Package com.vaadin.client.widget.grid.datasources

Class ListDataSource<T>

  • All Implemented Interfaces:
    DataSource<T>
    public class ListDataSource<T>
extends Object
implements DataSource<T>
    A simple list based on an in-memory data source for simply adding a list of row pojos to the grid. Based on a wrapped list instance which supports adding and removing of items.

    Usage: 

     ListDataSource<Integer> ds = new ListDataSource<Integer>(1, 2, 3, 4);

 // Add item to the data source
 ds.asList().add(5);

 // Remove item from the data source
 ds.asList().remove(3);

 // Add multiple items
 ds.asList().addAll(Arrays.asList(5, 6, 7));
    Since:
    7.4
    Author:
    Vaadin Ltd

    • Constructor Detail

      • ListDataSource

        public ListDataSource​(List<T> datasource)
        Constructs a new list data source.

        Note: Modifications to the original list will not be reflected in the data source after the data source has been constructed. To add or remove items to the data source after it has been constructed use asList().

        Parameters:
        datasource - The list to use for providing the data to the grid

      • ListDataSource

        public ListDataSource​(T... rows)
        Constructs a data source with a set of rows. You can dynamically add and remove rows from the data source via the list you get from asList()
        Parameters:
        rows - The rows to initially add to the data source

    • Method Detail

      • ensureAvailability

        public void ensureAvailability​(int firstRowIndex,
                               int numberOfRows)
        Description copied from interface: DataSource
        Informs the data source that data for the given range is needed. A data source only has one active region at a time, so calling this method discards the previously set range.

        This method triggers lazy loading of data if necessary. The change handler registered using DataSource.setDataChangeHandler(DataChangeHandler) is informed when new data has been loaded.

        After any possible lazy loading and updates are done, the change handler is informed that new data is available.

        Specified by:
        ensureAvailability in interface DataSource<T>
        Parameters:
        firstRowIndex - the index of the first needed row
        numberOfRows - the number of needed rows

      • getRow

        public T getRow​(int rowIndex)
        Description copied from interface: DataSource
        Retrieves the data for the row at the given index. If the row data is not available, returns null.

        This method does not trigger loading of unavailable data. DataSource.ensureAvailability(int, int) should be used to signal what data will be needed.

        Specified by:
        getRow in interface DataSource<T>
        Parameters:
        rowIndex - the index of the row to retrieve data for
        Returns:
        data for the row; or null if no data is available

      • size

        public int size()
        Description copied from interface: DataSource
        Returns the number of rows in the data source.
        Specified by:
        size in interface DataSource<T>
        Returns:
        the current size of the data source

      • setDataChangeHandler

        public void setDataChangeHandler​(DataChangeHandler dataChangeHandler)
        Description copied from interface: DataSource
        Sets a data change handler to inform when data is updated, added or removed.
        Specified by:
        setDataChangeHandler in interface DataSource<T>
        Parameters:
        dataChangeHandler - the data change handler

      • asList

        public List<T> asList()
        Gets the list that backs this datasource. Any changes made to this list will be reflected in the datasource.

        Note: The list is not the same list as passed into the data source via the constructor.

        Returns:
        Returns a list implementation that wraps the real list that backs the data source and provides events for the data source listeners.

      • sort

        public void sort​(Comparator<T> comparator)
        Sort entire container according to a Comparator.
        Parameters:
        comparator - a comparator object, which compares two data source entries (beans/pojos)

      • indexOf

        public int indexOf​(T row)
        Retrieves the index for given row object.

        Note: This method does not verify that the given row object exists at all in this DataSource.

        Parameters:
        row - the row object
        Returns:
        index of the row; or -1 if row is not available

      • isWaitingForData

        public boolean isWaitingForData()
        Description copied from interface: DataSource
        Checks whether this data source is currently waiting for more rows to become available.
        Specified by:
        isWaitingForData in interface DataSource<T>
        Returns:
        true if waiting for data; otherwise false