Add Statement, QueryExecution and QueryManager (#845)

Signed-off-by: Peng Huo <penghuo@gmail.com>

core/src/main/java/org/opensearch/sql/ast/AbstractNodeVisitor.java

@@ -35,6 +35,9 @@
 import org.opensearch.sql.ast.expression.When;
 import org.opensearch.sql.ast.expression.WindowFunction;
 import org.opensearch.sql.ast.expression.Xor;
+import org.opensearch.sql.ast.statement.Explain;
+import org.opensearch.sql.ast.statement.Query;
+import org.opensearch.sql.ast.statement.Statement;
 import org.opensearch.sql.ast.tree.AD;
 import org.opensearch.sql.ast.tree.Aggregation;
 import org.opensearch.sql.ast.tree.Dedupe;
@@ -269,4 +272,16 @@ public T visitAD(AD node, C context) {
   public T visitHighlightFunction(HighlightFunction node, C context) {
     return visitChildren(node, context);
   }
+
+  public T visitStatement(Statement node, C context) {
+    return visit(node, context);
+  }
+
+  public T visitQuery(Query node, C context) {
+    return visitStatement(node, context);
+  }
+
+  public T visitExplain(Explain node, C context) {
+    return visitStatement(node, context);
+  }
 }

core/src/main/java/org/opensearch/sql/ast/statement/Explain.java

@@ -0,0 +1,26 @@
+/*
+ * 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.sql.ast.statement;
+
+import lombok.Data;
+import org.opensearch.sql.ast.AbstractNodeVisitor;
+
+/**
+ * Explain Statement.
+ */
+@Data
+public class Explain extends Statement {
+
+  private final Statement statement;
+
+  @Override
+  public <R, C> R accept(AbstractNodeVisitor<R, C> visitor, C context) {
+    return visitor.visitExplain(this, context);
+  }
+}

core/src/main/java/org/opensearch/sql/ast/statement/Query.java

@@ -0,0 +1,35 @@
+/*
+ * 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.sql.ast.statement;
+
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import lombok.Setter;
+import lombok.ToString;
+import org.opensearch.sql.ast.AbstractNodeVisitor;
+import org.opensearch.sql.ast.tree.UnresolvedPlan;
+
+/**
+ * Query Statement.
+ */
+@Getter
+@Setter
+@ToString
+@EqualsAndHashCode(callSuper = false)
+@RequiredArgsConstructor
+public class Query extends Statement {
+
+  private final UnresolvedPlan plan;
+
+  @Override
+  public <R, C> R accept(AbstractNodeVisitor<R, C> visitor, C context) {
+    return visitor.visitQuery(this, context);
+  }
+}

core/src/main/java/org/opensearch/sql/ast/statement/Statement.java

@@ -0,0 +1,22 @@
+/*
+ * 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.sql.ast.statement;
+
+import org.opensearch.sql.ast.AbstractNodeVisitor;
+import org.opensearch.sql.ast.Node;
+
+/**
+ * Statement is the high interface of core engine.
+ */
+public abstract class Statement extends Node {
+  @Override
+  public <R, C> R accept(AbstractNodeVisitor<R, C> visitor, C context) {
+    return visitor.visitStatement(this, context);
+  }
+}

core/src/main/java/org/opensearch/sql/executor/DefaultQueryManager.java

@@ -0,0 +1,24 @@
+/*
+ * 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.sql.executor;
+
+import org.opensearch.sql.executor.execution.AbstractPlan;
+
+/**
+ * Default QueryManager implementation which execute {@link AbstractPlan} on caller thread.
+ */
+public class DefaultQueryManager implements QueryManager {
+
+  @Override
+  public QueryId submit(AbstractPlan queryExecution) {
+    queryExecution.execute();
+
+    return queryExecution.getQueryId();
+  }
+}

core/src/main/java/org/opensearch/sql/executor/QueryId.java

@@ -0,0 +1,36 @@
+/*
+ * 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.sql.executor;
+
+import lombok.Getter;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.opensearch.sql.executor.execution.AbstractPlan;
+
+/**
+ * Query id of {@link AbstractPlan}.
+ */
+public class QueryId {
+  /**
+   * Query id.
+   */
+  @Getter
+  private final String queryId;
+
+  /**
+   * Generate {@link QueryId}.
+   * @return {@link QueryId}.
+   */
+  public static QueryId queryId() {
+    return new QueryId(RandomStringUtils.random(10, true, true));
+  }
+
+  private QueryId(String queryId) {
+    this.queryId = queryId;
+  }
+}

core/src/main/java/org/opensearch/sql/executor/QueryManager.java

@@ -0,0 +1,25 @@
+/*
+ * 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.sql.executor;
+
+import org.opensearch.sql.executor.execution.AbstractPlan;
+
+/**
+ * QueryManager is the high-level interface of core engine.
+ * Frontend submit {@link AbstractPlan} to QueryManager.
+ */
+public interface QueryManager {
+
+  /**
+   * Submit {@link AbstractPlan}.
+   * @param queryPlan {@link AbstractPlan}.
+   * @return {@link QueryId}.
+   */
+  QueryId submit(AbstractPlan queryPlan);
+}

core/src/main/java/org/opensearch/sql/executor/QueryService.java

@@ -0,0 +1,70 @@
+/*
+ * 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.sql.executor;
+
+import lombok.RequiredArgsConstructor;
+import org.opensearch.sql.analysis.AnalysisContext;
+import org.opensearch.sql.analysis.Analyzer;
+import org.opensearch.sql.ast.tree.UnresolvedPlan;
+import org.opensearch.sql.common.response.ResponseListener;
+import org.opensearch.sql.planner.Planner;
+import org.opensearch.sql.planner.logical.LogicalPlan;
+import org.opensearch.sql.planner.physical.PhysicalPlan;
+
+/**
+ * The low level interface of core engine.
+ */
+@RequiredArgsConstructor
+public class QueryService {
+
+  private final Analyzer analyzer;
+
+  private final ExecutionEngine executionEngine;
+
+  private final Planner planner;
+
+  /**
+   * Execute the {@link UnresolvedPlan}, using {@link ResponseListener} to get response.
+   *
+   * @param plan  {@link UnresolvedPlan}
+   * @param listener {@link ResponseListener}
+   */
+  public void execute(UnresolvedPlan plan,
+                      ResponseListener<ExecutionEngine.QueryResponse> listener) {
+    try {
+      executionEngine.execute(plan(plan), listener);
+    } catch (Exception e) {
+      listener.onFailure(e);
+    }
+  }
+
+  /**
+   * Explain the query in {@link UnresolvedPlan} using {@link ResponseListener} to
+   * get and format explain response.
+   *
+   * @param plan {@link UnresolvedPlan}
+   * @param listener {@link ResponseListener} for explain response
+   */
+  public void explain(UnresolvedPlan plan,
+                      ResponseListener<ExecutionEngine.ExplainResponse> listener) {
+    try {
+      executionEngine.explain(plan(plan), listener);
+    } catch (Exception e) {
+      listener.onFailure(e);
+    }
+  }
+
+  private PhysicalPlan plan(UnresolvedPlan plan) {
+    // 1.Analyze abstract syntax to generate logical plan
+    LogicalPlan logicalPlan = analyzer.analyze(plan, new AnalysisContext());
+
+    // 2.Generate optimal physical plan from logical plan
+    return planner.plan(logicalPlan);
+  }
+}

core/src/main/java/org/opensearch/sql/executor/execution/AbstractPlan.java

@@ -0,0 +1,41 @@
+/*
+ * 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.sql.executor.execution;
+
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.opensearch.sql.common.response.ResponseListener;
+import org.opensearch.sql.executor.ExecutionEngine;
+import org.opensearch.sql.executor.QueryId;
+
+/**
+ * AbstractPlan represent the execution entity of the Statement.
+ */
+@RequiredArgsConstructor
+public abstract class AbstractPlan {
+
+  /**
+   * Uniq query id.
+   */
+  @Getter
+  private final QueryId queryId;
+
+  /**
+   * Start query execution.
+   */
+  public abstract void execute();
+
+  /**
+   * Explain query execution.
+   *
+   * @param listener query explain response listener.
+   */
+  public abstract void explain(ResponseListener<ExecutionEngine.ExplainResponse> listener);
+}

core/src/main/java/org/opensearch/sql/executor/execution/ExplainPlan.java

@@ -0,0 +1,44 @@
+/*
+ * 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.sql.executor.execution;
+
+import org.opensearch.sql.common.response.ResponseListener;
+import org.opensearch.sql.executor.ExecutionEngine;
+import org.opensearch.sql.executor.QueryId;
+
+/**
+ * Explain plan.
+ */
+public class ExplainPlan extends AbstractPlan {
+
+  private final AbstractPlan plan;
+
+  private final ResponseListener<ExecutionEngine.ExplainResponse> explainListener;
+
+  /**
+   * Constructor.
+   */
+  public ExplainPlan(QueryId queryId,
+                     AbstractPlan plan,
+                     ResponseListener<ExecutionEngine.ExplainResponse> explainListener) {
+    super(queryId);
+    this.plan = plan;
+    this.explainListener = explainListener;
+  }
+
+  @Override
+  public void execute() {
+    plan.explain(explainListener);
+  }
+
+  @Override
+  public void explain(ResponseListener<ExecutionEngine.ExplainResponse> listener) {
+    throw new UnsupportedOperationException("explain query can not been explained.");
+  }
+}