com.cloudera.exhibit.etl.SchemaProvider.java Source code

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Here is the source code for com.cloudera.exhibit.etl.SchemaProvider.java

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/*
 * Copyright (c) 2015, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. licenses this file to you 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
 *
 * This software 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.cloudera.exhibit.etl;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.avro.Schema;

import javax.annotation.Nullable;
import java.io.Serializable;
import java.util.List;
import java.util.Map;

public class SchemaProvider implements Serializable {
    private final List<String> json;
    private transient List<Schema> schemas;

    public SchemaProvider(List<Schema> schemas) {
        this.schemas = schemas;
        this.json = Lists.newArrayList(Lists.transform(schemas, new Function<Schema, String>() {
            @Nullable
            @Override
            public String apply(Schema schema) {
                return schema.toString();
            }
        }));
    }

    public Schema get(int i) {
        return getSchemas().get(i);
    }

    private List<Schema> getSchemas() {
        if (schemas == null) {
            Map<String, Schema> defined = Maps.newHashMap();
            this.schemas = Lists.newArrayList();
            for (String s : json) {
                if (defined.containsKey(s)) {
                    schemas.add(defined.get(s));
                } else {
                    Schema.Parser sp = new Schema.Parser();
                    Schema schema = sp.parse(s);
                    defined.put(s, schema);
                    schemas.add(schema);
                }
            }
        }
        return schemas;
    }
}