moved validation of too complex placeholders to parsing

Signed-off-by: Thomas Jaeckle <thomas.jaeckle@bosch-si.com>

model/placeholders/src/main/java/org/eclipse/ditto/model/placeholders/ExpressionResolver.java

@@ -42,6 +42,8 @@ public interface ExpressionResolver {
      * {@code true} and placeholders could not be resolved.
      * @throws org.eclipse.ditto.model.connectivity.UnresolvedPlaceholderException thrown if {@code allowUnresolved} was
      * set to {@code false} and the passed in {@code expressionTemplate} could not be resolved
+     * @throws PlaceholderFunctionTooComplexException thrown if the {@code expressionTemplate} contains a placeholder
+     * function chain which is too complex (e.g. too much chained function calls)
      */
     String resolve(String expressionTemplate, boolean allowUnresolved);
 

model/placeholders/src/main/java/org/eclipse/ditto/model/placeholders/ImmutableExpressionResolver.java

@@ -143,6 +143,10 @@ private List<String> getPipelineStagesExpressions(final String template) {
 
         while (matcher.find()) {
             pipelineStagesExpressions.add(matcher.group().trim());
+
+            if (pipelineStagesExpressions.size() > MAX_COUNT_PIPELINE_FUNCTIONS + 1) { // +1 for the starting placeholder
+                throw PlaceholderFunctionTooComplexException.newBuilder(MAX_COUNT_PIPELINE_FUNCTIONS).build();
+            }
         }
         return pipelineStagesExpressions;
     }
@@ -158,11 +162,6 @@ private Pipeline getPipelineFromExpressions(final List<String> pipelineStagesExp
         final List<String> pipelineStages = pipelineStagesExpressions.stream()
                 .skip(1) // ignore first, as the first one is a placeholder that will be used as the input for the pipeline
                 .collect(Collectors.toList());
-
-        if (pipelineStages.size() > MAX_COUNT_PIPELINE_FUNCTIONS) {
-            throw PlaceholderFunctionTooComplexException.newBuilder(MAX_COUNT_PIPELINE_FUNCTIONS).build();
-        }
-
         return new ImmutablePipeline(ImmutableFunctionExpression.INSTANCE, pipelineStages);
     }
 

model/placeholders/src/main/java/org/eclipse/ditto/model/placeholders/PlaceholderFilter.java

@@ -152,6 +152,8 @@ public static String apply(final String template, final ExpressionResolver expre
      * @return the template string with the resolved values
      * @throws UnresolvedPlaceholderException if {@code allowUnresolved} is true and not all
      * placeholders were resolved
+     * @throws PlaceholderFunctionTooComplexException thrown if the {@code template} contains a placeholder
+     * function chain which is too complex (e.g. too much chained function calls)
      */
     public static String apply(final String template, final ExpressionResolver expressionResolver,
             final boolean allowUnresolved) {
@@ -166,6 +168,8 @@ public static String apply(final String template, final ExpressionResolver expre
      * @param template a string potentially containing placeholders to replace
      * @param placeholders the {@link Placeholder}s to use for replacement
      * @throws UnresolvedPlaceholderException in case the template's placeholders could not completely be resolved
+     * @throws PlaceholderFunctionTooComplexException thrown if the {@code template} contains a placeholder
+     * function chain which is too complex (e.g. too much chained function calls)
      */
     public static void validate(final String template, final Placeholder<?>... placeholders) {
         String replaced = template;

model/placeholders/src/test/java/org/eclipse/ditto/model/placeholders/ImmutableExpressionResolverTest.java

@@ -12,7 +12,6 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.util.Arrays;
 import java.util.Map;
@@ -187,10 +186,9 @@ public void testResolveBarelyTooComplexFunctionChainWorks() {
     @Test
     public void testResolveTooComplexFunctionChainResultsInException() {
         // 11 functions should fail:
-        assertThatThrownBy(() ->
+        assertThatExceptionOfType(PlaceholderFunctionTooComplexException.class).isThrownBy(() ->
                 underTest.resolve(
                         "{{ header:unknown | fn:default('fallback') | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() }}",
-                        false))
-                .isInstanceOf(PlaceholderFunctionTooComplexException.class);
+                        false));
     }
 }

model/placeholders/src/test/java/org/eclipse/ditto/model/placeholders/PlaceholderFilterTest.java

@@ -220,6 +220,9 @@ public void testValidateFails() {
 
         assertThatExceptionOfType(UnresolvedPlaceholderException.class).isThrownBy(
                 () -> PlaceholderFilter.validate("{{thing:nam}}espace }}{{  thing:name }}{{header:device-id }}", placeholders));
+
+        assertThatExceptionOfType(PlaceholderFunctionTooComplexException.class).isThrownBy(
+                () -> PlaceholderFilter.validate("{{ header:unknown | fn:default('fallback') | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() | fn:upper() | fn:lower() }}", placeholders));
     }
 
     private static String filterChain(final String template, final FilterTuple... tuples) {