JsonUtil.java

  1. /*
  2.  * Portions of this software was developed by employees of the National Institute
  3.  * of Standards and Technology (NIST), an agency of the Federal Government and is
  4.  * being made available as a public service. Pursuant to title 17 United States
  5.  * Code Section 105, works of NIST employees are not subject to copyright
  6.  * protection in the United States. This software may be subject to foreign
  7.  * copyright. Permission in the United States and in foreign countries, to the
  8.  * extent that NIST may hold copyright, to use, copy, modify, create derivative
  9.  * works, and distribute this software and its documentation without fee is hereby
  10.  * granted on a non-exclusive basis, provided that this notice and disclaimer
  11.  * of warranty appears in all copies.
  12.  *
  13.  * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
  14.  * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
  15.  * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
  16.  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
  17.  * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
  18.  * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
  19.  * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
  20.  * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
  21.  * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
  22.  * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
  23.  * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
  24.  * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
  25.  */

  27. package gov.nist.secauto.metaschema.core.model.util;

  29. import com.fasterxml.jackson.core.JsonLocation;
  30. import com.fasterxml.jackson.core.JsonParser;
  31. import com.fasterxml.jackson.core.JsonToken;

  33. import gov.nist.secauto.metaschema.core.util.CustomCollectors;
  34. import gov.nist.secauto.metaschema.core.util.ObjectUtils;

  36. import org.apache.logging.log4j.LogManager;
  37. import org.apache.logging.log4j.Logger;
  38. import org.json.JSONObject;
  39. import org.json.JSONTokener;

  41. import java.io.IOException;
  42. import java.io.InputStream;
  43. import java.io.Reader;
  44. import java.util.Arrays;
  45. import java.util.Collection;
  46. import java.util.List;

  48. import edu.umd.cs.findbugs.annotations.NonNull;
  49. import edu.umd.cs.findbugs.annotations.Nullable;

  51. public final class JsonUtil {
  52.   private static final Logger LOGGER = LogManager.getLogger(JsonUtil.class);

  54.   private JsonUtil() {
  55.     // disable construction
  56.   }

  58.   @NonNull
  59.   public static JSONObject toJsonObject(@NonNull InputStream schemaInputStream) {
  60.     return new JSONObject(new JSONTokener(schemaInputStream));
  61.   }

  63.   @NonNull
  64.   public static JSONObject toJsonObject(@NonNull Reader reader) {
  65.     return new JSONObject(new JSONTokener(reader));
  66.   }

  68.   /**
  69.    * Generate an informational string describing the token at the current location
  70.    * of the provided {@code parser}.
  71.    *
  72.    * @param parser
  73.    *          the JSON parser
  74.    * @return the informational string
  75.    * @throws IOException
  76.    *           if an error occurred while getting the information from the parser
  77.    */
  78.   @SuppressWarnings("null")
  79.   @NonNull
  80.   public static String toString(@NonNull JsonParser parser) throws IOException {
  81.     return new StringBuilder(32)
  82.         .append(parser.currentToken().name())
  83.         .append(" '")
  84.         .append(parser.getText())
  85.         .append('\'')
  86.         .append(generateLocationMessage(parser))
  87.         .toString();
  88.   }

  90.   /**
  91.    * Generate an informational string describing the provided {@code location}.
  92.    *
  93.    * @param location
  94.    *          a JSON parser location
  95.    * @return the informational string
  96.    */
  97.   @SuppressWarnings("null")
  98.   @NonNull
  99.   public static String toString(@NonNull JsonLocation location) {
  100.     return new StringBuilder(8)
  101.         .append(location.getLineNr())
  102.         .append(':')
  103.         .append(location.getColumnNr())
  104.         .toString();
  105.   }

  107.   @Nullable
  108.   public static JsonToken advanceTo(@NonNull JsonParser parser, JsonToken token) throws IOException {
  109.     JsonToken currentToken = null;
  110.     while (parser.hasCurrentToken() && !token.equals(currentToken = parser.currentToken())) {
  111.       currentToken = parser.nextToken();
  112.       if (LOGGER.isWarnEnabled()) {
  113.         LOGGER.warn("skipping over: {}{}",
  114.             toString(parser),
  115.             generateLocationMessage(parser));
  116.       }
  117.     }
  118.     return currentToken;
  119.   }

  121.   @SuppressWarnings({
  122.       "resource", // parser not owned
  123.       "PMD.CyclomaticComplexity" // acceptable
  124.   })
  125.   @Nullable
  126.   public static JsonToken skipNextValue(@NonNull JsonParser parser) throws IOException {

  128.     JsonToken currentToken = parser.currentToken();
  129.     // skip the field name
  130.     if (JsonToken.FIELD_NAME.equals(currentToken)) {
  131.       currentToken = parser.nextToken();
  132.     }

  134.     switch (currentToken) {
  135.     case START_ARRAY:
  136.     case START_OBJECT:
  137.       parser.skipChildren();
  138.       break;
  139.     case VALUE_FALSE:
  140.     case VALUE_NULL:
  141.     case VALUE_NUMBER_FLOAT:
  142.     case VALUE_NUMBER_INT:
  143.     case VALUE_STRING:
  144.     case VALUE_TRUE:
  145.       // do nothing
  146.       break;
  147.     default:
  148.       // error
  149.       String msg = String.format("Unhandled JsonToken %s%s.",
  150.           toString(parser),
  151.           generateLocationMessage(parser));
  152.       LOGGER.error(msg);
  153.       throw new UnsupportedOperationException(msg);
  154.     }

  156.     // advance past the value
  157.     return parser.nextToken();
  158.   }

  160.   @SuppressWarnings("PMD.CyclomaticComplexity") // acceptable
  161.   public static boolean checkEndOfValue(@NonNull JsonParser parser, @NonNull JsonToken startToken) {
  162.     JsonToken currentToken = parser.getCurrentToken();

  164.     boolean retval;
  165.     switch (startToken) { // NOPMD - intentional fall through
  166.     case START_OBJECT:
  167.       retval = JsonToken.END_OBJECT.equals(currentToken);
  168.       break;
  169.     case START_ARRAY:
  170.       retval = JsonToken.END_ARRAY.equals(currentToken);
  171.       break;
  172.     case VALUE_EMBEDDED_OBJECT:
  173.     case VALUE_FALSE:
  174.     case VALUE_NULL:
  175.     case VALUE_NUMBER_FLOAT:
  176.     case VALUE_NUMBER_INT:
  177.     case VALUE_STRING:
  178.     case VALUE_TRUE:
  179.       retval = true;
  180.       break;
  181.     default:
  182.       retval = false;
  183.     }
  184.     return retval;
  185.   }

  187.   public static void assertCurrent(
  188.       @NonNull JsonParser parser,
  189.       @NonNull JsonToken... expectedTokens) {
  190.     JsonToken current = parser.currentToken();
  191.     assert Arrays.stream(expectedTokens)
  192.         .anyMatch(expected -> expected.equals(current)) : getAssertMessage(
  193.             parser,
  194.             expectedTokens,
  195.             parser.currentToken());
  196.   }

  198.   public static void assertCurrentIsFieldValue(@NonNull JsonParser parser) {
  199.     JsonToken token = parser.currentToken();
  200.     assert token.isStructStart() || token.isScalarValue() : String.format(
  201.         "Expected a START_OBJECT, START_ARRAY, or VALUE_xxx token, but found JsonToken '%s'%s.",
  202.         token,
  203.         generateLocationMessage(parser));
  204.   }

  206.   @Nullable
  207.   public static JsonToken assertAndAdvance(
  208.       @NonNull JsonParser parser,
  209.       @NonNull JsonToken expectedToken)
  210.       throws IOException {
  211.     JsonToken token = parser.currentToken();
  212.     assert expectedToken.equals(token) : getAssertMessage(
  213.         parser,
  214.         expectedToken,
  215.         token);
  216.     return parser.nextToken();
  217.   }

  219.   @Nullable
  220.   public static JsonToken advanceAndAssert(
  221.       @NonNull JsonParser parser,
  222.       @NonNull JsonToken expectedToken)
  223.       throws IOException {
  224.     JsonToken token = parser.nextToken();
  225.     assert expectedToken.equals(token) : getAssertMessage(
  226.         parser,
  227.         expectedToken,
  228.         token);
  229.     return token;
  230.   }

  232.   @NonNull
  233.   public static String getAssertMessage(
  234.       @NonNull JsonParser parser,
  235.       @NonNull JsonToken expected,
  236.       JsonToken actual) {
  237.     return ObjectUtils.notNull(
  238.         String.format("Expected JsonToken '%s', but found JsonToken '%s'%s.",
  239.             expected,
  240.             actual,
  241.             generateLocationMessage(parser)));
  242.   }

  244.   @NonNull
  245.   public static String getAssertMessage(
  246.       @NonNull JsonParser parser,
  247.       @NonNull JsonToken[] expected,
  248.       JsonToken actual) {
  249.     List<JsonToken> expectedTokens = ObjectUtils.notNull(Arrays.asList(expected));
  250.     return getAssertMessage(parser, expectedTokens, actual);
  251.   }

  253.   @NonNull
  254.   public static String getAssertMessage(
  255.       @NonNull JsonParser parser,
  256.       @NonNull Collection<JsonToken> expected,
  257.       JsonToken actual) {
  258.     return ObjectUtils.notNull(
  259.         String.format("Expected JsonToken(s) '%s', but found JsonToken '%s'%s.",
  260.             expected.stream().map(token -> token.name()).collect(CustomCollectors.joiningWithOxfordComma("and")),
  261.             actual,
  262.             generateLocationMessage(parser)));
  263.   }

  265.   @NonNull
  266.   public static CharSequence generateLocationMessage(@NonNull JsonParser parser) {
  267.     JsonLocation location = parser.getCurrentLocation();
  268.     return location == null ? "" : generateLocationMessage(location);
  269.   }

  271.   @SuppressWarnings("null")
  272.   @NonNull
  273.   public static CharSequence generateLocationMessage(@NonNull JsonLocation location) {
  274.     return new StringBuilder()
  275.         .append(" at location '")
  276.         .append(location.getLineNr())
  277.         .append(':')
  278.         .append(location.getColumnNr())
  279.         .append('\'');
  280.   }
  281. }
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