Package android.database

Class CursorWindow

  • All Implemented Interfaces:
    Parcelable, Closeable, AutoCloseable
    public class CursorWindow
extends SQLiteClosable
implements Parcelable
    A buffer containing multiple cursor rows.

    A CursorWindow is read-write when initially created and used locally. When sent to a remote process (by writing it to a Parcel), the remote process receives a read-only view of the cursor window. Typically the cursor window will be allocated by the producer, filled with data, and then sent to the consumer for reading.

    • Field Detail

      • mWindowPtr

        public long mWindowPtr
        The native CursorWindow object pointer. (FOR INTERNAL USE ONLY)

    • Constructor Detail

      • CursorWindow

        public CursorWindow​(String name)
        Creates a new empty cursor window and gives it a name.

        The cursor initially has no rows or columns. Call setNumColumns(int) to set the number of columns before adding any rows to the cursor.

        Parameters:
        name - The name of the cursor window, or null if none.

      • CursorWindow

        @Deprecated
public CursorWindow​(boolean localWindow)
        Deprecated.
        There is no longer a distinction between local and remote cursor windows. Use the CursorWindow(String) constructor instead.
        Creates a new empty cursor window.

        The cursor initially has no rows or columns. Call setNumColumns(int) to set the number of columns before adding any rows to the cursor.

        Parameters:
        localWindow - True if this window will be used in this process only, false if it might be sent to another processes. This argument is ignored.

    • Method Detail

      • finalize

        protected void finalize()
                 throws Throwable
        Description copied from class: Object
        Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

        Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

        If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

        Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

        Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

        Overrides:
        finalize in class Object
        Throws:
        Throwable

      • getName

        public String getName()
        Gets the name of this cursor window, never null.

      • clear

        public void clear()
        Clears out the existing contents of the window, making it safe to reuse for new data.

        The start position (getStartPosition()), number of rows (getNumRows()), and number of columns in the cursor are all reset to zero.

      • getStartPosition

        public int getStartPosition()
        Gets the start position of this cursor window.

        The start position is the zero-based index of the first row that this window contains relative to the entire result set of the Cursor.

        Returns:
        The zero-based start position.

      • setStartPosition

        public void setStartPosition​(int pos)
        Sets the start position of this cursor window.

        The start position is the zero-based index of the first row that this window contains relative to the entire result set of the Cursor.

        Parameters:
        pos - The new zero-based start position.

      • getNumRows

        public int getNumRows()
        Gets the number of rows in this window.
        Returns:
        The number of rows in this cursor window.

      • setNumColumns

        public boolean setNumColumns​(int columnNum)
        Sets the number of columns in this window.

        This method must be called before any rows are added to the window, otherwise it will fail to set the number of columns if it differs from the current number of columns.

        Parameters:
        columnNum - The new number of columns.
        Returns:
        True if successful.

      • allocRow

        public boolean allocRow()
        Allocates a new row at the end of this cursor window.
        Returns:
        True if successful, false if the cursor window is out of memory.

      • freeLastRow

        public void freeLastRow()
        Frees the last row in this cursor window.

      • getBlob

        public byte[] getBlob​(int row,
                      int column)
        Gets the value of the field at the specified row and column index as a byte array.

        The result is determined as follows:

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as a byte array.

      • getString

        public String getString​(int row,
                        int column)
        Gets the value of the field at the specified row and column index as a string.

        The result is determined as follows:

        • If the field is of type Cursor.FIELD_TYPE_NULL, then the result is null.
        • If the field is of type Cursor.FIELD_TYPE_STRING, then the result is the string value.
        • If the field is of type Cursor.FIELD_TYPE_INTEGER, then the result is a string representation of the integer in decimal, obtained by formatting the value with the printf family of functions using format specifier %lld.
        • If the field is of type Cursor.FIELD_TYPE_FLOAT, then the result is a string representation of the floating-point value in decimal, obtained by formatting the value with the printf family of functions using format specifier %g.
        • If the field is of type Cursor.FIELD_TYPE_BLOB, then a SQLiteException is thrown.

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as a string.

      • copyStringToBuffer

        public void copyStringToBuffer​(int row,
                               int column,
                               CharArrayBuffer buffer)
        Copies the text of the field at the specified row and column index into a CharArrayBuffer.

        The buffer is populated as follows:

        • If the buffer is too small for the value to be copied, then it is automatically resized.
        • If the field is of type Cursor.FIELD_TYPE_NULL, then the buffer is set to an empty string.
        • If the field is of type Cursor.FIELD_TYPE_STRING, then the buffer is set to the contents of the string.
        • If the field is of type Cursor.FIELD_TYPE_INTEGER, then the buffer is set to a string representation of the integer in decimal, obtained by formatting the value with the printf family of functions using format specifier %lld.
        • If the field is of type Cursor.FIELD_TYPE_FLOAT, then the buffer is set to a string representation of the floating-point value in decimal, obtained by formatting the value with the printf family of functions using format specifier %g.
        • If the field is of type Cursor.FIELD_TYPE_BLOB, then a SQLiteException is thrown.

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        buffer - The CharArrayBuffer to hold the string. It is automatically resized if the requested string is larger than the buffer's current capacity.

      • getLong

        public long getLong​(int row,
                    int column)
        Gets the value of the field at the specified row and column index as a long.

        The result is determined as follows:

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as a long.

      • getDouble

        public double getDouble​(int row,
                        int column)
        Gets the value of the field at the specified row and column index as a double.

        The result is determined as follows:

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as a double.

      • getShort

        public short getShort​(int row,
                      int column)
        Gets the value of the field at the specified row and column index as a short.

        The result is determined by invoking getLong(int, int) and converting the result to short.

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as a short.

      • getInt

        public int getInt​(int row,
                  int column)
        Gets the value of the field at the specified row and column index as an int.

        The result is determined by invoking getLong(int, int) and converting the result to int.

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as an int.

      • getFloat

        public float getFloat​(int row,
                      int column)
        Gets the value of the field at the specified row and column index as a float.

        The result is determined by invoking getDouble(int, int) and converting the result to float.

        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        The value of the field as an float.

      • putBlob

        public boolean putBlob​(byte[] value,
                       int row,
                       int column)
        Copies a byte array into the field at the specified row and column index.
        Parameters:
        value - The value to store.
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        True if successful.

      • putString

        public boolean putString​(String value,
                         int row,
                         int column)
        Copies a string into the field at the specified row and column index.
        Parameters:
        value - The value to store.
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        True if successful.

      • putLong

        public boolean putLong​(long value,
                       int row,
                       int column)
        Puts a long integer into the field at the specified row and column index.
        Parameters:
        value - The value to store.
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        True if successful.

      • putDouble

        public boolean putDouble​(double value,
                         int row,
                         int column)
        Puts a double-precision floating point value into the field at the specified row and column index.
        Parameters:
        value - The value to store.
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        True if successful.

      • putNull

        public boolean putNull​(int row,
                       int column)
        Puts a null value into the field at the specified row and column index.
        Parameters:
        row - The zero-based row index.
        column - The zero-based column index.
        Returns:
        True if successful.

      • describeContents

        public int describeContents()
        Description copied from interface: Parcelable
        Describe the kinds of special objects contained in this Parcelable's marshalled representation.
        Specified by:
        describeContents in interface Parcelable
        Returns:
        a bitmask indicating the set of special object types marshalled by the Parcelable.

      • writeToParcel

        public void writeToParcel​(Parcel dest,
                          int flags)
        Description copied from interface: Parcelable
        Flatten this object in to a Parcel.
        Specified by:
        writeToParcel in interface Parcelable
        Parameters:
        dest - The Parcel in which the object should be written.
        flags - Additional flags about how the object should be written. May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE.

      • toString

        public String toString()
        Description copied from class: Object
        Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression: 
           getClass().getName() + '@' + Integer.toHexString(hashCode())

        See Writing a useful toString method if you intend implementing your own toString method.

        Overrides:
        toString in class Object
        Returns:
        a printable representation of this object.