Introduce ClassMetadata#getMemberClassNames

ClassMetadata implementations can now introspect their member (nested)
classes. This will allow for automatic detection of nested
@Configuration types in SPR-8186.

Issue: SPR-8358,SPR-8186

org.springframework.core/src/main/java/org/springframework/core/type/ClassMetadata.java

@@ -89,9 +89,18 @@ public interface ClassMetadata {
 	String getSuperClassName();
 
 	/**
-	 * Return the name of all interfaces that the underlying class
+	 * Return the names of all interfaces that the underlying class
 	 * implements, or an empty array if there are none.
 	 */
 	String[] getInterfaceNames();
 
+	/**
+	 * Return the names of all classes declared as members of the class represented by
+	 * this ClassMetadata object. This includes public, protected, default (package)
+	 * access, and private classes and interfaces declared by the class, but excludes
+	 * inherited classes and interfaces. An empty array is returned if no member classes
+	 * or interfaces exist.
+	 */
+	String[] getMemberClassNames();
+
 }

org.springframework.core/src/main/java/org/springframework/core/type/StandardClassMetadata.java

@@ -17,6 +17,7 @@
 package org.springframework.core.type;
 
 import java.lang.reflect.Modifier;
+import java.util.LinkedHashSet;
 
 import org.springframework.util.Assert;
 
@@ -102,4 +103,12 @@ public class StandardClassMetadata implements ClassMetadata {
 		return ifcNames;
 	}
 
+	public String[] getMemberClassNames() {
+		LinkedHashSet<String> memberClassNames = new LinkedHashSet<String>();
+		for (Class<?> nestedClass : this.introspectedClass.getDeclaredClasses()) {
+			memberClassNames.add(nestedClass.getName());
+		}
+		return memberClassNames.toArray(new String[memberClassNames.size()]);
+	}
+
 }

org.springframework.core/src/main/java/org/springframework/core/type/classreading/ClassMetadataReadingVisitor.java

@@ -16,6 +16,9 @@
 
 package org.springframework.core.type.classreading;
 
+import java.util.LinkedHashSet;
+import java.util.Set;
+
 import org.springframework.asm.AnnotationVisitor;
 import org.springframework.asm.Attribute;
 import org.springframework.asm.ClassVisitor;
@@ -54,7 +57,9 @@ class ClassMetadataReadingVisitor implements ClassVisitor, ClassMetadata {
 	private String superClassName;
 
 	private String[] interfaces;
-	
+
+	private Set<String> memberClassNames = new LinkedHashSet<String>();
+
 
 	public void visit(int version, int access, String name, String signature, String supername, String[] interfaces) {
 		this.className = ClassUtils.convertResourcePathToClassName(name);
@@ -75,9 +80,16 @@ class ClassMetadataReadingVisitor implements ClassVisitor, ClassMetadata {
 	}
 
 	public void visitInnerClass(String name, String outerName, String innerName, int access) {
-		if (outerName != null && this.className.equals(ClassUtils.convertResourcePathToClassName(name))) {
-			this.enclosingClassName = ClassUtils.convertResourcePathToClassName(outerName);
-			this.independentInnerClass = ((access & Opcodes.ACC_STATIC) != 0);
+		String fqName = ClassUtils.convertResourcePathToClassName(name);
+		String fqOuterName = ClassUtils.convertResourcePathToClassName(outerName);
+		if (outerName != null) {
+			if (this.className.equals(fqName)) {
+				this.enclosingClassName = fqOuterName;
+				this.independentInnerClass = ((access & Opcodes.ACC_STATIC) != 0);
+			}
+			else if (this.className.equals(fqOuterName)) {
+				this.memberClassNames.add(fqName);
+			}
 		}
 	}
 
@@ -153,4 +165,8 @@ class ClassMetadataReadingVisitor implements ClassVisitor, ClassMetadata {
 		return this.interfaces;
 	}
 
+	public String[] getMemberClassNames() {
+		return this.memberClassNames.toArray(new String[this.memberClassNames.size()]);
+	}
+
 }

org.springframework.core/src/test/java/org/springframework/core/type/AbstractClassMetadataMemberClassTests.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2002-2011 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
+ *
+ *      http://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.core.type;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+
+/**
+ * Abstract base class for testing implementations of
+ * {@link ClassMetadata#getMemberClassNames()}.
+ *
+ * @author Chris Beams
+ * @since 3.1
+ */
+public abstract class AbstractClassMetadataMemberClassTests {
+
+	public abstract ClassMetadata getClassMetadataFor(Class<?> clazz);
+
+	@Test
+	public void withNoMemberClasses() {
+		ClassMetadata metadata = getClassMetadataFor(L0_a.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses, equalTo(new String[]{}));
+	}
+
+	public static class L0_a {
+	}
+
+
+	@Test
+	public void withPublicMemberClasses() {
+		ClassMetadata metadata = getClassMetadataFor(L0_b.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses, equalTo(new String[]{L0_b.L1.class.getName()}));
+	}
+
+	public static class L0_b {
+		public static class L1 { }
+	}
+
+
+	@Test
+	public void withNonPublicMemberClasses() {
+		ClassMetadata metadata = getClassMetadataFor(L0_c.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses, equalTo(new String[]{L0_c.L1.class.getName()}));
+	}
+
+	public static class L0_c {
+		private static class L1 { }
+	}
+
+
+	@Test
+	public void againstMemberClass() {
+		ClassMetadata metadata = getClassMetadataFor(L0_b.L1.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses, equalTo(new String[]{}));
+	}
+}

org.springframework.core/src/test/java/org/springframework/core/type/StandardClassMetadataMemberClassTests.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2002-2011 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
+ *
+ *      http://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.core.type;
+
+/**
+ * @author Chris Beams
+ * @since 3.1
+ * @see AbstractClassMetadataMemberClassTests
+ */
+public class StandardClassMetadataMemberClassTests
+		extends AbstractClassMetadataMemberClassTests {
+
+	@Override
+	public ClassMetadata getClassMetadataFor(Class<?> clazz) {
+		return new StandardClassMetadata(clazz);
+	}
+
+}

org.springframework.core/src/test/java/org/springframework/core/type/classreading/ClassMetadataReadingVisitorMemberClassTests.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2002-2011 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
+ *
+ *      http://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.core.type.classreading;
+
+import java.io.IOException;
+
+import org.springframework.core.type.AbstractClassMetadataMemberClassTests;
+import org.springframework.core.type.ClassMetadata;
+
+/**
+ * @author Chris Beams
+ * @since 3.1
+ * @see AbstractClassMetadataMemberClassTests
+ */
+public class ClassMetadataReadingVisitorMemberClassTests
+		extends AbstractClassMetadataMemberClassTests {
+
+	@Override
+	public ClassMetadata getClassMetadataFor(Class<?> clazz) {
+		try {
+			MetadataReader reader =
+				new SimpleMetadataReaderFactory().getMetadataReader(clazz.getName());
+			return reader.getAnnotationMetadata();
+		} catch (IOException ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+}