Package com.vaadin.flow.server

Interface VaadinContext

  • All Superinterfaces:
    Serializable
    All Known Implementing Classes:
    VaadinServletContext
    public interface VaadinContext
extends Serializable
    Context in which VaadinService is running. This is used to store service-scoped attributes and also works as a wrapper for context objects with properties e.g. ServletContext and PortletContext
    Since:
    2.0.0

    • Method Detail

      • getAttribute

        <T> T getAttribute​(Class<T> type,
                   Supplier<T> defaultValueSupplier)
        Returns value of the specified attribute, creating and storing a default value if attribute not present.

        If attribute is not yet available the defaultValueSupplier is used to get the default value which is set as the attribute value and the value is returned. The operation is executed atomically.

        Parameters:
        type - Type of the attribute.
        defaultValueSupplier - Supplier of the default value, called when there is no value already present. May be null.
        Returns:
        Value of the specified attribute.

      • getAttribute

        default <T> T getAttribute​(Class<T> type)
        Returns value of the specified attribute.
        Parameters:
        type - Type of the attribute.
        Returns:
        Value of the specified attribute.

      • setAttribute

        <T> void setAttribute​(Class<T> clazz,
                      T value)
        Sets the attribute value for the give type, overriding previously existing one. Values are based on exact type, meaning only one attribute of given type is possible at any given time.
        Parameters:
        clazz - the type to associate the value with, not null
        value - the attribute value to set, or null to remove the current value
        Since:

      • setAttribute

        default void setAttribute​(Object value)
        Sets the attribute value, overriding previously existing one. Values are based on exact type, meaning only one attribute of given type is possible at any given time.
        Parameters:
        value - attribute value, not null.
        See Also:
        for removing attributes.

      • removeAttribute

        void removeAttribute​(Class<?> clazz)
        Removes an attribute identified by the given type. If the attribute does not exist, no action will be taken.
        Parameters:
        clazz - Attribute type.
        See Also:
        for setting attributes.

      • getContextParameterNames

        Enumeration<String> getContextParameterNames()
        Returns the names of the initialization parameters as an Enumeration, or an empty Enumeration if there are o initialization parameters.
        Returns:
        initialization parameters as a Enumeration

      • getContextParameter

        String getContextParameter​(String name)
        Returns the value for the requested parameter, or null if the parameter does not exist.
        Parameters:
        name - name of the parameter whose value is requested
        Returns:
        parameter value as String or null for no parameter