/*
* #%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;
import java.io.IOException;
import java.io.Writer;
import java.security.Principal;
import javax.inject.Inject;
import javax.inject.Provider;
import org.slf4j.Logger;
import com.getperka.flatpack.ext.SerializationContext;
import com.getperka.flatpack.inject.FlatPackLogger;
import com.getperka.flatpack.inject.PackScope;
import com.getperka.flatpack.inject.PrettyPrint;
import com.getperka.flatpack.util.IoObserver;
import com.getperka.flatpack.visitors.PackScanner;
import com.getperka.flatpack.visitors.PackWriter;
import com.google.gson.JsonElement;
import com.google.gson.internal.bind.JsonTreeWriter;
import com.google.gson.stream.JsonWriter;
/**
* Writes {@link FlatPackEntity} objects into a {@link Writer}.
*/
public class Packer {
@Inject
private Provider<SerializationContext> contexts;
@Inject
@FlatPackLogger
private Logger logger;
@Inject
private PackScope packScope;
@Inject
private IoObserver ioObserver;
@Inject
@PrettyPrint
private boolean prettyPrint;
@Inject
private Provider<PackScanner> scanners;
@Inject
private Visitors visitorSupport;
@Inject
private Provider<PackWriter> writers;
protected Packer() {}
/**
* Write the properties for a single entity into a json structure.
*
* @param entity the entity to write
* @param principal an optional Principal for access control
* @return a json representation of the entity
*/
public JsonElement append(HasUuid entity, Principal principal) throws IOException {
JsonTreeWriter json = new JsonTreeWriter();
packScope.enter()
.withJsonWriter(json)
.withPrincipal(principal)
.withTraversalMode(TraversalMode.SPARSE);
SerializationContext context = contexts.get();
try {
context.add(entity);
visitorSupport.visit(writers.get(), entity);
return json.get();
} catch (Exception e) {
context.fail(e);
return null;
} finally {
packScope.exit();
}
}
/**
* Write the properties for a single entity into a {@link Writer}.
*
* @param entity the entity to write
* @param principal an optional Principal for access control
* @param out the destination output which will not be closed by this method
*/
public void append(HasUuid entity, Principal principal, Writer out) throws IOException {
JsonWriter json = jsonWriter(out);
packScope.enter()
.withJsonWriter(json)
.withPrincipal(principal)
.withTraversalMode(TraversalMode.SPARSE);
SerializationContext context = contexts.get();
try {
context.add(entity);
visitorSupport.visit(writers.get(), entity);
} catch (Exception e) {
context.fail(e);
} finally {
packScope.exit();
}
}
/**
* Pack the given entity into a json structure. If the entity is to be immediately written to a
* stream, consider using {@link #pack(FlatPackEntity, Writer)} instead.
*
* @param entity the entity to serialize
* @return a json representation of the entity
*/
public JsonElement pack(FlatPackEntity<?> entity) throws IOException {
JsonTreeWriter json = new JsonTreeWriter();
JsonElement toReturn;
json.setSerializeNulls(false);
packScope.enter().withEntity(entity).withJsonWriter(json);
try {
SerializationContext context = contexts.get();
doPack(entity, context);
toReturn = json.get();
context.runPostWork();
context.close();
} finally {
packScope.exit();
}
return toReturn;
}
/**
* Write the given entity into a {@link Writer}.
*
* @param entity the entity to write
* @param out the destination output which will be closed by this method
*/
public void pack(FlatPackEntity<?> entity, Writer out) throws IOException {
JsonWriter json = jsonWriter(out);
packScope.enter().withEntity(entity).withJsonWriter(json);
try {
SerializationContext context = contexts.get();
doPack(entity, context);
context.runPostWork();
context.close();
} finally {
packScope.exit();
}
}
protected void doPack(FlatPackEntity<?> entity, SerializationContext context) throws IOException {
try {
visitorSupport.visit(scanners.get(), entity);
visitorSupport.visit(writers.get(), entity);
} catch (Exception e) {
context.fail(e);
}
}
private JsonWriter jsonWriter(Writer out) {
out = ioObserver.observe(out);
JsonWriter json = new JsonWriter(out);
json.setSerializeNulls(false);
if (prettyPrint) {
json.setIndent(" ");
}
return json;
}
}