[Refactor]: separate context impl and interface (#223)

* separate context impl and interface

* remove ExecutionContext

Author: zhongkechen

docs/spec/waitForCondition.md

@@ -76,7 +76,7 @@ public interface WaitForConditionWaitStrategy<T> {
 ```
 
 - `state`: the current state returned by the check function
-- `attempt`: 1-based attempt number (first check is attempt 1)
+- `attempt`: 0-based attempt number (first check is attempt 0)
 - Returns a `WaitForConditionDecision` indicating whether to continue or stop
 
 ### WaitForConditionDecision

sdk-testing/src/main/java/software/amazon/lambda/durable/testing/TestOperation.java

@@ -85,9 +85,9 @@ public ErrorObject getError() {
         return details != null ? details.error() : null;
     }
 
-    /** Returns the current retry attempt number (1-based), defaulting to 1 if not available. */
+    /** Returns the current retry attempt number (0-based), defaulting to 0 if not available. */
     public int getAttempt() {
         var details = operation.stepDetails();
-        return details != null && details.attempt() != null ? details.attempt() : 1;
+        return details != null && details.attempt() != null ? details.attempt() : 0;
     }
 }

sdk/src/main/java/software/amazon/lambda/durable/BaseContext.java

@@ -3,134 +3,49 @@
 package software.amazon.lambda.durable;
 
 import com.amazonaws.services.lambda.runtime.Context;
-import software.amazon.lambda.durable.execution.ExecutionManager;
-import software.amazon.lambda.durable.execution.SuspendExecutionException;
-import software.amazon.lambda.durable.execution.ThreadContext;
-import software.amazon.lambda.durable.execution.ThreadType;
 import software.amazon.lambda.durable.logging.DurableLogger;
 
-public abstract class BaseContext implements AutoCloseable {
-    private final ExecutionManager executionManager;
-    private final DurableConfig durableConfig;
-    private final Context lambdaContext;
-    private final ExecutionContext executionContext;
-    private final String contextId;
-    private final String contextName;
-    private final ThreadType threadType;
-
-    private boolean isReplaying;
-
-    /**
-     * Creates a new BaseContext instance.
-     *
-     * @param executionManager the execution manager for thread coordination and state management
-     * @param durableConfig the durable execution configuration
-     * @param lambdaContext the AWS Lambda runtime context
-     * @param contextId the context ID, null for root context, set for child contexts
-     * @param contextName the human-readable name for this context
-     * @param threadType the type of thread this context runs on
-     */
-    protected BaseContext(
-            ExecutionManager executionManager,
-            DurableConfig durableConfig,
-            Context lambdaContext,
-            String contextId,
-            String contextName,
-            ThreadType threadType) {
-        this.executionManager = executionManager;
-        this.durableConfig = durableConfig;
-        this.lambdaContext = lambdaContext;
-        this.contextId = contextId;
-        this.contextName = contextName;
-        this.executionContext = new ExecutionContext(executionManager.getDurableExecutionArn());
-        this.isReplaying = executionManager.hasOperationsForContext(contextId);
-        this.threadType = threadType;
-
-        // write the thread id and type to thread local
-        executionManager.setCurrentThreadContext(new ThreadContext(contextId, threadType));
-    }
-
-    // =============== accessors ================
+public interface BaseContext extends AutoCloseable {
     /**
      * Gets a logger with additional information of the current execution context.
      *
      * @return a DurableLogger instance
      */
-    public abstract DurableLogger getLogger();
+    DurableLogger getLogger();
 
     /**
      * Returns the AWS Lambda runtime context.
      *
      * @return the Lambda context
      */
-    public Context getLambdaContext() {
-        return lambdaContext;
-    }
+    Context getLambdaContext();
 
     /**
-     * Returns metadata about the current durable execution.
-     *
-     * <p>The execution context provides information that remains constant throughout the execution lifecycle, such as
-     * the durable execution ARN. This is useful for tracking execution progress, correlating logs, and referencing this
-     * execution in external systems.
+     * Returns the current durable execution arn
      *
-     * @return the execution context
+     * @return the execution arn
      */
-    public ExecutionContext getExecutionContext() {
-        return executionContext;
-    }
+    String getExecutionArn();
 
     /**
      * Returns the configuration for durable execution behavior.
      *
      * @return the durable configuration
      */
-    public DurableConfig getDurableConfig() {
-        return durableConfig;
-    }
+    DurableConfig getDurableConfig();
 
-    // ============= internal utilities ===============
-
-    /** Gets the context ID for this context. Null for root context, set for child contexts. */
-    public String getContextId() {
-        return contextId;
-    }
-
-    public String getContextName() {
-        return contextName;
-    }
+    /**
+     * Gets the context ID for this context. Null for root context, operationId of the context operation for child
+     * contexts.
+     */
+    String getContextId();
 
-    public ExecutionManager getExecutionManager() {
-        return executionManager;
-    }
+    /** Gets the context name for this context. Null for root context. */
+    String getContextName();
 
     /** Returns whether this context is currently in replay mode. */
-    boolean isReplaying() {
-        return isReplaying;
-    }
-
-    /**
-     * Transitions this context from replay to execution mode. Called when the first un-cached operation is encountered.
-     */
-    void setExecutionMode() {
-        this.isReplaying = false;
-    }
+    boolean isReplaying();
 
-    public void close() {
-        // this is called in the user thread, after the context's user code has completed
-        if (getContextId() != null) {
-            // if this is a child context or a step context, we need to
-            // deregister the context's thread from the execution manager
-            try {
-                executionManager.deregisterActiveThread(getContextId());
-            } catch (SuspendExecutionException e) {
-                // Expected when this is the last active thread. Must catch here because:
-                // 1/ This runs in a worker thread detached from handlerFuture
-                // 2/ Uncaught exception would prevent stepAsync().get() from resume
-                // Suspension/Termination is already signaled via
-                // suspendExecutionFuture/terminateExecutionFuture
-                // before the throw.
-            }
-        }
-    }
+    /** Closes this context. */
+    void close();
 }