adql.query

Class ClauseSelect

java.lang.Object

adql.query.ADQLList<T>

adql.query.ClauseADQL<SelectItem>

adql.query.ClauseSelect

All Implemented Interfaces:

ADQLObject, java.lang.Iterable<SelectItem>

public class ClauseSelect
extends ClauseADQL<SelectItem>

The SELECT clause of an ADQL query.

This ADQL clause is not only a list of ADQL items:

• The user can specify the maximum number of rows the query must return.
• He can also ask that all the returned rows are unique according to the first returned column.

Version:

1.4 (09/2017)

Author:

Grégory Mantelet (CDS;ARI)

Nested Class Summary

Nested classes/interfaces inherited from class adql.query.ADQLList

ADQLList.ADQLListIterator

Constructor Summary

Constructors

Constructor and Description
ClauseSelect() Builds an empty SELECT clause.
ClauseSelect(boolean distinctColumns) Builds an empty SELECT clause by specifying whether the returned rows are unique (regarding the first returned columns).
ClauseSelect(boolean distinctColumns, int limit) Builds an empty SELECT clause.
ClauseSelect(ClauseSelect toCopy) Builds a SELECT clause by copying the given one.
ClauseSelect(int limit) Builds an empty SELECT clause whose the returned rows must be limited to the given number.

Method Summary

Modifier and Type	Method and Description
boolean	add(ADQLOperand operand) Adds an operand to this SELECT clause.
void	add(int index, ADQLOperand operand) Adds an operand to this SELECT clause at the given position.
boolean	distinctColumns() Tells whether this clause imposes that returned rows are unique (regarding the first returned column).
ADQLObject	getCopy() Gets a (deep) copy of this ADQL object.
int	getLimit() Gets the maximum number of rows imposed by this SELECT clause.
boolean	hasLimit() Indicates whether this SELECT clause imposes a maximum number of rows.
ADQLOperand	searchByAlias(java.lang.String alias) Gets the operand which is associated with the given alias (case sensitive).
java.util.List<SelectItem>	searchByAlias(java.lang.String alias, boolean caseSensitive) Gets all the select items which are associated with the given alias.
ADQLOperand	searchByIndex(int index) Gets the specified operand.
ADQLOperand	set(int index, ADQLOperand operand) Replaces the specified operand by the given one.
void	setDistinctColumns(boolean distinct) Changes the DISTINCT flag of this SELECT clause.
void	setLimit(int limit) Changes the maximum number of rows this clause imposes.
void	setNoLimit() Sets no maximum number of rows (classic SELECT).
java.lang.String	toADQL() Gets the ADQL expression of this object.

Methods inherited from class adql.query.ClauseADQL

getPossibleSeparators, getSeparator

Methods inherited from class adql.query.ADQLList

add, add, adqlIterator, clear, get, getName, getPosition, isEmpty, iterator, remove, set, setPosition, size

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ClauseSelect

public ClauseSelect()

Builds an empty SELECT clause.

ClauseSelect

public ClauseSelect(boolean distinctColumns)

Builds an empty SELECT clause by specifying whether the returned rows are unique (regarding the first returned columns).

Parameters:

distinctColumns - true means unique rows (= SELECT DISTINCT), false otherwise (= SELECT or = SELECT ALL).

ClauseSelect

public ClauseSelect(int limit)

Builds an empty SELECT clause whose the returned rows must be limited to the given number.

Parameters:

limit - Maximum number of returned rows (= SELECT TOP limit).

ClauseSelect

public ClauseSelect(boolean distinctColumns,
                    int limit)

Builds an empty SELECT clause.

Parameters:

distinctColumns - true means unique rows (= SELECT DISTINCT), false otherwise (= SELECT or = SELECT ALL).

limit - Maximum number of returned rows (= SELECT TOP limit).

ClauseSelect

public ClauseSelect(ClauseSelect toCopy)
             throws java.lang.Exception

Builds a SELECT clause by copying the given one.

Parameters:

toCopy - The SELECT clause to copy.

Throws:

java.lang.Exception - If there is an error during the copy.

Method Detail

distinctColumns

public final boolean distinctColumns()

Tells whether this clause imposes that returned rows are unique (regarding the first returned column).

Returns:

true for SELECT DISTINCT, false for SELECT ALL.

setDistinctColumns

public final void setDistinctColumns(boolean distinct)

Changes the DISTINCT flag of this SELECT clause.

Parameters:

distinct - true for SELECY DISTINCT, false for SELECT ALL.

hasLimit

public final boolean hasLimit()

Indicates whether this SELECT clause imposes a maximum number of rows.

Returns:

true this clause has a TOP flag, false otherwise.

getLimit

public final int getLimit()

Gets the maximum number of rows imposed by this SELECT clause.

Returns:

Maximum number of rows the query must return (SELECT TOP limit).

setNoLimit

public final void setNoLimit()

Sets no maximum number of rows (classic SELECT).

setLimit

public final void setLimit(int limit)

Changes the maximum number of rows this clause imposes.

Parameters:

limit - The maximum number of returned rows (SELECT TOP limit).

add

public boolean add(ADQLOperand operand)
            throws java.lang.NullPointerException

Adds an operand to this SELECT clause.

IMPORTANT: The given operand will not be added directly ! It will be encapsulated in a SelectItem object which will be then added to the SELECT clause.

Parameters:

operand - The operand to add.

Returns:

true if the operand has been successfully added, false otherwise.

Throws:

java.lang.NullPointerException - If the given item is null.

See Also:

SelectItem

add

public void add(int index,
                ADQLOperand operand)
         throws java.lang.NullPointerException,
                java.lang.ArrayIndexOutOfBoundsException

Adds an operand to this SELECT clause at the given position.

IMPORTANT: The given operand will not be added directly ! It will be encapsulated in a SelectItem object which will be then added to the SELECT clause.

Parameters:

index - The position at which the given operand must be added.

operand - The operand to add.

Throws:

java.lang.NullPointerException - If the given item is null.

java.lang.ArrayIndexOutOfBoundsException - If the index is out of range (index < 0 || index > size()).

See Also:

SelectItem

set

public ADQLOperand set(int index,
                       ADQLOperand operand)
                throws java.lang.NullPointerException,
                       java.lang.ArrayIndexOutOfBoundsException

Replaces the specified operand by the given one.

IMPORTANT: The given operand will not be added directly ! It will be encapsulated in a SelectItem object which will be then added to the SELECT clause.

Parameters:

index - The position of the SELECT item to replace.

operand - The replacer of the specified SELECT item.

Returns:

The replaced SELECT item.

Throws:

java.lang.NullPointerException - If the given item is null.

java.lang.ArrayIndexOutOfBoundsException - If the index is out of range (index < 0 || index > size()).

searchByIndex

public ADQLOperand searchByIndex(int index)
                          throws java.lang.ArrayIndexOutOfBoundsException

Gets the specified operand.

Parameters:

index - Index of the operand to retrieve.

Returns:

The corresponding operand.

Throws:

java.lang.ArrayIndexOutOfBoundsException - If the index is out of range (index < 0 || index > size()).

searchByAlias

public ADQLOperand searchByAlias(java.lang.String alias)

Gets the operand which is associated with the given alias (case sensitive).

Parameters:

alias - Alias of the operand to retrieve.

Returns:

The corresponding operand or null if none has been found.

See Also:

searchByAlias(String, boolean)

searchByAlias

public java.util.List<SelectItem> searchByAlias(java.lang.String alias,
                                                boolean caseSensitive)

Gets all the select items which are associated with the given alias.

Parameters:

alias - Alias of the operand to retrieve.

Returns:

All the corresponding select items.

getCopy

public ADQLObject getCopy()
                   throws java.lang.Exception

Description copied from interface: ADQLObject

Gets a (deep) copy of this ADQL object.

Specified by:

getCopy in interface ADQLObject

Overrides:

getCopy in class ClauseADQL<SelectItem>

Returns:

The copy of this ADQL object.

Throws:

java.lang.Exception - If there is any error during the copy.

toADQL

public java.lang.String toADQL()

Description copied from interface: ADQLObject

Gets the ADQL expression of this object.

Specified by:

toADQL in interface ADQLObject

Overrides:

toADQL in class ADQLList<SelectItem>

Returns:

The corresponding ADQL expression.