package com.google.gson;
import com.google.gson.internal.Preconditions;
import com.google.gson.internal.Streams;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
/**
* Adapts a Gson 1.x tree-style adapter as a streaming TypeAdapter. Since the tree adapter may be
* serialization-only or deserialization-only, this class has a facility to lookup a delegate type
* adapter on demand.
*/
final class TreeTypeAdapter<T> extends TypeAdapter<T> {
private final JsonSerializer<T> serializer;
private final JsonDeserializer<T> deserializer;
private final Gson gson;
private final TypeToken<T> typeToken;
private final TypeAdapterFactory skipPast;
/** The delegate is lazily created because it may not be needed, and creating it may fail. */
private TypeAdapter<T> delegate;
private TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer, Gson gson, TypeToken<T> typeToken,
TypeAdapterFactory skipPast) {
this.serializer = serializer;
this.deserializer = deserializer;
this.gson = gson;
this.typeToken = typeToken;
this.skipPast = skipPast;
}
@Override
public T read(JsonReader in) throws IOException {
if (deserializer == null) {
return delegate().read(in);
}
JsonElement value = Streams.parse(in);
if (value.isJsonNull()) {
return null;
}
return deserializer.deserialize(value, typeToken.getType(), gson.deserializationContext);
}
@Override
public void write(JsonWriter out, T value) throws IOException {
if (serializer == null) {
delegate().write(out, value);
return;
}
if (value == null) {
out.nullValue();
return;
}
JsonElement tree = serializer.serialize(value, typeToken.getType(), gson.serializationContext);
Streams.write(tree, out);
}
private TypeAdapter<T> delegate() {
TypeAdapter<T> d = delegate;
return d != null ? d : (delegate = gson.getDelegateAdapter(skipPast, typeToken));
}
/**
* Returns a new factory that will match each type against {@code exactType}.
*/
public static TypeAdapterFactory newFactory(TypeToken<?> exactType, Object typeAdapter) {
return new SingleTypeFactory(typeAdapter, exactType, false, null);
}
/**
* Returns a new factory that will match each type and its raw type against {@code exactType}.
*/
public static TypeAdapterFactory newFactoryWithMatchRawType(TypeToken<?> exactType, Object typeAdapter) {
// only bother matching raw types if exact type is a raw type
boolean matchRawType = exactType.getType() == exactType.getRawType();
return new SingleTypeFactory(typeAdapter, exactType, matchRawType, null);
}
/**
* Returns a new factory that will match each type's raw type for assignability to
* {@code hierarchyType}.
*/
public static TypeAdapterFactory newTypeHierarchyFactory(Class<?> hierarchyType, Object typeAdapter) {
return new SingleTypeFactory(typeAdapter, null, false, hierarchyType);
}
private static class SingleTypeFactory implements TypeAdapterFactory {
private final TypeToken<?> exactType;
private final boolean matchRawType;
private final Class<?> hierarchyType;
private final JsonSerializer<?> serializer;
private final JsonDeserializer<?> deserializer;
private SingleTypeFactory(Object typeAdapter, TypeToken<?> exactType, boolean matchRawType, Class<?> hierarchyType) {
serializer = typeAdapter instanceof JsonSerializer ? (JsonSerializer<?>) typeAdapter : null;
deserializer = typeAdapter instanceof JsonDeserializer ? (JsonDeserializer<?>) typeAdapter : null;
Preconditions.checkArgument(serializer != null || deserializer != null);
this.exactType = exactType;
this.matchRawType = matchRawType;
this.hierarchyType = hierarchyType;
}
@Override
@SuppressWarnings("unchecked")
// guarded by typeToken.equals() call
public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
boolean matches =
exactType != null ? exactType.equals(type) || matchRawType && exactType.getType() == type.getRawType() : hierarchyType
.isAssignableFrom(type.getRawType());
return matches
? new TreeTypeAdapter<T>((JsonSerializer<T>) serializer, (JsonDeserializer<T>) deserializer, gson, type, this)
: null;
}
}
}