Question: How to check which fields has been changed inside method annotated with #PreUpdate?
OPTIONAL: if the answer to the question above is "It's impossible, than maybe there are another ways to solve my problem"
I want automatically update modified Tourist's field each time we change something in it.
Except the situation when we modify only location. Means if we change location only - it should be persisted, but modified mustn't be changed.
Already present code:
#Entity
public class Tourist {
private long id;
private String firstName;
private String lastName;
private Date created;
private Date modified;
private String location;
#PreUpdate
public void preUpdate() {
modified = new Date(); //PROBLEM : change modified even if only location field has been changed!
}
....
}
Updated: After some investigations I found that I can solve it with help of interceptors (extend EmptyInterceptor):
public class TouristInterceptor extends EmptyInterceptor{
Session session;
private Set updates = new HashSet();
public void setSession(Session session) {
this.session=session;
}
public boolean onFlushDirty(Object entity,Serializable id,
Object[] currentState,Object[] previousState,
String[] propertyNames,Type[] types)
throws CallbackException {
if (entity instanceof Tourist){
if (somethingChangedExceptLocation())
updates.add(entity);
}
return false;
}
But disadvantage of this approach is to intercept everything when you need to intercept the single entity.
Updated Questions:
How to intercept only Tourist entity flush calls?
Is that possible to do the same with help of events? Means PreUpdateEvent which contains new and old state
There is a simple non-JPA solution which is as follows but which which does have some repetitive code but is a solution when you do not have too many fields:
#Entity
public class Tourist {
private long id;
private String firstName;
private String lastName;
private Date created;
private Date modified;
private String location;
public void setFirstName(String firstName){
if(! this.firstName.equals(firstName){
modified = new Date();
}
this.firstName = firstName;
}
public void setLastName(String lastName){
if(! this.lastName.equals(lastName){
modified = new Date();
}
this.lastName= lastName;
}
}
Otherwise I would go with saving the previous state on load as suggested in another answer but in a slightly cleaner way.
#Entity
public class Tourist {
private long id;
private String firstName;
private String lastName;
private Date created;
private Date modified;
private String location;
#Transient
private Tourist previousState;
#PostLoad
public void setPreviousState() {
previousState = new Tourist();
//copy fields
}
#PreUpdate
public void preUpdate() {
if (isModified()) {
modified = new Date();
}
}
private boolean isModified() {
boolean modified = false;
if (!firstName.equals(previousState.firstName) {
modified = true;
}
//check other fields
return modified;
}
}
I really encourage you not to do this logic in your Entity !
You should decide whether to change the modified or not at your business logic.
I mean, when you are changing only the location call merge only. And whenever you are changing something else call the <Tourist_instance>.setModified(new Date()); before you call the merge.
To verify if anything else got changed, I suggest having a transient boolean field in your Entity that you set to true whenever you change something else other than location (the idea in the comment won't be sufficient to test all the fields, only if you create a transient field to remember previous value of each one of them)
You will then test this boolean in your preUpdate method
But I highly don't recommend this workaround.
Or, another highly unrecommended way :
#Entity
public class Tourist {
private long id;
private String firstName;
private String lastName;
private Date created;
private Date modified;
private String location;
#Transient
private String firstNamePrevious;
#Transient
private String lastNamePrevious;
#Transient
private Date createdPrevious;
#Transient
private Date modifiedPrevious;
#Transient
private String locationPrevious;
#PreUpdate
public void preUpdate() {
if(!onlyLocationGotChanged()){
modified = new Date();
}
}
....
#PostLoad
public void postLoad(){
//Set all previous fields to actual values
firstNamePrevious = firstName;
lastNamePrevious = lastName;
//...etc.
}
}
Although it is much late, however I enountered a problem where I required to apply update security on certain fields in entity. I solved it using Reflections. Have a look at this thread. spring security for certain entity variables
Related
I have a model like this:
public class Employee {
#JsonProperty("emplyee_id")
private Integer id;
#JsonProperty("emplyee_first_name")
private String firstName;
#JsonProperty("emplyee_last_name")
private String lastName;
#JsonProperty("emplyee_address")
private String address;
#JsonProperty("emplyee_age")
private Byte age;
#JsonProperty("emplyee_level")
private Byte level;
//getters and setters
}
now I need to create two JSONs using this (only) model.
the first one must like this for example:
{
"employee_id":101,
"employee_first_name":"Alex",
"employee_last_name":"Light",
"employee_age":null,
"employee_address":null
}
and the second one must like this for example:
{
"employee_id":101,
"employee_level":5
}
by the way, I already tested #JsonIgnore and #JsonInclude(JsonInclude.Include.NON_NULL).
the problem of the first one (as much as I know) is, those fields can't be included in other JSONs (for example if level get this annotation, it won't be included in the second JSON)
and the problem of the second one is, null values can't be included in JSON.
so can I keep null values and prevent some other property to be included in JSON without creating extra models? if the answer is yes, so how can I do it? if it's not I really appreciate if anyone gives me the best solution for this state.
thanks very much.
it could be useful for you using #JsonView annotation
public class Views {
public static class Public {
}
public static class Base {
}
}
public class Employee {
#JsonProperty("emplyee_id")
#JsonView({View.Public.class,View.Base.class})
private Integer id;
#JsonProperty("emplyee_first_name")
#JsonView(View.Public.class)
private String firstName;
#JsonProperty("emplyee_last_name")
#JsonView(View.Public.class)
private String lastName;
#JsonProperty("emplyee_address")
private String address;
#JsonProperty("emplyee_age")
private Byte age;
#JsonProperty("emplyee_level")
#JsonView(View.Base.class)
private Byte level;
//getters and setters
}
in your json response add #JsonView(Public/Base.class) it will return based on jsonview annotations
//requestmapping
#JsonView(View.Public.class)
public ResponseEntity<Employee> getEmployeeWithPublicView(){
//do something
}
response:
{
"employee_id":101,
"employee_first_name":"Alex",
"employee_last_name":"Light",
"employee_age":null,
"employee_address":null
}
for the second one
//requestmapping
#JsonView(View.Base.class)
public ResponseEntity<Employee> getEmployeeWithBaseView(){
//do something
}
response
{
"employee_id":101,
"employee_level":5
}
I created a table in AWS DynamoDB which I'll be using for a basic questions and answers forum I'm developing and after table creation and some successful tests where I was able to insert data I decided to add an attribute for storing date of question, which I called time_stamp but for an unknown reason for me I'm not being able to refresh table structure, I mean, data is still saved with no errors but with no time_stamp field.
I tried deleting the table and recreating several times and modifying time_stamp data type with no success so I'm lost and I hope anyone can help me. I thought the only neccesary thing to alter table structure in DynamoDB is just modifing the mapping class in Java but cannot make it to work.
My mapping class is the next:
import com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.*;
#DynamoDBTable(tableName = "community_questions")
public class CommunityQuestion {
private long question_id;
private String time_stamp;
private String user_id;
private String subject;
private String question;
#DynamoDBHashKey(attributeName = "question_id")
public long getQuestionId() { return question_id; }
public void setQuestionId(long questionId) { this.question_id = questionId; }
#DynamoDBAttribute (attributeName = "time_stamp")
public String geTimeStamp() {
return time_stamp;
}
public void setTimeStamp(String timeStamp) {
this.time_stamp = timeStamp;
}
#DynamoDBAttribute (attributeName = "user_id")
public String getUserId() {
return user_id;
}
public void setUserId(String userId) {
this.user_id = userId;
}
#DynamoDBAttribute(attributeName = "subject")
public String getSubject() {
return subject;
}
public void setSubject(String subject) {
this.subject = subject;
}
#DynamoDBAttribute(attributeName = "question")
public String getQuestion() {
return question;
}
public void setQuestion(String question) {
this.question = question;
}
}
All data is being saved with no errors but time_stamp won't!!
I'm using mapper.save for saving operations.
Maybe anything I should refresh in AWS console?? Can't find anything.
Please help, and many thanks in advance.
There is a typo in your code. Rename geTimeStamp to getTimeStamp
DynamoDbMapper considers only methods with exactly "get" or "is" prefixes, and then checks for annotations on those in a second step. Its not picking up your added property because of that.
/**
* Returns whether the method given is a getter method we should serialize /
* deserialize to the service. The method must begin with "get" or "is",
* have no arguments, belong to a class that declares its table, and not be
* marked ignored.
*/
private static boolean isRelevantGetter(Method m) {
(soure)
I am rookie in Java Annotation and have been searching for applying single annotation on multiple variable simultaneously.
Code:
#Document(collection = "users")
public class User {
private ObjectId id;
#NotNull
private String email;
private String imageURL;
private String authToken;
private Date createdDate;
private Date updateDate;
private boolean isActivated;
private int credits;
.....getter/Setter Method
I want to apply #NotNull property on email, imageURL and authToken too. I can do it by writing #NotNull to each variable but not preferring. How to do it?
#NotNull annotation can be applied at element not at group of elements.
JavaDoc: The annotated element must not be null. Accepts any type.
If you really want to get away with boiler plate code, you can use frameworks like Lombok which can help you to certain extent.
Link : http://projectlombok.org/features/Data.html
OR you can use reflection to validate all the method.
for (Field f : obj.getClass().getDeclaredFields()) {
f.setAccessible(true); // optional
if (f.get(obj) == null) {
f.set(obj, getDefaultValueForType(f.getType()));
// OR throw error
}
}
Java does not support multiple annotation of this type. But you can write something like this
Create a class with annotated field.
Create setters and getters to access the field.
Create all your name,email field as instance of this class.
This way fields will implicitly annotated as NotNull.
public class NotNullString {
#NotNull
String str;
public void set(String str)
{
this.str = str;
}
public String get()
{
return this.str;
}
}
NotNullString name;
NotNullString email;
Well i want to know if there is a much appropriate way to tackle generating auto id with string values, my first idea is creating an auto increment id which we can call auto_id then before saving a new entity I'll query for the latest data inside the db to get the id then I'll add 1 to my auto generate value column that I assign name which is stringValue+(id+1) though I'm concerned on how it will affect the performance as to saving this entity needs two access in db which is fetching and saving... like my question earlier is there a much appropriate way to handle this scenario?
And also sorry for my English guys if you want to clarify things with my question kindly ask, thnx in advance..
Here's my code for AttributeModel for hibernate annotation
#Component
#Entity
#Table(name="attribute_info")
public class AttributeModel {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name="attr_id", nullable=false, unique=true)
private int id;
#Column(name="attr_name")
private String name;
#Column(name="attr_desc")
private String desc;
#Column(name="attr_active")
private int active;
#Column(name="attr_abbr")
private String abbr;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name="stats_id", referencedColumnName="stats_id")
private BaseStatisticModel baseStats;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
public int getActive() {
return active;
}
public void setActive(int active) {
this.active = active;
}
public String getAbbr() {
return abbr;
}
public void setAbbr(String abbr) {
this.abbr = abbr;
}
public BaseStatisticModel getBaseStats() {
return baseStats;
}
public void setBaseStats(BaseStatisticModel baseStats) {
this.baseStats = baseStats;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
I can only say "Don't do it". How is a String ID like "str10001" better than 10001? It can't be an optimization as strings take more memory and more time. So I guess you need to pass it to some String-expecting method later.
If so, then pass "str" + id instead. Constructing the string on the fly surely won't saturate your server.
If not, then let us know what you actually need rather than what you think it could help you to achieve it.
I'm pretty sure, Hibernate can't do it. It couldn't some long time ago I checked it recently and it makes no sense (in any case, it's not a feature crowds would request).
Hi i want to know if exist a way to avoid duplicate code in this code. Now i have an action class named CustomerAction this class handle the behaviour of the request (it's like a controller) and i have a CustomerPOJO with attributes like id, name, last_name etc. Now i have to add attributes to CustomerAction to handle the data submited from the form. Is there any way to bypass the action with my CustomerPOJO ?
public class CustomerAction {
private String nombre;
private String apellido;
private String dni;
private String fechaNac;
private String obraSocial;
private String nroAsociado;
private String plan;
private String password;
private String email;
private String telParticular;
private String telCelular;
private static final Log log = LogFactory
.getLog(CustomerAction.class);
public String execute() throws Exception {
if ("cancelar".equals(this.getAccion())) {
log.debug("Executing 'cancelar' action");
return "login";
}
if ("registro".equals(accion)) {
log.debug("Executing 'registro' action");
IReferenceDataBusinessDelegate ud = new ReferenceDataBusinessDelegate();
ud.signCustomer(this.getNombre(), this.getApellido(),
this.getDni(), this.getCorreo(), this.getContrasena());
return "login";
}
}
public class Customers implements java.io.Serializable {
private long id;
private String dni;
private String name;
private String lastName;
private String email;
private String password;
private String phone;
private String cellphone;
private Date birthDate;
private Date creationDate;
private Date lastAccessDate;
private byte active;
private Set<Profesionales> profesionaleses = new HashSet<Profesionales>(0);
private Set<Pacientes> pacienteses = new HashSet<Pacientes>(0);
public Customers() {
}
}
Yes, use ModelDriven, and use a Customers as the model.
http://struts.apache.org/2.x/docs/model-driven.html
You'll need to make sure the "modelDriven" interceptor is in your stack.
How/where to initialize the model depends on your particular usage scenario; you can do it in a getter as shown in the docs, in a prepare() method if you need to reload it from the DB, etc.
I'm not sure what you mean by "bypass the action."
Please note that the ad-hoc dispatch mechanism implemented here with the accion parameter duplicates functionality provided by Struts 2 using the method attribute of the action configuration. I don't recommend using ad-hoc dispatch mechanisms as it makes understand program flow more difficult than necessary.