Java tutorial
/** * Entity Essentials -- A Component-based Entity System * * Copyright (C) 2015 Elmar Schug <elmar.schug@jayware.org>, * Markus Neubauer <markus.neubauer@jayware.org> * * This file is part of Entity Essentials. * * Entity Essentials is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation, either version 3 of * the License, or any later version. * * Entity Essentials is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.jayware.e2.component.impl.generation.writer; import org.jayware.e2.component.api.Component; import org.jayware.e2.component.impl.generation.plan.ComponentGenerationPlan; import org.jayware.e2.component.impl.generation.plan.ComponentPropertyGenerationPlan; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.Label; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Type; import static org.jayware.e2.component.impl.generation.asm.TypeUtil.resolveOpcodePrimitiveType; 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.ANEWARRAY; import static org.objectweb.asm.Opcodes.ARETURN; import static org.objectweb.asm.Opcodes.ARRAYLENGTH; import static org.objectweb.asm.Opcodes.ASTORE; import static org.objectweb.asm.Opcodes.ATHROW; import static org.objectweb.asm.Opcodes.CHECKCAST; import static org.objectweb.asm.Opcodes.DUP; import static org.objectweb.asm.Opcodes.GOTO; import static org.objectweb.asm.Opcodes.IALOAD; import static org.objectweb.asm.Opcodes.IASTORE; import static org.objectweb.asm.Opcodes.ICONST_0; import static org.objectweb.asm.Opcodes.IFNE; import static org.objectweb.asm.Opcodes.IFNONNULL; import static org.objectweb.asm.Opcodes.IF_ICMPGE; import static org.objectweb.asm.Opcodes.ILOAD; import static org.objectweb.asm.Opcodes.INSTANCEOF; import static org.objectweb.asm.Opcodes.INVOKEINTERFACE; import static org.objectweb.asm.Opcodes.INVOKESPECIAL; import static org.objectweb.asm.Opcodes.ISTORE; import static org.objectweb.asm.Opcodes.NEW; import static org.objectweb.asm.Opcodes.NEWARRAY; import static org.objectweb.asm.Opcodes.PUTFIELD; import static org.objectweb.asm.Type.getDescriptor; import static org.objectweb.asm.Type.getInternalName; import static org.objectweb.asm.Type.getType; public class ComponentCopyOtherMethodWriter { public void writeCopyOtherMethodFor(ComponentGenerationPlan componentPlan) { final Class<? extends Component> componentClass = componentPlan.getComponentClass(); final ClassWriter classWriter = componentPlan.getClassWriter(); final MethodVisitor visitor = classWriter.visitMethod(ACC_PUBLIC, "copy", "(" + getDescriptor(Component.class) + ")" + getDescriptor(Component.class), null, null); final Label endIfNotInstanceOf = new Label(); visitor.visitCode(); visitor.visitVarInsn(ALOAD, 1); visitor.visitInsn(DUP); visitor.visitTypeInsn(INSTANCEOF, getInternalName(componentClass)); visitor.visitJumpInsn(IFNE, endIfNotInstanceOf); visitor.visitTypeInsn(NEW, getInternalName(IllegalArgumentException.class)); visitor.visitInsn(DUP); visitor.visitLdcInsn("Copy source type has to be: " + componentClass); visitor.visitMethodInsn(INVOKESPECIAL, getInternalName(IllegalArgumentException.class), "<init>", "(" + getDescriptor(String.class) + ")V", false); visitor.visitInsn(ATHROW); visitor.visitLabel(endIfNotInstanceOf); visitor.visitTypeInsn(CHECKCAST, getInternalName(componentClass)); visitor.visitVarInsn(ASTORE, 2); for (ComponentPropertyGenerationPlan propertyPlan : componentPlan.getComponentPropertyGenerationPlans()) { final String propertyName = propertyPlan.getPropertyName(); final Class<?> propertyType = propertyPlan.getPropertyType(); final String propertyTypeDescriptor = Type.getDescriptor(propertyPlan.getPropertyType()); visitor.visitVarInsn(ALOAD, 0); visitor.visitVarInsn(ALOAD, 2); visitor.visitMethodInsn(INVOKEINTERFACE, getInternalName(componentClass), propertyPlan.getPropertyGetterMethodName(), propertyPlan.getPropertyGetterMethodDescriptor(), true); final Label ifNotNull = new Label(); final Label endIfNotNull = new Label(); if (propertyType.isArray()) { visitor.visitVarInsn(ASTORE, 3); visitor.visitVarInsn(ALOAD, 3); visitor.visitJumpInsn(IFNONNULL, ifNotNull); visitor.visitInsn(ACONST_NULL); visitor.visitJumpInsn(GOTO, endIfNotNull); visitor.visitLabel(ifNotNull); visitor.visitVarInsn(ALOAD, 3); visitor.visitInsn(ARRAYLENGTH); if (propertyType.getComponentType().isPrimitive()) { visitor.visitIntInsn(NEWARRAY, resolveOpcodePrimitiveType(propertyType.getComponentType())); } else { visitor.visitTypeInsn(ANEWARRAY, getInternalName(propertyType.getComponentType())); } visitor.visitVarInsn(ASTORE, 4); final Label endForLoop = new Label(); final Label headForLoop = new Label(); visitor.visitInsn(ICONST_0); visitor.visitVarInsn(ISTORE, 5); visitor.visitLabel(headForLoop); visitor.visitVarInsn(ILOAD, 5); visitor.visitVarInsn(ALOAD, 3); visitor.visitInsn(ARRAYLENGTH); visitor.visitJumpInsn(IF_ICMPGE, endForLoop); visitor.visitVarInsn(ALOAD, 4); visitor.visitVarInsn(ILOAD, 5); visitor.visitVarInsn(ALOAD, 3); visitor.visitVarInsn(ILOAD, 5); visitor.visitInsn(getType(propertyType.getComponentType()).getOpcode(IALOAD)); visitor.visitInsn(getType(propertyType.getComponentType()).getOpcode(IASTORE)); visitor.visitIincInsn(5, 1); visitor.visitJumpInsn(GOTO, headForLoop); visitor.visitLabel(endForLoop); visitor.visitVarInsn(ALOAD, 4); } visitor.visitLabel(endIfNotNull); visitor.visitFieldInsn(PUTFIELD, componentPlan.getGeneratedClassInternalName(), propertyName, propertyTypeDescriptor); } visitor.visitVarInsn(ALOAD, 0); visitor.visitInsn(ARETURN); visitor.visitMaxs(0, 0); visitor.visitEnd(); } }