com.google.iosched.server.input.DataSourceInput.java Source code

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Here is the source code for com.google.iosched.server.input.DataSourceInput.java

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/*
 * 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.iosched.server.input;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.iosched.input.fetcher.EntityFetcher;
import com.google.iosched.model.JsonDataSource;
import com.google.iosched.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(DataSourceInput.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());
        }
    }

}