Detect config props using builder pattern and generics

See gh-19099

Author: ChunMengLu

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/TypeElementMembers.java

@@ -28,8 +28,10 @@
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
+import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
+import javax.lang.model.type.TypeVariable;
 import javax.lang.model.util.ElementFilter;
 
 /**
@@ -116,8 +118,26 @@ private boolean isSetter(ExecutableElement method) {
 
 	private boolean isSetterReturnType(ExecutableElement method) {
 		TypeMirror returnType = method.getReturnType();
-		return (TypeKind.VOID == returnType.getKind()
-				|| this.env.getTypeUtils().isSameType(method.getEnclosingElement().asType(), returnType));
+		// void
+		if (TypeKind.VOID == returnType.getKind()) {
+			return true;
+		}
+
+		TypeMirror classType = method.getEnclosingElement().asType();
+		TypeUtils typeUtils = this.env.getTypeUtils();
+		// Chain
+		if (typeUtils.isSameType(classType, returnType)) {
+			return true;
+		}
+
+		// Chain generic type, <T extends classType>
+		List<? extends TypeMirror> genericTypes = ((DeclaredType) classType).getTypeArguments();
+		return genericTypes.stream().anyMatch((genericType) -> {
+			TypeMirror upperBound = ((TypeVariable) genericType).getUpperBound();
+			String classTypeName = typeUtils.getQualifiedName(((DeclaredType) classType).asElement());
+			String genericTypeName = typeUtils.getQualifiedName(((DeclaredType) upperBound).asElement());
+			return classTypeName.equals(genericTypeName);
+		});
 	}
 
 	private String getAccessorName(String methodName) {

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/GenericsMetadataGenerationTests.java

@@ -21,6 +21,8 @@
 import org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata;
 import org.springframework.boot.configurationprocessor.metadata.Metadata;
 import org.springframework.boot.configurationsample.generic.AbstractGenericProperties;
+import org.springframework.boot.configurationsample.generic.ChainGenericConfig;
+import org.springframework.boot.configurationsample.generic.ChainGenericProperties;
 import org.springframework.boot.configurationsample.generic.ComplexGenericProperties;
 import org.springframework.boot.configurationsample.generic.GenericConfig;
 import org.springframework.boot.configurationsample.generic.SimpleGenericProperties;
@@ -110,4 +112,15 @@ void wildcardTypes() {
 		assertThat(metadata.getItems()).hasSize(3);
 	}
 
+	@Test
+	void chainGenericProperties() {
+		ConfigurationMetadata metadata = compile(ChainGenericProperties.class);
+		assertThat(metadata).has(Metadata.withGroup("generic").fromSource(ChainGenericProperties.class));
+		assertThat(metadata).has(Metadata.withGroup("generic.config", ChainGenericConfig.class)
+				.fromSource(ChainGenericProperties.class));
+		assertThat(metadata).has(Metadata.withProperty("generic.config.ping-timeout", Integer.class)
+				.fromSource(ChainGenericConfig.class).withDefaultValue(null));
+		assertThat(metadata.getItems()).hasSize(3);
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/generic/ChainGenericConfig.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2019 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.boot.configurationsample.generic;
+
+/**
+ * Chain Generic
+ *
+ * @param <T> name type
+ * @author L.cm
+ */
+public class ChainGenericConfig<T extends ChainGenericConfig> {
+
+	/**
+	 * Generic config pingTimeout.
+	 */
+	private Integer pingTimeout = 1000;
+
+	public int getPingTimeout() {
+		return this.pingTimeout;
+	}
+
+	public T setPingTimeout(int pingTimeout) {
+		this.pingTimeout = pingTimeout;
+		return (T) this;
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/generic/ChainGenericProperties.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2019 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.boot.configurationsample.generic;
+
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+import org.springframework.boot.configurationsample.NestedConfigurationProperty;
+
+/**
+ * Chain Generic Properties
+ *
+ * @author L.cm
+ */
+@ConfigurationProperties("generic")
+public class ChainGenericProperties {
+
+	/**
+	 * Generic config.
+	 */
+	@NestedConfigurationProperty
+	private ChainGenericConfig config;
+
+	public ChainGenericConfig getConfig() {
+		return this.config;
+	}
+
+	public void setConfig(ChainGenericConfig config) {
+		this.config = config;
+	}
+
+}