Package com.vaadin.client.data

Class DataSource.RowHandle<T>

  • Type Parameters:
    T - the row type
    Direct Known Subclasses:
    AbstractRemoteDataSource.RowHandleImpl
    Enclosing interface:
    DataSource<T>
    public abstract static class DataSource.RowHandle<T>
extends Object
    A handle that contains information on whether a row should be pinned or unpinned, and also always the most recent representation for that particular row.

    • Constructor Detail

      • RowHandle

        public RowHandle()

    • Method Detail

      • getRow

        public abstract T getRow()
                  throws IllegalStateException
        Gets the most recent representation for the row this handle represents.
        Returns:
        the most recent representation for the row this handle represents
        Throws:
        IllegalStateException - if this row handle isn't currently pinned
        See Also:
        pin()

      • pin

        public abstract void pin()
        Marks this row as pinned.

        Note: Pinning a row multiple times requires an equal amount of unpins to free the row from the "pinned" status.

        Technical Note: Pinning a row makes sure that the row object for a particular set of data is always kept as up to date as the data source is able to. Since the DataSource might create a new instance of an object, object references aren't necessarily kept up-to-date. This is a technical work-around for that.

        See Also:
        unpin()

      • unpin

        public abstract void unpin()
                    throws IllegalStateException
        Marks this row as unpinned.

        Note: Pinning a row multiple times requires an equal amount of unpins to free the row from the "pinned" status.

        Technical Note: Pinning a row makes sure that the row object for a particular set of data is always kept as up to date as the data source is able to. Since the DataSource might create a new instance of an object, object references aren't necessarily kept up-to-date. This is a technical work-around for that.

        Throws:
        IllegalStateException - if this row handle has not been pinned before
        See Also:
        pin()

      • updateRow

        public abstract void updateRow()
        Informs the DataSource that the row data represented by this RowHandle has been updated. DataChangeHandler for the DataSource should be informed that parts of data have been updated.
        See Also:
        DataChangeHandler.dataUpdated(int, int)

      • equalsExplicit

        protected abstract boolean equalsExplicit​(Object obj)
        An explicit override for Object.equals(Object). This method should be functionally equivalent to a properly implemented equals method.

        Having a properly implemented equals method is imperative for RowHandle to function. Because Java has no mechanism to force an override of an existing method, we're defining a new method for that instead.

        Parameters:
        rowHandle - the reference object with which to compare
        Returns:
        true if this object is the same as the obj argument; false otherwise.

      • hashCodeExplicit

        protected abstract int hashCodeExplicit()
        An explicit override for Object.hashCode(). This method should be functionally equivalent to a properly implemented hashCode method.

        Having a properly implemented hashCode method is imperative for RowHandle to function. Because Java has no mechanism to force an override of an existing method, we're defining a new method for that instead.

        Returns:
        a hash code value for this object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object