Adding Task related classes with protobuf integration

Signed-off-by: Vacha Shah <[email protected]>

server/src/main/java/org/opensearch/tasks/ProtobufCancellableTask.java

@@ -0,0 +1,91 @@
+/*
+* SPDX-License-Identifier: Apache-2.0
+*
+* The OpenSearch Contributors require contributions made to
+* this file be licensed under the Apache-2.0 license or a
+* compatible open source license.
+*/
+
+package org.opensearch.tasks;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.common.unit.TimeValue;
+
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.opensearch.search.SearchService.NO_TIMEOUT;
+
+/**
+ * A task that can be canceled
+*
+* @opensearch.internal
+*/
+public abstract class ProtobufCancellableTask extends ProtobufTask {
+
+    private volatile String reason;
+    private final AtomicBoolean cancelled = new AtomicBoolean(false);
+    private final TimeValue cancelAfterTimeInterval;
+
+    public ProtobufCancellableTask(long id, String type, String action, String description, ProtobufTaskId parentTaskId, Map<String, String> headers) {
+        this(id, type, action, description, parentTaskId, headers, NO_TIMEOUT);
+    }
+
+    public ProtobufCancellableTask(
+        long id,
+        String type,
+        String action,
+        String description,
+        ProtobufTaskId parentTaskId,
+        Map<String, String> headers,
+        TimeValue cancelAfterTimeInterval
+    ) {
+        super(id, type, action, description, parentTaskId, headers);
+        this.cancelAfterTimeInterval = cancelAfterTimeInterval;
+    }
+
+    /**
+     * This method is called by the task manager when this task is cancelled.
+    */
+    public void cancel(String reason) {
+        assert reason != null;
+        if (cancelled.compareAndSet(false, true)) {
+            this.reason = reason;
+            onCancelled();
+        }
+    }
+
+    /**
+     * Returns true if this task should be automatically cancelled if the coordinating node that
+    * requested this task left the cluster.
+    */
+    public boolean cancelOnParentLeaving() {
+        return true;
+    }
+
+    /**
+     * Returns true if this task can potentially have children that need to be cancelled when it parent is cancelled.
+    */
+    public abstract boolean shouldCancelChildrenOnCancellation();
+
+    public boolean isCancelled() {
+        return cancelled.get();
+    }
+
+    public TimeValue getCancellationTimeout() {
+        return cancelAfterTimeInterval;
+    }
+
+    /**
+     * The reason the task was cancelled or null if it hasn't been cancelled.
+    */
+    @Nullable
+    public final String getReasonCancelled() {
+        return reason;
+    }
+
+    /**
+     * Called after the task is cancelled so that it can take any actions that it has to take.
+    */
+    protected void onCancelled() {}
+}