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.

Nested and Inner Type Summary

Modifier and Type	Class and Description
public static enum	ReflectionAccessFilter.FilterResult Result of a filter check.

Field Summary

Modifier and Type	Field and Description
public static final ReflectionAccessFilter	BLOCK_ALL_ANDROID Blocks all reflection access to members of standard Android classes.
public static final ReflectionAccessFilter	BLOCK_ALL_JAVA Blocks all reflection access to members of standard Java classes.
public 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.
public static final ReflectionAccessFilter	BLOCK_INACCESSIBLE_JAVA Blocks all reflection access to members of standard Java classes which are not accessible by default.

Method Summary

Modifier and Type	Method and Description
public ReflectionAccessFilter.FilterResult	Returns: Result indicating whether reflection access is allowed check(Class<?> Class to check rawClass) Checks if reflection access should be allowed for a class.

Field Detail

BLOCK_ALL_ANDROID back to summary

BLOCK_ALL_ANDROID	back to summary
public 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 `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 `FilterResult#BLOCK_ALL`

public 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 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: FilterResult#BLOCK_ALL

BLOCK_ALL_JAVA back to summary

BLOCK_ALL_JAVA	back to summary
public 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 `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`, `FilterResult#BLOCK_ALL`

public 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 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, FilterResult#BLOCK_ALL

BLOCK_ALL_PLATFORM back to summary

BLOCK_ALL_PLATFORM	back to summary
public 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 `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 `FilterResult#BLOCK_ALL`

public 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 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: FilterResult#BLOCK_ALL

BLOCK_INACCESSIBLE_JAVA back to summary

BLOCK_INACCESSIBLE_JAVA	back to summary
public 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 `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 `FilterResult#BLOCK_INACCESSIBLE`

public 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 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.

See Also: FilterResult#BLOCK_INACCESSIBLE

Method Detail

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

check

back to summary

public ReflectionAccessFilter.FilterResult check(Class<?> rawClass)

Checks if reflection access should be allowed for a class.

Parameters

rawClass:Class<?>: Class to check

Returns:ReflectionAccessFilter.FilterResult

Result indicating whether reflection access is allowed

com.google.gson back to summary

public final Enum ReflectionAccessFilter.FilterResult

Class Inheritance

extends Enum<ReflectionAccessFilter.FilterResult>

java.lang.Object
java.lang.Enum
com.google.gson.ReflectionAccessFilter.FilterResult

Result of a filter check.

Since: 2.9.1

Field Summary

Modifier and Type	Field and Description
public static final ReflectionAccessFilter.FilterResult	ALLOW Reflection access for the class is allowed.
public static final ReflectionAccessFilter.FilterResult	BLOCK_ALL Blocks all reflection access for the class.
public static final ReflectionAccessFilter.FilterResult	BLOCK_INACCESSIBLE Blocks reflection access if a member of the class is not accessible by default and would have to be made accessible.
public static final ReflectionAccessFilter.FilterResult	INDECISIVE The filter is indecisive whether reflection access should be allowed.

Constructor Summary

Access	Constructor and Description
private	FilterResult()

Method Summary

Modifier and Type	Method and Description
public static ReflectionAccessFilter.FilterResult	valueOf(String name)
public static ReflectionAccessFilter.FilterResult[]	values()

Inherited from java.lang.Enum:: clone compareTo describeConstable equals finalize getDeclaringClass hashCode name ordinal toString valueOf

Field Detail

ALLOW	back to summary
public static final ReflectionAccessFilter.FilterResult ALLOW Reflection access for the class is allowed. Note that this does not affect the Java access checks in any way, it only permits Gson to try using reflection for a class. The Java runtime might still deny such access.

ALLOW

back to summary

public static final ReflectionAccessFilter.FilterResult ALLOW

Reflection access for the class is allowed.

Note that this does not affect the Java access checks in any way, it only permits Gson to try using reflection for a class. The Java runtime might still deny such access.

BLOCK_ALL	back to summary
public static final ReflectionAccessFilter.FilterResult BLOCK_ALL Blocks all reflection access for the class. Other means for serializing and deserializing the class, such as a `TypeAdapter`, have to be used.

BLOCK_INACCESSIBLE back to summary

BLOCK_INACCESSIBLE	back to summary
public static final ReflectionAccessFilter.FilterResult BLOCK_INACCESSIBLE Blocks reflection access if a member of the class is not accessible by default and would have to be made accessible. This is unaffected by any `java` command line arguments being used to make packages accessible, or by module declaration directives which open the complete module or certain packages for reflection and will consider such packages inaccessible. Note that this only works for Java 9 and higher, for older Java versions its functionality will be limited and it might behave like `ALLOW`. Access checks are only performed as defined by the Java Language Specification (JLS 11 §6.6), restrictions imposed by a `SecurityManager` are not considered. This result type is mainly intended to help enforce the access checks of the 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 using command line arguments. See Also `AccessibleObject#canAccess(Object)`

public static final ReflectionAccessFilter.FilterResult BLOCK_INACCESSIBLE

Blocks reflection access if a member of the class is not accessible by default and would have to be made accessible. This is unaffected by any java command line arguments being used to make packages accessible, or by module declaration directives which open the complete module or certain packages for reflection and will consider such packages inaccessible.

Note that this only works for Java 9 and higher, for older Java versions its functionality will be limited and it might behave like ALLOW. Access checks are only performed as defined by the Java Language Specification (JLS 11 §6.6), restrictions imposed by a SecurityManager are not considered.

This result type is mainly intended to help enforce the access checks of the 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 using command line arguments.

See Also: AccessibleObject#canAccess(Object)

INDECISIVE	back to summary
public static final ReflectionAccessFilter.FilterResult INDECISIVE The filter is indecisive whether reflection access should be allowed. The next registered filter will be consulted to get the result. If there is no next filter, this result acts like `ALLOW`.

Constructor Detail

FilterResult	back to summary
private FilterResult()

Method Detail

valueOf	back to summary
public static ReflectionAccessFilter.FilterResult valueOf(String name)

values	back to summary
public static ReflectionAccessFilter.FilterResult[] values()

public Interface ReflectionAccessFilter

Nested and Inner Type Summary

Field Summary

Method Summary

Field Detail

Method Detail

public final Enum ReflectionAccessFilter.FilterResult

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail