com.avaje.ebean.enhance.agent.MethodEquals Maven / Gradle / Ivy
package com.avaje.ebean.enhance.agent;
import com.avaje.ebean.enhance.asm.*;
/**
* Generate the equals hashCode method using the identity.
*
* This will add a _ebean_getIdentity() equals() and hashCode() methods based on
* having a single ID property and no existing equals() or hashCode() methods.
*
*/
public class MethodEquals implements Opcodes, EnhanceConstants {
private static final String _EBEAN_GET_IDENTITY = "_ebean_getIdentity";
/**
* Adds equals(), hashCode() and _ebean_getIdentity() methods.
*
* If the class already has a equals() or hashCode() method defined then
* these methods are not added (its a noop).
*
*
* @param idFieldIndex
* the index of the id field
*/
public static void addMethods(ClassVisitor cv, ClassMeta meta, int idFieldIndex, FieldMeta idFieldMeta) {
if (meta.hasEqualsOrHashCode()) {
// already has a equals or hashcode method...
// so we will not add our identity based one
if (meta.isLog(2)) {
meta.log("already has a equals() or hashCode() method. Not adding the identity based one.");
}
} else {
if (meta.isLog(2)) {
meta.log("adding equals() hashCode() and _ebean_getIdentity() with Id field "
+ idFieldMeta.getName()+ " index:" + idFieldIndex+" primitive:"+idFieldMeta.isPrimitiveType());
}
if (idFieldMeta.isPrimitiveType()){
addGetIdentityPrimitive(cv, meta, idFieldMeta);
} else {
addGetIdentityObject(cv, meta, idFieldIndex);
}
addEquals(cv, meta);
addHashCode(cv, meta);
}
}
/**
* The identity field used for implementing equals via the
* _ebean_getIdentity() method.
*/
public static void addIdentityField(ClassVisitor cv) {
int access = ACC_PROTECTED + ACC_TRANSIENT;
FieldVisitor f0 = cv.visitField(access, IDENTITY_FIELD, "Ljava/lang/Object;", null, null);
f0.visitEnd();
}
/**
* Generate the _ebean_getIdentity method for primitive id types.
*
* For primitives we need to check for == 0 rather than null.
*
*
* This is used for implementing equals().
*
*
*
* private Object _ebean_getIdentity() {
* synchronized (this) {
* if (_ebean_identity != null) {
* return _ebean_identity;
* }
*
* if (0 != getId()) {
* _ebean_identity = Integer.valueOf(getId());
* } else {
* _ebean_identity = new Object();
* }
*
* return _ebean_identity;
* }
* }
*
*/
private static void addGetIdentityPrimitive(ClassVisitor cv, ClassMeta classMeta, FieldMeta idFieldMeta) {
String className = classMeta.getClassName();
MethodVisitor mv;
mv = cv.visitMethod(ACC_PRIVATE, _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", null, null);
mv.visitCode();
Label l0 = new Label();
Label l1 = new Label();
Label l2 = new Label();
mv.visitTryCatchBlock(l0, l1, l2, null);
Label l3 = new Label();
Label l4 = new Label();
mv.visitTryCatchBlock(l3, l4, l2, null);
Label l5 = new Label();
mv.visitTryCatchBlock(l2, l5, l2, null);
Label l6 = new Label();
mv.visitLabel(l6);
mv.visitLineNumber(1, l6);
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitVarInsn(ASTORE, 1);
mv.visitInsn(MONITORENTER);
mv.visitLabel(l0);
mv.visitLineNumber(1, l0);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitJumpInsn(IFNULL, l3);
Label l7 = new Label();
mv.visitLabel(l7);
mv.visitLineNumber(1, l7);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l1);
mv.visitInsn(ARETURN);
mv.visitLabel(l3);
mv.visitLineNumber(1, l3);
mv.visitVarInsn(ALOAD, 0);
idFieldMeta.appendGetPrimitiveIdValue(mv, classMeta);
idFieldMeta.appendCompare(mv, classMeta);
Label l8 = new Label();
mv.visitJumpInsn(IFEQ, l8);
Label l9 = new Label();
mv.visitLabel(l9);
mv.visitLineNumber(1, l9);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 0);
idFieldMeta.appendGetPrimitiveIdValue(mv, classMeta);
idFieldMeta.appendValueOf(mv);
mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
Label l10 = new Label();
mv.visitJumpInsn(GOTO, l10);
mv.visitLabel(l8);
mv.visitLineNumber(1, l8);
mv.visitVarInsn(ALOAD, 0);
mv.visitTypeInsn(NEW, "java/lang/Object");
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "", "()V", false);
mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitLabel(l10);
mv.visitLineNumber(1, l10);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l4);
mv.visitInsn(ARETURN);
mv.visitLabel(l2);
mv.visitLineNumber(1, l2);
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l5);
mv.visitInsn(ATHROW);
Label l11 = new Label();
mv.visitLabel(l11);
mv.visitLocalVariable("this", "L"+className+";", null, l6, l11, 0);
mv.visitMaxs(3, 2);
mv.visitEnd();
}
/**
* Generate the _ebean_getIdentity method for used with equals().
*
*
* private Object _ebean_getIdentity() {
* synchronized (this) {
* if (_ebean_identity != null) {
* return _ebean_identity;
* }
*
* Object id = getId();
* if (id != null) {
* _ebean_identity = id;
* } else {
* _ebean_identity = new Object();
* }
*
* return _ebean_identity;
* }
* }
*
*/
private static void addGetIdentityObject(ClassVisitor cv, ClassMeta classMeta, int idFieldIndex) {
String className = classMeta.getClassName();
MethodVisitor mv;
mv = cv.visitMethod(ACC_PRIVATE, _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", null, null);
mv.visitCode();
Label l0 = new Label();
Label l1 = new Label();
Label l2 = new Label();
mv.visitTryCatchBlock(l0, l1, l2, null);
Label l3 = new Label();
Label l4 = new Label();
mv.visitTryCatchBlock(l3, l4, l2, null);
Label l5 = new Label();
mv.visitTryCatchBlock(l2, l5, l2, null);
Label l6 = new Label();
mv.visitLabel(l6);
mv.visitLineNumber(1, l6);
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitVarInsn(ASTORE, 1);
mv.visitInsn(MONITORENTER);
mv.visitLabel(l0);
mv.visitLineNumber(1, l0);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitJumpInsn(IFNULL, l3);
Label l7 = new Label();
mv.visitLabel(l7);
mv.visitLineNumber(1, l7);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l1);
mv.visitInsn(ARETURN);
mv.visitLabel(l3);
mv.visitLineNumber(1, l3);
mv.visitVarInsn(ALOAD, 0);
IndexFieldWeaver.visitIntInsn(mv, idFieldIndex);
mv.visitMethodInsn(INVOKESPECIAL, className, "_ebean_getField", "(I)Ljava/lang/Object;", false);
mv.visitVarInsn(ASTORE, 2);
Label l8 = new Label();
mv.visitLabel(l8);
mv.visitLineNumber(1, l8);
mv.visitVarInsn(ALOAD, 2);
Label l9 = new Label();
mv.visitJumpInsn(IFNULL, l9);
Label l10 = new Label();
mv.visitLabel(l10);
mv.visitLineNumber(1, l10);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 2);
mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
Label l11 = new Label();
mv.visitJumpInsn(GOTO, l11);
mv.visitLabel(l9);
mv.visitLineNumber(1, l9);
mv.visitVarInsn(ALOAD, 0);
mv.visitTypeInsn(NEW, "java/lang/Object");
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "", "()V", false);
mv.visitFieldInsn(PUTFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitLabel(l11);
mv.visitLineNumber(1, l11);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, className, IDENTITY_FIELD, "Ljava/lang/Object;");
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l4);
mv.visitInsn(ARETURN);
mv.visitLabel(l2);
mv.visitLineNumber(1, l2);
mv.visitVarInsn(ALOAD, 1);
mv.visitInsn(MONITOREXIT);
mv.visitLabel(l5);
mv.visitInsn(ATHROW);
Label l12 = new Label();
mv.visitLabel(l12);
mv.visitLocalVariable("this", "L"+className+";", null, l6, l12, 0);
mv.visitLocalVariable("tmpId", "Ljava/lang/Object;", null, l8, l2, 2);
mv.visitMaxs(3, 3);
mv.visitEnd();
}
/**
* Generate the equals method.
*
*
* public boolean equals(Object o) {
* if (o == null) {
* return false;
* }
* if (!this.getClass().equals(o.getClass())) {
* return false;
* }
* if (o == this) {
* return true;
* }
* return _ebean_getIdentity().equals(((FooEntity)o)._ebean_getIdentity());
* }
*
*/
private static void addEquals(ClassVisitor cv, ClassMeta classMeta) {
MethodVisitor mv;
mv = cv.visitMethod(ACC_PUBLIC, "equals", "(Ljava/lang/Object;)Z", null, null);
mv.visitCode();
Label l0 = new Label();
mv.visitLabel(l0);
mv.visitLineNumber(1, l0);
mv.visitVarInsn(ALOAD, 1);
Label l1 = new Label();
mv.visitJumpInsn(IFNONNULL, l1);
Label l2 = new Label();
mv.visitLabel(l2);
mv.visitLineNumber(2, l2);
mv.visitInsn(ICONST_0);
mv.visitInsn(IRETURN);
mv.visitLabel(l1);
mv.visitLineNumber(3, l1);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
mv.visitVarInsn(ALOAD, 1);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);
Label l3 = new Label();
mv.visitJumpInsn(IFNE, l3);
Label l4 = new Label();
mv.visitLabel(l4);
mv.visitLineNumber(4, l4);
mv.visitInsn(ICONST_0);
mv.visitInsn(IRETURN);
mv.visitLabel(l3);
mv.visitLineNumber(5, l3);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 0);
Label l5 = new Label();
mv.visitJumpInsn(IF_ACMPNE, l5);
Label l6 = new Label();
mv.visitLabel(l6);
mv.visitLineNumber(6, l6);
mv.visitInsn(ICONST_1);
mv.visitInsn(IRETURN);
mv.visitLabel(l5);
mv.visitLineNumber(7, l5);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, classMeta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, classMeta.getClassName());
mv.visitMethodInsn(INVOKEVIRTUAL, classMeta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);
mv.visitInsn(IRETURN);
Label l7 = new Label();
mv.visitLabel(l7);
mv.visitLocalVariable("this", "L"+classMeta.getClassName()+";", null, l0, l7, 0);
mv.visitLocalVariable("obj", "Ljava/lang/Object;", null, l0, l7, 1);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
/**
* Generate a hashCode method used to go with MethodEquals.
*
*
* public int hashCode() {
* return ebeanGetIdentity().hashCode();
* }
*
*/
private static void addHashCode(ClassVisitor cv, ClassMeta meta) {
MethodVisitor mv;
mv = cv.visitMethod(ACC_PUBLIC, "hashCode", "()I", null, null);
mv.visitCode();
Label l0 = new Label();
mv.visitLabel(l0);
mv.visitLineNumber(1, l0);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, meta.getClassName(), _EBEAN_GET_IDENTITY, "()Ljava/lang/Object;", false);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "hashCode", "()I", false);
mv.visitInsn(IRETURN);
Label l1 = new Label();
mv.visitLabel(l1);
mv.visitLocalVariable("this", "L" + meta.getClassName() + ";", null, l0, l1, 0);
mv.visitMaxs(1, 1);
mv.visitEnd();
}
}
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