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Class InMemoryDataProviderHelpers

  • public class InMemoryDataProviderHelpers
extends Object

    A class containing a number of static helper methods for implementing InMemoryDataProviders.

    This class is intended primarily for internal use.

    Since:

    8.1

    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.

    • Constructor Detail

      • InMemoryDataProviderHelpers

        public InMemoryDataProviderHelpers()

    • 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.

        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.

        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.

        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.

        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.

        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.

        Parameters:

        valueProvider - the value provider to use

        requiredValue - the required value

        Returns:

        the created predicate