Unified OpenSearch PPL Data Type

core/src/main/java/org/opensearch/sql/lang/LangSpec.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.lang;
+
+import static org.opensearch.sql.lang.LangSpec.LangType.PPL;
+
+import org.opensearch.sql.data.type.ExprType;
+
+/**
+ * Represents a language specification for query processing.
+ *
+ * <p>This interface defines basic methods for language-specific behaviors, such as determining the
+ * language type and mapping expression types to type names. Two language specifications are
+ * provided: SQL and PPL.
+ */
+public interface LangSpec {
+  /** Enumerates the supported language types. */
+  enum LangType {
+    /** SQL language specification. */
+    SQL,
+    /** PPL (Piped Processing Language) language specification. */
+    PPL
+  }
+
+  /** The default SQL language specification instance. */
+  LangSpec SQL_SPEC = new LangSpec() {};
+
+  /**
+   * Returns a language specification instance based on the provided language name.
+   *
+   * @param language the name of the language, case-insensitive.
+   * @return the PPL language specification if the language is PPL (ignoring case); otherwise, the
+   *     SQL language specification.
+   */
+  static LangSpec fromLanguage(String language) {
+    if (PPL.name().equalsIgnoreCase(language)) {
+      return PPLLangSpec.PPL_SPEC;
+    } else {
+      return SQL_SPEC;
+    }
+  }
+
+  /**
+   * Returns the language type of this specification.
+   *
+   * <p>By default, the language is considered SQL.
+   *
+   * @return the language type, SQL by default.
+   */
+  default LangType language() {
+    return LangType.SQL;
+  }
+
+  /**
+   * Returns the type name for the given expression type.
+   *
+   * <p>This default implementation returns the result of {@code exprType.typeName()}.
+   *
+   * @param exprType the expression type.
+   * @return the type name of the expression.
+   */
+  default String typeName(ExprType exprType) {
+    return exprType.typeName();
+  }
+}

core/src/main/java/org/opensearch/sql/lang/PPLLangSpec.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.lang;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.opensearch.sql.data.type.ExprCoreType;
+import org.opensearch.sql.data.type.ExprType;
+
+/**
+ * PPL language specification implementation.
+ *
+ * <p>This class provides a singleton implementation of {@link LangSpec} for PPL. It defines a
+ * custom mapping from expression types to PPL type names.
+ */
+public class PPLLangSpec implements LangSpec {
+
+  public static final PPLLangSpec PPL_SPEC = new PPLLangSpec();
+
+  private static Map<ExprType, String> exprTypeToPPLType = new HashMap<>();
+
+  static {
+    exprTypeToPPLType.put(ExprCoreType.BYTE, "tinyint");
+    exprTypeToPPLType.put(ExprCoreType.SHORT, "smallint");
+    exprTypeToPPLType.put(ExprCoreType.INTEGER, "int");
+    exprTypeToPPLType.put(ExprCoreType.LONG, "bigint");
+  }
+
+  private PPLLangSpec() {}
+
+  @Override
+  public LangType language() {
+    return LangType.PPL;
+  }
+
+  /**
+   * Returns the corresponding PPL type name for the given expression type. If the expression type
+   * is not mapped, it returns the default type name.
+   *
+   * @param exprType the expression type.
+   * @return the PPL type name associated with the expression type, or the default type name.
+   */
+  @Override
+  public String typeName(ExprType exprType) {
+    return exprTypeToPPLType.getOrDefault(exprType, exprType.typeName());
+  }
+}

core/src/main/java/org/opensearch/sql/utils/SystemIndexUtils.java

@@ -8,6 +8,7 @@
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import lombok.experimental.UtilityClass;
+import org.opensearch.sql.lang.LangSpec;
 
 /** System Index Utils. Todo. Find the better name for this class. */
 @UtilityClass
@@ -39,7 +40,47 @@ public static Boolean isSystemIndex(String indexName) {
    * @return system mapping table.
    */
   public static String mappingTable(String indexName) {
-    return String.join(".", indexName, SYS_MAPPINGS_SUFFIX);
+    return mappingTable(indexName, LangSpec.SQL_SPEC);
+  }
+
+  public static String mappingTable(String indexName, LangSpec langSpec) {
+
+    return String.join(".", indexName, encodeLangSpec(langSpec));
+  }
+
+  /**
+   * Encodes the language specification into a system mappings suffix.
+   *
+   * <p>The returned suffix is composed of the language name (e.g., "SQL" or "PPL") concatenated
+   * with an underscore and the system mappings suffix constant. For example:
+   * "SQL_MAPPINGS_ODFE_SYS_TABLE".
+   *
+   * @param spec the language specification.
+   * @return the encoded system mappings suffix.
+   */
+  public static String encodeLangSpec(LangSpec spec) {
+    return spec.language().name() + "_" + SYS_MAPPINGS_SUFFIX;
+  }
+
+  /**
+   * Extracts the language specification from a given system mappings suffix.
+   *
+   * <p>This method expects the suffix to start with the language name followed by an underscore.
+   * For example, given "SQL_MAPPINGS_ODFE_SYS_TABLE", it extracts "SQL" and returns the
+   * corresponding language specification via {@link LangSpec#fromLanguage(String)}. If the expected
+   * format is not met, the default SQL specification is returned.
+   *
+   * @param systemMappingsSuffix the system mappings suffix.
+   * @return the language specification extracted from the suffix, or {@link LangSpec#SQL_SPEC} if
+   *     the format is invalid.
+   */
+  public static LangSpec extractLangSpec(String systemMappingsSuffix) {
+    int underscoreIndex = systemMappingsSuffix.indexOf('_');
+    if (underscoreIndex <= 0) {
+      return LangSpec.SQL_SPEC;
+    }
+    String langName = systemMappingsSuffix.substring(0, underscoreIndex);
+    return LangSpec.fromLanguage(langName);
   }
 
   /**
@@ -52,10 +93,10 @@ public static SystemTable systemTable(String indexName) {
     String suffix = indexName.substring(lastDot + 1);
     String tableName = indexName.substring(0, lastDot).replace("%", "*");
 
-    if (suffix.equalsIgnoreCase(SYS_META_SUFFIX)) {
+    if (suffix.endsWith(SYS_META_SUFFIX)) {
       return new SystemInfoTable(tableName);
-    } else if (suffix.equalsIgnoreCase(SYS_MAPPINGS_SUFFIX)) {
-      return new MetaInfoTable(tableName);
+    } else if (suffix.endsWith(SYS_MAPPINGS_SUFFIX)) {
+      return new MetaInfoTable(tableName, extractLangSpec(suffix));
     } else {
       throw new IllegalStateException("Invalid system index name: " + indexName);
     }
@@ -66,6 +107,10 @@ public interface SystemTable {
 
     String getTableName();
 
+    default LangSpec getLangSpec() {
+      return LangSpec.SQL_SPEC;
+    }
+
     default boolean isSystemInfoTable() {
       return false;
     }
@@ -93,6 +138,7 @@ public boolean isSystemInfoTable() {
   public static class MetaInfoTable implements SystemTable {
 
     private final String tableName;
+    private final LangSpec langSpec;
 
     public boolean isMetaInfoTable() {
       return true;

core/src/test/java/org/opensearch/sql/lang/LangSpecTest.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.lang;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.opensearch.sql.data.type.ExprCoreType;
+
+class LangSpecTest {
+  @Test
+  public void testFromLanguageSQL() {
+    LangSpec spec = LangSpec.fromLanguage("SQL");
+    assertEquals(LangSpec.LangType.SQL, spec.language(), "Expected language type to be SQL");
+    assertSame(LangSpec.SQL_SPEC, spec, "Expected SQL_SPEC instance for SQL language.");
+  }
+
+  @Test
+  public void testSQLSpecDefaultTypeName() {
+    String result = LangSpec.SQL_SPEC.typeName(ExprCoreType.BYTE);
+    assertEquals("BYTE", result, "SQL_SPEC should return the expression type's default type name.");
+  }
+}

core/src/test/java/org/opensearch/sql/lang/PPLLangSpecTest.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.lang;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.opensearch.sql.lang.PPLLangSpec.PPL_SPEC;
+
+import org.junit.jupiter.api.Test;
+import org.opensearch.sql.data.type.ExprCoreType;
+
+class PPLLangSpecTest {
+  /** Tests that the language type of the PPL specification is PPL. */
+  @Test
+  public void testPPLSpecLanguage() {
+    PPLLangSpec spec = PPL_SPEC;
+    assertEquals(LangSpec.LangType.PPL, spec.language(), "Expected language to be PPL.");
+  }
+
+  /**
+   * Tests that the PPL specification returns the correct type name mapping for known expression
+   * types. Assumes that ExprCoreType constants are available.
+   */
+  @Test
+  public void testPPLSpecTypeNameMapping() {
+    PPLLangSpec spec = PPL_SPEC;
+    assertEquals("tinyint", spec.typeName(ExprCoreType.BYTE), "BYTE should map to tinyint.");
+    assertEquals("smallint", spec.typeName(ExprCoreType.SHORT), "SHORT should map to smallint.");
+    assertEquals("int", spec.typeName(ExprCoreType.INTEGER), "INTEGER should map to int.");
+    assertEquals("bigint", spec.typeName(ExprCoreType.LONG), "LONG should map to bigint.");
+  }
+
+  /**
+   * Tests that an unmapped expression type returns its default type name in the PPL specification.
+   */
+  @Test
+  public void testPPLSpecDefaultTypeName() {
+    String result = PPL_SPEC.typeName(ExprCoreType.STRING);
+    assertEquals("STRING", result, "Unmapped expression type should return its default type name.");
+  }
+}

core/src/test/java/org/opensearch/sql/utils/SystemIndexUtilsTest.java

@@ -14,6 +14,8 @@
 import static org.opensearch.sql.utils.SystemIndexUtils.systemTable;
 
 import org.junit.jupiter.api.Test;
+import org.opensearch.sql.lang.LangSpec;
+import org.opensearch.sql.lang.PPLLangSpec;
 
 class SystemIndexUtilsTest {
 
@@ -25,7 +27,7 @@ void test_system_index() {
 
   @Test
   void test_compose_mapping_table() {
-    assertEquals("employee.MAPPINGS_ODFE_SYS_TABLE", mappingTable("employee"));
+    assertEquals("employee.SQL_MAPPINGS_ODFE_SYS_TABLE", mappingTable("employee"));
   }
 
   @Test
@@ -61,4 +63,50 @@ void throw_exception_for_invalid_index() {
         assertThrows(IllegalStateException.class, () -> systemTable("employee._ODFE_SYS_TABLE"));
     assertEquals("Invalid system index name: employee._ODFE_SYS_TABLE", exception.getMessage());
   }
+
+  /** Tests that encoding the SQL specification produces the expected suffix. */
+  @Test
+  public void testEncodeLangSpecSQL() {
+    String expected = "SQL_MAPPINGS_ODFE_SYS_TABLE";
+    String encoded = SystemIndexUtils.encodeLangSpec(LangSpec.SQL_SPEC);
+    assertEquals(expected, encoded, "Encoded SQL lang spec should match expected suffix.");
+  }
+
+  /** Tests that encoding the PPL specification produces the expected suffix. */
+  @Test
+  public void testEncodeLangSpecPPL() {
+    String expected = "PPL_MAPPINGS_ODFE_SYS_TABLE";
+    String encoded = SystemIndexUtils.encodeLangSpec(PPLLangSpec.PPL_SPEC);
+    assertEquals(expected, encoded, "Encoded PPL lang spec should match expected suffix.");
+  }
+
+  /** Tests that extracting the language specification from a valid SQL suffix returns SQL_SPEC. */
+  @Test
+  public void testExtractLangSpecValidSQL() {
+    LangSpec spec = SystemIndexUtils.extractLangSpec("SQL_MAPPINGS_ODFE_SYS_TABLE");
+    assertEquals(LangSpec.SQL_SPEC, spec, "Extracting from SQL suffix should return SQL_SPEC.");
+  }
+
+  /** Tests that extracting the language specification from a valid PPL suffix returns PPL_SPEC. */
+  @Test
+  public void testExtractLangSpecValidPPL() {
+    LangSpec spec = SystemIndexUtils.extractLangSpec("PPL_MAPPINGS_ODFE_SYS_TABLE");
+    assertEquals(PPLLangSpec.PPL_SPEC, spec, "Extracting from PPL suffix should return PPL_SPEC.");
+  }
+
+  /** Tests that an improperly formatted suffix defaults to SQL_SPEC. */
+  @Test
+  public void testExtractLangSpecInvalidFormat() {
+    assertEquals(
+        LangSpec.SQL_SPEC,
+        SystemIndexUtils.extractLangSpec("FORMAT"),
+        "Invalid format should default to SQL_SPEC.");
+  }
+
+  @Test
+  public void testGetLangSpec() {
+    assertEquals(
+        LangSpec.SQL_SPEC,
+        new SystemIndexUtils.SystemInfoTable("employee.MAPPINGS_ODFE_SYS_TABLE").getLangSpec());
+  }
 }