Module com.google.gson
Package com.google.gson

Interface ReflectionAccessFilter

  • public interface ReflectionAccessFilter
    Filter for determining whether reflection based serialization and deserialization is allowed for a class.

    A filter can be useful in multiple scenarios, for example when upgrading to newer Java versions which use the Java Platform Module System (JPMS). A filter then allows to prevent making inaccessible members accessible, even if the used Java version might still allow illegal access (but logs a warning), or if java command line arguments are used to open the inaccessible packages to other parts of the application. This interface defines some convenience filters for this task, such as BLOCK_INACCESSIBLE_JAVA.

    A filter can also be useful to prevent mixing model classes of a project with other non-model classes; the filter could block all reflective access to non-model classes.

    A reflection access filter is similar to an ExclusionStrategy with the major difference that a filter will cause an exception to be thrown when access is disallowed while an exclusion strategy just skips fields and classes.

    Since:
    2.9.1
    See Also:
    GsonBuilder.addReflectionAccessFilter(ReflectionAccessFilter)

    • Field Detail

      • BLOCK_INACCESSIBLE_JAVA

        static final ReflectionAccessFilter BLOCK_INACCESSIBLE_JAVA
        Blocks all reflection access to members of standard Java classes which are not accessible by default. However, reflection access is still allowed for classes for which all fields are accessible and which have an accessible no-args constructor (or for which an InstanceCreator has been registered).

        If this filter encounters a class other than a standard Java class it returns ReflectionAccessFilter.FilterResult.INDECISIVE.

        This filter is mainly intended to help enforcing the access checks of Java Platform Module System. It allows detecting illegal access, even if the used Java version would only log a warning, or is configured to open packages for reflection. However, this filter only works for Java 9 and higher, when using an older Java version its functionality will be limited.

        Note that this filter might not cover all standard Java classes. Currently only classes in a java.* or javax.* package are considered. The set of detected classes might be expanded in the future without prior notice.

        See Also:
        ReflectionAccessFilter.FilterResult.BLOCK_INACCESSIBLE

      • BLOCK_ALL_JAVA

        static final ReflectionAccessFilter BLOCK_ALL_JAVA
        Blocks all reflection access to members of standard Java classes.

        If this filter encounters a class other than a standard Java class it returns ReflectionAccessFilter.FilterResult.INDECISIVE.

        This filter is mainly intended to prevent depending on implementation details of the Java platform and to help applications prepare for upgrading to the Java Platform Module System.

        Note that this filter might not cover all standard Java classes. Currently only classes in a java.* or javax.* package are considered. The set of detected classes might be expanded in the future without prior notice.

        See Also:
        BLOCK_INACCESSIBLE_JAVA, ReflectionAccessFilter.FilterResult.BLOCK_ALL

      • BLOCK_ALL_ANDROID

        static final ReflectionAccessFilter BLOCK_ALL_ANDROID
        Blocks all reflection access to members of standard Android classes.

        If this filter encounters a class other than a standard Android class it returns ReflectionAccessFilter.FilterResult.INDECISIVE.

        This filter is mainly intended to prevent depending on implementation details of the Android platform.

        Note that this filter might not cover all standard Android classes. Currently only classes in an android.* or androidx.* package, and standard Java classes in a java.* or javax.* package are considered. The set of detected classes might be expanded in the future without prior notice.

        See Also:
        ReflectionAccessFilter.FilterResult.BLOCK_ALL

      • BLOCK_ALL_PLATFORM

        static final ReflectionAccessFilter BLOCK_ALL_PLATFORM
        Blocks all reflection access to members of classes belonging to programming language platforms, such as Java, Android, Kotlin or Scala.

        If this filter encounters a class other than a standard platform class it returns ReflectionAccessFilter.FilterResult.INDECISIVE.

        This filter is mainly intended to prevent depending on implementation details of the platform classes.

        Note that this filter might not cover all platform classes. Currently it combines the filters BLOCK_ALL_JAVA and BLOCK_ALL_ANDROID, and checks for other language-specific platform classes like kotlin.*. The set of detected classes might be expanded in the future without prior notice.

        See Also:
        ReflectionAccessFilter.FilterResult.BLOCK_ALL

    • Method Detail

      • check

        ReflectionAccessFilter.FilterResult check​(Class<?> rawClass)
        Checks if reflection access should be allowed for a class.
        Parameters:
        rawClass - Class to check
        Returns:
        Result indicating whether reflection access is allowed