refactor(cli): Improve CLI commands with better error handling and output formatting

clients/cli/src/main/java/org/apache/gravitino/cli/commands/CatalogAudit.java

@@ -53,12 +53,20 @@ public void handle() {
       result = client.loadCatalog(this.catalog);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
+      return; // Stop execution after handling error
     } catch (NoSuchCatalogException err) {
       exitWithError(ErrorMessages.UNKNOWN_CATALOG);
+      return; // Stop execution after handling error
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
+      return; // Stop execution after handling error
     }
 
-    displayAuditInfo(result.auditInfo());
+    // **Null check before accessing auditInfo()**
+    if (result != null && result.auditInfo() != null) {
+      displayAuditInfo(result.auditInfo());
+    } else {
+      exitWithError("Audit information is not available for this catalog.");
+    }
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/CreateTable.java

@@ -82,27 +82,47 @@ public void handle() {
       client = buildClient(metalake);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
+      return; // Stop execution
     } catch (Exception exp) {
       exitWithError("Error initializing client or table name: " + exp.getMessage());
+      return;
+    }
+
+    if (client == null) {
+      exitWithError("Client initialization failed.");
+      return;
     }
 
     try {
       tableData = readTableCSV.parse(columnFile);
       columns = readTableCSV.columns(tableData);
+      if (columns == null || columns.length == 0) {
+        exitWithError("No valid columns found in the provided file.");
+        return;
+      }
     } catch (Exception exp) {
       exitWithError("Error reading or parsing column file: " + exp.getMessage());
+      return;
     }
 
     try {
+      if (tableName == null) {
+        exitWithError("Table name could not be determined.");
+        return;
+      }
       client.loadCatalog(catalog).asTableCatalog().createTable(tableName, columns, comment, null);
     } catch (NoSuchCatalogException err) {
       exitWithError(ErrorMessages.UNKNOWN_CATALOG);
+      return;
     } catch (NoSuchSchemaException err) {
       exitWithError(ErrorMessages.UNKNOWN_SCHEMA);
+      return;
     } catch (TableAlreadyExistsException err) {
       exitWithError(ErrorMessages.TABLE_EXISTS);
+      return;
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
+      return;
     }
 
     printInformation(table + " created");

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListCatalogProperties.java

@@ -50,18 +50,30 @@ public ListCatalogProperties(CommandContext context, String metalake, String cat
   @Override
   public void handle() {
     Catalog gCatalog = null;
-    try {
-      GravitinoClient client = buildClient(metalake);
+
+    try (GravitinoClient client = buildClient(metalake)) { // Ensures client is closed
       gCatalog = client.loadCatalog(catalog);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
+      return;
     } catch (NoSuchCatalogException err) {
       exitWithError(ErrorMessages.UNKNOWN_CATALOG);
+      return;
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
+      return;
+    }
+
+    if (gCatalog == null) { // Null check before accessing properties
+      exitWithError("Failed to load catalog.");
+      return;
     }
 
     Map<String, String> properties = gCatalog.properties();
+    if (properties == null || properties.isEmpty()) {
+      exitWithError("No properties found for the catalog.");
+      return;
+    }
     printProperties(properties);
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListColumns.java

@@ -59,10 +59,42 @@ public void handle() {
     } catch (NoSuchTableException noSuchTableException) {
       exitWithError(
           ErrorMessages.UNKNOWN_TABLE + Joiner.on(".").join(metalake, catalog, schema, table));
+      return;
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
+      return;
     }
 
-    printResults(columns);
+    // Null / empty check before processing columns
+    if (columns == null || columns.length == 0) {
+      exitWithError("No columns found for table: " + table);
+      return;
+    }
+
+    StringBuilder all = new StringBuilder();
+    all.append("name,datatype,comment,nullable,auto_increment").append(System.lineSeparator());
+
+    for (Column column : columns) {
+      if (column == null) continue; // Skip any unexpected null columns
+
+      String name = column.name();
+      String dataType = column.dataType() != null ? column.dataType().simpleString() : "UNKNOWN";
+      String comment = column.comment() != null ? column.comment() : "N/A";
+      String nullable = column.nullable() ? "true" : "false";
+      String autoIncrement = column.autoIncrement() ? "true" : "false";
+
+      all.append(name)
+          .append(",")
+          .append(dataType)
+          .append(",")
+          .append(comment)
+          .append(",")
+          .append(nullable)
+          .append(",")
+          .append(autoIncrement)
+          .append(System.lineSeparator());
+    }
+
+    printResults(all.toString());
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListFilesetProperties.java

@@ -19,6 +19,7 @@
 
 package org.apache.gravitino.cli.commands;
 
+import java.util.Collections;
 import java.util.Map;
 import org.apache.gravitino.NameIdentifier;
 import org.apache.gravitino.cli.CommandContext;
@@ -59,21 +60,40 @@ public ListFilesetProperties(
   @Override
   public void handle() {
     Fileset gFileset = null;
+    NameIdentifier name = null;
     try {
-      NameIdentifier name = NameIdentifier.of(schema, fileset);
-      GravitinoClient client = buildClient(metalake);
+      name = NameIdentifier.of(schema, fileset);
+    } catch (Exception exp) {
+      exitWithError("Invalid schema or fileset name: " + exp.getMessage());
+      return;
+    }
+    try (GravitinoClient client = buildClient(metalake)) {
       gFileset = client.loadCatalog(catalog).asFilesetCatalog().loadFileset(name);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
+      return;
     } catch (NoSuchCatalogException err) {
       exitWithError(ErrorMessages.UNKNOWN_CATALOG);
+      return;
     } catch (NoSuchSchemaException err) {
       exitWithError(ErrorMessages.UNKNOWN_SCHEMA);
+      return;
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
+      return;
+    }
+
+    // Null check for gFileset before accessing its properties
+    if (gFileset == null) {
+      exitWithError("Failed to load fileset: " + fileset);
+      return;
     }
 
     Map<String, String> properties = gFileset.properties();
+    // Use an empty map if properties is null to avoid NPE later on
+    if (properties == null) {
+      properties = Collections.emptyMap();
+    }
     printProperties(properties);
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListMetalakeProperties.java

@@ -45,18 +45,20 @@ public ListMetalakeProperties(CommandContext context, String metalake) {
   /** List the properties of a metalake. */
   @Override
   public void handle() {
-    Metalake gMetalake = null;
-    try {
-      GravitinoAdminClient client = buildAdminClient();
-      gMetalake = client.loadMetalake(metalake);
+    try (GravitinoAdminClient client = buildAdminClient()) { // Ensure resource cleanup
+      Metalake gMetalake = client.loadMetalake(metalake);
+
+      if (gMetalake == null) {
+        exitWithError("Metalake not found: " + metalake);
+        return;
+      }
+
+      Map<String, String> properties = gMetalake.properties();
+      printProperties(properties);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
     }
-
-    Map<String, String> properties = gMetalake.properties();
-
-    printProperties(properties);
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListSchemaProperties.java

@@ -54,10 +54,16 @@ public ListSchemaProperties(
   /** List the properties of a schema. */
   @Override
   public void handle() {
-    Schema gSchema = null;
-    try {
-      GravitinoClient client = buildClient(metalake);
-      gSchema = client.loadCatalog(catalog).asSchemas().loadSchema(schema);
+    try (GravitinoClient client = buildClient(metalake)) { // Ensure resource cleanup
+      Schema gSchema = client.loadCatalog(catalog).asSchemas().loadSchema(schema);
+
+      if (gSchema == null) {
+        exitWithError("Schema not found: " + schema);
+        return;
+      }
+
+      Map<String, String> properties = gSchema.properties();
+      printProperties(properties);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
     } catch (NoSuchCatalogException err) {
@@ -67,8 +73,5 @@ public void handle() {
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
     }
-
-    Map<String, String> properties = gSchema.properties();
-    printProperties(properties);
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListTableProperties.java

@@ -59,11 +59,17 @@ public ListTableProperties(
   /** List the properties of a table. */
   @Override
   public void handle() {
-    Table gTable = null;
-    try {
+    try (GravitinoClient client = buildClient(metalake)) { // Ensures resource cleanup
       NameIdentifier name = NameIdentifier.of(schema, table);
-      GravitinoClient client = buildClient(metalake);
-      gTable = client.loadCatalog(catalog).asTableCatalog().loadTable(name);
+      Table gTable = client.loadCatalog(catalog).asTableCatalog().loadTable(name);
+
+      if (gTable == null) {
+        exitWithError("Table not found: " + table);
+        return;
+      }
+
+      Map<String, String> properties = gTable.properties();
+      printProperties(properties);
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
     } catch (NoSuchCatalogException err) {
@@ -75,8 +81,5 @@ public void handle() {
     } catch (Exception exp) {
       exitWithError(exp.getMessage());
     }
-
-    Map<String, String> properties = gTable.properties();
-    printProperties(properties);
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListTables.java

@@ -47,43 +47,49 @@ public ListTables(CommandContext context, String metalake, String catalog, Strin
   /** List the names of all tables in a schema. */
   @Override
   public void handle() {
-    NameIdentifier[] tables = null;
-    Namespace name = Namespace.of(schema);
-
     try {
-      tables = tableCatalog().listTables(name);
-    } catch (Exception exp) {
-      exitWithError(exp.getMessage());
-    }
+      Namespace name = Namespace.of(schema);
+      NameIdentifier[] tables = tableCatalog().listTables(name);
 
-    if (tables.length == 0) {
-      printInformation("No tables exist.");
-      return;
-    }
+      if (tables == null || tables.length == 0) {
+        printInformation("No tables exist.");
+        return;
+      }
 
-    Table[] gTables = new Table[tables.length];
-    for (int i = 0; i < tables.length; i++) {
-      String tableName = tables[i].name();
-      gTables[i] =
-          new Table() {
+      Table[] gTables = new Table[tables.length];
+      for (int i = 0; i < tables.length; i++) {
+        String tableName = tables[i].name();
+        gTables[i] = createTableStub(tableName);
+      }
 
-            @Override
-            public String name() {
-              return tableName;
-            }
+      printResults(gTables);
+    } catch (Exception exp) {
+      exitWithError(exp.getMessage());
+    }
+  }
 
-            @Override
-            public Column[] columns() {
-              return new Column[0];
-            }
+  /**
+   * Creates a stub Table instance with only the table name.
+   *
+   * @param tableName The name of the table.
+   * @return A minimal Table instance.
+   */
+  private Table createTableStub(String tableName) {
+    return new Table() {
+      @Override
+      public String name() {
+        return tableName;
+      }
 
-            @Override
-            public Audit auditInfo() {
-              return null;
-            }
-          };
-    }
+      @Override
+      public Column[] columns() {
+        return new Column[0]; // Empty columns since only table names are needed
+      }
 
-    printResults(gTables);
+      @Override
+      public Audit auditInfo() {
+        return null; // No audit info needed for listing tables
+      }
+    };
   }
 }

clients/cli/src/main/java/org/apache/gravitino/cli/commands/ListTagProperties.java

@@ -53,12 +53,22 @@ public void handle() {
     try {
       GravitinoClient client = buildClient(metalake);
       gTag = client.getTag(tag);
+
+      // Ensure tag exists before accessing properties
+      if (gTag == null) {
+        exitWithError(ErrorMessages.UNKNOWN_TAG);
+        return;
+      }
+
     } catch (NoSuchMetalakeException err) {
       exitWithError(ErrorMessages.UNKNOWN_METALAKE);
+      return;
     } catch (NoSuchTagException err) {
       exitWithError(ErrorMessages.UNKNOWN_TAG);
+      return;
     } catch (Exception exp) {
-      exitWithError(exp.getMessage());
+      exitWithError("An unexpected error occurred: " + exp.getMessage());
+      return;
     }
 
     Map<String, String> properties = gTag.properties();