Examples with FieldInsnNode org.apache.xbean.asm5.tree.FieldInsnNode used on opensource projects

Example 6 with FieldInsnNode

use of org.apache.xbean.asm5.tree.FieldInsnNode in project apex-malhar by apache.

the class BeanClassGenerator method addEqualsMethod.

/**
 * Adds a equals method to underlying class. <br>
 * Algorithm is as follows: <br>
 * <i><p>
 * if (this == other) return true;
 * if (other == null) return false;
 * if (other is not instanceof <this class>) return false;
 * for (field: all fields) {
 * if (other.getField() != this.field) return false;
 * }
 * return true;
 * </p></i>
 * <br>
 *
 * @param classNode
 * @param fieldList
 * @throws JSONException
 */
@SuppressWarnings("unchecked")
private static void addEqualsMethod(ClassNode classNode, List<TupleSchemaRegistry.SQLFieldInfo> fieldList) throws JSONException {
    MethodNode equalsNode = new MethodNode(Opcodes.ACC_PUBLIC, "equals", "(Ljava/lang/Object;)Z", null, null);
    equalsNode.visitAnnotation("Ljava/lang/Override;", true);
    LabelNode l0 = new LabelNode();
    LabelNode l1 = new LabelNode();
    LabelNode l2 = new LabelNode();
    LabelNode l3 = new LabelNode();
    LabelNode l4 = new LabelNode();
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 0));
    // if (this == other) return true;
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 1));
    equalsNode.instructions.add(new JumpInsnNode(Opcodes.IF_ACMPNE, l0));
    equalsNode.instructions.add(new InsnNode(Opcodes.ICONST_1));
    equalsNode.instructions.add(new InsnNode(Opcodes.IRETURN));
    equalsNode.instructions.add(l0);
    // if (other == null) return false;
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 1));
    equalsNode.instructions.add(new JumpInsnNode(Opcodes.IFNULL, l1));
    // if (!(other instanceof <this class>)) return false;
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 1));
    equalsNode.instructions.add(new TypeInsnNode(Opcodes.INSTANCEOF, classNode.name));
    equalsNode.instructions.add(new JumpInsnNode(Opcodes.IFNE, l2));
    equalsNode.instructions.add(l1);
    equalsNode.instructions.add(new InsnNode(Opcodes.ICONST_0));
    equalsNode.instructions.add(new InsnNode(Opcodes.IRETURN));
    equalsNode.instructions.add(l2);
    // Check if it other object can cast to <this class>
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 1));
    equalsNode.instructions.add(new TypeInsnNode(Opcodes.CHECKCAST, classNode.name));
    equalsNode.instructions.add(new VarInsnNode(Opcodes.ASTORE, 2));
    for (int i = 0; i < fieldList.size(); i++) {
        boolean isLast = ((i + 1) == fieldList.size());
        TupleSchemaRegistry.SQLFieldInfo info = fieldList.get(i);
        String fieldName = info.getColumnName();
        String fieldType = info.getType().getJavaType().getName();
        String fieldJavaType = getJavaType(fieldType);
        String getterMethodName = (fieldType.equals("boolean") ? "is" : "get") + Character.toUpperCase(fieldName.charAt(0)) + fieldName.substring(1);
        equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 2));
        equalsNode.instructions.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, classNode.name, getterMethodName, "()" + fieldJavaType, false));
        equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 0));
        equalsNode.instructions.add(new FieldInsnNode(Opcodes.GETFIELD, classNode.name, fieldName, fieldJavaType));
        switch(fieldType) {
            case "boolean":
            case "byte":
            case "char":
            case "short":
            case "int":
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IF_ICMPEQ : Opcodes.IF_ICMPNE, isLast ? l4 : l3));
                break;
            case "long":
                equalsNode.instructions.add(new InsnNode(Opcodes.LCMP));
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IFEQ : Opcodes.IFNE, isLast ? l4 : l3));
                break;
            case "float":
                equalsNode.instructions.add(new InsnNode(Opcodes.FCMPL));
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IFEQ : Opcodes.IFNE, isLast ? l4 : l3));
                break;
            case "double":
                equalsNode.instructions.add(new InsnNode(Opcodes.DCMPL));
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IFEQ : Opcodes.IFNE, isLast ? l4 : l3));
                break;
            default:
                String objectOwnerType = fieldType.replace('.', '/');
                LabelNode nonNullNode = new LabelNode();
                LabelNode continueNode = new LabelNode();
                equalsNode.instructions.add(new JumpInsnNode(Opcodes.IFNONNULL, nonNullNode));
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IFNULL : Opcodes.IFNONNULL, isLast ? l4 : l3));
                equalsNode.instructions.add(new JumpInsnNode(Opcodes.GOTO, continueNode));
                equalsNode.instructions.add(nonNullNode);
                equalsNode.instructions.add(new InsnNode(Opcodes.POP));
                equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 0));
                equalsNode.instructions.add(new FieldInsnNode(Opcodes.GETFIELD, classNode.name, fieldName, fieldJavaType));
                equalsNode.instructions.add(new VarInsnNode(Opcodes.ALOAD, 2));
                equalsNode.instructions.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, classNode.name, getterMethodName, "()" + fieldJavaType, false));
                equalsNode.instructions.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, objectOwnerType, "equals", "(Ljava/lang/Object;)Z", false));
                equalsNode.instructions.add(new JumpInsnNode(isLast ? Opcodes.IFNE : Opcodes.IFEQ, isLast ? l4 : l3));
                equalsNode.instructions.add(continueNode);
                break;
        }
    }
    equalsNode.instructions.add(l3);
    equalsNode.instructions.add(new InsnNode(Opcodes.ICONST_0));
    equalsNode.instructions.add(new InsnNode(Opcodes.IRETURN));
    equalsNode.instructions.add(l4);
    equalsNode.instructions.add(new InsnNode(Opcodes.ICONST_1));
    equalsNode.instructions.add(new InsnNode(Opcodes.IRETURN));
    classNode.methods.add(equalsNode);
}