We have four specific products with a massive amount of variants. When running the Product Indexer we run out of memory because of these products.
So we want to exclude these specific products from the Product Indexer Job.
My first approach was to use the ProductIndexerEvent, but the event is dispatched at the end of the handle() method :
(vendor/shopware/core/Content/Product/DataAbstractionLayer/ProductIndexer.php:187),
which is probably too late.
What is the best approach to implement that behaviour?
I would advise against excluding products from being indexed. There's business logic relying on the data being indexed.
If you're confident in what you're doing and know about the consequences, you could decorate the ProductIndexer service.
<service id="Foo\MyPlugin\ProductIndexerDecorator" decorates="Shopware\Core\Content\Product\DataAbstractionLayer\ProductIndexer">
<argument type="service" id="Foo\MyPlugin\ProductIndexerDecorator.inner"/>
</service>
In the decorator you would have to deconstruct the original event, filter the WriteResult instances by excluded IDs and then pass the reconstructed event to the decorated service.
class ProductIndexerDecorator extends EntityIndexer
{
const FILTERED_IDS = ['9b180c61ddef4dad89e9f3b9fa13f3be'];
private EntityIndexer $decorated;
public function __construct(EntityIndexer $decorated)
{
$this->decorated = $decorated;
}
public function getDecorated(): EntityIndexer
{
return $this->decorated;
}
public function getName(): string
{
return $this->getDecorated()->getName();
}
public function iterate($offset): ?EntityIndexingMessage
{
return $this->getDecorated()->iterate($offset);
}
public function update(EntityWrittenContainerEvent $event): ?EntityIndexingMessage
{
$originalEvents = clone $event->getEvents();
if (!$originalEvents) {
return $this->getDecorated()->update($event);
}
$event->getEvents()->clear();
/** #var EntityWrittenEvent $writtenEvent */
foreach ($originalEvents as $writtenEvent) {
if ($writtenEvent->getEntityName() !== 'product') {
$event->getEvents()->add($writtenEvent);
continue;
}
$results = [];
foreach ($writtenEvent->getWriteResults() as $result) {
if (\in_array($result->getPrimaryKey(), self::FILTERED_IDS, true)) {
continue;
}
$results[] = $result;
}
$event->getEvents()->add(new EntityWrittenEvent('product', $results, $event->getContext()));
}
return $this->getDecorated()->update($event);
}
public function handle(EntityIndexingMessage $message): void
{
$data = array_diff($message->getData(), self::FILTERED_IDS);
$newMessage = new ProductIndexingMessage($data, $message->getOffset(), $message->getContext(), $message->forceQueue());
$this->getDecorated()->handle($newMessage);
}
public function getTotal(): int
{
return $this->getDecorated()->getTotal();
}
public function getOptions(): array
{
return $this->getDecorated()->getOptions();
}
}
i've written a utility to monitor individual business transactions. For example, Alice calls a method which calls more methods and i want info on just Alice's call, separate from Bob's call to the same method.
Right now the entry point creates a Transaction object and it's passed as an argument to each method:
class Example {
public Item getOrderEntryPoint(int orderId) {
Transaction transaction = transactionManager.create();
transaction.trace("getOrderEntryPoint");
Order order = getOrder(orderId, transaction);
transaction.stop();
logger.info(transaction);
return item;
}
private Order getOrder(int orderId, Transaction t) {
t.trace("getOrder");
Order order = getItems(itemId, t);
t.addStat("number of items", order.getItems().size());
for (Item item : order.getItems()) {
SpecialOffer offer = getSpecialOffer(item, t);
if (null != offer) {
t.incrementStat("offers", 1);
}
}
t.stop();
return order;
}
private SpecialOffer getSpecialOffer(Item item, Transaction t) {
t.trace("getSpecialOffer(" + item.id + ")", TraceCategory.Database);
return offerRepository.getByItem(item);
t.stop();
}
}
This will print to the log something like:
Transaction started by Alice at 10:42
Statistics:
number of items : 3
offers : 1
Category Timings (longest first):
DB : 2s 903ms
code : 187ms
Timings (longest first):
getSpecialOffer(1013) : 626ms
getItems : 594ms
Trace:
getOrderEntryPoint (7ms)
getOrder (594ms)
getSpecialOffer(911) (90ms)
getSpecialOffer(1013) (626ms)
getSpecialOffer(2942) (113ms)
It works great but passing the transaction object around is ugly. Someone suggested AOP but i don't see how to pass the transaction created in the first method to all the other methods.
The Transaction object is pretty simple:
public class Transaction {
private String uuid = UUID.createRandom();
private List<TraceEvent> events = new ArrayList<>();
private Map<String,Int> stats = new HashMap<>();
}
class TraceEvent {
private String name;
private long durationInMs;
}
The app that uses it is a Web app, and this multi-threaded, but the individual transactions are on a single thread - no multi-threading, async code, competition for resources, etc.
My attempt at an annotation:
#Around("execution(* *(..)) && #annotation(Trace)")
public Object around(ProceedingJoinPoint point) {
String methodName = MethodSignature.class.cast(point.getSignature()).getMethod().getName();
//--- Where do i get this call's instance of TRANSACTION from?
if (null == transaction) {
transaction = TransactionManager.createTransaction();
}
transaction.trace(methodName);
Object result = point.proceed();
transaction.stop();
return result;
Introduction
Unfortunately, your pseudo code does not compile. It contains several syntactical and logical errors. Furthermore, some helper classes are missing. If I did not have spare time today and was looking for a puzzle to solve, I would not have bothered making my own MCVE out of it, because that would actually have been your job. Please do read the MCVE article and learn to create one next time, otherwise you will not get a lot of qualified help here. This was your free shot because you are new on SO.
Original situation: passing through transaction objects in method calls
Application helper classes:
package de.scrum_master.app;
public class Item {
private int id;
public Item(int id) {
this.id = id;
}
public int getId() {
return id;
}
#Override
public String toString() {
return "Item[id=" + id + "]";
}
}
package de.scrum_master.app;
public class SpecialOffer {}
package de.scrum_master.app;
public class OfferRepository {
public SpecialOffer getByItem(Item item) {
if (item.getId() < 30)
return new SpecialOffer();
return null;
}
}
package de.scrum_master.app;
import java.util.ArrayList;
import java.util.List;
public class Order {
private int id;
public Order(int id) {
this.id = id;
}
public List<Item> getItems() {
List<Item> items = new ArrayList<>();
int offset = id == 12345 ? 0 : 1;
items.add(new Item(11 + offset, this));
items.add(new Item(22 + offset, this));
items.add(new Item(33 + offset, this));
return items;
}
}
Trace classes:
package de.scrum_master.trace;
public enum TraceCategory {
Code, Database
}
package de.scrum_master.trace;
class TraceEvent {
private String name;
private TraceCategory category;
private long durationInMs;
private boolean finished = false;
public TraceEvent(String name, TraceCategory category, long startTime) {
this.name = name;
this.category = category;
this.durationInMs = startTime;
}
public long getDurationInMs() {
return durationInMs;
}
public void setDurationInMs(long durationInMs) {
this.durationInMs = durationInMs;
}
public boolean isFinished() {
return finished;
}
public void setFinished(boolean finished) {
this.finished = finished;
}
#Override
public String toString() {
return "TraceEvent[name=" + name + ", category=" + category +
", durationInMs=" + durationInMs + ", finished=" + finished + "]";
}
}
Transaction classes:
Here I tried to mimic your own Transaction class with as few as possible changes, but there was a lot I had to add and modify in order to emulate a simplified version of your trace output. This is not thread-safe and the way I am locating the last unfinished TraceEvent is not nice and only works cleanly if there are not exceptions. But you get the idea, I hope. The point is to just make it basically work and subsequently get log output similar to your example. If this was originally my code, I would have solved it differently.
package de.scrum_master.trace;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.UUID;
public class Transaction {
private String uuid = UUID.randomUUID().toString();
private List<TraceEvent> events = new ArrayList<>();
private Map<String, Integer> stats = new HashMap<>();
public void trace(String message) {
trace(message, TraceCategory.Code);
}
public void trace(String message, TraceCategory category) {
events.add(new TraceEvent(message, category, System.currentTimeMillis()));
}
public void stop() {
TraceEvent event = getLastUnfinishedEvent();
event.setDurationInMs(System.currentTimeMillis() - event.getDurationInMs());
event.setFinished(true);
}
private TraceEvent getLastUnfinishedEvent() {
return events
.stream()
.filter(event -> !event.isFinished())
.reduce((first, second) -> second)
.orElse(null);
}
public void addStat(String text, int size) {
stats.put(text, size);
}
public void incrementStat(String text, int increment) {
Integer currentCount = stats.get(text);
if (currentCount == null)
currentCount = 0;
stats.put(text, currentCount + increment);
}
#Override
public String toString() {
return "Transaction {" +
toStringUUID() +
toStringStats() +
toStringEvents() +
"\n}\n";
}
private String toStringUUID() {
return "\n uuid = " + uuid;
}
private String toStringStats() {
String result = "\n stats = {";
for (Entry<String, Integer> statEntry : stats.entrySet())
result += "\n " + statEntry;
return result + "\n }";
}
private String toStringEvents() {
String result = "\n events = {";
for (TraceEvent event : events)
result += "\n " + event;
return result + "\n }";
}
}
package de.scrum_master.trace;
public class TransactionManager {
public Transaction create() {
return new Transaction();
}
}
Example driver application:
package de.scrum_master.app;
import de.scrum_master.trace.TraceCategory;
import de.scrum_master.trace.Transaction;
import de.scrum_master.trace.TransactionManager;
public class Example {
private TransactionManager transactionManager = new TransactionManager();
private OfferRepository offerRepository = new OfferRepository();
public Order getOrderEntryPoint(int orderId) {
Transaction transaction = transactionManager.create();
transaction.trace("getOrderEntryPoint");
sleep(100);
Order order = getOrder(orderId, transaction);
transaction.stop();
System.out.println(transaction);
return order;
}
private Order getOrder(int orderId, Transaction t) {
t.trace("getOrder");
sleep(200);
Order order = new Order(orderId);
t.addStat("number of items", order.getItems().size());
for (Item item : order.getItems()) {
SpecialOffer offer = getSpecialOffer(item, t);
if (null != offer)
t.incrementStat("special offers", 1);
}
t.stop();
return order;
}
private SpecialOffer getSpecialOffer(Item item, Transaction t) {
t.trace("getSpecialOffer(" + item.getId() + ")", TraceCategory.Database);
sleep(50);
SpecialOffer specialOffer = offerRepository.getByItem(item);
t.stop();
return specialOffer;
}
private void sleep(long millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
new Example().getOrderEntryPoint(12345);
new Example().getOrderEntryPoint(23456);
}
}
If you run this code, the output is as follows:
Transaction {
uuid = 62ec9739-bd32-4a56-b6b3-a8a13624961a
stats = {
special offers=2
number of items=3
}
events = {
TraceEvent[name=getOrderEntryPoint, category=Code, durationInMs=561, finished=true]
TraceEvent[name=getOrder, category=Code, durationInMs=451, finished=true]
TraceEvent[name=getSpecialOffer(11), category=Database, durationInMs=117, finished=true]
TraceEvent[name=getSpecialOffer(22), category=Database, durationInMs=69, finished=true]
TraceEvent[name=getSpecialOffer(33), category=Database, durationInMs=63, finished=true]
}
}
Transaction {
uuid = a420cd70-96e5-44c4-a0a4-87e421d05e87
stats = {
special offers=2
number of items=3
}
events = {
TraceEvent[name=getOrderEntryPoint, category=Code, durationInMs=469, finished=true]
TraceEvent[name=getOrder, category=Code, durationInMs=369, finished=true]
TraceEvent[name=getSpecialOffer(12), category=Database, durationInMs=53, finished=true]
TraceEvent[name=getSpecialOffer(23), category=Database, durationInMs=63, finished=true]
TraceEvent[name=getSpecialOffer(34), category=Database, durationInMs=53, finished=true]
}
}
AOP refactoring
Preface
Please note that I am using AspectJ here because two things about your code would never work with Spring AOP because it works with a delegation pattern based on dynamic proxies:
self-invocation (internally calling a method of the same class or super-class)
intercepting private methods
Because of these Spring AOP limitations I advise you to either refactor your code so as to avoid the two issues above or to configure your Spring applications to use full AspectJ via LTW (load-time weaving) instead.
As you noticed, my sample code does not use Spring at all because AspectJ is completely independent of Spring and works with any Java application (or other JVM languages, too).
Refactoring idea
Now what should you do in order to get rid of passing around tracing information (Transaction objects), polluting your core application code and tangling it with trace calls?
You extract transaction tracing into an aspect taking care of all trace(..) and stop() calls.
Unfortunately your Transaction class contains different types of information and does different things, so you cannot completely get rid of context information about how to trace for each affected method. But at least you can extract that context information from the method bodies and transform it into a declarative form using annotations with parameters.
These annotations can be targeted by an aspect taking care of handling transaction tracing.
Added and updated code, iteration 1
Annotations related to transaction tracing:
package de.scrum_master.trace;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
#Retention(RUNTIME)
#Target(METHOD)
public #interface TransactionEntryPoint {}
package de.scrum_master.trace;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
#Retention(RUNTIME)
#Target(METHOD)
public #interface TransactionTrace {
String message() default "__METHOD_NAME__";
TraceCategory category() default TraceCategory.Code;
String addStat() default "";
String incrementStat() default "";
}
Refactored application classes with annotations:
package de.scrum_master.app;
import java.util.ArrayList;
import java.util.List;
import de.scrum_master.trace.TransactionTrace;
public class Order {
private int id;
public Order(int id) {
this.id = id;
}
#TransactionTrace(message = "", addStat = "number of items")
public List<Item> getItems() {
List<Item> items = new ArrayList<>();
int offset = id == 12345 ? 0 : 1;
items.add(new Item(11 + offset));
items.add(new Item(22 + offset));
items.add(new Item(33 + offset));
return items;
}
}
Nothing much here, only added an annotation to getItems(). But the sample application class changes massively, getting much cleaner and simpler:
package de.scrum_master.app;
import de.scrum_master.trace.TraceCategory;
import de.scrum_master.trace.TransactionEntryPoint;
import de.scrum_master.trace.TransactionTrace;
public class Example {
private OfferRepository offerRepository = new OfferRepository();
#TransactionEntryPoint
#TransactionTrace
public Order getOrderEntryPoint(int orderId) {
sleep(100);
Order order = getOrder(orderId);
return order;
}
#TransactionTrace
private Order getOrder(int orderId) {
sleep(200);
Order order = new Order(orderId);
for (Item item : order.getItems()) {
SpecialOffer offer = getSpecialOffer(item);
// Do something with special offers
}
return order;
}
#TransactionTrace(category = TraceCategory.Database, incrementStat = "specialOffers")
private SpecialOffer getSpecialOffer(Item item) {
sleep(50);
SpecialOffer specialOffer = offerRepository.getByItem(item);
return specialOffer;
}
private void sleep(long millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
new Example().getOrderEntryPoint(12345);
new Example().getOrderEntryPoint(23456);
}
}
See? Except for a few annotations there is nothing left of the transaction tracing logic, the application code only takes care of its core concern. If you also remove the sleep() method which only makes the application slower for demonstration purposes (because we want some nice statistics with measured times >0 ms), the class gets even more compact.
But of course we need to put the transaction tracing logic somewhere, more precisely modularise it into an AspectJ aspect:
Transaction tracing aspect:
package de.scrum_master.trace;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.stream.Collectors;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
#Aspect("percflow(entryPoint())")
public class TransactionTraceAspect {
private static TransactionManager transactionManager = new TransactionManager();
private Transaction transaction = transactionManager.create();
#Pointcut("execution(* *(..)) && #annotation(de.scrum_master.trace.TransactionEntryPoint)")
private static void entryPoint() {}
#Around("execution(* *(..)) && #annotation(transactionTrace)")
public Object doTrace(ProceedingJoinPoint joinPoint, TransactionTrace transactionTrace) throws Throwable {
preTrace(transactionTrace, joinPoint);
Object result = joinPoint.proceed();
postTrace(transactionTrace);
addStat(transactionTrace, result);
incrementStat(transactionTrace, result);
return result;
}
private void preTrace(TransactionTrace transactionTrace, ProceedingJoinPoint joinPoint) {
String traceMessage = transactionTrace.message();
if ("".equals(traceMessage))
return;
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
if ("__METHOD_NAME__".equals(traceMessage)) {
traceMessage = signature.getName() + "(";
traceMessage += Arrays.stream(joinPoint.getArgs()).map(arg -> arg.toString()).collect(Collectors.joining(", "));
traceMessage += ")";
}
transaction.trace(traceMessage, transactionTrace.category());
}
private void postTrace(TransactionTrace transactionTrace) {
if ("".equals(transactionTrace.message()))
return;
transaction.stop();
}
private void addStat(TransactionTrace transactionTrace, Object result) {
if ("".equals(transactionTrace.addStat()) || result == null)
return;
if (result instanceof Collection)
transaction.addStat(transactionTrace.addStat(), ((Collection<?>) result).size());
else if (result.getClass().isArray())
transaction.addStat(transactionTrace.addStat(), Array.getLength(result));
}
private void incrementStat(TransactionTrace transactionTrace, Object result) {
if ("".equals(transactionTrace.incrementStat()) || result == null)
return;
transaction.incrementStat(transactionTrace.incrementStat(), 1);
}
#After("entryPoint()")
public void logFinishedTransaction(JoinPoint joinPoint) {
System.out.println(transaction);
}
}
Let me explain what this aspect does:
#Pointcut(..) entryPoint() says: Find me all methods in the code annotated by #TransactionEntryPoint. This pointcut is used in two places:
#Aspect("percflow(entryPoint())") says: Create one aspect instance for each control flow beginning at a transaction entry point.
#After("entryPoint()") logFinishedTransaction(..) says: Execute this advice (AOP terminology for a method linked to a pointcut) after an entry point methods is finished. The corresponding method just prints the transaction statistics just like in the original code at the end of Example.getOrderEntryPoint(..).
#Around("execution(* *(..)) && #annotation(transactionTrace)") doTrace(..)says: Wrap methods annotated by TransactionTrace and do the following (method body):
add new trace element and start measuring time
execute original (wrapped) method and store result
update trace element with measured time
add one type of statistics (optional)
increment another type of statistics (optional)
return wrapped method's result to its caller
The private methods are just helpers for the #Around advice.
The console log when running the updated Example class and active AspectJ is:
Transaction {
uuid = 4529d325-c604-441d-8997-45ca659abb14
stats = {
specialOffers=2
number of items=3
}
events = {
TraceEvent[name=getOrderEntryPoint(12345), category=Code, durationInMs=468, finished=true]
TraceEvent[name=getOrder(12345), category=Code, durationInMs=366, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=11]), category=Database, durationInMs=59, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=22]), category=Database, durationInMs=50, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=33]), category=Database, durationInMs=51, finished=true]
}
}
Transaction {
uuid = ef76a996-8621-478b-a376-e9f7a729a501
stats = {
specialOffers=2
number of items=3
}
events = {
TraceEvent[name=getOrderEntryPoint(23456), category=Code, durationInMs=452, finished=true]
TraceEvent[name=getOrder(23456), category=Code, durationInMs=351, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=12]), category=Database, durationInMs=50, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=23]), category=Database, durationInMs=50, finished=true]
TraceEvent[name=getSpecialOffer(Item[id=34]), category=Database, durationInMs=50, finished=true]
}
}
You see, it looks almost identical to the original application.
Idea for further simplification, iteration 2
When reading method Example.getOrder(int orderId) I was wondering why you are calling order.getItems(), looping over it and calling getSpecialOffer(item) inside the loop. In your sample code you do not use the results for anything other than updating the transaction trace object. I am assuming that in your real code you do something with the order and with the special offers in that method.
But just in case you really do not need those calls inside that method, I suggest
you factor the calls out right into the aspect, getting rid of the TransactionTrace annotation parameters String addStat() and String incrementStat().
The Example code would get even simpler and
the annotation #TransactionTrace(message = "", addStat = "number of items") in class would go away, too.
I am leaving this refactoring to you if you think it makes sense.
I am very new to TDD. I am using phpunit 7.4x-dev. I have the following abstract class that I am trying to develop unit tests for.
use PDO;
abstract class Model {
protected static function getDB() {
static $db = null;
if ($db === null) {
$db = new PDO(ConfigDatabase::DSN, ConfigDatabase::USER, ConfigDatabase::PASSWORD);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
return $db;
}
}
I have created the following test to get around the need to deal with the static protected method. And it works if I provide "ConfigureDatabase" class.
use PHPUnit\Framework\TestCase;
class ModelTest extends TestCase {
function newMockClass(){
$stub = new class() extends Model{
function getStaticMethod($methodName){
return self::$methodName();
}
};
return $stub;
}
public function testDatabaseExists() {
$stub = $this->newMockClass();
$db = $stub->getStaticMethod('getDB');
$this->assertInstanceOf(PDO::class,$db);
}
}
Since I do not want my tests to rely on any actual database, How would I fake the calls to PDO.
Following Dormilich suggestion I developed a database interface, just in case I decide later I do not want to use PDO.
interface CRUDImp {
function __construct($datbaseBridgeLikePDO);
...
}
Next I wrote my tests for the constructor. I used setup to make sure I was starting with a fresh mock of \PDO.
class PDOWrapperTest extends TestCase {
private $pdoMock;
private $db;
function setup() {
$this->pdoMock = $this->createMock('\PDO');
$this->db = new PDOWrapper($this->pdoMock);
}
public function testWrapperExists() {
$this->pdoMock->method('getAttribute')->willReturn(\PDO::ERRMODE_EXCEPTION);
$db = new PDOWrapper($this->pdoMock);
$x = $db instanceof CRUDImp;
$this->assertTrue($x);
}
/**
* #expectedException \Exception
*/
public function testNonPDOPassedToConstructor() {
$mock = $this->createMock('\Exception');
$x = new PDOWrapper($mock);
}
...
}
Since PHP is loosely typed I check to make sure that the class passed to the constructor was an instance of \PDO. I implemented the concrete class as follows
class PDOWrapper implements CRUDImp {
private $pdo;
private $dataOutputType = \PDO::FETCH_ASSOC;
public function __construct($pdo) {
if (!($pdo instanceof \PDO)) {
throw new \Exception("PDOWrapper must be passed instance of \PDO");
}
$attr_Errmode = $pdo->getAttribute(\PDO::ATTR_ERRMODE);
if ($attr_Errmode !== \PDO::ERRMODE_EXCEPTION) {
$pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
}
$this->pdo = $pdo;
}
...
}
Now that I have an independent database wrapper the original Model tests are at the moment trivial and no longer needed. The abstract class Model was modified as follows:
abstract class Model {
protected $database=null;
function __construct(CRUDWrapper $database) {
$this->database = $database;
}
...
}
So for those not familiar with dependency injection I found the following links helpful:
http://php-di.org/doc/understanding-di.html
https://codeinphp.github.io/post/dependency-injection-in-php/
https://designpatternsphp.readthedocs.io/en/latest/Structural/DependencyInjection/README.html
Hope this shortens someone's work.
I have a REST API. I need to create presentation (DTO) object, but the construction of this object depends on request - it differs in 15%.
I wonder what pattern should I use.
My case:
//presentation-DTO
class Item {
private $name;
private $price;
private $tags;
private $liked; //is Liked by logged user
...
public function __construct(Item $item, bool $liked, ...)
{
$this->name = $item->getName();
$this->price = $item->getPrice();
$this->tags = $item->getTags();
$this->liked = $liked;
...
}
}
When user is not logged in - I don't need $liked
When showing list of items - I don't need $tags
And there are more attributes that works as above.
My first idea was to use Builder principle.
$itemBuilder = new ItemBuilder();
$itemBuilder->setItem($item);
...
if($user) {
$itemBuilder->setUserLiked($userLiked);
...
}
return $itemBuilder->build();
It solves my problem with too many parameters in constructor.
But still, I also don't need all parameters to be constructed - eg. I don't need tags (on lists). As I use lazy load, I don't want my dto constructor to call them.
So I thought, maybe Factory.. but then my problem with too many (and optional) parameters is returning.
How will you solve this?
Sorry I don't have required points to make a comment hence an answer.
What are you trying to do with the Item class. Your class is Item and first parameter is also of type Item. I cannot visualizes how its going to work.
I will prefer to keep business login to set proper properties in a separate class:
/**
* A class for business logic to set the proper properties
*/
class ItemProperties {
private $item;
public $isLogin = false;
public $showList = false;
.....
public function __construct(Item &$item) {
// set all properties;
}
public function getProperties() {
$retVal = [];
if($this->isLogin == true) {
$retVal['liked'] = true;
}
if($this->showList == true) {
$retVal['tags'] = $this->item->getTags();
}
if(....) {
$retVal['...'] = $this->item->.....();
}
return $retVal;
}
}
/**
* DTO
*/
class Item {
public function __construct(ItemProperties $itemProps) {
$this->setItemProps($itemProps);
}
// If you prefer lazy loading here...maybe make it public
// and remove call from constructor.
private function setItemProps(&$itemProps) {
$properties = $itemProps->getProperties();
foreach($properties AS $propName => $propValue) {
$this->$propName = $propValue;
}
}
}
// Usage:
$itemProps = new ItemProperties($Item);
// set other properties if you need to...
$itemProps->isLogin = false;
$item = new Item($itemProps);
for my Wicket Wizard I want to display an information like: "Wizard step 1 of 4". I started by getting the number of steps and I already came across the first problem:
public WizardPanel(String id) {
super(id, false);
// false deactivates the default style.
setDefaultModel(new CompoundPropertyModel<WizardPanel>(this));
WizardModel model = new WizardModel();
model.add(new FirstStep());
model.add(new SecondStep());
model.add(new ThirdStep());
model.add(new ConfirmationStep());
Iterator<IWizardStep> iterator = model.stepIterator();
for(int i = 1; iterator.hasNext(); i ++){
System.out.println(String.valueOf(i));
}
init(model);
}
My Iterator creates an infinite loop. Shouldn't there only be four objects he can iterate through?
Or is there even a basic implementation for this kind of pagination I haven't found yet?
Because my next step would be to get the current index out of model.getActiveStep(); and find which number it is.
I thought I share my solution (as far as it now is)
public class OverviewComponent extends Panel{
private static final long serialVersionUID = 1L;
private List<WizardStep> steps;
private WizardModel model;
public OverviewComponent(String id, WizardModel model) {
super(id);
this.model = model;
steps = fillList();
this.add(new ListView<WizardStep>("steps", steps) {
private static final long serialVersionUID = 1L;
/**
* Wrap a markup container around the item append a css attribute to every item
*/
#Override
protected void populateItem(ListItem<WizardStep> item) {
WebMarkupContainer stepOverviewItem;
item.add(stepOverviewItem = new WebMarkupContainer("stepOverviewItem"));
stepOverviewItem.add(new Label("index", Model.of(item.getIndex()+1)));
stepOverviewItem.add(new AttributeModifier("class", getCSSProperty(item.getModelObject())));
stepOverviewItem.setOutputMarkupId(true);
stepOverviewItem.setOutputMarkupPlaceholderTag(true);
}
});
}
public String getCSSProperty(WizardStep step) {
if (step.equals(model.getActiveStep())) {
return "active";
} else if (!step.isComplete()) {
return "pending";
} else if (step.isComplete()) {
return "completed";
}
return "";
}
public List<WizardStep> fillList() {
List<WizardStep> iSteps = new ArrayList<WizardStep>();
Iterator<IWizardStep> iterator = model.stepIterator();
while (iterator.hasNext()) {
iSteps.add((WizardStep)iterator.next());
}
return iSteps;
}
}