Incorporated code review comments from r1061.
Made nullSafe() an instance method instead of a static method. Updated code javadoc to match Guava style.
This commit is contained in:
parent
d5ed0716db
commit
0b734e46e1
@ -141,47 +141,49 @@ public abstract class TypeAdapter<T> {
|
||||
* This wrapper method is used to make a type adapter null tolerant. In general, a
|
||||
* type adapter is required to handle nulls in write and read methods. Here is how this
|
||||
* is typically done:<br>
|
||||
* <pre>{@code
|
||||
Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
|
||||
new TypeAdapter<Foo>() {
|
||||
public Foo read(JsonReader in) throws IOException {
|
||||
if (in.peek() == JsonToken.NULL) {
|
||||
in.nextNull();
|
||||
return null;
|
||||
}
|
||||
// read a Foo from in and return it
|
||||
}
|
||||
public void write(JsonWriter out, Foo src) throws IOException {
|
||||
if (src == null) {
|
||||
out.nullValue();
|
||||
return;
|
||||
}
|
||||
// write src as JSON to out
|
||||
}
|
||||
).create();
|
||||
* <pre> {@code
|
||||
*
|
||||
* Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
|
||||
* new TypeAdapter<Foo>() {
|
||||
* public Foo read(JsonReader in) throws IOException {
|
||||
* if (in.peek() == JsonToken.NULL) {
|
||||
* in.nextNull();
|
||||
* return null;
|
||||
* }
|
||||
* // read a Foo from in and return it
|
||||
* }
|
||||
* public void write(JsonWriter out, Foo src) throws IOException {
|
||||
* if (src == null) {
|
||||
* out.nullValue();
|
||||
* return;
|
||||
* }
|
||||
* // write src as JSON to out
|
||||
* }
|
||||
* }).create();
|
||||
* }</pre>
|
||||
* You can avoid this boilerplate handling of nulls by wrapping your type adapter with
|
||||
* {@link #nullSafe(TypeAdapter)} method. Here is how we will rewrite the above example:
|
||||
* <pre>{@code
|
||||
Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
|
||||
TypeAdapter.nullSafe(new TypeAdapter<Foo>() {
|
||||
public Foo read(JsonReader in) throws IOException {
|
||||
// read a Foo from in and return it
|
||||
}
|
||||
public void write(JsonWriter out, Foo src) throws IOException {
|
||||
// write src as JSON to out
|
||||
}
|
||||
)).create();
|
||||
* <pre> {@code
|
||||
*
|
||||
* Gson gson = new GsonBuilder().registerTypeAdapter(Foo.class,
|
||||
* new TypeAdapter<Foo>() {
|
||||
* public Foo read(JsonReader in) throws IOException {
|
||||
* // read a Foo from in and return it
|
||||
* }
|
||||
* public void write(JsonWriter out, Foo src) throws IOException {
|
||||
* // write src as JSON to out
|
||||
* }
|
||||
* }.nullSafe()).create();
|
||||
* }</pre>
|
||||
* Note that we didn't need to check for nulls in our type adapter after we used nullSafe.
|
||||
*/
|
||||
public static <T> TypeAdapter<T> nullSafe(final TypeAdapter<T> typeAdapter) {
|
||||
public TypeAdapter<T> nullSafe() {
|
||||
return new TypeAdapter<T>() {
|
||||
@Override public void write(JsonWriter out, T value) throws IOException {
|
||||
if (value == null) {
|
||||
out.nullValue();
|
||||
} else {
|
||||
typeAdapter.write(out, value);
|
||||
write(out, value);
|
||||
}
|
||||
}
|
||||
@Override public T read(JsonReader reader) throws IOException {
|
||||
@ -189,7 +191,7 @@ public abstract class TypeAdapter<T> {
|
||||
reader.nextNull();
|
||||
return null;
|
||||
}
|
||||
return typeAdapter.read(reader);
|
||||
return read(reader);
|
||||
}
|
||||
};
|
||||
}
|
||||
|
@ -173,8 +173,7 @@ public final class StreamingTypeAdaptersTest extends TestCase {
|
||||
gson.fromJson(json, Truck.class);
|
||||
fail();
|
||||
} catch (JsonSyntaxException expected) {}
|
||||
gson = new GsonBuilder().registerTypeAdapter(
|
||||
Person.class, TypeAdapter.nullSafe(typeAdapter)).create();
|
||||
gson = new GsonBuilder().registerTypeAdapter(Person.class, typeAdapter.nullSafe()).create();
|
||||
assertEquals("{\"horsePower\":1.0,\"passengers\":[null]}", gson.toJson(truck, Truck.class));
|
||||
truck = gson.fromJson(json, Truck.class);
|
||||
assertEquals(1.0D, truck.horsePower);
|
||||
|
Loading…
Reference in New Issue
Block a user