Restore remaining checkNotNull guards dropped during matchers migration

Guards for STARTS_WITH, ENDS_WITH, CONTAINS_STRING, MATCHES_STRING,
EQUAL_TO_SEMVER, GREATER_THAN_OR_EQUAL_TO_SEMVER, LESS_THAN_OR_EQUAL_TO_SEMVER,
IN_LIST_SEMVER, BETWEEN_SEMVER, IN_RULE_BASED_SEGMENT, and the final
delegate null check were lost when matchers were migrated from
io.split.engine.matchers to io.split.rules.matchers. Also restores
checkNotNull with message for IN_SPLIT_TREATMENT and EQUAL_TO_BOOLEAN
(previously replaced with manual NPE throws).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

AI-Session-Id: 588a98fd-ba49-4318-8286-5fb79f9efaca
AI-Tool: claude-code
AI-Model: unknown

Author: gthea

client/src/main/java/io/split/engine/experiments/ParserUtils.java

@@ -145,50 +145,64 @@ public static AttributeMatcher toMatcher(Matcher matcher) {
                 delegate = new ContainsAnyOfSetMatcher(matcher.whitelistMatcherData.whitelist);
                 break;
             case STARTS_WITH:
+                checkNotNull(matcher.whitelistMatcherData);
                 delegate = new StartsWithAnyOfMatcher(matcher.whitelistMatcherData.whitelist);
                 break;
             case ENDS_WITH:
+                checkNotNull(matcher.whitelistMatcherData);
                 delegate = new EndsWithAnyOfMatcher(matcher.whitelistMatcherData.whitelist);
                 break;
             case CONTAINS_STRING:
+                checkNotNull(matcher.whitelistMatcherData);
                 delegate = new ContainsAnyOfMatcher(matcher.whitelistMatcherData.whitelist);
                 break;
             case MATCHES_STRING:
+                checkNotNull(matcher.stringMatcherData);
                 delegate = new RegularExpressionMatcher(matcher.stringMatcherData);
                 break;
             case IN_SPLIT_TREATMENT:
-                if (matcher.dependencyMatcherData == null) throw new NullPointerException(
-                        "MatcherType is " + matcher.matcherType + ". matcher.dependencyMatcherData() MUST NOT BE null");
+                checkNotNull(matcher.dependencyMatcherData,
+                        "MatcherType is " + matcher.matcherType
+                                + ". matcher.dependencyMatcherData() MUST NOT BE null");
                 delegate = new DependencyMatcher(matcher.dependencyMatcherData.split, matcher.dependencyMatcherData.treatments);
                 break;
             case EQUAL_TO_BOOLEAN:
-                if (matcher.booleanMatcherData == null) throw new NullPointerException(
-                        "MatcherType is " + matcher.matcherType + ". matcher.booleanMatcherData() MUST NOT BE null");
+                checkNotNull(matcher.booleanMatcherData,
+                        "MatcherType is " + matcher.matcherType
+                                + ". matcher.booleanMatcherData() MUST NOT BE null");
                 delegate = new BooleanMatcher(matcher.booleanMatcherData);
                 break;
             case EQUAL_TO_SEMVER:
+                checkNotNull(matcher.stringMatcherData, "stringMatcherData is required for EQUAL_TO_SEMVER matcher type");
                 delegate = new EqualToSemverMatcher(matcher.stringMatcherData);
                 break;
             case GREATER_THAN_OR_EQUAL_TO_SEMVER:
+                checkNotNull(matcher.stringMatcherData, "stringMatcherData is required for GREATER_THAN_OR_EQUAL_TO_SEMVER matcher type");
                 delegate = new GreaterThanOrEqualToSemverMatcher(matcher.stringMatcherData);
                 break;
             case LESS_THAN_OR_EQUAL_TO_SEMVER:
+                checkNotNull(matcher.stringMatcherData, "stringMatcherData is required for LESS_THAN_OR_EQUAL_SEMVER matcher type");
                 delegate = new LessThanOrEqualToSemverMatcher(matcher.stringMatcherData);
                 break;
             case IN_LIST_SEMVER:
+                checkNotNull(matcher.whitelistMatcherData, "whitelistMatcherData is required for IN_LIST_SEMVER matcher type");
                 delegate = new InListSemverMatcher(matcher.whitelistMatcherData.whitelist);
                 break;
             case BETWEEN_SEMVER:
+                checkNotNull(matcher.betweenStringMatcherData, "betweenStringMatcherData is required for BETWEEN_SEMVER matcher type");
                 delegate = new BetweenSemverMatcher(matcher.betweenStringMatcherData.start, matcher.betweenStringMatcherData.end);
                 break;
             case IN_RULE_BASED_SEGMENT:
+                checkNotNull(matcher.userDefinedSegmentMatcherData);
                 String ruleBasedSegmentName = matcher.userDefinedSegmentMatcherData.segmentName;
                 delegate = new RuleBasedSegmentMatcher(ruleBasedSegmentName);
                 break;
             default:
                 throw new IllegalArgumentException("Unknown matcher type: " + matcher.matcherType);
         }
 
+        checkNotNull(delegate, "We were not able to create a matcher for: " + matcher.matcherType);
+
         String attribute = null;
         if (matcher.keySelector != null && matcher.keySelector.attribute != null) {
             attribute = matcher.keySelector.attribute;