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MongoSortKeyMappingFunction.java
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MongoSortKeyMappingFunction.java
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/*
* Copyright (c) 2017 Contributors to the Eclipse Foundation
*
* See the NOTICE file(s) distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0
*
* SPDX-License-Identifier: EPL-2.0
*/
package org.eclipse.ditto.thingsearch.service.persistence;
import java.util.Arrays;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.eclipse.ditto.internal.utils.persistence.mongo.KeyNameReviser;
/**
* This function does (in this order)
* <ol>
* <li>encode each element of the array (real {@code .} and {@code $} with Unicode character),</li>
* <li>replace {@code /} (slash) with {@code .} (dot, the real one),</li>
* <li>join the elements using a {@code .} (dot, the real one).</li>
* </ol>
*/
public final class MongoSortKeyMappingFunction implements Function<String[], String> {
private static final MongoSortKeyMappingFunction INSTANCE = new MongoSortKeyMappingFunction();
private static final KeyNameReviser KEY_NAME_REVISER = KeyNameReviser.escapeProblematicPlainChars();
@Override
public String apply(final String[] values) {
return Arrays.stream(values)
.map(KEY_NAME_REVISER::apply)
.map(s -> s.replace('/', '.'))
.collect(Collectors.joining(PersistenceConstants.DOT));
}
public static String mapSortKey(final String... values) {
return INSTANCE.apply(values);
}
}