Package android.database

Class AbstractWindowedCursor

java.lang.Object

android.database.AbstractCursor

android.database.AbstractWindowedCursor

All Implemented Interfaces:

CrossProcessCursor, Cursor, Closeable, AutoCloseable

Direct Known Subclasses:

SQLiteCursor

public abstract class AbstractWindowedCursor
extends AbstractCursor

A base class for Cursors that store their data in CursorWindows.

The cursor owns the cursor window it uses. When the cursor is closed, its window is also closed. Likewise, when the window used by the cursor is changed, its old window is closed. This policy of strict ownership ensures that cursor windows are not leaked.

Subclasses are responsible for filling the cursor window with data during AbstractCursor.onMove(int, int), allocating a new cursor window if necessary. During AbstractCursor.requery(), the existing cursor window should be cleared and filled with new data.

If the contents of the cursor change or become invalid, the old window must be closed (because it is owned by the cursor) and set to null.

Field Summary

Fields

Modifier and Type	Field	Description
protected CursorWindow	mWindow	The cursor window owned by this cursor.

Fields inherited from class android.database.AbstractCursor

mClosed, mCurrentRowID, mPos, mRowIdColumnIndex, mUpdatedRows

Fields inherited from interface android.database.Cursor

FIELD_TYPE_BLOB, FIELD_TYPE_FLOAT, FIELD_TYPE_INTEGER, FIELD_TYPE_NULL, FIELD_TYPE_STRING

Constructor Summary

Constructors

Constructor	Description
AbstractWindowedCursor()

Method Summary

Modifier and Type	Method	Description
protected void	checkPosition()	This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds.
protected void	clearOrCreateWindow(String name)	If there is a window, clear it.
protected void	closeWindow()	Closes the cursor window and sets mWindow to null.
void	copyStringToBuffer(int columnIndex, CharArrayBuffer buffer)	Retrieves the requested column text and stores it in the buffer provided.
byte[]	getBlob(int columnIndex)	Returns the value of the requested column as a byte array.
double	getDouble(int columnIndex)	Returns the value of the requested column as a double.
float	getFloat(int columnIndex)	Returns the value of the requested column as a float.
int	getInt(int columnIndex)	Returns the value of the requested column as an int.
long	getLong(int columnIndex)	Returns the value of the requested column as a long.
short	getShort(int columnIndex)	Returns the value of the requested column as a short.
String	getString(int columnIndex)	Returns the value of the requested column as a String.
int	getType(int columnIndex)	Returns data type of the given column's value.
CursorWindow	getWindow()	If the cursor is backed by a CursorWindow, returns a pre-filled window with the contents of the cursor, otherwise null.
boolean	hasWindow()	Returns true if the cursor has an associated cursor window.
boolean	isBlob(int columnIndex)	Deprecated. Use getType(int)
boolean	isFloat(int columnIndex)	Deprecated. Use getType(int)
boolean	isLong(int columnIndex)	Deprecated. Use getType(int)
boolean	isNull(int columnIndex)	Returns true if the value in the indicated column is null.
boolean	isString(int columnIndex)	Deprecated. Use getType(int)
protected void	onDeactivateOrClose()
void	setWindow(CursorWindow window)	Sets a new cursor window for the cursor to use.

Methods inherited from class android.database.AbstractCursor

close, deactivate, fillWindow, finalize, getColumnCount, getColumnIndex, getColumnIndexOrThrow, getColumnName, getColumnNames, getCount, getExtras, getPosition, getUpdatedField, getWantsAllOnMoveCalls, isAfterLast, isBeforeFirst, isClosed, isFieldUpdated, isFirst, isLast, move, moveToFirst, moveToLast, moveToNext, moveToPosition, moveToPrevious, onChange, onMove, registerDataSetObserver, requery, respond, setExtras, unregisterDataSetObserver

Methods inherited from class java.lang.Object

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

Field Detail

mWindow

protected CursorWindow mWindow

The cursor window owned by this cursor.

Constructor Detail

AbstractWindowedCursor

public AbstractWindowedCursor()

Method Detail

getBlob

public byte[] getBlob(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a byte array.

The result and whether this method throws an exception when the column value is null or the column type is not a blob type is implementation-defined.

Specified by:

getBlob in interface Cursor

Overrides:

getBlob in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a byte array.

getString

public String getString(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a String.

The result and whether this method throws an exception when the column value is null or the column type is not a string type is implementation-defined.

Specified by:

getString in interface Cursor

Specified by:

getString in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a String.

copyStringToBuffer

public void copyStringToBuffer(int columnIndex,
                               CharArrayBuffer buffer)

Description copied from interface: Cursor

Retrieves the requested column text and stores it in the buffer provided. If the buffer size is not sufficient, a new char buffer will be allocated and assigned to CharArrayBuffer.data

Specified by:

copyStringToBuffer in interface Cursor

Overrides:

copyStringToBuffer in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column. if the target column is null, return buffer

buffer - the buffer to copy the text into.

getShort

public short getShort(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a short.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [Short.MIN_VALUE, Short.MAX_VALUE] is implementation-defined.

Specified by:

getShort in interface Cursor

Specified by:

getShort in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a short.

getInt

public int getInt(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as an int.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [Integer.MIN_VALUE, Integer.MAX_VALUE] is implementation-defined.

Specified by:

getInt in interface Cursor

Specified by:

getInt in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as an int.

getLong

public long getLong(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a long.

The result and whether this method throws an exception when the column value is null, the column type is not an integral type, or the integer value is outside the range [Long.MIN_VALUE, Long.MAX_VALUE] is implementation-defined.

Specified by:

getLong in interface Cursor

Specified by:

getLong in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a long.

getFloat

public float getFloat(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a float.

The result and whether this method throws an exception when the column value is null, the column type is not a floating-point type, or the floating-point value is not representable as a float value is implementation-defined.

Specified by:

getFloat in interface Cursor

Specified by:

getFloat in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a float.

getDouble

public double getDouble(int columnIndex)

Description copied from interface: Cursor

Returns the value of the requested column as a double.

The result and whether this method throws an exception when the column value is null, the column type is not a floating-point type, or the floating-point value is not representable as a double value is implementation-defined.

Specified by:

getDouble in interface Cursor

Specified by:

getDouble in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

the value of that column as a double.

isNull

public boolean isNull(int columnIndex)

Description copied from interface: Cursor

Returns true if the value in the indicated column is null.

Specified by:

isNull in interface Cursor

Specified by:

isNull in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

whether the column value is null.

isBlob

@Deprecated
public boolean isBlob(int columnIndex)

Deprecated.

Use getType(int)

isString

@Deprecated
public boolean isString(int columnIndex)

Deprecated.

Use getType(int)

isLong

@Deprecated
public boolean isLong(int columnIndex)

Deprecated.

Use getType(int)

isFloat

@Deprecated
public boolean isFloat(int columnIndex)

Deprecated.

Use getType(int)

getType

public int getType(int columnIndex)

Description copied from interface: Cursor

Returns data type of the given column's value. The preferred type of the column is returned but the data may be converted to other types as documented in the get-type methods such as Cursor.getInt(int), Cursor.getFloat(int) etc.

Returned column types are

• Cursor.FIELD_TYPE_NULL
• Cursor.FIELD_TYPE_INTEGER
• Cursor.FIELD_TYPE_FLOAT
• Cursor.FIELD_TYPE_STRING
• Cursor.FIELD_TYPE_BLOB

Specified by:

getType in interface Cursor

Overrides:

getType in class AbstractCursor

Parameters:

columnIndex - the zero-based index of the target column.

Returns:

column value type

checkPosition

protected void checkPosition()

Description copied from class: AbstractCursor

This function throws CursorIndexOutOfBoundsException if the cursor position is out of bounds. Subclass implementations of the get functions should call this before attempting to retrieve data.

Overrides:

checkPosition in class AbstractCursor

getWindow

public CursorWindow getWindow()

Description copied from class: AbstractCursor

If the cursor is backed by a CursorWindow, returns a pre-filled window with the contents of the cursor, otherwise null.

Specified by:

getWindow in interface CrossProcessCursor

Overrides:

getWindow in class AbstractCursor

Returns:

The pre-filled window that backs this cursor, or null if none.

setWindow

public void setWindow(CursorWindow window)

Sets a new cursor window for the cursor to use.

The cursor takes ownership of the provided cursor window; the cursor window will be closed when the cursor is closed or when the cursor adopts a new cursor window.

If the cursor previously had a cursor window, then it is closed when the new cursor window is assigned.

Parameters:

window - The new cursor window, typically a remote cursor window.

hasWindow

public boolean hasWindow()

Returns true if the cursor has an associated cursor window.

Returns:

True if the cursor has an associated cursor window.

closeWindow

protected void closeWindow()

Closes the cursor window and sets mWindow to null.

clearOrCreateWindow

protected void clearOrCreateWindow(String name)

If there is a window, clear it. Otherwise, creates a new window.

Parameters:

name - The window name.

onDeactivateOrClose

protected void onDeactivateOrClose()

Overrides:

onDeactivateOrClose in class AbstractCursor