initial commit

src/net/horizoncode/tickettest/TicketTest.java

@@ -0,0 +1,33 @@
+package net.horizoncode.tickettest;
+
+import lombok.Getter;
+import net.horizoncode.tickettest.manager.Ticket;
+import net.horizoncode.tickettest.manager.TicketCallback;
+import net.horizoncode.tickettest.manager.TicketManager;
+
+import java.util.stream.IntStream;
+
+public class TicketTest {
+
+  @Getter private final TicketManager ticketManager;
+
+  public static void main(String[] args) {
+    new TicketTest();
+  }
+
+  public TicketTest() {
+    this.ticketManager = TicketManager.builder().ticketLifespan(5000).maxTicketsExisting(2).build();
+
+    IntStream.range(0, 10)
+        .forEach(
+            (value) ->
+                getTicketManager()
+                    .addTicket(
+                        () -> {
+                          System.out.println("i expired oof");
+                        })
+                    .use());
+
+    while (true) {}
+  }
+}

src/net/horizoncode/tickettest/manager/Ticket.java

@@ -0,0 +1,56 @@
+package net.horizoncode.tickettest.manager;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+@Builder(
+    toBuilder = true,
+    builderClassName = "InternalTicketBuilder",
+    builderMethodName = "internalBuilder")
+public class Ticket extends CompletableFuture<Boolean> {
+  @Getter private UUID ticketID;
+  @Getter private Long timeTicketCreated;
+  private TicketManager ticketManager;
+  @Getter @Setter private Runnable onExpire;
+
+  void init() {
+    ticketID = UUID.randomUUID();
+  }
+
+  public void use() {
+    ticketManager.getTicketSet().add(this);
+    ticketManager
+        .getService()
+        .submit(
+            () -> {
+              TimeUnit.MILLISECONDS.sleep(ticketManager.getTicketLifespan());
+              System.out.println("ticket with UUID: " + getTicketID() + " expired.");
+              ticketManager.getTicketSet().remove(this);
+              getOnExpire().run();
+              return null;
+            });
+  }
+
+  public static Ticket.Builder builder() {
+    return new Ticket.Builder();
+  }
+
+  public static class Builder extends InternalTicketBuilder {
+
+    Builder() {
+      super();
+    }
+
+    @Override
+    public Ticket build() {
+      Ticket ticket = super.build();
+      ticket.init();
+      return ticket;
+    }
+  }
+}

src/net/horizoncode/tickettest/manager/TicketCallback.java

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+package net.horizoncode.tickettest.manager;
+
+public class TicketCallback{
+    public Ticket call(Ticket ticket) {
+        System.out.println("Ticket " + ticket.getTicketID() + " expired.");
+        return ticket;
+    }
+}

src/net/horizoncode/tickettest/manager/TicketManager.java

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+package net.horizoncode.tickettest.manager;
+
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.ListeningExecutorService;
+import com.google.common.util.concurrent.MoreExecutors;
+import lombok.Builder;
+import lombok.Getter;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+@Builder(
+    toBuilder = true,
+    builderClassName = "InternalTicketManagerBuilder",
+    builderMethodName = "internalBuilder")
+@Getter
+public class TicketManager {
+
+  private ListeningExecutorService service;
+  private Set<Ticket> ticketSet;
+  private int maxTicketsExisting;
+  private long ticketLifespan;
+
+  public Ticket addTicket(Runnable onExpire) {
+    ListenableFuture<Ticket> asyncTask =
+        service.submit(
+            () -> {
+              if (waitForFreeTicket())
+                System.out.println("max amount of tickets reached, waiting...");
+
+              while (waitForFreeTicket()) {
+                TimeUnit.MILLISECONDS.sleep(1);
+              }
+              Ticket t =
+                  Ticket.builder().timeTicketCreated(ticketLifespan).onExpire(onExpire).ticketManager(this).build();
+              System.out.println("Got ticket with UUID: " + t.getTicketID());
+              return t;
+            });
+    try {
+      return asyncTask.get();
+    } catch (InterruptedException | ExecutionException e) {
+      e.printStackTrace();
+      return null;
+    }
+  }
+
+  private boolean waitForFreeTicket() {
+    return ticketSet.size() >= maxTicketsExisting;
+  }
+
+  void init() {
+    service = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
+    ticketSet = new HashSet<>();
+  }
+
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  public static class Builder extends InternalTicketManagerBuilder {
+
+    Builder() {
+      super();
+    }
+
+    @Override
+    public TicketManager build() {
+      TicketManager ticketManager = super.build();
+      ticketManager.init();
+      return ticketManager;
+    }
+  }
+}