com.cloudera.exhibit.mongodb.BSONObsDescriptor.java Source code

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Here is the source code for com.cloudera.exhibit.mongodb.BSONObsDescriptor.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.mongodb;

import com.cloudera.exhibit.core.ObsDescriptor;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.google.common.collect.UnmodifiableIterator;

import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class BSONObsDescriptor implements ObsDescriptor {

    private final List<String> names;
    private final List<FieldType> fieldTypes;
    private final List<String> columns;

    public BSONObsDescriptor(List<String> names, List<FieldType> fieldTypes) {
        this(names, fieldTypes, ImmutableMap.<String, String>of());
    }

    public BSONObsDescriptor(List<String> names, List<FieldType> fieldTypes, Map<String, String> mappings) {
        this.names = names;
        this.fieldTypes = fieldTypes;
        this.columns = getColumns(names, mappings);
    }

    private static List<String> getColumns(List<String> names, final Map<String, String> mappings) {
        List<String> ret = Lists.newArrayListWithExpectedSize(names.size());
        for (int i = 0; i < names.size(); i++) {
            String key = names.get(i);
            String col = mappings.get(key);
            ret.add(col == null ? key : col);
        }
        return ret;
    }

    @Override
    public Field get(int i) {
        return new Field(names.get(i), fieldTypes.get(i));
    }

    String getBSONColumn(int i) {
        return columns.get(i);
    }

    @Override
    public int indexOf(String name) {
        return names.indexOf(name);
    }

    @Override
    public int size() {
        return names.size();
    }

    @Override
    public Iterator<Field> iterator() {
        return new UnmodifiableIterator<Field>() {
            private int index = 0;

            @Override
            public boolean hasNext() {
                return index < size();
            }

            @Override
            public Field next() {
                Field f = get(index);
                index++;
                return f;
            }
        };
    }
}