Terracotta

https://www.terracotta.org/documentation/
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Terracotta is an in-memory computing platform that provides distributed caching, clustering, and...
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### Java: Coordinate Services with Terracotta Coordinator

Source: https://www.terracotta.org/documentation/coordinator.html

Demonstrates joining a coordination group, acquiring a role, executing a task as the role holder, and observing role ownership. Ensure the Terracotta cluster is running and accessible via the provided URI.

```java
URI clusterUri = URI.create("terracotta://localhost:9410");

// Create an executor for handling reconnection tasks
ExecutorService executor = Executors.newFixedThreadPool(1, Thread::new);

try {
  // Create a coordination group with token "sample-group"
  // Each member of the group must use the same token to join
  System.out.println("Creating coordinator for 'sample-group'...");

  // Create a coordinator listener to receive notifications
  SampleCoordinationListener listener = new SampleCoordinationListener();

  // Build the coordinator with a unique member name "myservice-instance-1"
  try (Coordinator coordinator = ClusteredCoordinator.coordinator(clusterUri, "sample-group", "myservice-instance-1", executor)
      .withListener(listener)
      .build()) {

    System.out.println("Successfully joined the coordination group.");
    System.out.println("Current members: " + coordinator.getMembers());

    // Try to acquire the "primary" role
    System.out.println("Attempting to acquire 'primary' role...");
    try (Role primaryRole = coordinator.acquireRole("primary", Duration.ofSeconds(10))) {
      System.out.println("Successfully acquired 'primary' role.");

      // Execute a task as the role holder with a lease time
      String result = primaryRole.execute(() -> {
        System.out.println("Executing task as the 'primary' role holder...");
        // Simulate some work
        try { Thread.sleep(1000); } catch (InterruptedException ignore) { Thread.currentThread().interrupt(); }
        return "Task completed successfully";
      }, Duration.ofSeconds(10));

      System.out.println("Task result: " + result);

      // Check who holds the role
      System.out.println("Current holder of 'primary' role: " + coordinator.holder("primary").orElse("None"));

      // Wait a bit to observe the coordination
      System.out.println("Holding the role for 5 seconds...");
      try { Thread.sleep(5000); } catch (InterruptedException ignore) { Thread.currentThread().interrupt(); }
    }

```
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