refactor(hive): remove retired Java agent

agents/drivers/hive/build.gradle

@@ -1,11 +0,0 @@
-dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'org.apache.hive:hive-jdbc:4.0.1:standalone'
-    implementation 'org.slf4j:slf4j-nop:1.7.30'
-}
-
-tasks.named('shadowJar') {
-    manifest {
-        attributes('Agent-Label': 'Apache Hive', 'Main-Class': 'com.dbx.agent.hive.HiveAgent')
-    }
-}

agents/drivers/hive/src/main/java/com/dbx/agent/hive/HiveAgent.java

@@ -1,293 +0,0 @@
-package com.dbx.agent.hive;
-
-import com.dbx.agent.AbstractJdbcAgent;
-import com.dbx.agent.ColumnInfo;
-import com.dbx.agent.ConnectParams;
-import com.dbx.agent.DatabaseInfo;
-import com.dbx.agent.ForeignKeyInfo;
-import com.dbx.agent.IndexInfo;
-import com.dbx.agent.JdbcIdentifiers;
-import com.dbx.agent.MultiSessionJsonRpcServer;
-import com.dbx.agent.TableInfo;
-import com.dbx.agent.TriggerInfo;
-import com.dbx.agent.ExecuteQueryOptions;
-import com.dbx.agent.QueryPageOptions;
-import com.dbx.agent.QueryPageResult;
-import com.dbx.agent.QueryResult;
-import java.sql.Connection;
-import java.sql.DatabaseMetaData;
-import java.sql.ResultSet;
-import java.sql.Statement;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.List;
-import java.util.Locale;
-
-public final class HiveAgent extends AbstractJdbcAgent {
-
-    @Override
-    protected String driverClass() {
-        return "org.apache.hive.jdbc.HiveDriver";
-    }
-
-    @Override
-    protected String buildJdbcUrl(ConnectParams params) {
-        return buildUrl(params);
-    }
-
-    @Override
-    public List<DatabaseInfo> listDatabases() {
-        return unchecked(() -> {
-            List<DatabaseInfo> result = new ArrayList<>();
-            try (java.sql.Statement stmt = requireConnected().createStatement();
-                 ResultSet rs = stmt.executeQuery("SHOW DATABASES")) {
-                while (rs.next()) {
-                    result.add(new DatabaseInfo(rs.getString(1)));
-                }
-            }
-            result.sort(Comparator.comparing(DatabaseInfo::getName));
-            return result;
-        });
-    }
-
-    @Override
-    public List<String> listSchemas() {
-        List<String> result = new ArrayList<>();
-        for (DatabaseInfo database : listDatabases()) {
-            result.add(database.getName());
-        }
-        return result;
-    }
-
-    @Override
-    public List<TableInfo> listTables(String schema) {
-        return unchecked(() -> {
-            List<TableInfo> result = new ArrayList<>();
-            useSchema(schema);
-            try (java.sql.Statement stmt = requireConnected().createStatement();
-                 ResultSet rs = stmt.executeQuery("SHOW TABLES")) {
-                while (rs.next()) {
-                    result.add(new TableInfo(rs.getString(1), "TABLE", null));
-                }
-            }
-            result.sort(Comparator.comparing(TableInfo::getName));
-            return result;
-        });
-    }
-
-    @Override
-    public List<ColumnInfo> getColumns(String schema, String table) {
-        return unchecked(() -> {
-            try {
-                return getColumnsFromDescribe(schema, table);
-            } catch (Exception ignored) {
-                return getColumnsFromMetadata(requireConnected(), schema, table);
-            }
-        });
-    }
-
-    @Override
-    public String getTableDdl(String schema, String table) {
-        return unchecked(() -> {
-            String qualifiedName = schema == null || schema.trim().isEmpty()
-                ? JdbcIdentifiers.INSTANCE.backtick(table)
-                : JdbcIdentifiers.INSTANCE.backtick(schema) + "." + JdbcIdentifiers.INSTANCE.backtick(table);
-            try (Statement stmt = requireConnected().createStatement();
-                 ResultSet rs = stmt.executeQuery("SHOW CREATE TABLE " + qualifiedName)) {
-                StringBuilder ddl = new StringBuilder();
-                while (rs.next()) {
-                    String line = rs.getString(1);
-                    if (line != null) {
-                        ddl.append(line).append('\n');
-                    }
-                }
-                return ddl.toString();
-            }
-        });
-    }
-
-    @Override
-    public List<IndexInfo> listIndexes(String schema, String table) {
-        return Collections.emptyList();
-    }
-
-    @Override
-    public List<ForeignKeyInfo> listForeignKeys(String schema, String table) {
-        return Collections.emptyList();
-    }
-
-    @Override
-    public List<TriggerInfo> listTriggers(String schema, String table) {
-        return Collections.emptyList();
-    }
-
-    @Override
-    public String setSchemaSQL(String schema) {
-        return "USE " + JdbcIdentifiers.INSTANCE.backtick(schema);
-    }
-
-    @Override
-    public QueryResult executeQuery(String sql, String schema, ExecuteQueryOptions options) {
-        // Hive JDBC fetches rows via Thrift FetchResults in batches controlled
-        // by fetchSize. A large fetchSize can fail with "Error retrieving next
-        // row" when the result contains large binary/struct columns. Use a
-        // small fetchSize (50) so each Thrift batch stays within limits.
-        return super.executeQuery(sql, schema, new ExecuteQueryOptions(
-            options.getMaxRows(),
-            50,
-            options.getTimeoutSecs()
-        ));
-    }
-
-    @Override
-    public QueryPageResult executeQueryPage(String sql, String schema, QueryPageOptions options) {
-        return super.executeQueryPage(sql, schema, withSmallFetchSize(options));
-    }
-
-    @Override
-    public QueryPageResult startTableRead(String sql, String schema, QueryPageOptions options) {
-        return super.startTableRead(sql, schema, withSmallFetchSize(options));
-    }
-
-    private static QueryPageOptions withSmallFetchSize(QueryPageOptions options) {
-        return new QueryPageOptions(
-            options.getPageSize(), 50, options.getMaxRows(), options.getTimeoutSecs()
-        );
-    }
-
-    @Override
-    protected Object resultValue(ResultSet rs, int index, int sqlType) {
-        return unchecked(() -> {
-            Object value = rs.getObject(index);
-            return rs.wasNull() ? null : value == null ? null : value.toString();
-        });
-    }
-
-    private void useSchema(String schema) throws Exception {
-        applySchemaContext(requireConnected(), schema);
-    }
-
-    private List<ColumnInfo> getColumnsFromDescribe(String schema, String table) throws Exception {
-        List<ColumnInfo> result = new ArrayList<>();
-        useSchema(schema);
-        try (java.sql.Statement stmt = requireConnected().createStatement();
-             ResultSet rs = stmt.executeQuery("DESCRIBE " + JdbcIdentifiers.INSTANCE.backtick(table))) {
-            while (rs.next()) {
-                String colName = trimToNull(rs.getString(1));
-                if (colName == null || colName.startsWith("#")) {
-                    continue;
-                }
-                result.add(new ColumnInfo(
-                    colName,
-                    trimToEmpty(rs.getString(2)),
-                    true,
-                    null,
-                    false,
-                    null,
-                    optionalComment(rs),
-                    null,
-                    null,
-                    null
-                ));
-            }
-        }
-        return result;
-    }
-
-    private static List<ColumnInfo> getColumnsFromMetadata(Connection conn, String schema, String table) throws Exception {
-        List<ColumnInfo> result = new ArrayList<>();
-        DatabaseMetaData meta = conn.getMetaData();
-        try (ResultSet rs = meta.getColumns(null, trimToNull(schema), table, "%")) {
-            while (rs.next()) {
-                String name = rs.getString("COLUMN_NAME");
-                if (trimToNull(name) == null) {
-                    continue;
-                }
-                result.add(new ColumnInfo(
-                    name,
-                    trimToEmpty(rs.getString("TYPE_NAME")),
-                    rs.getInt("NULLABLE") != DatabaseMetaData.columnNoNulls,
-                    rs.getString("COLUMN_DEF"),
-                    false,
-                    null,
-                    rs.getString("REMARKS"),
-                    intOrNull(rs, "COLUMN_SIZE"),
-                    intOrNull(rs, "DECIMAL_DIGITS"),
-                    characterLength(rs)
-                ));
-            }
-        }
-        return result;
-    }
-
-    static String buildUrl(ConnectParams params) {
-        String connectionString = trimToEmpty(params.getConnection_string());
-        if (!connectionString.isEmpty()) {
-            return connectionString;
-        }
-        String url = "jdbc:hive2://" + params.getHost() + ":" + params.getPort() + "/" + params.getDatabase();
-        return appendHiveUrlParams(url, params.getUrl_params());
-    }
-
-    private static String appendHiveUrlParams(String url, String urlParams) {
-        String params = trimHiveUrlParams(urlParams);
-        if (params.isEmpty()) {
-            return url;
-        }
-        // Hive JDBC authentication options use semicolon-separated URL properties.
-        return url + (url.endsWith(";") ? "" : ";") + params;
-    }
-
-    private static String trimHiveUrlParams(String urlParams) {
-        String value = trimToEmpty(urlParams);
-        while (value.startsWith("?") || value.startsWith("&") || value.startsWith(";")) {
-            value = value.substring(1);
-        }
-        return value;
-    }
-
-    private static String trimToNull(String value) {
-        if (value == null) {
-            return null;
-        }
-        String trimmed = value.trim();
-        return trimmed.isEmpty() ? null : trimmed;
-    }
-
-    private static String trimToEmpty(String value) {
-        return value == null ? "" : value.trim();
-    }
-
-    private static Integer intOrNull(ResultSet rs, String column) throws Exception {
-        Object value = rs.getObject(column);
-        return value instanceof Number ? ((Number) value).intValue() : null;
-    }
-
-    private static Integer characterLength(ResultSet rs) throws Exception {
-        String typeName = rs.getString("TYPE_NAME");
-        if (typeName == null) {
-            return null;
-        }
-        String normalized = typeName.toLowerCase(Locale.ROOT);
-        if (!normalized.contains("char") && !normalized.contains("text") && !normalized.contains("string")) {
-            return null;
-        }
-        return intOrNull(rs, "COLUMN_SIZE");
-    }
-
-    private static String optionalComment(ResultSet rs) {
-        return unchecked(() -> {
-            try {
-                String comment = trimToNull(rs.getString(3));
-                return comment;
-            } catch (Exception e) {
-                return null;
-            }
-        });
-    }
-
-    public static void main(String[] args) {
-        new MultiSessionJsonRpcServer(HiveAgent::new).run();
-    }
-}

agents/drivers/hive/src/test/java/com/dbx/agent/hive/HiveAgentExecutionTest.java

@@ -1,77 +0,0 @@
-package com.dbx.agent.hive;
-
-import com.dbx.agent.DatabaseAgent;
-import com.dbx.agent.ExecuteQueryOptions;
-import com.dbx.agent.QueryPageOptions;
-import com.dbx.agent.QueryResult;
-import com.dbx.agent.test.JdbcAgentFake;
-import com.dbx.agent.test.JdbcFakeExecutionBehaviorTest;
-import com.dbx.agent.test.TestSupport;
-import org.junit.jupiter.api.Test;
-
-import java.util.Arrays;
-import java.util.Collections;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-class HiveAgentExecutionTest extends JdbcFakeExecutionBehaviorTest {
-    @Override
-    protected DatabaseAgent createAgent() {
-        return new HiveAgent();
-    }
-
-    @Override
-    protected String resultSetSql() {
-        return "MSCK REPAIR TABLE sample";
-    }
-
-    // Override: HiveAgent.executeQuery forces fetchSize=50 to keep Thrift
-    // FetchResults batches small (prevents "Error retrieving next row" on
-    // tables with large binary/struct columns).
-    @Override
-    @Test
-    protected void executesNonSelectStatementsThatReturnResultSets() {
-        DatabaseAgent agent = createAgent();
-        TestSupport.setPrivateConnection(agent, JdbcAgentFake.connection());
-
-        QueryResult result = agent.executeQuery(resultSetSql(), null, new ExecuteQueryOptions());
-
-        assertEquals(Collections.singletonList("VALUE"), result.getColumns());
-        assertEquals(Collections.singletonList(Collections.singletonList("row-value")), result.getRows());
-        assertEquals(Arrays.asList("setMaxRows:10001", "setFetchSize:50", "execute"), JdbcAgentFake.calls);
-    }
-
-    @Override
-    @Test
-    protected void appliesExecutionRowAndFetchLimitsToJdbcStatements() {
-        DatabaseAgent agent = createAgent();
-        TestSupport.setPrivateConnection(agent, JdbcAgentFake.connection());
-
-        QueryResult result = agent.executeQuery(resultSetSql(), null, new ExecuteQueryOptions(1, 25));
-
-        assertEquals(Collections.singletonList(Collections.singletonList("row-value")), result.getRows());
-        assertEquals(Arrays.asList("setMaxRows:2", "setFetchSize:50", "execute"), JdbcAgentFake.calls);
-    }
-
-    @Override
-    @Test
-    protected void pagedQueryExecutionPassesCallerFetchSizeToStatement() {
-        DatabaseAgent agent = createAgent();
-        TestSupport.setPrivateConnection(agent, JdbcAgentFake.connection());
-
-        agent.executeQueryPage(resultSetSql(), null, new QueryPageOptions(100, 500, 1000));
-
-        assertEquals(Arrays.asList("setFetchSize:50", "execute"), JdbcAgentFake.calls);
-    }
-
-    @Override
-    @Test
-    protected void tableReadPassesCallerFetchSizeToStatement() {
-        DatabaseAgent agent = createAgent();
-        TestSupport.setPrivateConnection(agent, JdbcAgentFake.connection());
-
-        agent.startTableRead(resultSetSql(), null, new QueryPageOptions(100, 500, 1000));
-
-        assertEquals(Arrays.asList("setFetchSize:50", "execute"), JdbcAgentFake.calls);
-    }
-}

agents/drivers/hive/src/test/java/com/dbx/agent/hive/HiveAgentMetadataTest.java

@@ -1,186 +0,0 @@
-package com.dbx.agent.hive;
-
-import com.dbx.agent.test.TestSupport;
-import com.dbx.agent.test.JdbcMetadataSqlFake;
-import com.dbx.agent.ColumnInfo;
-import java.lang.reflect.InvocationHandler;
-import java.lang.reflect.Method;
-import java.lang.reflect.Proxy;
-import java.sql.Connection;
-import java.sql.DatabaseMetaData;
-import java.util.List;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.LinkedHashMap;
-import java.util.Map;
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
-
-class HiveAgentMetadataTest {
-    @Test
-    void quotesSchemaAndTableIdentifiersInMetadataSql() {
-        HiveAgent agent = new HiveAgent();
-        Connection fake = JdbcMetadataSqlFake.connection();
-        TestSupport.setPrivateConnection(agent, fake);
-
-        agent.listTables("bad`schema");
-        agent.getColumns("bad`schema", "bad`table");
-
-        Assertions.assertEquals(
-            List.of(
-                "USE `bad``schema`",
-                "SHOW TABLES",
-                "USE `bad``schema`",
-                "DESCRIBE `bad``table`"
-            ),
-            JdbcMetadataSqlFake.statements
-        );
-    }
-
-    @Test
-    void fallsBackToJdbcMetadataWhenDescribeCannotCreateResultSet() {
-        HiveAgent agent = new HiveAgent();
-        Connection fake = describeFailingMetadataConnection();
-        TestSupport.setPrivateConnection(agent, fake);
-
-        List<ColumnInfo> columns = agent.getColumns("default", "events");
-
-        Assertions.assertEquals(2, columns.size());
-        Assertions.assertEquals("id", columns.get(0).getName());
-        Assertions.assertEquals("bigint", columns.get(0).getData_type());
-        Assertions.assertFalse(columns.get(0).getIs_nullable());
-        Assertions.assertEquals("name", columns.get(1).getName());
-        Assertions.assertEquals("string", columns.get(1).getData_type());
-        Assertions.assertEquals(Integer.valueOf(255), columns.get(1).getCharacter_maximum_length());
-    }
-
-    private static Connection describeFailingMetadataConnection() {
-        DatabaseMetaData meta = proxy(DatabaseMetaData.class, (method, args) -> {
-            if ("getColumns".equals(method.getName())) {
-                return rows(
-                    row(
-                        "COLUMN_NAME", "id",
-                        "TYPE_NAME", "bigint",
-                        "NULLABLE", DatabaseMetaData.columnNoNulls,
-                        "COLUMN_DEF", null,
-                        "REMARKS", "identifier",
-                        "COLUMN_SIZE", 19,
-                        "DECIMAL_DIGITS", 0
-                    ),
-                    row(
-                        "COLUMN_NAME", "name",
-                        "TYPE_NAME", "string",
-                        "NULLABLE", DatabaseMetaData.columnNullable,
-                        "COLUMN_DEF", null,
-                        "REMARKS", null,
-                        "COLUMN_SIZE", 255,
-                        "DECIMAL_DIGITS", 0
-                    )
-                );
-            }
-            return defaultValue(method.getReturnType());
-        });
-        return proxy(Connection.class, (method, args) -> {
-            String name = method.getName();
-            if ("createStatement".equals(name)) {
-                return describeFailingStatement();
-            }
-            if ("getMetaData".equals(name)) {
-                return meta;
-            }
-            if ("isClosed".equals(name)) {
-                return false;
-            }
-            return defaultValue(method.getReturnType());
-        });
-    }
-
-    private static Statement describeFailingStatement() {
-        return proxy(Statement.class, (method, args) -> {
-            String name = method.getName();
-            if ("execute".equals(name)) {
-                return false;
-            }
-            if ("executeQuery".equals(name)) {
-                throw new SQLException("Could not create ResultSet: Required field 'type' is unset! Struct:TPrimitiveTypeEntry(type:null)");
-            }
-            return defaultValue(method.getReturnType());
-        });
-    }
-
-    @SafeVarargs
-    private static ResultSet rows(Map<String, Object>... rows) {
-        return proxy(ResultSet.class, new MethodHandler() {
-            private int index = -1;
-
-            @Override
-            public Object handle(Method method, Object[] args) {
-                String name = method.getName();
-                if ("next".equals(name)) {
-                    index += 1;
-                    return index < rows.length;
-                }
-                if ("close".equals(name)) {
-                    return null;
-                }
-                Object value = rows[index].get(args[0]);
-                if ("getString".equals(name)) {
-                    return value == null ? null : String.valueOf(value);
-                }
-                if ("getObject".equals(name)) {
-                    return value;
-                }
-                if ("getInt".equals(name)) {
-                    return value instanceof Number ? ((Number) value).intValue() : 0;
-                }
-                return defaultValue(method.getReturnType());
-            }
-        });
-    }
-
-    private static Map<String, Object> row(Object... values) {
-        Map<String, Object> row = new LinkedHashMap<>();
-        for (int i = 0; i < values.length; i += 2) {
-            row.put(String.valueOf(values[i]), values[i + 1]);
-        }
-        return row;
-    }
-
-    private static <T> T proxy(Class<T> type, MethodHandler handler) {
-        InvocationHandler invocationHandler = (proxy, method, args) -> handler.handle(method, args);
-        return type.cast(Proxy.newProxyInstance(type.getClassLoader(), new Class<?>[]{type}, invocationHandler));
-    }
-
-    private static Object defaultValue(Class<?> type) {
-        if (Boolean.TYPE.equals(type)) {
-            return false;
-        }
-        if (Byte.TYPE.equals(type)) {
-            return (byte) 0;
-        }
-        if (Short.TYPE.equals(type)) {
-            return (short) 0;
-        }
-        if (Integer.TYPE.equals(type)) {
-            return 0;
-        }
-        if (Long.TYPE.equals(type)) {
-            return 0L;
-        }
-        if (Float.TYPE.equals(type)) {
-            return 0f;
-        }
-        if (Double.TYPE.equals(type)) {
-            return 0.0d;
-        }
-        if (Character.TYPE.equals(type)) {
-            return '\0';
-        }
-        return null;
-    }
-
-    private interface MethodHandler {
-        Object handle(Method method, Object[] args) throws Throwable;
-    }
-}

agents/drivers/hive/src/test/java/com/dbx/agent/hive/HiveAgentTest.java

@@ -1,127 +0,0 @@
-package com.dbx.agent.hive;
-
-import com.dbx.agent.ConnectParams;
-import com.dbx.agent.test.TestSupport;
-import org.junit.jupiter.api.Test;
-
-import java.lang.reflect.InvocationHandler;
-import java.lang.reflect.Method;
-import java.lang.reflect.Proxy;
-import java.sql.Connection;
-import java.sql.ResultSet;
-import java.sql.Statement;
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-class HiveAgentTest {
-    @Test
-    void hiveJdbcStandaloneRuntimeClassesAreAvailable() throws ClassNotFoundException {
-        Class.forName("org.apache.hive.jdbc.HiveDriver");
-        Class.forName("org.apache.hive.org.apache.thrift.protocol.TProtocol");
-    }
-
-    @Test
-    void buildUrlAppendsKerberosUrlParams() {
-        ConnectParams params = new ConnectParams();
-        params.setHost("hive.example.com");
-        params.setPort(10000);
-        params.setDatabase("default");
-        params.setUrl_params(";principal=hive/hive.example.com@EXAMPLE.COM;auth=kerberos");
-
-        assertEquals(
-            "jdbc:hive2://hive.example.com:10000/default;principal=hive/hive.example.com@EXAMPLE.COM;auth=kerberos",
-            HiveAgent.buildUrl(params)
-        );
-    }
-
-    @Test
-    void buildUrlUsesCustomJdbcUrlAsIs() {
-        ConnectParams params = new ConnectParams();
-        params.setConnection_string(
-            "jdbc:hive2://zk1.example.com,zk2.example.com/default;serviceDiscoveryMode=zooKeeper;zooKeeperNamespace=hiveserver2;principal=hive/_HOST@EXAMPLE.COM"
-        );
-        params.setUrl_params("principal=hive/ignored@EXAMPLE.COM");
-
-        assertEquals(
-            "jdbc:hive2://zk1.example.com,zk2.example.com/default;serviceDiscoveryMode=zooKeeper;zooKeeperNamespace=hiveserver2;principal=hive/_HOST@EXAMPLE.COM",
-            HiveAgent.buildUrl(params)
-        );
-    }
-
-    @Test
-    void getTableDdlUsesHiveShowCreateTable() {
-        HiveAgent agent = new HiveAgent();
-        List<String> queries = new ArrayList<>();
-        String expectedDdl = "CREATE TABLE `hive_test`.`cleaned_data_table`(col string)\n"
-            + "ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe'\n"
-            + "LOCATION 'hdfs://warehouse/cleaned_data_table'";
-        ResultSet resultSet = proxy(ResultSet.class, new InvocationHandler() {
-            private int row = -1;
-
-            @Override
-            public Object invoke(Object proxy, Method method, Object[] args) {
-                if ("next".equals(method.getName())) {
-                    return ++row == 0;
-                }
-                if ("getString".equals(method.getName())) {
-                    return expectedDdl;
-                }
-                return defaultValue(method.getReturnType());
-            }
-        });
-        Statement statement = proxy(Statement.class, (proxy, method, args) -> {
-            if ("executeQuery".equals(method.getName())) {
-                queries.add((String) args[0]);
-                return resultSet;
-            }
-            return defaultValue(method.getReturnType());
-        });
-        Connection connection = proxy(Connection.class, (proxy, method, args) -> {
-            if ("createStatement".equals(method.getName())) {
-                return statement;
-            }
-            if ("isClosed".equals(method.getName())) {
-                return false;
-            }
-            return defaultValue(method.getReturnType());
-        });
-        TestSupport.setPrivateConnection(agent, connection);
-
-        assertEquals(expectedDdl + "\n", agent.getTableDdl("hive_test", "cleaned_data_table"));
-        assertEquals(List.of("SHOW CREATE TABLE `hive_test`.`cleaned_data_table`"), queries);
-    }
-
-    private static <T> T proxy(Class<T> type, InvocationHandler handler) {
-        return type.cast(Proxy.newProxyInstance(type.getClassLoader(), new Class<?>[]{type}, handler));
-    }
-
-    private static Object defaultValue(Class<?> type) {
-        if (type == boolean.class) {
-            return false;
-        }
-        if (type == int.class) {
-            return 0;
-        }
-        if (type == long.class) {
-            return 0L;
-        }
-        if (type == float.class) {
-            return 0F;
-        }
-        if (type == double.class) {
-            return 0D;
-        }
-        if (type == byte.class) {
-            return (byte) 0;
-        }
-        if (type == short.class) {
-            return (short) 0;
-        }
-        if (type == char.class) {
-            return '\0';
-        }
-        return null;
-    }
-}