ActorContext.getParent for Java API #22413
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Johan Andrén
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213 changed files with 1319 additions and 1523 deletions
273
akka-docs/rst/java/code/jdocs/ddata/ShoppingCart.java
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273
akka-docs/rst/java/code/jdocs/ddata/ShoppingCart.java
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package jdocs.ddata;
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import static java.util.concurrent.TimeUnit.SECONDS;
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import java.io.Serializable;
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import java.util.HashSet;
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import java.util.Optional;
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import java.util.Set;
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import scala.concurrent.duration.Duration;
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import akka.actor.AbstractActor;
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import akka.actor.ActorRef;
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import akka.actor.Props;
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import akka.cluster.Cluster;
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import akka.cluster.ddata.DistributedData;
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import akka.cluster.ddata.Key;
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import akka.cluster.ddata.LWWMap;
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import akka.cluster.ddata.LWWMapKey;
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import akka.cluster.ddata.Replicator;
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import akka.cluster.ddata.Replicator.GetFailure;
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import akka.cluster.ddata.Replicator.GetResponse;
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import akka.cluster.ddata.Replicator.GetSuccess;
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import akka.cluster.ddata.Replicator.NotFound;
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import akka.cluster.ddata.Replicator.ReadConsistency;
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import akka.cluster.ddata.Replicator.ReadMajority;
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import akka.cluster.ddata.Replicator.Update;
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import akka.cluster.ddata.Replicator.UpdateFailure;
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import akka.cluster.ddata.Replicator.UpdateSuccess;
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import akka.cluster.ddata.Replicator.UpdateTimeout;
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import akka.cluster.ddata.Replicator.WriteConsistency;
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import akka.cluster.ddata.Replicator.WriteMajority;
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@SuppressWarnings("unchecked")
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public class ShoppingCart extends AbstractActor {
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//#read-write-majority
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private final WriteConsistency writeMajority =
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new WriteMajority(Duration.create(3, SECONDS));
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private final static ReadConsistency readMajority =
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new ReadMajority(Duration.create(3, SECONDS));
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//#read-write-majority
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public static final String GET_CART = "getCart";
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public static class AddItem {
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public final LineItem item;
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public AddItem(LineItem item) {
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this.item = item;
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}
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}
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public static class RemoveItem {
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public final String productId;
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public RemoveItem(String productId) {
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this.productId = productId;
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}
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}
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public static class Cart {
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public final Set<LineItem> items;
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public Cart(Set<LineItem> items) {
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this.items = items;
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}
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}
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public static class LineItem implements Serializable {
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private static final long serialVersionUID = 1L;
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public final String productId;
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public final String title;
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public final int quantity;
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public LineItem(String productId, String title, int quantity) {
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this.productId = productId;
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this.title = title;
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this.quantity = quantity;
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}
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@Override
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public int hashCode() {
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final int prime = 31;
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int result = 1;
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result = prime * result + ((productId == null) ? 0 : productId.hashCode());
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result = prime * result + quantity;
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result = prime * result + ((title == null) ? 0 : title.hashCode());
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return result;
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}
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@Override
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public boolean equals(Object obj) {
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if (this == obj)
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return true;
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if (obj == null)
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return false;
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if (getClass() != obj.getClass())
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return false;
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LineItem other = (LineItem) obj;
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if (productId == null) {
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if (other.productId != null)
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return false;
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} else if (!productId.equals(other.productId))
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return false;
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if (quantity != other.quantity)
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return false;
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if (title == null) {
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if (other.title != null)
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return false;
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} else if (!title.equals(other.title))
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return false;
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return true;
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}
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@Override
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public String toString() {
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return "LineItem [productId=" + productId + ", title=" + title + ", quantity=" + quantity + "]";
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}
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}
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public static Props props(String userId) {
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return Props.create(ShoppingCart.class, userId);
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}
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private final ActorRef replicator = DistributedData.get(getContext().getSystem()).replicator();
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private final Cluster node = Cluster.get(getContext().getSystem());
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@SuppressWarnings("unused")
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private final String userId;
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private final Key<LWWMap<String, LineItem>> dataKey;
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public ShoppingCart(String userId) {
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this.userId = userId;
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this.dataKey = LWWMapKey.create("cart-" + userId);
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}
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@Override
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public Receive createReceive() {
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return matchGetCart()
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.orElse(matchAddItem())
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.orElse(matchRemoveItem())
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.orElse(matchOther());
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}
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//#get-cart
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private Receive matchGetCart() {
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return receiveBuilder()
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.matchEquals(GET_CART, s -> receiveGetCart())
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.match(GetSuccess.class, this::isResponseToGetCart,
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g -> receiveGetSuccess((GetSuccess<LWWMap<String, LineItem>>) g))
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.match(NotFound.class, this::isResponseToGetCart,
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n -> receiveNotFound((NotFound<LWWMap<String, LineItem>>) n))
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.match(GetFailure.class, this::isResponseToGetCart,
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f -> receiveGetFailure((GetFailure<LWWMap<String, LineItem>>) f))
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.build();
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}
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private void receiveGetCart() {
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Optional<Object> ctx = Optional.of(getSender());
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replicator.tell(new Replicator.Get<LWWMap<String, LineItem>>(dataKey, readMajority, ctx),
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getSelf());
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}
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private boolean isResponseToGetCart(GetResponse<?> response) {
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return response.key().equals(dataKey) &&
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(response.getRequest().orElse(null) instanceof ActorRef);
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}
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private void receiveGetSuccess(GetSuccess<LWWMap<String, LineItem>> g) {
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Set<LineItem> items = new HashSet<>(g.dataValue().getEntries().values());
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ActorRef replyTo = (ActorRef) g.getRequest().get();
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replyTo.tell(new Cart(items), getSelf());
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}
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private void receiveNotFound(NotFound<LWWMap<String, LineItem>> n) {
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ActorRef replyTo = (ActorRef) n.getRequest().get();
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replyTo.tell(new Cart(new HashSet<>()), getSelf());
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}
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private void receiveGetFailure(GetFailure<LWWMap<String, LineItem>> f) {
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// ReadMajority failure, try again with local read
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Optional<Object> ctx = Optional.of(getSender());
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replicator.tell(new Replicator.Get<LWWMap<String, LineItem>>(dataKey, Replicator.readLocal(),
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ctx), getSelf());
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}
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//#get-cart
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//#add-item
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private Receive matchAddItem() {
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return receiveBuilder()
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.match(AddItem.class, this::receiveAddItem)
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.build();
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}
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private void receiveAddItem(AddItem add) {
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Update<LWWMap<String, LineItem>> update = new Update<>(dataKey, LWWMap.create(), writeMajority,
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cart -> updateCart(cart, add.item));
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replicator.tell(update, getSelf());
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}
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//#add-item
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private LWWMap<String, LineItem> updateCart(LWWMap<String, LineItem> data, LineItem item) {
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if (data.contains(item.productId)) {
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LineItem existingItem = data.get(item.productId).get();
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int newQuantity = existingItem.quantity + item.quantity;
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LineItem newItem = new LineItem(item.productId, item.title, newQuantity);
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return data.put(node, item.productId, newItem);
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} else {
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return data.put(node, item.productId, item);
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}
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}
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private Receive matchRemoveItem() {
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return receiveBuilder()
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.match(RemoveItem.class, this::receiveRemoveItem)
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.match(GetSuccess.class, this::isResponseToRemoveItem,
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g -> receiveRemoveItemGetSuccess((GetSuccess<LWWMap<String, LineItem>>) g))
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.match(GetFailure.class, this::isResponseToRemoveItem,
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f -> receiveRemoveItemGetFailure((GetFailure<LWWMap<String, LineItem>>) f))
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.match(NotFound.class, this::isResponseToRemoveItem, n -> {/* nothing to remove */})
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.build();
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}
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//#remove-item
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private void receiveRemoveItem(RemoveItem rm) {
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// Try to fetch latest from a majority of nodes first, since ORMap
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// remove must have seen the item to be able to remove it.
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Optional<Object> ctx = Optional.of(rm);
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replicator.tell(new Replicator.Get<LWWMap<String, LineItem>>(dataKey, readMajority, ctx),
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getSelf());
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}
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private void receiveRemoveItemGetSuccess(GetSuccess<LWWMap<String, LineItem>> g) {
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RemoveItem rm = (RemoveItem) g.getRequest().get();
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removeItem(rm.productId);
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}
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private void receiveRemoveItemGetFailure(GetFailure<LWWMap<String, LineItem>> f) {
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// ReadMajority failed, fall back to best effort local value
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RemoveItem rm = (RemoveItem) f.getRequest().get();
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removeItem(rm.productId);
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}
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private void removeItem(String productId) {
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Update<LWWMap<String, LineItem>> update = new Update<>(dataKey, LWWMap.create(), writeMajority,
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cart -> cart.remove(node, productId));
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replicator.tell(update, getSelf());
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}
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private boolean isResponseToRemoveItem(GetResponse<?> response) {
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return response.key().equals(dataKey) &&
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(response.getRequest().orElse(null) instanceof RemoveItem);
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}
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//#remove-item
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private Receive matchOther() {
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return receiveBuilder()
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.match(UpdateSuccess.class, u -> {
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// ok
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})
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.match(UpdateTimeout.class, t -> {
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// will eventually be replicated
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})
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.match(UpdateFailure.class, f -> {
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throw new IllegalStateException("Unexpected failure: " + f);
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})
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.build();
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}
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}
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