com.aspc.DBObj

Class DBResult<T extends DBObject>

java.lang.Object

com.aspc.DBObj.DBResult<T>

Type Parameters:

T - the type of DBObject returned by this result

All Implemented Interfaces:

java.lang.Iterable<T>

public final class DBResult<T extends DBObject>
extends java.lang.Object
implements java.lang.Iterable<T>

DBResult is a record set of DBObjects. The record set will contain only DBObjects that you have read access to.
THREAD MODE: SINGLE-THREADED query result

Since:

August 19, 2000, 11:08 AM

Author:

Nigel Leck

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.concurrent.atomic.AtomicInteger	PREFETCH_THRESHOLD The threshold to before we use pre-fetch
static VersionENV	VERSION the version to use

Constructor Summary

Constructors

Constructor and Description
DBResult(DBClassAbstract dbClassAbstract, DataSource ds) Creates new DBResult
DBResult(DBClassAbstract dbClassAbstract, DataSource ds, java.util.ArrayList aList, DBCriteria criteria) Creates new DBResult
DBResult(DBClassAbstract dbClassAbstract, DataSource ds, PossibleRowsHolder pr, DBCriteria criteria) Creates new DBResult

Method Summary

Modifier and Type	Method and Description
boolean	contains(long rowId) does this record set contain this record ?
boolean	doesIntersect(DBResult otherSet) does this result set intersect with the other ?
T	findNext() The next DBObject
int	getActRowCount() Get the actual row count
DBCriteria	getCriteria() Get the current criteria for the DBResult
int	getCurrentRowNumber() Return the current row number zero offset, -1 is before the first record.
DBClassConcrete	getDBClassConcrete() Returns the DBClassConcrete for this result set
DataSource	getDS() get the data source
int	getEstDatabaseLoadCount() The Estimated number of records that will need to be loaded from the database.
int	getEstRowCount() The estimated row count.
T	getObject(int requestedRow) Map requested row to the sorted row number and then call the getObjectUnsorted method
T	getObjectUnsorted(int row) Returned the object at the requested row.
java.lang.String	getOrderBy() Returns the current order by clause.
PossibleRowsHolder	getPossibleRows() Get the possible rows holder for the DBResult
boolean	has2Plus() Do we have 2 or more matching rows ?
boolean	hasAllRowsBeenScanned() Have we scanned to the end of the list of possible rows ?
boolean	hasMore() Are we at the end of the record set.
boolean	hasRow(int row) Do we have this row ?
boolean	hasRows() Do we have any rows ? 1 or more
DBResult<T>	intersect(DBResult otherSet) get the result that intersect
boolean	isRowCountEstimate() Will/did getEstRowCount() return an estimate or actual row count
boolean	isSorted() Is it sorted ?
java.util.Iterator<T>	iterator()
DBObject[]	makeList() Make a array of matching DBObjects
long[]	makeRowList() Deprecated.
LargeLongArray	makeRowLLA() The list of row IDs
DBObject[]	makeUnsortedList() the unsorted list of results.
T	next() The next DBObject
DBResult<T>	rewind() Rewinds the record set to the first row.
DBResult<T>	setMaxRowForEstimate(int maxRows) Set the maximum number of rows to load from database for getEstRowCount() If estimation is greater than this value, we don't get the actual row count.
DBResult<T>	setOrderBy(java.lang.String order) Sets the order of that the result set is in the format of the order statement is :- fieldPath DESC;fieldPath ASC
DBResult<T>	setOrderBy(java.lang.String fieldPath, boolean sortDescending) A short hand method to set the order by for a particular field.
DBResult<T>	setOrderByKey() A short hand method of setting the order by clause to be the primary key.
DBResult<T>	setPrefetchSize(int size) Sets the number of records to pre-fetch ( scan ahead)

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

Field Detail

PREFETCH_THRESHOLD

public static final java.util.concurrent.atomic.AtomicInteger PREFETCH_THRESHOLD

The threshold to before we use pre-fetch

VERSION

public static final VersionENV VERSION

the version to use

Constructor Detail

DBResult

public DBResult(@Nonnull
                DBClassAbstract dbClassAbstract,
                @Nonnull
                DataSource ds)

Creates new DBResult

Parameters:

dbClassAbstract - The base class for this record set

ds - Your data source

DBResult

public DBResult(@Nonnull
                DBClassAbstract dbClassAbstract,
                @Nonnull
                DataSource ds,
                @Nullable
                java.util.ArrayList aList,
                @Nullable
                DBCriteria criteria)

Creates new DBResult

Parameters:

dbClassAbstract - The base class for this record set

aList - The list of possible DBObjects

criteria - The criteria to filter the list with.

ds - Your data source

DBResult

public DBResult(@Nonnull
                DBClassAbstract dbClassAbstract,
                @Nonnull
                DataSource ds,
                @Nullable
                PossibleRowsHolder pr,
                @Nullable
                DBCriteria criteria)

Creates new DBResult

Parameters:

dbClassAbstract - The base class for this record set

pr - The list of possible rows

criteria - The criteria to filter the rows with.

ds - Your data source

Method Detail

doesIntersect

@CheckReturnValue
public boolean doesIntersect(@Nonnull
                                               DBResult otherSet)

does this result set intersect with the other ?

Parameters:

otherSet - the other result set

Returns:

TRUE if it intersects

intersect

@CheckReturnValue
 @Nonnull
public DBResult<T> intersect(@Nonnull
                                                         DBResult otherSet)

get the result that intersect

Parameters:

otherSet - the other result set

Returns:

the intersect result set

contains

@CheckReturnValue
public boolean contains(long rowId)

does this record set contain this record ?

Parameters:

rowId - The row to check

Returns:

true if contains.

setOrderByKey

@Nonnull
public DBResult<T> setOrderByKey()
                                   throws java.lang.NoSuchFieldException

A short hand method of setting the order by clause to be the primary key. NB: This is NOT done by default as it puts load on the system where it's not really required.

Returns:

return itself

Throws:

java.lang.NoSuchFieldException

getOrderBy

@CheckReturnValue
 @Nonnull
public java.lang.String getOrderBy()

Returns the current order by clause.

Returns:

The clause.

isSorted

@CheckReturnValue
public boolean isSorted()

Is it sorted ?

Returns:

true if sorted

getDS

@CheckReturnValue
 @Nonnull
public DataSource getDS()

get the data source

Returns:

the DS

setOrderBy

@Nonnull
public DBResult<T> setOrderBy(@Nullable
                                       java.lang.String order)
                                throws java.lang.NoSuchFieldException

Sets the order of that the result set is in the format of the order statement is :- fieldPath DESC;fieldPath ASC

Parameters:

order - The order by clause.

Returns:

itself for chaining.

Throws:

java.lang.NoSuchFieldException

setPrefetchSize

@Nonnull
public DBResult<T> setPrefetchSize(int size)
                                     throws java.lang.NoSuchFieldException

Sets the number of records to pre-fetch ( scan ahead)

Parameters:

size - positive number will enable scan ahead.

Returns:

itself for chaining.

Throws:

java.lang.NoSuchFieldException

setOrderBy

@Nonnull
public DBResult<T> setOrderBy(@Nonnull
                                       java.lang.String fieldPath,
                                       boolean sortDescending)
                                throws java.lang.NoSuchFieldException

A short hand method to set the order by for a particular field.

Parameters:

fieldPath - The field path

sortDescending - Descending ?

Returns:

itself for chaining.

Throws:

java.lang.NoSuchFieldException

rewind

public DBResult<T> rewind()

Rewinds the record set to the first row.

Returns:

this

hasMore

@CheckReturnValue
public boolean hasMore()
                                  throws java.lang.Exception

Are we at the end of the record set.

Returns:

True if more records available.

Throws:

java.lang.Exception - A serious problem occurred.

getCurrentRowNumber

@CheckReturnValue
public int getCurrentRowNumber()

Return the current row number zero offset, -1 is before the first record.

Returns:

the current row.

next

@CheckReturnValue
 @Nullable
public T next()

The next DBObject

Returns:

The next DBObject

findNext

@CheckReturnValue
 @Nonnull
public T findNext()
                                       throws NotFoundException

The next DBObject

Returns:

The next DBObject

Throws:

NotFoundException - if there is no more rows.

hasRow

@CheckReturnValue
public boolean hasRow(@Nonnegative
                                        int row)

Do we have this row ?

Parameters:

row - The row to check. Starting from 0

Returns:

Row count

hasRows

@CheckReturnValue
public boolean hasRows()

Do we have any rows ? 1 or more

Returns:

true if we have any rows.

has2Plus

@CheckReturnValue
public boolean has2Plus()

Do we have 2 or more matching rows ?

Returns:

true if we have 2+ rows.

getActRowCount

@CheckReturnValue
 @Nonnegative
public int getActRowCount()

Get the actual row count

Returns:

The number of rows

isRowCountEstimate

@CheckReturnValue
public boolean isRowCountEstimate()

Will/did getEstRowCount() return an estimate or actual row count

Returns:

true if an estimate.

getEstDatabaseLoadCount

@CheckReturnValue
 @Nonnegative
public int getEstDatabaseLoadCount()

The Estimated number of records that will need to be loaded from the database.

Returns:

The estimate count of records that will be loaded

setMaxRowForEstimate

@Nonnull
public DBResult<T> setMaxRowForEstimate(@Nonnegative
                                                 int maxRows)

Set the maximum number of rows to load from database for getEstRowCount() If estimation is greater than this value, we don't get the actual row count.

Parameters:

maxRows - the max rows.

Returns:

this

hasAllRowsBeenScanned

@CheckReturnValue
public boolean hasAllRowsBeenScanned()

Have we scanned to the end of the list of possible rows ?

Returns:

true if the estimate and actual are the same.

getEstRowCount

@CheckReturnValue
 @Nonnegative
public int getEstRowCount()

The estimated row count. The rows haven't been filtered out yet.

Returns:

The estimated number of rows. This is calculated without scanning to the end of the record set.

makeList

@CheckReturnValue
 @Nonnull
public DBObject[] makeList()

Make a array of matching DBObjects

Returns:

The list of objects

makeUnsortedList

@CheckReturnValue
 @Nonnull
public DBObject[] makeUnsortedList()

the unsorted list of results.

Returns:

the list

getPossibleRows

@CheckReturnValue
 @Nonnull
public PossibleRowsHolder getPossibleRows()

Get the possible rows holder for the DBResult

Returns:

The possible rows.

getCriteria

@CheckReturnValue
 @Nullable
public DBCriteria getCriteria()

Get the current criteria for the DBResult

Returns:

The criteria

makeRowList

@CheckReturnValue
 @Nonnull
 @Deprecated
public long[] makeRowList()

Deprecated.

The list of row IDs

Returns:

The array of rows.

makeRowLLA

@CheckReturnValue
 @Nonnull
public LargeLongArray makeRowLLA()

The list of row IDs

Returns:

The array of rows.

getDBClassConcrete

@CheckReturnValue
 @Nullable
public DBClassConcrete getDBClassConcrete()

Returns the DBClassConcrete for this result set

Returns:

The DBClass

getObject

@CheckReturnValue
 @Nullable
public T getObject(@Nonnegative
                                                int requestedRow)

Map requested row to the sorted row number and then call the getObjectUnsorted method

Parameters:

requestedRow - The row to fetch.

Returns:

The matching DBObject

getObjectUnsorted

@CheckReturnValue
 @Nullable
public T getObjectUnsorted(@Nonnegative
                                                        int row)

Returned the object at the requested row. There may be physical rows that do not match the current criteria so we need to keep track of the requested row based on the rows that match rather then the physical rows. lastMatchedRow = last requested row lastMatchedObj = object found at requested row lastMatchedOffset = physical offset of requested row

Parameters:

row - The row to retrieve.

Returns:

The DBObject from the unsorted list.

iterator

@CheckReturnValue
 @Nonnull
public java.util.Iterator<T> iterator()

Specified by:

iterator in interface java.lang.Iterable<T extends DBObject>