/*
* #%L
* FlatPack serialization code
* %%
* Copyright (C) 2012 Perka Inc.
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
package com.getperka.flatpack.codexes;
import java.io.IOException;
import java.util.Collection;
import javax.inject.Inject;
import com.getperka.flatpack.ext.Codex;
import com.getperka.flatpack.ext.DeserializationContext;
import com.getperka.flatpack.ext.JsonKind;
import com.getperka.flatpack.ext.SerializationContext;
import com.getperka.flatpack.ext.Type;
import com.getperka.flatpack.ext.TypeContext;
import com.getperka.flatpack.ext.UpdatingCodex;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.stream.JsonWriter;
import com.google.inject.TypeLiteral;
/**
* A base type to serialize a collection of objects as an array.
*
* @param <T> the type of collection to be serialized
* @param <V> the value type contained in the collection
*/
public abstract class CollectionCodex<T extends Collection<V>, V> extends UpdatingCodex<T> {
/**
* Initialized in {@link #setType(TypeLiteral, TypeContext)} so subclasses need not call an
* explicit super-constructor.
*/
private Codex<V> valueCodex;
protected CollectionCodex() {}
@Override
public Type describe() {
return new Type.Builder()
.withJsonKind(JsonKind.LIST)
.withListElement(valueCodex.describe())
.build();
}
@Override
public String getPropertySuffix() {
return valueCodex.getPropertySuffix();
}
@Override
public T readNotNull(JsonElement element, DeserializationContext context)
throws Exception {
T toReturn = newCollection();
JsonArray array = element.getAsJsonArray();
int count = 0;
for (JsonElement elt : array) {
context.pushPath("[" + count++ + "]");
toReturn.add(valueCodex.read(elt, context));
context.popPath();
}
return toReturn;
}
@Override
public T replacementValueNotNull(T oldValue, T newValue) {
oldValue.clear();
oldValue.addAll(newValue);
return oldValue;
}
@Override
public void writeNotNull(T collection, SerializationContext context) throws IOException {
JsonWriter writer = context.getWriter();
writer.beginArray();
int count = 0;
for (V t : collection) {
context.pushPath("[" + count++ + "]");
valueCodex.write(t, context);
context.popPath();
}
writer.endArray();
}
/**
* The codex for the elements in the collection.
*/
protected Codex<V> getValueCodex() {
return valueCodex;
}
protected abstract T newCollection();
@Inject
@SuppressWarnings("unchecked")
void setType(TypeLiteral<V> valueType, TypeContext context) {
valueCodex = (Codex<V>) context.getCodex(valueType.getType());
}
}