com.cloudera.oryx.als.computation.known.CollectKnownItemsFn.java Source code

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Here is the source code for com.cloudera.oryx.als.computation.known.CollectKnownItemsFn.java

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/*
 * Copyright (c) 2013, 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.oryx.als.computation.known;

import com.cloudera.oryx.common.collection.LongFloatMap;
import com.cloudera.oryx.common.iterator.LongPrimitiveIterator;
import com.cloudera.oryx.common.io.DelimitedDataUtils;
import com.cloudera.oryx.computation.common.fn.OryxMapFn;

import com.google.common.collect.Lists;
import org.apache.crunch.Pair;

import java.util.Collection;

public final class CollectKnownItemsFn extends OryxMapFn<Pair<Long, LongFloatMap>, String> {
    @Override
    public String map(Pair<Long, LongFloatMap> input) {
        return input.first().toString() + '\t' + setToString(input.second());
    }

    private static String setToString(LongFloatMap map) {
        LongPrimitiveIterator it = map.keySetIterator();
        Collection<String> keyStrings = Lists.newArrayListWithCapacity(map.size());
        while (it.hasNext()) {
            keyStrings.add(Long.toString(it.nextLong()));
        }
        return DelimitedDataUtils.encode(keyStrings);
    }
}