Feature.java

/*-
 * #%L
 * JSQLParser library
 * %%
 * Copyright (C) 2004 - 2020 JSQLParser
 * %%
 * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
 * #L%
 */
package net.sf.jsqlparser.parser.feature;

import net.sf.jsqlparser.expression.Function;
import net.sf.jsqlparser.expression.JdbcNamedParameter;
import net.sf.jsqlparser.expression.JdbcParameter;
import net.sf.jsqlparser.expression.OracleHierarchicalExpression;
import net.sf.jsqlparser.expression.OracleHint;
import net.sf.jsqlparser.expression.operators.relational.SupportsOldOracleJoinSyntax;
import net.sf.jsqlparser.parser.AbstractJSqlParser;
import net.sf.jsqlparser.statement.Block;
import net.sf.jsqlparser.statement.Commit;
import net.sf.jsqlparser.statement.CreateFunctionalStatement;
import net.sf.jsqlparser.statement.DeclareStatement;
import net.sf.jsqlparser.statement.DescribeStatement;
import net.sf.jsqlparser.statement.ExplainStatement;
import net.sf.jsqlparser.statement.ResetStatement;
import net.sf.jsqlparser.statement.SetStatement;
import net.sf.jsqlparser.statement.ShowColumnsStatement;
import net.sf.jsqlparser.statement.ShowStatement;
import net.sf.jsqlparser.statement.TableMaintenanceStatement;
import net.sf.jsqlparser.statement.UseStatement;
import net.sf.jsqlparser.statement.alter.Alter;
import net.sf.jsqlparser.statement.alter.sequence.AlterSequence;
import net.sf.jsqlparser.statement.analyze.Analyze;
import net.sf.jsqlparser.statement.comment.Comment;
import net.sf.jsqlparser.statement.create.database.CreateDatabase;
import net.sf.jsqlparser.statement.create.function.CreateFunction;
import net.sf.jsqlparser.statement.create.index.CreateIndex;
import net.sf.jsqlparser.statement.create.procedure.CreateProcedure;
import net.sf.jsqlparser.statement.create.schema.CreateSchema;
import net.sf.jsqlparser.statement.create.sequence.CreateSequence;
import net.sf.jsqlparser.statement.create.synonym.CreateSynonym;
import net.sf.jsqlparser.statement.create.table.CreateTable;
import net.sf.jsqlparser.statement.create.view.AlterView;
import net.sf.jsqlparser.statement.create.view.CreateView;
import net.sf.jsqlparser.statement.delete.Delete;
import net.sf.jsqlparser.statement.drop.Drop;
import net.sf.jsqlparser.statement.execute.Execute;
import net.sf.jsqlparser.statement.grant.Grant;
import net.sf.jsqlparser.statement.merge.Merge;
import net.sf.jsqlparser.statement.refresh.RefreshMaterializedViewStatement;
import net.sf.jsqlparser.statement.select.Fetch;
import net.sf.jsqlparser.statement.select.First;
import net.sf.jsqlparser.statement.select.KSQLWindow;
import net.sf.jsqlparser.statement.select.Limit;
import net.sf.jsqlparser.statement.select.Offset;
import net.sf.jsqlparser.statement.select.OptimizeFor;
import net.sf.jsqlparser.statement.select.Pivot;
import net.sf.jsqlparser.statement.select.PivotXml;
import net.sf.jsqlparser.statement.select.Skip;
import net.sf.jsqlparser.statement.select.TableFunction;
import net.sf.jsqlparser.statement.select.Top;
import net.sf.jsqlparser.statement.select.UnPivot;
import net.sf.jsqlparser.statement.show.*;
import net.sf.jsqlparser.statement.truncate.Truncate;
import net.sf.jsqlparser.statement.update.Update;
import net.sf.jsqlparser.statement.upsert.Upsert;

public enum Feature {

    // SQL KEYWORD FEATURES
    /**
     * "SELECT"
     */
    select,
    /** Structured FROM row pattern recognition. */
    matchRecognize,
    /** BigQuery longest-match option. */
    matchRecognizeOptions,
    /**
     * "GROUP BY"
     */
    selectGroupBy,
    /** Explicit ASC/DESC on GROUP BY items in legacy MySQL. */
    selectGroupByOrdering,
    /**
     * "GROUPING SETS"
     */
    selectGroupByGroupingSets,
    /**
     * "HAVING"
     */
    selectHaving,
    /**
     * "INTO table(, table)*"
     */
    selectInto,

    /**
     * @see Limit
     */
    limit,
    /**
     * "LIMIT NULL"
     *
     * @see Limit#isLimitNull()
     */
    limitNull,
    /**
     * "LIMIT ALL"
     *
     * @see Limit#isLimitAll()
     */
    limitAll,
    /**
     * "LIMIT offset, limit"
     *
     * @see Limit#getOffset()
     */
    limitOffset,
    /**
     * "OFFSET offset"
     *
     * @see Offset
     */
    offset,
    /**
     * "OFFSET offset param" where param is ROW | ROWS
     *
     * @see Offset#getOffsetParam()
     */
    offsetParam,

    /**
     * @see Fetch
     */
    fetch,
    /**
     * "FETCH FIRST row_count (ROW | ROWS) ONLY"
     *
     * @see Fetch#isFetchParamFirst()
     */
    fetchFirst,
    /**
     * "FETCH NEXT row_count (ROW | ROWS) ONLY" if not {@link #fetchFirst}
     *
     * @see Fetch#isFetchParamFirst()
     */
    fetchNext,

    /**
     * "JOIN"
     */
    join,
    /**
     * join tables by ", OUTER" placing the join specification in WHERE-clause
     */
    joinOuterSimple,
    /**
     * join tables by "," placing the join specification in WHERE-clause
     */
    joinSimple,
    /**
     * "RIGHT" join
     */
    joinRight,
    /**
     * "NATURAL" join
     */
    joinNatural,
    /**
     * "FULL" join
     */
    joinFull,
    /**
     * "LEFT" join
     */
    joinLeft,
    /**
     * "CROSS" join
     */
    joinCross,
    /**
     * "OUTER" join
     */
    joinOuter,
    /**
     * "SEMI" join
     */
    joinSemi,
    /**
     * @see net.sf.jsqlparser.statement.select.Join#isAnti()
     */
    joinAnti,
    /**
     * "INNER" join
     */
    joinInner,
    /**
     * "STRAIGHT_JOIN" join
     */
    joinStraight,
    /**
     * "APPLY" join
     */
    joinApply,

    /** Nearest-match ASOF join. */
    joinAsOf,

    joinWindow, joinUsingColumns,

    /**
     * "SKIP variable" | "SKIP ?" | "SKIP rowCount"
     *
     * @see Skip
     */
    skip,
    /**
     * "FIRST" \?|[0-9]+|variable or "LIMIT" \?|[0-9]+|variable
     *
     * @see First
     */
    first,
    /**
     * "TOP" ? "PERCENT"
     *
     * @see Top
     */
    top,
    /**
     * "OPTIMIZE FOR rowCount ROWS"
     *
     * @see OptimizeFor
     */
    optimizeFor,

    /**
     * "UNIQUE" keyword
     */
    selectUnique,
    /**
     * "DISTINCT" keyword
     */
    distinct,
    /**
     * "DISTINCT ON (col1, ...)"
     */
    distinctOn,

    /**
     * "ORDER BY"
     */
    orderBy,
    /**
     * "ORDER BY expression [ NULLS { FIRST | LAST } ]"
     */
    orderByNullOrdering,

    /**
     * "FOR UPDATE"
     */
    selectForUpdate,

    /**
     * "FOR SHARE"
     */
    selectForShare,

    /**
     * "FOR KEY SHARE"
     */
    selectForKeyShare,

    /**
     * "NO KEY UPDATE"
     */
    selectForNoKeyUpdate,

    /**
     * "FOR UPDATE OF table"
     */
    selectForUpdateOfTable,
    /**
     * "FOR UPDATE WAIT timeout"
     */
    selectForUpdateWait,
    /**
     * "FOR UPDATE NOWAIT"
     */
    selectForUpdateNoWait,
    /**
     * "FOR UPDATE SKIP LOCKED"
     */
    selectForUpdateSkipLocked,


    /**
     * SQL "INSERT" statement is allowed
     */
    insert,
    /**
     * "INSERT .. SELECT"
     */
    insertFromSelect,
    /**
     * "LOW_PRIORITY | DELAYED | HIGH_PRIORITY | IGNORE"
     */
    insertModifierPriority,
    /**
     * "IGNORE"
     */
    insertModifierIgnore,
    /**
     * "INSERT .. SET"
     */
    insertUseSet,
    /**
     * "ON DUPLICATE KEY UPDATE"
     */
    insertUseDuplicateKeyUpdate,
    /**
     * "RETURNING *"
     */
    insertReturningAll,
    /**
     * "RETURNING expr(, expr)*"
     *
     * @see net.sf.jsqlparser.expression.operators.relational.ExpressionList
     */
    insertReturningExpressionList,

    /**
     * "VALUES"
     */
    insertValues,
    /**
     * @see net.sf.jsqlparser.statement.select.Values
     */
    values,

    /**
     * SQL "TABLE table_name [ORDER BY column_name] [LIMIT number [OFFSET number]]“
     */
    tableStatement,

    /**
     * SQL "UPDATE" statement is allowed
     *
     * @see Update
     */
    update,

    /** Application-time FOR PORTION OF in UPDATE and DELETE. */
    forPortion,
    /**
     * "UPDATE table1 SET ... FROM table2
     */
    updateFrom,
    /**
     * "UPDATE table1, table2 ..."
     */
    updateJoins,
    /**
     * UPDATE table SET (col, ...) = (SELECT col, ... )"
     */
    updateUseSelect, updateOrderBy, updateLimit,
    /**
     * "RETURNING expr(, expr)*"
     *
     * @see net.sf.jsqlparser.statement.select.SelectItem
     */
    updateReturning,
    /**
     * SQL "DELETE" statement is allowed
     *
     * @see Delete
     */
    delete,
    /**
     * "DELETE FROM table1, table1 ..."
     */
    deleteJoin,
    /**
     * "DELETE table1, table1 FROM table ..."
     */
    deleteTables,
    /**
     * "LIMIT row_count"
     */
    deleteLimit,
    /**
     * "ORDER BY ..."
     */
    deleteOrderBy,
    /**
     * "RETURNING expr(, expr)*"
     *
     * @see net.sf.jsqlparser.statement.select.SelectItem
     */
    deleteReturningExpressionList,

    /**
     * SQL "UPSERT" statement is allowed
     *
     * @see Upsert
     * @see <a href=
     *      "https://wiki.postgresql.org/wiki/UPSERT">https://wiki.postgresql.org/wiki/UPSERT</a>
     */
    upsert,
    /**
     * SQL "MERGE" statement is allowed
     *
     * @see Merge
     */
    merge,

    /**
     * SQL "ALTER" statement is allowed
     *
     * @see Alter
     */
    alterTable,
    /**
     * SQL "ALTER SEQUENCE" statement is allowed
     *
     * @see AlterSequence
     */
    alterSequence,
    /**
     * SQL "ALTER VIEW" statement is allowed
     *
     * @see AlterView
     */
    alterView,

    /**
     * SQL "REFRESH MATERIALIZED VIEW" statement is allowed
     *
     * @see RefreshMaterializedViewStatement
     */
    refreshMaterializedView, refreshMaterializedWithDataView, refreshMaterializedWithNoDataView,

    /**
     * SQL "REPLACE VIEW" statement is allowed
     *
     * @see AlterView
     */
    alterViewReplace,
    /**
     * SQL "ALTER INDEX" statement is allowed
     */
    alterIndex,


    /**
     * SQL "ANALYZE" statement is allowed
     *
     * @see Analyze
     */
    analyze,

    /**
     * MySQL/MariaDB "CHECK TABLE", "OPTIMIZE TABLE" and "REPAIR TABLE" statements are allowed
     *
     * @see TableMaintenanceStatement
     */
    tableMaintenance,

    /**
     * SQL "TRUNCATE" statement is allowed
     *
     * @see Truncate
     */
    truncate,
    /**
     * SQL "CALL|EXEC|EXECUTE" stored procedure is allowed
     *
     * @see Execute
     */
    oracleBlock,

    execute, executeExec, executeCall, executeExecute, doStatement, insertBulk,

    /**
     * SQL "EXECUTE" statement is allowed
     */
    executeStatement,
    /**
     * SQL "EXECUTE IMMEDIATE" statement is allowed
     */
    executeStatementImmediate,

    executeUsing,
    /**
     * SQL "REPLACE" statement is allowed
     */
    @Deprecated
    replace,
    /**
     * SQL "DROP" statement is allowed
     *
     * @see Drop
     */
    drop, dropTable, dropIndex, dropView, dropSchema, dropSequence, dropTableIfExists, dropIndexIfExists, dropViewIfExists, dropSchemaIfExists, dropSequenceIfExists,

    /**
     * SQL "CREATE DATABASE" statement is allowed
     *
     * @see CreateDatabase
     */
    createDatabase,
    /**
     * SQL "CREATE SCHEMA" statement is allowed
     *
     * @see CreateSchema
     */
    createSchema,
    /** SQL ALTER SCHEMA rename and owner changes. */
    alterSchema,
    /**
     * SQL "CREATE VIEW" statement is allowed
     *
     * @see CreateView
     */
    createView,
    /**
     * "CREATE FORCE VIEW"
     */
    createViewForce,
    /**
     * "CREATE TEMPORARAY VIEW"
     */
    createViewTemporary,
    /**
     * "CREATE OR REPLACE VIEW"
     */
    createOrReplaceView,
    /**
     * SQL "CREATE MATERIALIZED VIEW" statement is allowed
     */
    createViewMaterialized,

    /**
     * SQL "CREATE VIEW(x comment 'x', y comment 'y') comment 'view'" statement is allowed
     */
    createViewWithComment,

    /**
     * SQL "CREATE TABLE" statement is allowed
     *
     * @see CreateTable
     */
    createTable,
    /**
     * "CREATE GLOBAL UNLOGGED"
     */
    createTableUnlogged,
    /**
     * i.e. "CREATE GLOBAL TEMPORARY TABLE", "CREATE SHARDED TABLE"
     */
    createTableCreateOptionStrings,
    /**
     * i.e. "ENGINE = InnoDB AUTO_INCREMENT = 8761 DEFAULT CHARSET = utf8"
     */
    createTableTableOptionStrings,
    /**
     * "CREATE TABLE IF NOT EXISTS table"
     */
    createTableIfNotExists,
    /**
     * " ROW MOVEMENT"
     */
    createTableRowMovement,
    /**
     * "CREATE TABLE (colspec) SELECT ...
     */
    createTableFromSelect,
    /**
     * SQL "CREATE INDEX" statement is allowed
     *
     * @see CreateIndex
     */
    createIndex,
    /**
     * SQL "CREATE SEQUENCE" statement is allowed
     *
     * @see CreateSequence
     */
    createSequence, createAccessMethod, createAccessMethodTable,
    /** Publication and subscription definitions. */
    createForeignDataWrapper, alterForeignDataWrapper, createServer, alterServer, createUserMapping, alterUserMapping,

    createRule, notifyStatement, createTextSearchConfiguration, alterTextSearchConfiguration, createCollation, alterCollation,

    createPublication, alterPublication, createSubscription, alterSubscription,
    /**
     * Structured type, domain and extension statements.
     */
    createType, alterType, createDomain, alterDomain, createExtension, alterExtension,
    /**
     * SQL "CREATE SYNONYM" statement is allowed
     *
     * @see CreateSynonym
     */
    createSynonym,
    /**
     * SQL "CREATE TRIGGER" statement is allowed
     */
    createTrigger,
    /**
     * SQL "COMMIT" statement is allowed
     *
     * @see Commit
     */
    commit,
    /** START TRANSACTION and dialect-specific BEGIN transaction statements. */
    startTransaction,
    /** RELEASE [SAVEPOINT] statements. */
    releaseSavepoint,
    /** Explicit AND [NO] CHAIN transaction completion. */
    transactionChain,
    /** Isolation level specified directly on BEGIN or START TRANSACTION. */
    transactionIsolationLevel,
    /** PostgreSQL [NOT] DEFERRABLE transaction characteristic. */
    transactionDeferrable,
    /** MySQL WITH CONSISTENT SNAPSHOT transaction characteristic. */
    transactionConsistentSnapshot,
    /**
     * SQL "COMMENT ON" statement is allowed
     *
     * @see Comment
     */
    comment,
    /**
     * "COMMENT ON table"
     */
    commentOnTable,
    /**
     * "COMMENT ON column"
     */
    commentOnColumn,
    /**
     * "COMMENT ON view"
     */
    commentOnView,

    /** Additional structured catalog targets of COMMENT ON. */
    commentOnIndex, commentOnSchema, commentOnSequence, commentOnDomain, commentOnType, commentOnMaterializedView, commentOnFunction, commentOnConstraint,

    /**
     * SQL "DESCRIBE" statement is allowed
     *
     * @see DescribeStatement
     */
    describe,

    /**
     * SQL "DESC" statement is allowed
     *
     * @see DescribeStatement
     */
    desc,

    /**
     * SQL "EXPLAIN" statement is allowed
     *
     * @see ExplainStatement
     */
    explain,
    /**
     * @see ShowStatement
     */
    show,
    /**
     * @see ShowTablesStatement
     */
    showTables,
    /**
     * @see ShowColumnsStatement
     */
    showColumns,
    /**
     * @see ShowIndexStatement
     */
    showIndex,
    /**
     * @see UseStatement
     */
    use,
    /** SQL Server session permission to insert explicit identity values into a table. */
    setIdentityInsert,
    /**
     * @see Grant
     */
    grant, revoke, createRole, alterRole, alterDefaultPrivileges,
    /**
     * MySQL/MariaDB account management: "ALTER USER", "RENAME USER", "SET ROLE", "SET DEFAULT ROLE"
     * and "SET PASSWORD"
     *
     * @see net.sf.jsqlparser.statement.alter.AlterUser
     * @see net.sf.jsqlparser.statement.alter.RenameUser
     * @see net.sf.jsqlparser.statement.SetRoleStatement
     * @see net.sf.jsqlparser.statement.SetDefaultRoleStatement
     * @see net.sf.jsqlparser.statement.SetPasswordStatement
     */
    alterUser, renameUser, setRole, setDefaultRole, setPassword,
    /**
     * @see Function
     */
    function,
    /**
     * @see CreateFunction
     */
    createFunction,
    /**
     * @see CreateProcedure
     */
    createProcedure,
    /**
     * @see CreateFunctionalStatement
     */
    functionalStatement,

    alterFunction, alterProcedure, createOrAlterRoutine,
    /**
     * SQL block starting with "BEGIN" and ends with "END" statement is allowed
     *
     * @see Block
     */
    block,
    /**
     * @see DeclareStatement
     */
    declare,

    /** SQL Server local table variables in queries and DML targets. */
    tableVariable,
    /**
     * @see SetStatement
     */
    set,
    /** PostgreSQL SET configuration_parameter TO value. */
    setAssignmentTo,
    /** SQL Server SET option [, option] ON | OFF. */
    sqlServerSetOptions,
    /**
     * @see ResetStatement
     */
    reset,
    /**
     * @see Pivot
     */
    pivot,
    /**
     * @see UnPivot
     */
    unpivot,
    /**
     * @see PivotXml
     */
    pivotXml,

    setOperation, setOperationUnion, setOperationIntersect, setOperationExcept, setOperationMinus,

    /**
     * "WITH name query"
     */
    withItem, withItemRecursive,

    lateralSubSelect,
    /**
     * @see net.sf.jsqlparser.statement.select.Values
     */
    valuesList,
    /**
     * @see TableFunction
     */
    tableFunction,

    // JDBC
    /**
     * @see JdbcParameter
     */
    jdbcParameter,
    /**
     * @see JdbcNamedParameter
     */
    jdbcNamedParameter,

    // EXPRESSIONS
    /**
     * "LIKE"
     */
    exprLike,
    /**
     * "SIMILAR TO"
     */
    exprSimilarTo,

    // VENDOR SPECIFIC SYNTAX FEATURES

    /**
     * @see KSQLWindow
     */
    kSqlWindow,

    // ORACLE

    /**
     * allows old oracle join syntax (+)
     *
     * @see SupportsOldOracleJoinSyntax
     */
    oracleOldJoinSyntax,
    /**
     * allows oracle prior position
     *
     * @see SupportsOldOracleJoinSyntax
     */
    oraclePriorPosition,
    /**
     * @see OracleHint
     */
    oracleHint,
    /**
     * oracle SQL "CONNECT BY"
     *
     * @see OracleHierarchicalExpression
     */
    oracleHierarchicalExpression, oracleOrderBySiblings,

    // MYSQL

    mySqlHintStraightJoin, mysqlSqlCacheFlag, mysqlCalcFoundRows, mysqlSelectModifiers,

    // SQLSERVER

    /**
     * "FOR XML PATH(...)"
     */
    selectForXmlPath,

    /**
     * allows square brackets for names, disabled by default
     */
    allowSquareBracketQuotation(false),

    /**
     * allow parsing of RDBMS specific syntax by switching off SQL Standard Compliant Syntax
     */
    allowPostgresSpecificSyntax(false),

    /** Enables legacy GROUP BY ordering with the MYSQL dialect; disabled by default. */
    allowLegacyMySqlGroupBy(false),

    /**
     * Target MySQL version for executable comments, encoded as major * 10000 + minor * 100 + patch.
     * A negative value leaves the version unspecified: conditional comments then fail instead of
     * silently discarding SQL. Only used with the MYSQL dialect; unversioned comments need no
     * value.
     */
    mySqlServerVersion(-1),

    // PERFORMANCE

    /**
     * allows complex expression parameters or named parameters for functions will be switched off,
     * when deep nesting of functions is detected
     */
    allowComplexParsing(true),

    /**
     * allows passing through Unsupported Statements as a plain List of Tokens needs to be switched
     * off, when VALIDATING statements or parsing blocks
     */
    allowUnsupportedStatements(false),

    timeOut(8000),

    /**
     * allows Backslash '\' as Escape Character
     */
    allowBackslashEscapeCharacter(false),

    /**
     * allows double quoted String Literals (BigQuery, Spark/Databricks, MySQL default sql_mode);
     * disabled by default, where double quotes stay quoted identifiers (ANSI SQL)
     */
    allowDoubleQuotedStrings(false),

    /**
     * Recognizes PostgreSQL $tag$...$tag$ literals; disabled by default to preserve unquoted
     * identifiers, enabled by the PostgreSQL dialect preset. Untagged $$ literals are unaffected.
     */
    allowDollarQuotedStringTags(false),

    /**
     * concatenates adjacent String Literals: NEWLINE when separated by whitespace with at least one
     * newline (the SQL standard and PostgreSQL), WHITESPACE across any whitespace (GoogleSQL,
     * Spark/Databricks); OFF by default, where the second literal stays an alias (MySQL, SQL
     * Server) or fails (everywhere else)
     */
    adjacentStringLiterals(AbstractJSqlParser.AdjacentStringLiterals.OFF),

    /**
     * allows MySQL `#` line comments; disabled by default, where a lone `#` stays the binary
     * operator (#2507: PostgreSQL bitwise XOR / geometric intersection)
     */
    allowHashLineComments(false),

    /**
     * treats three consecutive newlines as a statement separator (enabled by default). When
     * disabled, blank lines are plain whitespace, so a statement containing them is parsed whole
     * instead of ending, or failing to parse, at the first run of blank lines
     */
    allowBlankLinesAsStatementSeparator(true),

    /**
     * allows digit separators in numeric literals, e.g. {@code 1_000_000} (DuckDB, PostgreSQL 16);
     * disabled by default, where MySQL reads {@code 2024_01} as an identifier
     */
    allowDigitSeparators(false),

    /**
     * allows sub selects without parentheses, e.g. `select * from dual where 1 = select 1`
     */
    allowUnparenthesizedSubSelects(false),

    /**
     * maximum nesting depth for trying complex parsing, can bet set to -1 to ignore
     */
    allowedNestingDepth(10),

    dialect(null),

    /**
     * "IMPORT"
     */
    imprt,

    /**
     * "EXPORT"
     */
    export,

    /**
     * MySQL allows a ',' as a separator between key and value entries. We allow that by default,
     * but it can be disabled here
     */
    allowCommaAsKeyValueSeparator(true),

    /**
     * DB2 and Oracle allow Expressions as JSON_OBJECT key values. This clashes with Informix and
     * Snowflake Json-Extraction syntax
     */
    allowExpressionAsJsonObjectKey(false)

    ;

    private final Object value;
    private final boolean configurable;

    /**
     * a feature which can't configured within the parser
     */
    Feature() {
        this.value = null;
        this.configurable = false;
    }

    /**
     * a feature which can be configured by {@link FeatureConfiguration}
     *
     * @param value The Value Object of the Parameter.
     */
    Feature(Object value) {
        this.value = value;
        this.configurable = true;
    }

    public Object getDefaultValue() {
        return value;
    }

    public boolean isConfigurable() {
        return configurable;
    }

}