/*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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.samples.apps.iosched.server.schedule.server.input;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.samples.apps.iosched.server.schedule.input.fetcher.EntityFetcher;
import com.google.samples.apps.iosched.server.schedule.input.fetcher.VendorAPIEntityFetcher;
import com.google.samples.apps.iosched.server.schedule.model.JsonDataSource;
import com.google.samples.apps.iosched.server.schedule.model.JsonDataSources;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Encapsulates the logic to extract a set of datasources from a source.
*/
public abstract class DataSourceInput<EnumType extends Enum<EnumType>> {
static Logger LOG = Logger.getLogger(VendorAPIEntityFetcher.class.getName());
public abstract Class<EnumType> getType();
private EntityFetcher fetcher;
public DataSourceInput(EntityFetcher fetcher) {
this.fetcher = fetcher;
}
public EntityFetcher getFetcher() {
return fetcher;
}
void setFetcher(EntityFetcher fetcher) {
this.fetcher = fetcher;
}
public JsonDataSources fetchAllDataSources() throws IOException {
JsonDataSources sources = new JsonDataSources();
for (EnumType type: getType().getEnumConstants()) {
JsonArray data = fetch(type);
if (LOG.isLoggable(Level.INFO)) {
LOG.info("result for "+type+": entities="+data.size());
}
sources.addSource(new JsonDataSource(type, data));
}
return sources;
}
public JsonArray fetch(EnumType entityType) throws IOException {
JsonElement element = getFetcher().fetch(entityType, null);
if (element == null) {
return null;
}
if (element.isJsonArray()) {
return element.getAsJsonArray();
} else {
throw new JsonParseException("Invalid response from DataSourceInput. Expected "
+ "a JsonArray, but fetched "+element.getClass().getName()
+". Entity fetcher is "+getFetcher());
} }
}