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 Summary

    Modifier and Type
    Method
    Description
    default <T> T
    getAttribute(Class<T> type)
    Returns value of the specified attribute.
    <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.
    String
    getContextParameter(String name)
    Returns the value for the requested parameter, or null if the parameter does not exist.
    Enumeration<String>
    getContextParameterNames()
    Returns the names of the initialization parameters as an Enumeration, or an empty Enumeration if there are o initialization parameters.
    void
    removeAttribute(Class<?> clazz)
    Removes an attribute identified by the given type.
    <T> void
    setAttribute(Class<T> clazz, T value)
    Sets the attribute value for the give type, overriding previously existing one.
    default void
    setAttribute(Object value)
    Sets the attribute value, overriding previously existing one.

  • Method Details

    • 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.

      Type Parameters:
      T - the type of the attribute value
      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.
      Type Parameters:
      T - the type of the attribute value
      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.
      Type Parameters:
      T - the type of the attribute value
      Parameters:
      clazz - the type to associate the value with, not null
      value - the attribute value to set, or null to remove the current value

    • 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:

    • 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:

    • 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