| java.lang.Object | ||
| ↳ | com.tencent.wcdb.AbstractCursor | |
| ↳ | com.tencent.wcdb.database.SQLiteDirectCursor | |
Class Overview
Cursor implementation that acts directly on the underlying SQLite statement object.
Differ from the default implementation SQLiteCursor, which backed
with a linear buffer called CursorWindow, this implementation maps directly
to sqlite3_stmt, thus cost less memory and CPU time on certain situation.
Summary
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Inherited Constants | |||||||||||
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 From interface
android.database.Cursor
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From interface
com.tencent.wcdb.Cursor
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| Fields | |||||||||||
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| public static final SQLiteDatabase.CursorFactory | FACTORY | Static factory object of SQLiteDirectCursor. |
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| Public Constructors | |||||||||||
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SQLiteDirectCursor(SQLiteCursorDriver driver, String editTable, SQLiteDirectQuery query)
Execute a query and provide access to its result set through a Cursor
interface.
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| Public Methods | |||||||||||
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| void |
close()
Closes the Cursor, releasing all of its resources and making it completely invalid.
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| void |
deactivate()
Deactivates the Cursor, making all calls on it fail until
requery() is called. | ||||||||||
| byte[] |
getBlob(int column)
Returns the value of the requested column as a byte array.
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| String[] |
getColumnNames()
Returns a string array holding the names of all of the columns in the
result set in the order in which they were listed in the result.
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| int |
getCount()
Returns the numbers of rows in the cursor.
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| double |
getDouble(int column)
Returns the value of the requested column as a double.
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| float |
getFloat(int column)
Returns the value of the requested column as a float.
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| int |
getInt(int column)
Returns the value of the requested column as an int.
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| long |
getLong(int column)
Returns the value of the requested column as a long.
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| short |
getShort(int column)
Returns the value of the requested column as a short.
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| String |
getString(int column)
Returns the value of the requested column as a String.
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| int |
getType(int column)
Returns data type of the given column's value.
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| boolean |
isNull(int column)
Returns
true if the value in the indicated column is null. | ||||||||||
| boolean |
moveToPosition(int position)
Move the cursor to an absolute position.
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| boolean |
requery()
Performs the query that created the cursor again, refreshing its
contents.
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[Expand]
Inherited Methods | |||||||||||
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From class
com.tencent.wcdb.AbstractCursor
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From class
java.lang.Object
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From interface
android.database.Cursor
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From interface
com.tencent.wcdb.CrossProcessCursor
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From interface
com.tencent.wcdb.Cursor
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From interface
java.io.Closeable
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From interface
java.lang.AutoCloseable
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Fields
public static final SQLiteDatabase.CursorFactory FACTORY
Static factory object of SQLiteDirectCursor.
Pass to queryWithFactory(SQLiteDatabase.CursorFactory, boolean, String, String[], String, String[], String, String, String, String)
or rawQueryWithFactory(SQLiteDatabase.CursorFactory, String, String[], String, CancellationSignal) to get a cursor object of SQLiteDirectCursor .
Public Constructors
public SQLiteDirectCursor (SQLiteCursorDriver driver, String editTable, SQLiteDirectQuery query)
Execute a query and provide access to its result set through a Cursor
interface. For a query such as: SELECT name, birth, phone FROM
myTable WHERE ... LIMIT 1,20 ORDER BY... the column names (name, birth,
phone) would be in the projection argument and everything from
FROM onward would be in the params argument.
Parameters
| editTable | the name of the table used for this query |
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| query | the SQLiteDirectQuery object associated with this cursor object. |
Public Methods
public void close ()
Closes the Cursor, releasing all of its resources and making it completely invalid.
Unlike deactivate() a call to requery() will not make the Cursor valid
again.
public void deactivate ()
public byte[] getBlob (int column)
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.
Parameters
| column | the zero-based index of the target column. |
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Returns
- the value of that column as a byte array.
public String[] getColumnNames ()
Returns a string array holding the names of all of the columns in the result set in the order in which they were listed in the result.
Returns
- the names of the columns returned in this query.
public int getCount ()
Returns the numbers of rows in the cursor.
Returns
- the number of rows in the cursor.
public double getDouble (int column)
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.
Parameters
| column | the zero-based index of the target column. |
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Returns
- the value of that column as a double.
public float getFloat (int column)
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.
Parameters
| column | the zero-based index of the target column. |
|---|
Returns
- the value of that column as a float.
public int getInt (int column)
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.
Parameters
| column | the zero-based index of the target column. |
|---|
Returns
- the value of that column as an int.
public long getLong (int column)
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.
Parameters
| column | the zero-based index of the target column. |
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Returns
- the value of that column as a long.
public short getShort (int column)
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.
Parameters
| column | the zero-based index of the target column. |
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Returns
- the value of that column as a short.
public String getString (int column)
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.
Parameters
| column | the zero-based index of the target column. |
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Returns
- the value of that column as a String.
public int getType (int column)
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 getInt(int), getFloat(int)
etc.
Returned column types are
Parameters
| column | the zero-based index of the target column. |
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Returns
- column value type
public boolean isNull (int column)
Returns true if the value in the indicated column is null.
Parameters
| column | the zero-based index of the target column. |
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Returns
- whether the column value is null.
public boolean moveToPosition (int position)
Move the cursor to an absolute position. The valid range of values is -1 <= position <= count.
This method will return true if the request destination was reachable, otherwise, it returns false.
Parameters
| position | the zero-based position to move to. |
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Returns
- whether the requested move fully succeeded.
public boolean requery ()
Performs the query that created the cursor again, refreshing its
contents. This may be done at any time, including after a call to deactivate().
Since this method could execute a query on the database and potentially take
a while, it could cause ANR if it is called on Main (UI) thread.
A warning is printed if this method is being executed on Main thread.
Returns
- true if the requery succeeded, false if not, in which case the cursor becomes invalid.