/*
* Copyright 2010 Nabeel Mukhtar
*
* 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.
*
*/
package com.google.code.stackexchange.client.impl;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;
import java.lang.reflect.Type;
import java.nio.charset.Charset;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import com.google.code.stackexchange.client.constant.ApplicationConstants;
import com.google.code.stackexchange.client.exception.StackExchangeApiException;
import com.google.code.stackexchange.client.provider.url.ApiUrlBuilder;
import com.google.code.stackexchange.common.PagedArrayList;
import com.google.code.stackexchange.common.PagedList;
import com.google.code.stackexchange.schema.Answer;
import com.google.code.stackexchange.schema.Badge;
import com.google.code.stackexchange.schema.BadgeRank;
import com.google.code.stackexchange.schema.Comment;
import com.google.code.stackexchange.schema.Error;
import com.google.code.stackexchange.schema.PostTimeline;
import com.google.code.stackexchange.schema.PostTimelineType;
import com.google.code.stackexchange.schema.PostType;
import com.google.code.stackexchange.schema.Question;
import com.google.code.stackexchange.schema.Reputation;
import com.google.code.stackexchange.schema.Revision;
import com.google.code.stackexchange.schema.RevisionType;
import com.google.code.stackexchange.schema.SchemaEntity;
import com.google.code.stackexchange.schema.SiteState;
import com.google.code.stackexchange.schema.Statistics;
import com.google.code.stackexchange.schema.Tag;
import com.google.code.stackexchange.schema.TagRestriction;
import com.google.code.stackexchange.schema.User;
import com.google.code.stackexchange.schema.UserTimeline;
import com.google.code.stackexchange.schema.UserTimelineType;
import com.google.code.stackexchange.schema.UserType;
import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;
/**
* The Class StackExchangeApiJsonClient.
*/
public class StackExchangeApiJsonClient extends BaseStackExchangeApiClient {
private static final Map<Class<? extends SchemaEntity>, String> LIST_PLACE_HOLDERS = new HashMap<Class<? extends SchemaEntity>, String>();
static {
LIST_PLACE_HOLDERS.put(Answer.class, "answers");
LIST_PLACE_HOLDERS.put(Badge.class, "badges");
LIST_PLACE_HOLDERS.put(Comment.class, "comments");
LIST_PLACE_HOLDERS.put(Question.class, "questions");
LIST_PLACE_HOLDERS.put(PostTimeline.class, "post_timelines");
LIST_PLACE_HOLDERS.put(Reputation.class, "rep_changes");
LIST_PLACE_HOLDERS.put(Statistics.class, "statistics");
LIST_PLACE_HOLDERS.put(Tag.class, "tags");
LIST_PLACE_HOLDERS.put(User.class, "users");
LIST_PLACE_HOLDERS.put(UserTimeline.class, "user_timelines");
LIST_PLACE_HOLDERS.put(Revision.class, "revisions");
}
/** The parser. */
private final JsonParser parser = new JsonParser();
protected static final Charset UTF_8_CHAR_SET = Charset.forName(ApplicationConstants.CONTENT_ENCODING);
/**
* Instantiates a new stack exchange api json client.
*
* @param applicationKey the application key
*/
public StackExchangeApiJsonClient(String applicationKey) {
super(applicationKey);
}
/**
* Instantiates a new stack exchange api json client.
*
* @param applicationKey the application key
* @param apiVersion the api version
*/
public StackExchangeApiJsonClient(String applicationKey, String apiVersion) {
super(applicationKey, apiVersion);
}
protected <T> PagedList<T> unmarshallList(Class<T> clazz, InputStream jsonContent) {
try {
JsonElement response = parser.parse(new InputStreamReader(jsonContent, UTF_8_CHAR_SET));
if (response.isJsonObject()) {
JsonObject adaptee = response.getAsJsonObject();
PagedList<T> list = new PagedArrayList<T>();
if (adaptee.has("total")) {
list.setTotal(adaptee.get("total").getAsLong());
}
if (adaptee.has("page")) {
list.setPage(adaptee.get("page").getAsInt());
}
if (adaptee.has("pagesize")) {
list.setPageSize(adaptee.get("pagesize").getAsInt());
}
String placeHolder = LIST_PLACE_HOLDERS.get(clazz);
if (adaptee.has(placeHolder)) {
JsonArray elements = adaptee.get(placeHolder).getAsJsonArray();
if (elements != null) {
Gson gson = getGsonBuilder().create();
for (JsonElement o : elements) {
list.add(gson.fromJson(o, clazz));
}
}
}
return list;
}
throw new StackExchangeApiException("Unknown content found in response:" + response.toString());
} catch (Exception e) {
throw new StackExchangeApiException(e);
}
}
protected <T> T unmarshallObject(Class<T> clazz, InputStream jsonContent) {
if (clazz.equals(Error.class)) {
try {
JsonElement response = parser.parse(new InputStreamReader(jsonContent, UTF_8_CHAR_SET));
if (response.isJsonObject()) {
JsonObject adaptee = response.getAsJsonObject();
Gson gson = getGsonBuilder().create();
return gson.fromJson(adaptee.get("error"), clazz);
}
} catch (Exception e) {
throw new StackExchangeApiException(e);
}
}
return null;
}
/* (non-Javadoc)
* @see com.google.code.stackexchange.client.impl.StackOverflowApiGateway#marshallObject(java.lang.Object)
*/
protected String marshallObject(Object element) {
try {
StringWriter writer = new StringWriter();
return writer.toString();
} catch (Exception e) {
throw new StackExchangeApiException(e);
}
}
/* (non-Javadoc)
* @see com.google.code.stackexchange.client.impl.BaseStackOverflowApiClient#createStackOverflowApiUrlBuilder(java.lang.String)
*/
protected ApiUrlBuilder createStackOverflowApiUrlBuilder(String methodName) {
return getApiProvider().createApiUrlBuilder(methodName, getApplicationKey(), getApiVersion());
}
protected GsonBuilder getGsonBuilder() {
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(Date.class, new JsonDeserializer<Date>() {
@Override
public Date deserialize(JsonElement source, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return new Date(source.getAsLong() * 1000);
}
});
builder.registerTypeAdapter(BadgeRank.class, new JsonDeserializer<BadgeRank>() {
@Override
public BadgeRank deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return BadgeRank.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(PostType.class, new JsonDeserializer<PostType>() {
@Override
public PostType deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return PostType.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(PostTimelineType.class, new JsonDeserializer<PostTimelineType>() {
@Override
public PostTimelineType deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return PostTimelineType.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(UserTimelineType.class, new JsonDeserializer<UserTimelineType>() {
@Override
public UserTimelineType deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return UserTimelineType.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(UserType.class, new JsonDeserializer<UserType>() {
@Override
public UserType deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return UserType.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(RevisionType.class, new JsonDeserializer<RevisionType>() {
@Override
public RevisionType deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return RevisionType.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(TagRestriction.class, new JsonDeserializer<TagRestriction>() {
@Override
public TagRestriction deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return TagRestriction.fromValue(arg0.getAsString());
}
});
builder.registerTypeAdapter(SiteState.class, new JsonDeserializer<SiteState>() {
@Override
public SiteState deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {
return SiteState.fromValue(arg0.getAsString());
}
});
builder.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES);
return builder;
}
}