The following are a few examples that shows how you can use this exclusion mechanism. - * - *
Exclude fields and objects based on a particular class type: - *
- * private static class SpecificClassExclusionStrategy implements ExclusionStrategy {
- * private final Class<?> excludedThisClass;
- *
- * public SpecificClassExclusionStrategy(Class<?> excludedThisClass) {
- * this.excludedThisClass = excludedThisClass;
- * }
- *
- * public boolean shouldSkipClass(Class<?> clazz) {
- * return excludedThisClass.equals(clazz);
- * }
- *
- * public boolean shouldSkipField(FieldAttributes f) {
- * return excludedThisClass.equals(f.getDeclaredClass());
- * }
- * }
- *
- *
- * Excludes fields and objects based on a particular annotation: - *
- * public @interface FooAnnotation {
- * // some implementation here
- * }
- *
- * // Excludes any field (or class) that is tagged with an "@FooAnnotation"
- * private static class FooAnnotationExclusionStrategy implements ExclusionStrategy {
- * public boolean shouldSkipClass(Class<?> clazz) {
- * return clazz.getAnnotation(FooAnnotation.class) != null;
- * }
- *
- * public boolean shouldSkipField(FieldAttributes f) {
- * return f.getAnnotation(FooAnnotation.class) != null;
- * }
- * }
- *
- *
- * Now if you want to configure {@code Gson} to use a user defined exclusion strategy, then - * the {@code GsonBuilder} is required. The following is an example of how you can use the - * {@code GsonBuilder} to configure Gson to use one of the above sample: - *
- * ExclusionStrategy excludeStrings = new UserDefinedExclusionStrategy(String.class); - * Gson gson = new GsonBuilder() - * .setExclusionStrategies(excludeStrings) - * .create(); - *- * - *
For certain model classes, you may only want to serialize a field, but exclude it for - * deserialization. To do that, you can write an {@code ExclusionStrategy} as per normal; - * however, you would register it with the - * {@link GsonBuilder#addDeserializationExclusionStrategy(ExclusionStrategy)} method. - * For example: - *
- * ExclusionStrategy excludeStrings = new UserDefinedExclusionStrategy(String.class); - * Gson gson = new GsonBuilder() - * .addDeserializationExclusionStrategy(excludeStrings) - * .create(); - *- * - * @author Inderjeet Singh - * @author Joel Leitch - * - * @see GsonBuilder#setExclusionStrategies(ExclusionStrategy...) - * @see GsonBuilder#addDeserializationExclusionStrategy(ExclusionStrategy) - * @see GsonBuilder#addSerializationExclusionStrategy(ExclusionStrategy) - * - * @since 1.4 - */ -public interface ExclusionStrategy { - - /** - * @param f the field object that is under test - * @return true if the field should be ignored; otherwise false - */ - public boolean shouldSkipField(FieldAttributes f); - - /** - * @param clazz the class object that is under test - * @return true if the class should be ignored; otherwise false - */ - public boolean shouldSkipClass(Class clazz); -}