+ * Variables start with {@code $$}. If not, the given value gets prefixed with {@code $$}. + * + * @param value must not be {@literal null}. + * @return new instance of {@link AggregationVariable}. + * @throws IllegalArgumentException if given value is {@literal null}. + */ + static AggregationVariable variable(String value) { + + Assert.notNull(value, "Value must not be null"); + return new AggregationVariable() { + + private final String val = AggregationVariable.prefixVariable(value); + + @Override + public String getTarget() { + return val; + } + }; + } + + /** + * Create a new {@link #isInternal() local} {@link AggregationVariable} for the given name. + *
+ * Variables start with {@code $$}. If not, the given value gets prefixed with {@code $$}.
+ *
+ * @param value must not be {@literal null}.
+ * @return new instance of {@link AggregationVariable}.
+ * @throws IllegalArgumentException if given value is {@literal null}.
+ */
+ static AggregationVariable localVariable(String value) {
+
+ Assert.notNull(value, "Value must not be null");
+ return new AggregationVariable() {
+
+ private final String val = AggregationVariable.prefixVariable(value);
+
+ @Override
+ public String getTarget() {
+ return val;
+ }
+
+ @Override
+ public boolean isInternal() {
+ return true;
+ }
+ };
+ }
+
+ /**
+ * Check if the given field name reference may be variable.
+ *
+ * @param fieldRef can be {@literal null}.
+ * @return true if given value matches the variable identification pattern.
+ */
+ static boolean isVariable(@Nullable String fieldRef) {
+ return fieldRef != null && fieldRef.stripLeading().matches("^\\$\\$\\w.*");
+ }
+
+ /**
+ * Check if the given field may be variable.
+ *
+ * @param field can be {@literal null}.
+ * @return true if given {@link Field field} is an {@link AggregationVariable} or if its value is a
+ * {@link #isVariable(String) variable}.
+ */
+ static boolean isVariable(Field field) {
+
+ if (field instanceof AggregationVariable) {
+ return true;
+ }
+ return isVariable(field.getTarget());
+ }
+
+ private static String prefixVariable(String variable) {
+
+ var trimmed = variable.stripLeading();
+ return trimmed.startsWith(PREFIX) ? trimmed : (PREFIX + trimmed);
+ }
+}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ArrayOperators.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ArrayOperators.java
index 1ea699852f..94f7fc6736 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ArrayOperators.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ArrayOperators.java
@@ -1471,24 +1471,15 @@ public interface AsBuilder {
}
}
- public enum Variable implements Field {
+ public enum Variable implements AggregationVariable {
THIS {
- @Override
- public String getName() {
- return "$$this";
- }
@Override
public String getTarget() {
return "$$this";
}
- @Override
- public boolean isAliased() {
- return false;
- }
-
@Override
public String toString() {
return getName();
@@ -1496,27 +1487,23 @@ public String toString() {
},
VALUE {
- @Override
- public String getName() {
- return "$$value";
- }
@Override
public String getTarget() {
return "$$value";
}
- @Override
- public boolean isAliased() {
- return false;
- }
-
@Override
public String toString() {
return getName();
}
};
+ @Override
+ public boolean isInternal() {
+ return true;
+ }
+
/**
* Create a {@link Field} reference to a given {@literal property} prefixed with the {@link Variable} identifier.
* eg. {@code $$value.product}
@@ -1548,6 +1535,16 @@ public String toString() {
}
};
}
+
+ public static boolean isVariable(Field field) {
+
+ for (Variable var : values()) {
+ if (field.getTarget().startsWith(var.getTarget())) {
+ return true;
+ }
+ }
+ return false;
+ }
}
}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java
index 4dac936871..277b447a9b 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java
@@ -245,7 +245,7 @@ public AggregationField(String name, @Nullable String target) {
private static String cleanUp(String source) {
- if (SystemVariable.isReferingToSystemVariable(source)) {
+ if (AggregationVariable.isVariable(source)) {
return source;
}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SystemVariable.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SystemVariable.java
index 15c5bf6e90..bb3cc49808 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SystemVariable.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SystemVariable.java
@@ -24,7 +24,7 @@
* @author Christoph Strobl
* @see Aggregation Variables.
*/
-public enum SystemVariable {
+public enum SystemVariable implements AggregationVariable {
/**
* Variable for the current datetime.
@@ -82,8 +82,6 @@ public enum SystemVariable {
*/
SEARCH_META;
- private static final String PREFIX = "$$";
-
/**
* Return {@literal true} if the given {@code fieldRef} denotes a well-known system variable, {@literal false}
* otherwise.
@@ -93,13 +91,12 @@ public enum SystemVariable {
*/
public static boolean isReferingToSystemVariable(@Nullable String fieldRef) {
- if (fieldRef == null || !fieldRef.startsWith(PREFIX) || fieldRef.length() <= 2) {
+ String candidate = variableNameFrom(fieldRef);
+ if (candidate == null) {
return false;
}
- int indexOfFirstDot = fieldRef.indexOf('.');
- String candidate = fieldRef.substring(2, indexOfFirstDot == -1 ? fieldRef.length() : indexOfFirstDot);
-
+ candidate = candidate.startsWith(PREFIX) ? candidate.substring(2) : candidate;
for (SystemVariable value : values()) {
if (value.name().equals(candidate)) {
return true;
@@ -113,4 +110,20 @@ public static boolean isReferingToSystemVariable(@Nullable String fieldRef) {
public String toString() {
return PREFIX.concat(name());
}
+
+ @Override
+ public String getTarget() {
+ return toString();
+ }
+
+ @Nullable
+ static String variableNameFrom(@Nullable String fieldRef) {
+
+ if (fieldRef == null || !fieldRef.startsWith(PREFIX) || fieldRef.length() <= 2) {
+ return null;
+ }
+
+ int indexOfFirstDot = fieldRef.indexOf('.');
+ return indexOfFirstDot == -1 ? fieldRef : fieldRef.substring(2, indexOfFirstDot);
+ }
}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java
index 7dd07e5940..f179165984 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java
@@ -133,7 +133,7 @@ public AggregationOperationContext continueOnMissingFieldReference(Class type
protected FieldReference getReferenceFor(Field field) {
- if(entity.getNullable() == null) {
+ if(entity.getNullable() == null || AggregationVariable.isVariable(field)) {
return new DirectFieldReference(new ExposedField(field, true));
}
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationVariableUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationVariableUnitTests.java
new file mode 100644
index 0000000000..a4af334013
--- /dev/null
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationVariableUnitTests.java
@@ -0,0 +1,95 @@
+/*
+ * Copyright 2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+/**
+ * @author Christoph Strobl
+ */
+class AggregationVariableUnitTests {
+
+ @Test // GH-4070
+ void variableErrorsOnNullValue() {
+ assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> AggregationVariable.variable(null));
+ }
+
+ @Test // GH-4070
+ void createsVariable() {
+
+ var variable = AggregationVariable.variable("$$now");
+
+ assertThat(variable.getTarget()).isEqualTo("$$now");
+ assertThat(variable.isInternal()).isFalse();
+ }
+
+ @Test // GH-4070
+ void prefixesVariableIfNeeded() {
+
+ var variable = AggregationVariable.variable("this");
+
+ assertThat(variable.getTarget()).isEqualTo("$$this");
+ }
+
+ @Test // GH-4070
+ void localVariableErrorsOnNullValue() {
+ assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> AggregationVariable.localVariable(null));
+ }
+
+ @Test // GH-4070
+ void localVariable() {
+
+ var variable = AggregationVariable.localVariable("$$this");
+
+ assertThat(variable.getTarget()).isEqualTo("$$this");
+ assertThat(variable.isInternal()).isTrue();
+ }
+
+ @Test // GH-4070
+ void prefixesLocalVariableIfNeeded() {
+
+ var variable = AggregationVariable.localVariable("this");
+
+ assertThat(variable.getTarget()).isEqualTo("$$this");
+ }
+
+ @Test // GH-4070
+ void isVariableReturnsTrueForAggregationVariableTypes() {
+
+ var variable = Mockito.mock(AggregationVariable.class);
+
+ assertThat(AggregationVariable.isVariable(variable)).isTrue();
+ }
+
+ @Test // GH-4070
+ void isVariableReturnsTrueForFieldThatTargetsVariable() {
+
+ var variable = Fields.field("value", "$$this");
+
+ assertThat(AggregationVariable.isVariable(variable)).isTrue();
+ }
+
+ @Test // GH-4070
+ void isVariableReturnsFalseForFieldThatDontTargetsVariable() {
+
+ var variable = Fields.field("value", "$this");
+
+ assertThat(AggregationVariable.isVariable(variable)).isFalse();
+ }
+}
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContextUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContextUnitTests.java
index c770e22fba..9ac1606559 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContextUnitTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContextUnitTests.java
@@ -39,8 +39,11 @@
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.mapping.MappingException;
+import org.springframework.data.mongodb.core.aggregation.ArrayOperators.Reduce;
+import org.springframework.data.mongodb.core.aggregation.ArrayOperators.Reduce.Variable;
import org.springframework.data.mongodb.core.aggregation.ExposedFields.DirectFieldReference;
import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.SetOperators.SetUnion;
import org.springframework.data.mongodb.core.convert.DbRefResolver;
import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
@@ -455,6 +458,30 @@ void rendersProjectOnNestedPrefixedUnwrappedFieldWithAtFieldAnnotationCorrectly(
.isEqualTo(new Document("val", "$withUnwrapped.prefix-with-at-field-annotation"));
}
+ @Test // GH-4070
+ void rendersLocalVariables() {
+
+ AggregationOperationContext context = getContext(WithLists.class);
+
+ Document agg = newAggregation(WithLists.class,
+ project()
+ .and(Reduce.arrayOf("listOfListOfString").withInitialValue(field("listOfString"))
+ .reduce(SetUnion.arrayAsSet(Variable.VALUE.getTarget()).union(Variable.THIS.getTarget())))
+ .as("listOfString")).toDocument("collection", context);
+
+ assertThat(getPipelineElementFromAggregationAt(agg, 0).get("$project")).isEqualTo(Document.parse("""
+ {
+ "listOfString" : {
+ "$reduce" : {
+ "in" : { "$setUnion" : ["$$value", "$$this"] },
+ "initialValue" : "$listOfString",
+ "input" : "$listOfListOfString"
+ }
+ }
+ }
+ """));
+ }
+
@org.springframework.data.mongodb.core.mapping.Document(collection = "person")
@AllArgsConstructor
public static class FooPerson {
@@ -553,4 +580,9 @@ static class UnwrappableType {
@org.springframework.data.mongodb.core.mapping.Field("with-at-field-annotation") //
String atFieldAnnotatedValue;
}
+
+ static class WithLists {
+ public List