Package adql.db

## Class DBChecker

- java.lang.Object
- - adql.db.DBChecker

- All Implemented Interfaces:
    `QueryChecker`

      public class DBChecker
      extends java.lang.Object
      implements QueryChecker

  This `QueryChecker` implementation is able to do the following verifications on an ADQL query:
  1. Check the existence of all table and column references found in a query
  2. Resolve all unknown functions as supported User Defined Functions (UDFs)
  3. Check whether all used geometrical functions are supported
  4. Check whether all used coordinate systems are supported
  5. Check that types of columns and UDFs match with their context

  ### Check tables and columns

  In addition to check the existence of tables and columns referenced in the query, this checked will also attach database metadata on these references (`ADQLTable` and `ADQLColumn` instances when they are resolved.

  These information are:

  - the corresponding `DBTable` or `DBColumn` (see getter and setter for DBLink in `ADQLTable` and `ADQLColumn`)
  - the link between an `ADQLColumn` and its `ADQLTable`

  Note: Knowing DB metadata of `ADQLTable` and `ADQLColumn` is particularly useful for the translation of the ADQL query to SQL, because the ADQL name of columns and tables can be replaced in SQL by their DB name, if different. This mapping is done automatically by `JDBCTranslator`.

  Version:
    1.4 (11/2017)
  Author:
    Grégory Mantelet (CDS;ARI)

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class | Description
    --- | --- | ---
    `protected static class` | `DBChecker.BinarySearch<T,​S>` | Implement the binary search algorithm over a sorted array.

  - ### Field Summary

    Fields
    Modifier and Type | Field | Description
    --- | --- | ---
    `protected java.lang.String[]` | `allowedCoordSys` | List of all allowed coordinate systems.
    `protected java.lang.String[]` | `allowedGeo` | List of all allowed geometrical functions (i.e.
    `protected FunctionDef[]` | `allowedUdfs` | List of all allowed User Defined Functions (UDFs).
    `protected java.lang.String` | `coordSysRegExp` | A regular expression built using the list of allowed coordinate systems.
    `protected SearchTableApi` | `lstTables` | List of all available tables (`DBTable`).

  - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `DBChecker()` | Builds a `DBChecker` with an empty list of tables.
    `DBChecker​(java.util.Collection<? extends DBTable> tables)` | Builds a `DBChecker` with the given list of known tables.
    `DBChecker​(java.util.Collection<? extends DBTable> tables, java.util.Collection<? extends FunctionDef> allowedUdfs)` | Builds a `DBChecker` with the given list of known tables and with a restricted list of user defined functions.
    `DBChecker​(java.util.Collection<? extends DBTable> tables, java.util.Collection<? extends FunctionDef> allowedUdfs, java.util.Collection<java.lang.String> allowedGeoFcts, java.util.Collection<java.lang.String> allowedCoordSys)` | Builds a `DBChecker`.
    `DBChecker​(java.util.Collection<? extends DBTable> tables, java.util.Collection<java.lang.String> allowedGeoFcts, java.util.Collection<java.lang.String> allowedCoordSys)` | Builds a `DBChecker` with the given list of known tables and with a restricted list of user defined functions.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `check​(ADQLQuery query)` | Check all the columns, tables and UDFs references inside the given query.
    `protected void` | `check​(ADQLQuery query, java.util.Stack<SearchColumnList> fathersList)` | Process several (semantic) verifications in the given ADQL query.
    `protected DBColumn` | `checkColumnReference​(ColumnReference colRef, ClauseSelect select, SearchColumnList dbColumns)` | Check whether the given column reference corresponds to a selected item (column or an expression with an alias) or to an existing column.
    `protected void` | `checkCoordinateSystem​(STCS.CoordSys coordSys, ADQLOperand operand, UnresolvedIdentifiersException errors)` | Check whether the given coordinate system is allowed by this implementation.
    `protected void` | `checkCoordinateSystem​(StringConstant adqlCoordSys, UnresolvedIdentifiersException errors)` | Parse and then check the coordinate system contained in the given `StringConstant` instance.
    `protected SearchColumnList` | `checkDBItems​(ADQLQuery query, java.util.Stack<SearchColumnList> fathersList, UnresolvedIdentifiersException errors)` | Check DB items (tables and columns) used in the given ADQL query.
    `protected void` | `checkGeometries​(ADQLQuery query, UnresolvedIdentifiersException errors)` | Check all geometries.
    `protected void` | `checkGeometryFunction​(java.lang.String fctName, ADQLFunction fct, DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch, UnresolvedIdentifiersException errors)` | Check whether the specified geometrical function is allowed by this implementation.
    `protected DBColumn` | `checkGroupByItem​(ADQLColumn col, ClauseSelect select, SearchColumnList dbColumns)` | Check whether the given column corresponds to a selected item's alias or to an existing column.
    `protected void` | `checkRegion​(STCS.Region r, RegionFunction fct, DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch, UnresolvedIdentifiersException errors)` | Check the given region.
    `protected void` | `checkSubQueries​(ADQLQuery query, java.util.Stack<SearchColumnList> fathersList, SearchColumnList availableColumns, UnresolvedIdentifiersException errors)` | Search all sub-queries found in the given query but not in the clause FROM.
    `protected void` | `checkTypes​(ADQLQuery query, UnresolvedIdentifiersException errors)` | Search all operands whose the type is not yet known and try to resolve it now and to check whether it matches the type expected by the syntactic parser.
    `protected void` | `checkUDFs​(ADQLQuery query, UnresolvedIdentifiersException errors)` | Search all UDFs (User Defined Functions) inside the given query, and then check their signature against the list of allowed UDFs.
    `static DBTable` | `generateDBTable​(ADQLQuery subQuery, java.lang.String tableName)` | Generate a `DBTable` corresponding to the given sub-query with the given table name.
    `protected boolean` | `isAllParamTypesResolved​(ADQLFunction fct)` | Tell whether the type of all parameters of the given ADQL function is resolved.
    `protected DBColumn` | `resolveColumn​(ADQLColumn column, SearchColumnList dbColumns, java.util.Stack<SearchColumnList> fathersList)` | Resolve the given column, that's to say search for the corresponding `DBColumn`.
    `protected void` | `resolveColumns​(ADQLQuery query, java.util.Stack<SearchColumnList> fathersList, java.util.Map<DBTable,​ADQLTable> mapTables, SearchColumnList list, UnresolvedIdentifiersException errors)` | Search all column references inside the given query, resolve them thanks to the given tables' metadata, and if there is only one match, attach the matching metadata to them.
    `protected void` | `resolveCoordinateSystems​(ADQLQuery query, UnresolvedIdentifiersException errors)` | Search all explicit coordinate system declarations, check their syntax and whether they are allowed by this implementation.
    `protected void` | `resolveGeometryFunctions​(ADQLQuery query, DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch, UnresolvedIdentifiersException errors)` | Search for all geometrical functions and check whether they are allowed.
    `protected void` | `resolveSTCSExpressions​(ADQLQuery query, DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch, UnresolvedIdentifiersException errors)` | Search all STC-S expressions inside the given query, parse them (and so check their syntax) and then determine whether the declared coordinate system and the expressed region are allowed in this implementation.
    `protected DBTable` | `resolveTable​(ADQLTable table)` | Resolve the given table, that's to say search for the corresponding `DBTable`.
    `protected java.util.Map<DBTable,​ADQLTable>` | `resolveTables​(ADQLQuery query, java.util.Stack<SearchColumnList> fathersList, UnresolvedIdentifiersException errors)` | Search all table references inside the given query, resolve them against the available tables, and if there is only one match, attach the matching metadata to them.
    `void` | `setTables​(java.util.Collection<? extends DBTable> tables)` | Sets the list of all available tables.
    `protected static java.lang.String[]` | `specialSort​(java.util.Collection<java.lang.String> items)` | Transform the given collection of string elements in a sorted array.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### lstTables

          protected SearchTableApi lstTables

      List of all available tables (`DBTable`).

    - #### allowedGeo

          protected java.lang.String[] allowedGeo

      List of all allowed geometrical functions (i.e. CONTAINS, REGION, POINT, COORD2, ...).

      If this list is NULL, all geometrical functions are allowed. However, if not, all items of this list must be the only allowed geometrical functions. So, if the list is empty, no such function is allowed.

      Since:
        1.3

    - #### allowedCoordSys

          protected java.lang.String[] allowedCoordSys

      List of all allowed coordinate systems.

      Each item of this list must be of the form: "{frame} {refpos} {flavor}". Each of these 3 items can be either of value, a list of values expressed with the syntax "({value1}|{value2}|...)" or a '*' to mean all possible values.

      Note: since a default value (corresponding to the empty string - '') should always be possible for each part of a coordinate system, the checker will always add the default value (UNKNOWNFRAME, UNKNOWNREFPOS or SPHERICAL2) into the given list of possible values for each coord. sys. part.

      If this list is NULL, all coordinates systems are allowed. However, if not, all items of this list must be the only allowed coordinate systems. So, if the list is empty, none is allowed.

      Since:
        1.3

    - #### coordSysRegExp

          protected java.lang.String coordSysRegExp

      A regular expression built using the list of allowed coordinate systems. With this regex, it is possible to known whether a coordinate system expression is allowed or not.

      If NULL, all coordinate systems are allowed.

      Since:
        1.3

    - #### allowedUdfs

          protected FunctionDef[] allowedUdfs

      List of all allowed User Defined Functions (UDFs).

      If this list is NULL, any encountered UDF will be allowed. However, if not, all items of this list must be the only allowed UDFs. So, if the list is empty, no UDF is allowed.

      Since:
        1.3

  - ### Constructor Detail

    - #### DBChecker

          public DBChecker()

      Builds a `DBChecker` with an empty list of tables.

      Verifications done by this object after creation:

      - Existence of tables and columns: NO (even unknown or fake tables and columns are allowed)
      - Existence of User Defined Functions (UDFs): NO (any "unknown" function is allowed)
      - Support of geometrical functions: NO (all valid geometrical functions are allowed)
      - Support of coordinate systems: NO (all valid coordinate systems are allowed)

    - #### DBChecker

          public DBChecker​(java.util.Collection<? extends DBTable> tables)

      Builds a `DBChecker` with the given list of known tables.

      Verifications done by this object after creation:

      - Existence of tables and columns: OK
      - Existence of User Defined Functions (UDFs): NO (any "unknown" function is allowed)
      - Support of geometrical functions: NO (all valid geometrical functions are allowed)
      - Support of coordinate systems: NO (all valid coordinate systems are allowed)
      Parameters:
        `tables` - List of all available tables.

    - #### DBChecker

          public DBChecker​(java.util.Collection<? extends DBTable> tables,
                           java.util.Collection<? extends FunctionDef> allowedUdfs)

      Builds a `DBChecker` with the given list of known tables and with a restricted list of user defined functions.

      Verifications done by this object after creation:

      - Existence of tables and columns: OK
      - Existence of User Defined Functions (UDFs): OK
      - Support of geometrical functions: NO (all valid geometrical functions are allowed)
      - Support of coordinate systems: NO (all valid coordinate systems are allowed)
      Parameters:
        `tables` - List of all available tables.
        `allowedUdfs` - List of all allowed user defined functions. If NULL, no verification will be done (and so, all UDFs are allowed). If empty list, no "unknown" (or UDF) is allowed. Note: match with items of this list are done case insensitively.
      Since:
        1.3

    - #### DBChecker

          public DBChecker​(java.util.Collection<? extends DBTable> tables,
                           java.util.Collection<java.lang.String> allowedGeoFcts,
                           java.util.Collection<java.lang.String> allowedCoordSys)
                    throws ParseException

      Builds a `DBChecker` with the given list of known tables and with a restricted list of user defined functions.

      Verifications done by this object after creation:

      - Existence of tables and columns: OK
      - Existence of User Defined Functions (UDFs): NO (any "unknown" function is allowed)
      - Support of geometrical functions: OK
      - Support of coordinate systems: OK
      Parameters:
        `tables` - List of all available tables.
        `allowedGeoFcts` - List of all allowed geometrical functions (i.e. CONTAINS, POINT, UNION, CIRCLE, COORD1). If NULL, no verification will be done (and so, all geometries are allowed). If empty list, no geometry function is allowed. Note: match with items of this list are done case insensitively.
        `allowedCoordSys` - List of all allowed coordinate system patterns. The syntax of a such pattern is the following: "{frame} {refpos} {flavor}" ; on the contrary to a coordinate system expression, here no part is optional. Each part of this pattern can be one the possible values (case insensitive), a list of possible values expressed with the syntax "({value1}|{value2}|...)", or a '*' for any valid value. For instance: "ICRS (GEOCENTER|heliocenter) *". If the given list is NULL, no verification will be done (and so, all coordinate systems are allowed). If it is empty, no coordinate system is allowed (except the default values - generally expressed by an empty string: '').
      Throws:
        `ParseException`
      Since:
        1.3

    - #### DBChecker

          public DBChecker​(java.util.Collection<? extends DBTable> tables,
                           java.util.Collection<? extends FunctionDef> allowedUdfs,
                           java.util.Collection<java.lang.String> allowedGeoFcts,
                           java.util.Collection<java.lang.String> allowedCoordSys)
                    throws ParseException

      Builds a `DBChecker`.

      Verifications done by this object after creation:

      - Existence of tables and columns: OK
      - Existence of User Defined Functions (UDFs): OK
      - Support of geometrical functions: OK
      - Support of coordinate systems: OK
      Parameters:
        `tables` - List of all available tables.
        `allowedUdfs` - List of all allowed user defined functions. If NULL, no verification will be done (and so, all UDFs are allowed). If empty list, no "unknown" (or UDF) is allowed. Note: match with items of this list are done case insensitively.
        `allowedGeoFcts` - List of all allowed geometrical functions (i.e. CONTAINS, POINT, UNION, CIRCLE, COORD1). If NULL, no verification will be done (and so, all geometries are allowed). If empty list, no geometry function is allowed. Note: match with items of this list are done case insensitively.
        `allowedCoordSys` - List of all allowed coordinate system patterns. The syntax of a such pattern is the following: "{frame} {refpos} {flavor}" ; on the contrary to a coordinate system expression, here no part is optional. Each part of this pattern can be one the possible values (case insensitive), a list of possible values expressed with the syntax "({value1}|{value2}|...)", or a '*' for any valid value. For instance: "ICRS (GEOCENTER|heliocenter) *". If the given list is NULL, no verification will be done (and so, all coordinate systems are allowed). If it is empty, no coordinate system is allowed (except the default values - generally expressed by an empty string: '').
      Throws:
        `ParseException`
      Since:
        1.3

  - ### Method Detail

    - #### specialSort

          protected static final java.lang.String[] specialSort​(java.util.Collection<java.lang.String> items)

      Transform the given collection of string elements in a sorted array. Only non-NULL and non-empty strings are kept.
      Parameters:
        `items` - Items to copy and sort.
      Returns:
        A sorted array containing all - except NULL and empty strings - items of the given collection.
      Since:
        1.3

    - #### setTables

          public final void setTables​(java.util.Collection<? extends DBTable> tables)

      Sets the list of all available tables.

      Note: Only if the given collection is NOT an implementation of `SearchTableApi`, the collection will be copied inside a new `SearchTableList`, otherwise it is used as provided.

      Parameters:
        `tables` - List of `DBTable`s.

    - #### check

          public final void check​(ADQLQuery query)
                           throws ParseException

      Check all the columns, tables and UDFs references inside the given query.

      Note: This query has already been parsed ; thus it is already syntactically correct. Only the consistency with the published tables, columns and all the defined UDFs must be checked.

      Specified by:
        `check` in interface `QueryChecker`
      Parameters:
        `query` - The query to check.
      Throws:
        `ParseException` - An `UnresolvedIdentifiersException` if some tables or columns can not be resolved.
      See Also:
        `check(ADQLQuery, Stack)`

    - #### check

          protected void check​(ADQLQuery query,
                               java.util.Stack<SearchColumnList> fathersList)
                        throws UnresolvedIdentifiersException

      Process several (semantic) verifications in the given ADQL query.

      Main verifications done in this function:

      1. Existence of DB items (tables and columns)
      2. Semantic verification of sub-queries
      3. Support of every encountered User Defined Functions (UDFs - functions unknown by the syntactic parser)
      4. Support of every encountered geometries (functions, coordinate systems and STC-S expressions)
      5. Consistency of types still unknown (because the syntactic parser could not yet resolve them)
      Parameters:
        `query` - The query to check.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
      Throws:
        `UnresolvedIdentifiersException` - An `UnresolvedIdentifiersException` if one or several of the above listed tests have detected some semantic errors (i.e. unresolved table, columns, function).
      Since:
        1.2
      See Also:
        `checkDBItems(ADQLQuery, Stack, UnresolvedIdentifiersException)`, `checkSubQueries(ADQLQuery, Stack, SearchColumnList, UnresolvedIdentifiersException)`, `checkUDFs(ADQLQuery, UnresolvedIdentifiersException)`, `checkGeometries(ADQLQuery, UnresolvedIdentifiersException)`, `checkTypes(ADQLQuery, UnresolvedIdentifiersException)`

    - #### checkDBItems

          protected SearchColumnList checkDBItems​(ADQLQuery query,
                                                  java.util.Stack<SearchColumnList> fathersList,
                                                  UnresolvedIdentifiersException errors)

      Check DB items (tables and columns) used in the given ADQL query.

      Operations done in this function:

      1. Resolve all found tables
      2. Get the whole list of all available columns Note: this list is returned by this function.
      3. Resolve all found columns
      Parameters:
        `query` - Query in which the existence of DB items must be checked.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
        `errors` - List of errors to complete in this function each time an unknown table or column is encountered.
      Returns:
        List of all columns available in the given query.
      Since:
        1.3
      See Also:
        `resolveTables(ADQLQuery, Stack, UnresolvedIdentifiersException)`, `FromContent.getDBColumns()`, `resolveColumns(ADQLQuery, Stack, Map, SearchColumnList, UnresolvedIdentifiersException)`

    - #### resolveTables

          protected java.util.Map<DBTable,​ADQLTable> resolveTables​(ADQLQuery query,
                                                                         java.util.Stack<SearchColumnList> fathersList,
                                                                         UnresolvedIdentifiersException errors)

      Search all table references inside the given query, resolve them against the available tables, and if there is only one match, attach the matching metadata to them. Management of sub-query tables

      If a table is not a DB table reference but a sub-query, this latter is first checked (using `check(ADQLQuery, Stack)` ; but the father list must not contain tables of the given query, because on the same level) and then corresponding table metadata are generated (using `generateDBTable(ADQLQuery, String)`) and attached to it.

      Management of "{table}.*" in the SELECT clause

      For each of this SELECT item, this function tries to resolve the table name. If only one match is found, the corresponding ADQL table object is got from the list of resolved tables and attached to this SELECT item (thus, the joker item will also have the good metadata, particularly if the referenced table is a sub-query).

      Table alias

      When a simple table (i.e. not a sub-query) is aliased, the metadata of this table will be wrapped inside a `DBTableAlias` in order to keep the original metadata but still declare use the table with the alias instead of its original name. The original name will be used only when translating the corresponding FROM item ; the rest of the time (i.e. for references when using a column), the alias name must be used.

      In order to avoid unpredictable behavior at execution of the SQL query, the alias will be put in lower case if not defined between double quotes.

      Parameters:
        `query` - Query in which the existence of tables must be checked.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
        `errors` - List of errors to complete in this function each time an unknown table or column is encountered.
      Returns:
        An associative map of all the resolved tables.

    - #### resolveTable

          protected DBTable resolveTable​(ADQLTable table)
                                  throws ParseException

      Resolve the given table, that's to say search for the corresponding `DBTable`.
      Parameters:
        `table` - The table to resolve.
      Returns:
        The corresponding `DBTable` if found, null otherwise.
      Throws:
        `ParseException` - An `UnresolvedTableException` if the given table can't be resolved.

    - #### resolveColumns

          protected void resolveColumns​(ADQLQuery query,
                                        java.util.Stack<SearchColumnList> fathersList,
                                        java.util.Map<DBTable,​ADQLTable> mapTables,
                                        SearchColumnList list,
                                        UnresolvedIdentifiersException errors)

      Search all column references inside the given query, resolve them thanks to the given tables' metadata, and if there is only one match, attach the matching metadata to them.

      Management of selected columns' references

      A column reference is not only a direct reference to a table column using a column name. It can also be a reference to an item of the SELECT clause (which will then call a "selected column"). That kind of reference can be either an index (an unsigned integer starting from 1 to N, where N is the number selected columns), or the name/alias of the column.

      These references are also checked, in a second step, in this function. Thus, column metadata are also attached to them, as common columns.

      Parameters:
        `query` - Query in which the existence of tables must be checked.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
        `mapTables` - List of all resolved tables.
        `list` - List of column metadata to complete in this function each time a column reference is resolved.
        `errors` - List of errors to complete in this function each time an unknown table or column is encountered.

    - #### resolveColumn

          protected DBColumn resolveColumn​(ADQLColumn column,
                                           SearchColumnList dbColumns,
                                           java.util.Stack<SearchColumnList> fathersList)
                                    throws ParseException

      Resolve the given column, that's to say search for the corresponding `DBColumn`.

      The third parameter is used only if this function is called inside a sub-query. In this case, the column is tried to be resolved with the first list (dbColumns). If no match is found, the resolution is tried with the father columns list (fathersList).

      Parameters:
        `column` - The column to resolve.
        `dbColumns` - List of all available `DBColumn`s.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
      Returns:
        The corresponding `DBColumn` if found. Otherwise an exception is thrown.
      Throws:
        `ParseException` - An `UnresolvedColumnException` if the given column can't be resolved or an `UnresolvedTableException` if its table reference can't be resolved.

    - #### checkGroupByItem

          protected DBColumn checkGroupByItem​(ADQLColumn col,
                                              ClauseSelect select,
                                              SearchColumnList dbColumns)
                                       throws ParseException

      Check whether the given column corresponds to a selected item's alias or to an existing column.
      Parameters:
        `col` - The column to check.
        `select` - The SELECT clause of the ADQL query.
        `dbColumns` - The list of all available columns.
      Returns:
        The corresponding `DBColumn` if this column corresponds to an existing column, NULL otherwise.
      Throws:
        `ParseException` - An `UnresolvedColumnException` if the given column can't be resolved or an `UnresolvedTableException` if its table reference can't be resolved.
      Since:
        1.4
      See Also:
        `ClauseSelect.searchByAlias(String)`, `resolveColumn(ADQLColumn, SearchColumnList, Stack)`

    - #### checkColumnReference

          protected DBColumn checkColumnReference​(ColumnReference colRef,
                                                  ClauseSelect select,
                                                  SearchColumnList dbColumns)
                                           throws ParseException

      Check whether the given column reference corresponds to a selected item (column or an expression with an alias) or to an existing column.
      Parameters:
        `colRef` - The column reference which must be checked.
        `select` - The SELECT clause of the ADQL query.
        `dbColumns` - The list of all available columns.
      Returns:
        The corresponding `DBColumn` if this reference is actually the name of a column, null otherwise.
      Throws:
        `ParseException` - An `UnresolvedColumnException` if the given column can't be resolved or an `UnresolvedTableException` if its table reference can't be resolved.
      See Also:
        `ClauseSelect.searchByAlias(String)`, `resolveColumn(ADQLColumn, SearchColumnList, Stack)`

    - #### generateDBTable

          public static DBTable generateDBTable​(ADQLQuery subQuery,
                                                java.lang.String tableName)
                                         throws ParseException

      Generate a `DBTable` corresponding to the given sub-query with the given table name. This `DBTable` will contain all `DBColumn` returned by `ADQLQuery.getResultingColumns()`.
      Parameters:
        `subQuery` - Sub-query in which the specified table must be searched.
        `tableName` - Name of the table to search.
      Returns:
        The corresponding `DBTable` if the table has been found in the given sub-query, null otherwise.
      Throws:
        `ParseException` - Can be used to explain why the table has not been found. Note: not used by default.

    - #### checkUDFs

          protected void checkUDFs​(ADQLQuery query,
                                   UnresolvedIdentifiersException errors)

      Search all UDFs (User Defined Functions) inside the given query, and then check their signature against the list of allowed UDFs.

      Note: When more than one allowed function match, the function is considered as correct and no error is added. However, in case of multiple matches, the return type of matching functions could be different and in this case, there would be an error while checking later the types. In such case, throwing an error could make sense, but the user would then need to cast some parameters to help the parser identifying the right function. But the type-casting ability is not yet possible in ADQL.

      Parameters:
        `query` - Query in which UDFs must be checked.
        `errors` - List of errors to complete in this function each time a UDF does not match to any of the allowed UDFs.
      Since:
        1.3

    - #### isAllParamTypesResolved

          protected final boolean isAllParamTypesResolved​(ADQLFunction fct)

      Tell whether the type of all parameters of the given ADQL function is resolved.

      A parameter type may not be resolved for 2 main reasons:

      - the parameter is a column, but this column has not been successfully resolved. Thus its type is still unknown.
      - the parameter is a UDF, but this UDF has not been already resolved. Thus, as for the column, its return type is still unknown. But it could be known later if the UDF is resolved later ; a second try should be done afterwards.
      Parameters:
        `fct` - ADQL function whose the parameters' type should be checked.
      Returns:
        true if the type of all parameters is known, false otherwise.
      Since:
        1.3

    - #### checkGeometries

          protected void checkGeometries​(ADQLQuery query,
                                         UnresolvedIdentifiersException errors)

      Check all geometries.

      Operations done in this function:

      1. Check that all geometrical functions are supported
      2. Check that all explicit (string constant) coordinate system definitions are supported
      3. Check all STC-S expressions (only in `RegionFunction` for the moment) and Apply the 2 previous checks on them
      Parameters:
        `query` - Query in which geometries must be checked.
        `errors` - List of errors to complete in this function each time a geometry item is not supported.
      Since:
        1.3
      See Also:
        `resolveGeometryFunctions(ADQLQuery, BinarySearch, UnresolvedIdentifiersException)`, `resolveCoordinateSystems(ADQLQuery, UnresolvedIdentifiersException)`, `resolveSTCSExpressions(ADQLQuery, BinarySearch, UnresolvedIdentifiersException)`

    - #### resolveGeometryFunctions

          protected void resolveGeometryFunctions​(ADQLQuery query,
                                                  DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch,
                                                  UnresolvedIdentifiersException errors)

      Search for all geometrical functions and check whether they are allowed.
      Parameters:
        `query` - Query in which geometrical functions must be checked.
        `errors` - List of errors to complete in this function each time a geometrical function is not supported.
      Since:
        1.3
      See Also:
        `checkGeometryFunction(String, ADQLFunction, BinarySearch, UnresolvedIdentifiersException)`

    - #### checkGeometryFunction

          protected void checkGeometryFunction​(java.lang.String fctName,
                                               ADQLFunction fct,
                                               DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch,
                                               UnresolvedIdentifiersException errors)

      Check whether the specified geometrical function is allowed by this implementation.

      Note: If the list of allowed geometrical functions is empty, this function will always add an errors to the given list. Indeed, it means that no geometrical function is allowed and so that the specified function is automatically not supported.

      Parameters:
        `fctName` - Name of the geometrical function to test.
        `fct` - The function instance being or containing the geometrical function to check. Note: this function can be the function to test or a function embedding the function under test (i.e. RegionFunction).
        `binSearch` - The object to use in order to search a function name inside the list of allowed functions. It is able to perform a binary search inside a sorted array of String objects. The interest of this object is its compare function which must be overridden and tells how to compare the item to search and the items of the array (basically, a non-case-sensitive comparison between 2 strings).
        `errors` - List of errors to complete in this function each time a geometrical function is not supported.
      Since:
        1.3

    - #### resolveCoordinateSystems

          protected void resolveCoordinateSystems​(ADQLQuery query,
                                                  UnresolvedIdentifiersException errors)

      Search all explicit coordinate system declarations, check their syntax and whether they are allowed by this implementation.

      Note: "explicit" means here that all `StringConstant` instances. Only coordinate systems expressed as string can be parsed and so checked. So if a coordinate system is specified by a column, no check can be done at this stage... it will be possible to perform such test only at the execution.

      Parameters:
        `query` - Query in which coordinate systems must be checked.
        `errors` - List of errors to complete in this function each time a coordinate system has a wrong syntax or is not supported.
      Since:
        1.3
      See Also:
        `checkCoordinateSystem(StringConstant, UnresolvedIdentifiersException)`

    - #### checkCoordinateSystem

          protected void checkCoordinateSystem​(StringConstant adqlCoordSys,
                                               UnresolvedIdentifiersException errors)

      Parse and then check the coordinate system contained in the given `StringConstant` instance.
      Parameters:
        `adqlCoordSys` - The `StringConstant` object containing the coordinate system to check.
        `errors` - List of errors to complete in this function each time a coordinate system has a wrong syntax or is not supported.
      Since:
        1.3
      See Also:
        `STCS.parseCoordSys(String)`, `checkCoordinateSystem(adql.db.STCS.CoordSys, ADQLOperand, UnresolvedIdentifiersException)`

    - #### checkCoordinateSystem

          protected void checkCoordinateSystem​(STCS.CoordSys coordSys,
                                               ADQLOperand operand,
                                               UnresolvedIdentifiersException errors)

      Check whether the given coordinate system is allowed by this implementation.
      Parameters:
        `coordSys` - Coordinate system to test.
        `operand` - The operand representing or containing the coordinate system under test.
        `errors` - List of errors to complete in this function each time a coordinate system is not supported.
      Since:
        1.3

    - #### resolveSTCSExpressions

          protected void resolveSTCSExpressions​(ADQLQuery query,
                                                DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch,
                                                UnresolvedIdentifiersException errors)

      Search all STC-S expressions inside the given query, parse them (and so check their syntax) and then determine whether the declared coordinate system and the expressed region are allowed in this implementation.

      Note: In the current ADQL language definition, STC-S expressions can be found only as only parameter of the REGION function.

      Parameters:
        `query` - Query in which STC-S expressions must be checked.
        `binSearch` - The object to use in order to search a region name inside the list of allowed functions/regions. It is able to perform a binary search inside a sorted array of String objects. The interest of this object is its compare function which must be overridden and tells how to compare the item to search and the items of the array (basically, a non-case-sensitive comparison between 2 strings).
        `errors` - List of errors to complete in this function each time the STC-S syntax is wrong or each time the declared coordinate system or region is not supported.
      Since:
        1.3
      See Also:
        `STCS.parseRegion(String)`, `checkRegion(adql.db.STCS.Region, RegionFunction, BinarySearch, UnresolvedIdentifiersException)`

    - #### checkRegion

          protected void checkRegion​(STCS.Region r,
                                     RegionFunction fct,
                                     DBChecker.BinarySearch<java.lang.String,​java.lang.String> binSearch,
                                     UnresolvedIdentifiersException errors)

      Check the given region.

      The following points are checked in this function:

      - whether the coordinate system is allowed
      - whether the type of region is allowed
      - whether the inner regions are correct (here this function is called recursively on each inner region).
      Parameters:
        `r` - The region to check.
        `fct` - The REGION function containing the region to check.
        `errors` - List of errors to complete in this function if the given region or its inner regions are not supported.
      Since:
        1.3
      See Also:
        `checkCoordinateSystem(adql.db.STCS.CoordSys, ADQLOperand, UnresolvedIdentifiersException)`, `checkGeometryFunction(String, ADQLFunction, BinarySearch, UnresolvedIdentifiersException)`, `checkRegion(adql.db.STCS.Region, RegionFunction, BinarySearch, UnresolvedIdentifiersException)`

    - #### checkTypes

          protected void checkTypes​(ADQLQuery query,
                                    UnresolvedIdentifiersException errors)

      Search all operands whose the type is not yet known and try to resolve it now and to check whether it matches the type expected by the syntactic parser.

      Only two operands may have an unresolved type: columns and user defined functions. Indeed, their type can be resolved only if the list of available columns and UDFs is known, and if columns and UDFs used in the query are resolved successfully.

      When an operand type is still unknown, they will own the three kinds of type and so this function won't raise an error: it is thus automatically on the expected type. This behavior is perfectly correct because if the type is not resolved that means the item/operand has not been resolved in the previous steps and so that an error about this item has already been raised.

      Important note: This function does not check the types exactly, but just roughly by considering only three categories: string, numeric and geometry.

      Parameters:
        `query` - Query in which unknown types must be resolved and checked.
        `errors` - List of errors to complete in this function each time a types does not match to the expected one.
      Since:
        1.3
      See Also:
        `UnknownType`

    - #### checkSubQueries

          protected void checkSubQueries​(ADQLQuery query,
                                         java.util.Stack<SearchColumnList> fathersList,
                                         SearchColumnList availableColumns,
                                         UnresolvedIdentifiersException errors)

      Search all sub-queries found in the given query but not in the clause FROM. These sub-queries are then checked using `check(ADQLQuery, Stack)`.

      Fathers stack

      Each time a sub-query must be checked with `check(ADQLQuery, Stack)`, the list of all columns available in each of its father queries must be provided. This function is composing itself this stack by adding the given list of available columns (= all columns resolved in the given query) at the end of the given stack. If this stack is given empty, then a new stack is created.

      This modification of the given stack is just the execution time of this function. Before returning, this function removes the last item of the stack.

      Parameters:
        `query` - Query in which sub-queries must be checked.
        `fathersList` - List of all columns available in the father queries and that should be accessed in sub-queries. Each item of this stack is a list of columns available in each father-level query. Note: this parameter is NULL if this function is called with the root/father query as parameter.
        `availableColumns` - List of all columns resolved in the given query.
        `errors` - List of errors to complete in this function each time a semantic error is encountered.
      Since:
        1.3