com.cloudera.cdk.data.filesystem.PathConversion.java Source code

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Here is the source code for com.cloudera.cdk.data.filesystem.PathConversion.java

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/*
 * Copyright 2013 Cloudera.
 *
 * 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.cloudera.cdk.data.filesystem;

import com.cloudera.cdk.data.FieldPartitioner;
import com.cloudera.cdk.data.partition.DayOfMonthFieldPartitioner;
import com.cloudera.cdk.data.partition.HourFieldPartitioner;
import com.cloudera.cdk.data.partition.MinuteFieldPartitioner;
import com.cloudera.cdk.data.partition.MonthFieldPartitioner;
import com.cloudera.cdk.data.spi.Conversions;
import com.cloudera.cdk.data.spi.StorageKey;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import org.apache.hadoop.fs.Path;

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

class PathConversion {

    public StorageKey toKey(Path fromPath, StorageKey storage) {
        final List<FieldPartitioner> partitioners = storage.getPartitionStrategy().getFieldPartitioners();
        final List<Object> values = Lists.newArrayList(new Object[partitioners.size()]);

        Path currentPath = fromPath;
        int index = partitioners.size() - 1;
        while (currentPath != null && index >= 0) {
            values.set(index,
                    valueForDirname((FieldPartitioner<?, ?>) partitioners.get(index), currentPath.getName()));

            // update
            currentPath = currentPath.getParent();
            index -= 1;
        }

        storage.replaceValues(values);
        return storage;
    }

    public Path fromKey(StorageKey key) {
        final StringBuilder pathBuilder = new StringBuilder();
        final List<FieldPartitioner> partitioners = key.getPartitionStrategy().getFieldPartitioners();

        for (int i = 0; i < partitioners.size(); i++) {
            final FieldPartitioner fp = partitioners.get(i);
            if (i != 0) {
                pathBuilder.append(Path.SEPARATOR_CHAR);
            }
            @SuppressWarnings("unchecked")
            String dirname = dirnameForValue(fp, key.get(i));
            pathBuilder.append(dirname);
        }

        return new Path(pathBuilder.toString());
    }

    private static final Splitter PART_SEP = Splitter.on('=');
    private static final Joiner PART_JOIN = Joiner.on('=');
    private static final Map<Class<?>, Integer> WIDTHS = ImmutableMap.<Class<?>, Integer>builder()
            .put(MinuteFieldPartitioner.class, 2).put(HourFieldPartitioner.class, 2)
            .put(DayOfMonthFieldPartitioner.class, 2).put(MonthFieldPartitioner.class, 2).build();

    public <T> String dirnameForValue(FieldPartitioner<?, T> field, T value) {
        return PART_JOIN.join(field.getName(), Conversions.makeString(value, WIDTHS.get(field.getClass())));
    }

    public <T> T valueForDirname(FieldPartitioner<?, T> field, String name) {
        // this could check that the field name matches the directory name
        return Conversions.convert(valueStringForDirname(name), field.getType());
    }

    public String valueStringForDirname(String name) {
        return Iterables.getLast(PART_SEP.split(name));
    }
}