Example usage for java.util Collections emptyMap

List of usage examples for java.util Collections emptyMap

  1. HOME
  2. Java
  3. java
  4. java.util.*
  5. Collections
  6. emptyMap

Introduction

In this page you can find the example usage for java.util Collections emptyMap.

Prototype

@SuppressWarnings("unchecked")
public static final <K, V> Map<K, V> emptyMap()

Source Link

Document

Returns an empty map (immutable).

Usage

From source file:com.discovery.darchrow.util.MapUtil.java

/**
 * ??map??map./*from   w  w  w .j  a  va  2 s .co  m*/
 * 
 * <p style="color:green">
 *  {@link LinkedHashMap},??? ? <code>singleValueMap</code>??
 * </p>
 * 
 * <p>
 * ?? {@link #toSingleValueMap(Map)}
 * </p>
 * 
 * <h3>:</h3>
 * <blockquote>
 * 
 * <pre class="code">
 * Map{@code <String, String>} singleValueMap = new LinkedHashMap{@code <String, String>}();
 * 
 * singleValueMap.put("province", "??");
 * singleValueMap.put("city", "?");
 * 
 * LOGGER.info(JsonUtil.format(ParamUtil.toArrayValueMap(singleValueMap)));
 * </pre>
 * 
 * :
 * 
 * <pre class="code">
 * {
 * "province": ["??"],
 * "city": ["?"]
 * }
 * </pre>
 * 
 * </blockquote>
 *
 * @param <K>
 *            the key type
 * @param singleValueMap
 *            the name and value map
 * @return ? <code>singleValueMap</code> nullempty, {@link Collections#emptyMap()}<br>
 *         ? <code>singleValueMap</code> value?, <code>arrayValueMap</code>
 * @since 1.6.2
 */
public static <K> Map<K, String[]> toArrayValueMap(Map<K, String> singleValueMap) {
    if (Validator.isNullOrEmpty(singleValueMap)) {
        return Collections.emptyMap();
    }
    Map<K, String[]> arrayValueMap = newLinkedHashMap(singleValueMap.size());//????singleValueMap??
    for (Map.Entry<K, String> entry : singleValueMap.entrySet()) {
        arrayValueMap.put(entry.getKey(), ConvertUtil.toArray(entry.getValue()));//?Value???V,???Object
    }
    return arrayValueMap;
}

From source file:ar.com.tadp.xml.rinzo.core.model.tags.dtd.DTDTagTypeDefinition.java

public DTDTagTypeDefinition(DTDElement tagDeclaration, DTDComment comment,
        Map<String, TagTypeDefinition> tagsInDocument, Map<String, DTDComment> attributeComments) {
    this.tagDeclaration = tagDeclaration;
    this.tagComment = comment;
    this.tagsInDocument = tagsInDocument;
    this.attributeComments = (Map<String, DTDComment>) ((attributeComments != null) ? attributeComments
            : Collections.emptyMap());
}

From source file:com.lovebridge.library.volley.toolbox.BasicNetwork.java

@Override
public NetworkResponse performRequest(Request<?> request) throws VolleyError {
    long requestStart = SystemClock.elapsedRealtime();
    while (true) {
        HttpResponse httpResponse = null;
        byte[] responseContents = null;
        Map<String, String> responseHeaders = Collections.emptyMap();
        try {/*from   w w  w.  j av a  2s . c  o  m*/
            // Gather headers.
            Map<String, String> headers = new HashMap<String, String>();
            addCacheHeaders(headers, request.getCacheEntry());
            httpResponse = mHttpStack.performRequest(request, headers);
            StatusLine statusLine = httpResponse.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            responseHeaders = convertHeaders(httpResponse.getAllHeaders());
            // Handle cache validation.
            if (statusCode == HttpStatus.SC_NOT_MODIFIED) {
                Entry entry = request.getCacheEntry();
                if (entry == null) {
                    return new NetworkResponse(HttpStatus.SC_NOT_MODIFIED, null, responseHeaders, true);
                }
                // A HTTP 304 response does not have all header fields. We
                // have to use the header fields from the cache entry plus
                // the new ones from the response.
                // http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5
                entry.responseHeaders.putAll(responseHeaders);
                return new NetworkResponse(HttpStatus.SC_NOT_MODIFIED, entry.data, entry.responseHeaders, true);
            }
            // Some responses such as 204s do not have content. We must
            // check.
            if (httpResponse.getEntity() != null) {
                responseContents = entityToBytes(httpResponse.getEntity());
            } else {
                // Add 0 byte response as a way of honestly representing a
                // no-content request.
                responseContents = new byte[0];
            }
            // if the request is slow, log it.
            long requestLifetime = SystemClock.elapsedRealtime() - requestStart;
            logSlowRequests(requestLifetime, request, responseContents, statusLine);
            if (statusCode < 200 || statusCode > 299) {
                throw new IOException();
            }
            return new NetworkResponse(statusCode, responseContents, responseHeaders, false);
        } catch (SocketTimeoutException e) {
            attemptRetryOnException("socket", request, new TimeoutError());
        } catch (ConnectTimeoutException e) {
            attemptRetryOnException("connection", request, new TimeoutError());
        } catch (MalformedURLException e) {
            throw new RuntimeException("Bad URL " + request.getUrl(), e);
        } catch (IOException e) {
            int statusCode = 0;
            NetworkResponse networkResponse = null;
            if (httpResponse != null) {
                statusCode = httpResponse.getStatusLine().getStatusCode();
            } else {
                throw new NoConnectionError(e);
            }
            VolleyLog.e("Unexpected response code %d for %s", statusCode, request.getUrl());
            if (responseContents != null) {
                networkResponse = new NetworkResponse(statusCode, responseContents, responseHeaders, false);
                if (statusCode == HttpStatus.SC_UNAUTHORIZED || statusCode == HttpStatus.SC_FORBIDDEN) {
                    attemptRetryOnException("auth", request, new AuthFailureError(networkResponse));
                } else {
                    // TODO: Only throw ServerError for 5xx status codes.
                    throw new ServerError(networkResponse);
                }
            } else {
                throw new NetworkError(networkResponse);
            }
        }
    }
}

From source file:org.datacleaner.util.http.HttpXmlUtils.java

public String getUrlContent(String url, Map<String, String> params) throws IOException {
    if (params == null) {
        params = Collections.emptyMap();
    }/*w w  w.j a  v a  2s . com*/
    logger.info("getUrlContent({},{})", url, params);
    HttpPost method = new HttpPost(url);
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
    for (Entry<String, String> entry : params.entrySet()) {
        nameValuePairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
    }
    method.setEntity(new UrlEncodedFormEntity(nameValuePairs, "UTF-8"));
    ResponseHandler<String> responseHandler = new BasicResponseHandler();
    String response = getHttpClient().execute(method, responseHandler);
    return response;
}

From source file:piecework.content.concrete.RemoteResource.java

@Override
public Map<String, String> getMetadata() {
    return Collections.emptyMap();
}

From source file:io.fabric8.camel.FabricLocatorEndpoint.java

@Override
public synchronized void groupEvent(Group<CamelNodeState> group, GroupEvent event) {
    Map<String, CamelNodeState> members;
    if (event == GroupEvent.DISCONNECTED || !isStarted()) {
        members = Collections.emptyMap();
    } else {/*www . ja  v a 2 s.  c  o  m*/
        members = group.members();
    }
    //Find what has been removed.
    Set<String> removed = new LinkedHashSet<String>();

    for (Map.Entry<String, Processor> entry : processors.entrySet()) {
        String key = entry.getKey();
        if (!members.containsKey(key)) {
            removed.add(key);
        }
    }

    //Add existing processors
    for (Map.Entry<String, CamelNodeState> entry : members.entrySet()) {
        try {
            String key = entry.getKey();
            if (!processors.containsKey(key)) {
                Processor p = getProcessor(entry.getValue().consumer);
                processors.put(key, p);
                loadBalancer.addProcessor(p);
            }
        } catch (URISyntaxException e) {
            LOG.warn("Unable to add endpoint " + entry.getValue().consumer, e);
        }
    }

    //Update the list by removing old and adding new.
    for (String key : removed) {
        Processor p = processors.remove(key);
        loadBalancer.removeProcessor(p);
    }
}

From source file:enmasse.controller.flavor.FlavorController.java

@Override
public void configUpdated(Watcher.Action action, ConfigMap configMap) throws IOException {
    if (action.equals(Watcher.Action.MODIFIED) || action.equals(Watcher.Action.ADDED)) {
        if (configMap.getData().containsKey("json")) {
            log.debug("Got new config for " + configMap.getMetadata().getName() + " with data: "
                    + configMap.getData().get("json"));
            JsonNode root = mapper.readTree(configMap.getData().get("json"));
            flavorManager.flavorsUpdated(FlavorParser.parse(root));
        } else {//from   w ww.ja v  a  2  s.co m
            log.debug("Got empty config for " + configMap.getMetadata().getName());
            flavorManager.flavorsUpdated(Collections.emptyMap());
        }
    }
}

From source file:fr.gael.dhus.util.functional.collect.TransformedMapTest.java

/** Constructor: If Transformer param is null, must throw an IllegalArgumentException. */
@Test(expectedExceptions = NullPointerException.class)
@SuppressWarnings("ResultOfObjectAllocationIgnored")
public void nullComparatorTest() {
    new TransformedMap(Collections.emptyMap(), null);
}

From source file:alfio.controller.api.admin.AdminWaitingQueueApiController.java

@RequestMapping(value = "/status", method = RequestMethod.GET)
public Map<String, Boolean> getStatusForEvent(@PathVariable("eventName") String eventName,
        Principal principal) {//from  w  ww  .  ja va  2  s  . c  om
    return optionally(() -> eventManager.getSingleEvent(eventName, principal.getName())).map(this::loadStatus)
            .orElse(Collections.emptyMap());
}

From source file:com.amazon.speech.slu.Intent.java

/**
 * Private constructor used for JSON serialization.
 *
 * @param name// ww  w . j av  a 2  s  .c  o m
 *            the intent name
 * @param slots
 *            the slots associated with the intent
 */
private Intent(@JsonProperty("name") final String name, @JsonProperty("slots") final Map<String, Slot> slots) {
    this.name = name;

    if (slots != null) {
        this.slots = Collections.unmodifiableMap(slots);
    } else {
        this.slots = Collections.emptyMap();
    }
}