Package com.vaadin.flow.data.provider

Class InMemoryDataProviderHelpers

  • public class InMemoryDataProviderHelpers
extends Object
    Helper methods for implementing InMemoryDataProviders.

    This class is intended primarily for internal use.

    Since:
    1.0
    Author:
    Vaadin Ltd

    • Field Detail

      • CURRENT_LOCALE_SUPPLIER

        public static final SerializableSupplier<Locale> CURRENT_LOCALE_SUPPLIER
        Supplier that attempts to resolve a locale from the current UI. Returns the system's default locale as a fallback.

    • Method Detail

      • filteringByIgnoreNull

        public static <T,​V,​Q> DataProvider<T,​Q> filteringByIgnoreNull​(InMemoryDataProvider<T> dataProvider,
                                                                                ValueProvider<T,​V> valueProvider,
                                                                                SerializableBiPredicate<V,​Q> predicate)
        Wraps a given data provider so that its filter ignores null items returned by the given value provider.
        Type Parameters:
        T - the provided data type
        Q - the filter type
        V - the data provider object type
        Parameters:
        dataProvider - the data provider to wrap
        valueProvider - the value provider for providing values to filter
        predicate - the predicate to combine null filtering with
        Returns:
        the wrapped data provider

      • filteringByCaseInsensitiveString

        public static <T> DataProvider<T,​String> filteringByCaseInsensitiveString​(InMemoryDataProvider<T> dataProvider,
                                                                                ValueProvider<T,​String> valueProvider,
                                                                                SerializableBiPredicate<String,​String> predicate,
                                                                                SerializableSupplier<Locale> localeSupplier)
        Wraps a given data provider so that its filter tests the given predicate with the lower case string provided by the given value provider.
        Type Parameters:
        T - the data provider object type
        Parameters:
        dataProvider - the data provider to wrap
        valueProvider - the value provider for providing string values to filter
        predicate - the predicate to use for comparing the resulting lower case strings
        localeSupplier - the locale to use when converting strings to lower case
        Returns:
        the wrapped data provider

      • propertyComparator

        public static <V extends Comparable<? super V>,​T> SerializableComparator<T> propertyComparator​(ValueProvider<T,​V> valueProvider,
                                                                                                     SortDirection sortDirection)
        Creates a comparator for the return type of the given ValueProvider, sorted in the direction specified by the given SortDirection.
        Type Parameters:
        T - the data provider object type
        V - the provided value type
        Parameters:
        valueProvider - the value provider to use
        sortDirection - the sort direction to use
        Returns:
        the created comparator

      • getNaturalSortComparator

        public static <V extends Comparable<? super V>> Comparator<V> getNaturalSortComparator​(SortDirection sortDirection)
        Gets the natural order comparator for the type argument, or the natural order comparator reversed if the given sorting direction is SortDirection.DESCENDING.
        Type Parameters:
        V - the objects to compare
        Parameters:
        sortDirection - the sort direction to use
        Returns:
        the natural comparator, with ordering defined by the given sort direction

      • createValueProviderFilter

        public static <T,​V> SerializablePredicate<T> createValueProviderFilter​(ValueProvider<T,​V> valueProvider,
                                                                             SerializablePredicate<V> valueFilter)
        Creates a new predicate from the given predicate and value provider. This allows using a predicate of the value providers return type with objects of the value providers type.
        Type Parameters:
        T - the data provider object type
        V - the provided value type
        Parameters:
        valueProvider - the value provider to use
        valueFilter - the original predicate
        Returns:
        the created predicate

      • createEqualsFilter

        public static <T,​V> SerializablePredicate<T> createEqualsFilter​(ValueProvider<T,​V> valueProvider,
                                                                      V requiredValue)
        Creates a predicate that compares equality of the given required value to the value the given value provider obtains.
        Type Parameters:
        T - the data provider object type
        V - the provided value type
        Parameters:
        valueProvider - the value provider to use
        requiredValue - the required value
        Returns:
        the created predicate