fields.size()]; Label labelForInvalidTypes = new Label(); boolean hasAnyBadTypeLabel = false; for (int i = 0, n = labels.length; i < n; i++) { if (Type.getType(fields.get(i).getType()).equals(primitiveType)) labels[i] = new Label(); else { labels[i] = labelForInvalidTypes; hasAnyBadTypeLabel = true; } } Label defaultLabel = new Label(); mv.visitTableSwitchInsn(0, labels.length - 1, defaultLabel, labels); for (int i = 0, n = labels.length; i < n; i++) { Field field = fields.get(i); if (!labels[i].equals(labelForInvalidTypes)) { mv.visitLabel(labels[i]); mv.visitFrame(F_SAME, 0, null, 0, null); mv.visitVarInsn(ALOAD, 1); mv.visitTypeInsn(CHECKCAST, classNameInternal); mv.visitFieldInsn(GETFIELD, classNameInternal, field.getName(), typeNameInternal); mv.visitInsn(returnValueInstruction); } } // Rest of fields: different type if (hasAnyBadTypeLabel) { mv.visitLabel(labelForInvalidTypes); mv.visitFrame(F_SAME, 0, null, 0, null); insertThrowExceptionForFieldType(mv, primitiveType.getClassName()); } // Default: field not found mv.visitLabel(defaultLabel); mv.visitFrame(F_SAME, 0, null, 0, null); } mv = insertThrowExceptionForFieldNotFound(mv); mv.visitMaxs(maxStack, 3); mv.visitEnd(); } static private MethodVisitor insertThrowExceptionForFieldNotFound(MethodVisitor mv) { mv.visitTypeInsn(NEW, "java/lang/IllegalArgumentException"); mv.visitInsn(DUP); mv.visitTypeInsn(NEW, "java/lang/StringBuilder"); mv.visitInsn(DUP); mv.visitLdcInsn("Field not found: "); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "(Ljava/lang/String;)V"); mv.visitVarInsn(ILOAD, 2); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(I)Ljava/lang/StringBuilder;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;"); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/IllegalArgumentException", "<init>", "(Ljava/lang/String;)V"); mv.visitInsn(ATHROW); return mv; } static private MethodVisitor insertThrowExceptionForFieldType(MethodVisitor mv, String fieldType) { mv.visitTypeInsn(NEW, "java/lang/IllegalArgumentException"); mv.visitInsn(DUP); mv.visitTypeInsn(NEW, "java/lang/StringBuilder"); mv.visitInsn(DUP); mv.visitLdcInsn("Field not declared as " + fieldType + ": "); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "(Ljava/lang/String;)V"); mv.visitVarInsn(ILOAD, 2); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(I)Ljava/lang/StringBuilder;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;"); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/IllegalArgumentException", "<init>", "(Ljava/lang/String;)V"); mv.visitInsn(ATHROW); return mv; } }