Example usage for org.apache.commons.collections4 MapUtils invertMap

Introduction

In this page you can find the example usage for org.apache.commons.collections4 MapUtils invertMap.

Prototype

public static <K, V> Map<V, K> invertMap(final Map<K, V> map) 

Source Link

Document

Inverts the supplied map returning a new HashMap such that the keys of the input are swapped with the values.

Usage

From source file:com.sunchenbin.store.feilong.core.util.MapUtil.java

/**
 * mapkeyvalue./*from   w  ww  . j a  va2 s  .c  o m*/
 * 
 * <p>
 * <span style="color:red">?map</span>.?map,??key?value,map(key)?(value),??key
 * </p>
 *
 * @param <K>
 *            the key type
 * @param <V>
 *            the value type
 * @param map
 *            the map
 * @return mapnullOrEmpty , empty map
 * @see org.apache.commons.collections4.MapUtils#invertMap(Map)
 * @since 1.2.2
 */
public static <K, V> Map<V, K> invertMap(Map<K, V> map) {
    return MapUtils.invertMap(map);
}

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From source file:com.feilong.core.util.MapUtil.java

/**
 *  <code>map</code> keyvalue.
 * //  w  w  w . ja v  a 2s  .  c o  m
 * <p>
 * <span style="color:red">?map</span>.<br>
 * ?map,??key?value,map(key)?(value),??key
 * </p>
 * 
 * <h3>:</h3>
 * <blockquote>
 * 
 * <pre class="code">
 * Map{@code <String, Integer>} map = new HashMap{@code <String, Integer>}();
 * map.put("a", 3007);
 * map.put("b", 3001);
 * map.put("c", 3001);
 * map.put("d", 3003);
 * LOGGER.debug(JsonUtil.format(MapUtil.invertMap(map)));
 * </pre>
 * 
 * <b>:</b>
 * 
 * <pre class="code">
 * {
 * "3001": "c",
 * "3007": "a",
 * "3003": "d"
 * }
 * </pre>
 * 
 * ? b
 * 
 * </blockquote>
 * 
 * @param <K>
 *            the key type
 * @param <V>
 *            the value type
 * @param map
 *            the map
 * @return <code>map</code> null, {@link NullPointerException}<br>
 *         <code>map</code> empty,  new HashMap
 * @see org.apache.commons.collections4.MapUtils#invertMap(Map)
 * @since 1.2.2
 */
public static <K, V> Map<V, K> invertMap(Map<K, V> map) {
    return MapUtils.invertMap(map);// HashMap
}

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From source file:org.apache.nutch.mapreduce.NutchCounter.java

private void registerCounters(ArrayList<String> names) {
    countersCount.set(names.size());//from  w ww .  ja  v  a  2  s  .  c om

    for (int i = 0; i < countersCount.get(); ++i) {
        counterNames.add(names.get(i));
        counterIndexes.put(names.get(i), i);
        globalCounters.add(new AtomicInteger(0));
        nativeCounters.add(new AtomicInteger(0));
    }

    if (countersCount.get() == 0) {
        LOG.warn("No counters, will not run report thread");
    }

    Validate.isTrue(counterIndexes.size() == counterNames.size());
    Validate.isTrue(counterIndexes.size() == countersCount.get());
    Validate.isTrue(CollectionUtils.containsAll(counterIndexes.keySet(), counterNames));

    LOG.info("Registered counters : " + StringUtils.join(MapUtils.invertMap(counterIndexes).entrySet(), ", "));
}

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From source file:org.apache.samza.storage.ContainerStorageManager.java

/**
 * For each standby task, we remove its changeLogSSPs from changelogSSP map and add it to the task's taskSideInputSSPs.
 * The task's sideInputManager will consume and restore these as well.
 *
 * @param containerModel the container's model
 * @param changelogSystemStreams the passed in set of changelogSystemStreams
 * @return A map of changeLogSSP to storeName across all tasks, assuming no two stores have the same changelogSSP
 *///w w w.j av a2 s . c om
private Map<String, SystemStream> getChangelogSystemStreams(ContainerModel containerModel,
        Map<String, SystemStream> changelogSystemStreams) {

    if (MapUtils.invertMap(changelogSystemStreams).size() != changelogSystemStreams.size()) {
        throw new SamzaException("Two stores cannot have the same changelog system-stream");
    }

    Map<SystemStreamPartition, String> changelogSSPToStore = new HashMap<>();
    changelogSystemStreams
            .forEach((storeName, systemStream) -> containerModel.getTasks().forEach((taskName, taskModel) -> {
                changelogSSPToStore.put(
                        new SystemStreamPartition(systemStream, taskModel.getChangelogPartition()), storeName);
            }));

    getTasks(containerModel, TaskMode.Standby).forEach((taskName, taskModel) -> {
        changelogSystemStreams.forEach((storeName, systemStream) -> {
            SystemStreamPartition ssp = new SystemStreamPartition(systemStream,
                    taskModel.getChangelogPartition());
            changelogSSPToStore.remove(ssp);
            this.taskSideInputSSPs.putIfAbsent(taskName, new HashMap<>());
            this.sideInputSystemStreams.put(storeName, Collections.singleton(ssp.getSystemStream()));
            this.taskSideInputSSPs.get(taskName).put(storeName, Collections.singleton(ssp));
        });
    });

    // changelogSystemStreams correspond only to active tasks (since those of standby-tasks moved to side inputs above)
    return MapUtils.invertMap(changelogSSPToStore).entrySet().stream()
            .collect(Collectors.toMap(Map.Entry::getKey, x -> x.getValue().getSystemStream()));
}

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