DATACMNS-1206 - Polishing.
Moved PropertyDescriptor lookup into dedicated subclass to group functionality around the type and MethodsMetadata instances. Extracted individual stream handling steps into dedicated methods for better understandability. Moved MethodsMetadataReader into classreading package for symmetry with Spring Framework's metadata arrangement. Removed manually declared getters in DefaultMethodsMetadataReader in favor of Lombok getters. Inlined MethodsMetadataReadingVisitor into DefaultMethodsMetadataReader as it's only used there. Original pull request: #263.
This commit is contained in:
Oliver Gierke
committed by
Mark Paluch
Mark Paluch
parent
9e013d3c14
commit
5eb10a0817
@@ -15,10 +15,11 @@
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*/
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package org.springframework.data.projection;
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import lombok.extern.slf4j.Slf4j;
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import java.beans.PropertyDescriptor;
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import java.io.IOException;
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import java.lang.reflect.Method;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Comparator;
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import java.util.List;
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@@ -29,11 +30,11 @@ import java.util.stream.IntStream;
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import java.util.stream.Stream;
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import org.springframework.beans.BeanUtils;
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import org.springframework.core.type.ClassMetadata;
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import org.springframework.core.type.MethodMetadata;
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import org.springframework.data.type.MethodsMetadata;
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import org.springframework.data.type.MethodsMetadataReader;
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import org.springframework.data.type.classreading.MethodsMetadataReader;
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import org.springframework.data.type.classreading.MethodsMetadataReaderFactory;
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import org.springframework.data.util.StreamUtils;
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import org.springframework.util.Assert;
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import org.springframework.util.ClassUtils;
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@@ -61,7 +62,7 @@ class DefaultProjectionInformation implements ProjectionInformation {
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Assert.notNull(type, "Projection type must not be null!");
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this.projectionType = type;
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this.properties = collectDescriptors(type);
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this.properties = new PropertyDescriptorSource(type).getDescriptors();
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}
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/*
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@@ -106,95 +107,6 @@ class DefaultProjectionInformation implements ProjectionInformation {
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return true;
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}
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/**
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* Collects {@link PropertyDescriptor}s for all properties exposed by the given type and all its super interfaces.
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*
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* @param type must not be {@literal null}.
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* @return
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*/
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private static List<PropertyDescriptor> collectDescriptors(Class<?> type) {
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List<PropertyDescriptor> result = new ArrayList<>();
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Optional<MethodsMetadata> metadata = getMetadata(type);
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Stream<PropertyDescriptor> stream = Arrays.stream(BeanUtils.getPropertyDescriptors(type))//
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.filter(it -> !hasDefaultGetter(it));
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Stream<PropertyDescriptor> streamToUse = metadata.map(DefaultProjectionInformation::getMethodOrder)
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.filter(it -> !it.isEmpty()) //
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.map(it -> stream.filter(descriptor -> it.containsKey(descriptor.getReadMethod().getName()))
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.sorted(Comparator.comparingInt(left -> it.get(left.getReadMethod().getName())))) //
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.orElse(stream);
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result.addAll(streamToUse.collect(Collectors.toList()));
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if (metadata.isPresent()) {
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Stream<String> interfaceNames = metadata.map(ClassMetadata::getInterfaceNames) //
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.map(Arrays::stream) //
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.orElse(Stream.empty());
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result.addAll(interfaceNames.map(it -> loadClass(it, type.getClassLoader())) //
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.map(DefaultProjectionInformation::collectDescriptors) //
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.flatMap(List::stream) //
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.collect(Collectors.toList()));
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} else {
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for (Class<?> interfaze : type.getInterfaces()) {
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result.addAll(collectDescriptors(interfaze));
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}
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}
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return result.stream().distinct().collect(Collectors.toList());
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}
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private static Class<?> loadClass(String className, ClassLoader classLoader) {
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try {
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return ClassUtils.forName(className, classLoader);
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} catch (ClassNotFoundException e) {
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throw new IllegalArgumentException(String.format("Cannot load class %s", className));
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}
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}
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/**
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* Returns a {@link Map} containing method name to its positional index according to {@link MethodsMetadata}.
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*
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* @param metadata
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* @return
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*/
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private static Map<String, Integer> getMethodOrder(MethodsMetadata metadata) {
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List<String> methods = metadata.getMethods() //
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.stream() //
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.map(MethodMetadata::getMethodName) //
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.distinct() //
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.collect(Collectors.toList());
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return IntStream.range(0, methods.size()) //
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.boxed() //
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.collect(Collectors.toMap(methods::get, i -> i));
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}
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/**
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* Attempts to obtain {@link MethodsMetadata} from {@link Class}. Returns {@link Optional} containing
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* {@link MethodsMetadata} if metadata was read successfully, {@link Optional#empty()} otherwise.
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*
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* @param type must not be {@literal null}.
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* @return the optional {@link MethodsMetadata}.
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*/
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private static Optional<MethodsMetadata> getMetadata(Class<?> type) {
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try {
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MethodsMetadataReaderFactory factory = new MethodsMetadataReaderFactory(type.getClassLoader());
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MethodsMetadataReader metadataReader = factory.getMetadataReader(ClassUtils.getQualifiedName(type));
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return Optional.of(metadataReader.getMethodsMetadata());
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} catch (IOException e) {
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return Optional.empty();
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}
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}
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/**
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* Returns whether the given {@link PropertyDescriptor} has a getter that is a Java 8 default method.
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*
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@@ -204,6 +116,163 @@ class DefaultProjectionInformation implements ProjectionInformation {
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private static boolean hasDefaultGetter(PropertyDescriptor descriptor) {
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Method method = descriptor.getReadMethod();
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return method == null ? false : method.isDefault();
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}
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/**
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* Internal helper to detect {@link PropertyDescriptor} instances for a given type.
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*
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* @author Mark Paluch
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* @author Oliver Gierke
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* @since 2.1
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* @soundtrack The Meters - Cissy Strut (Here Comes The Meter Man)
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*/
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@Slf4j
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private static class PropertyDescriptorSource {
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private final Class<?> type;
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private final Optional<MethodsMetadata> metadata;
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/**
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* Creates a new {@link PropertyDescriptorSource} for the given type.
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*
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* @param type must not be {@literal null}.
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*/
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public PropertyDescriptorSource(Class<?> type) {
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Assert.notNull(type, "Type must not be null!");
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this.type = type;
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this.metadata = getMetadata(type);
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}
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/**
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* Returns {@link PropertyDescriptor}s for all properties exposed by the given type and all its super interfaces.
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*
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* @return
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*/
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public List<PropertyDescriptor> getDescriptors() {
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return collectDescriptors().distinct().collect(StreamUtils.toUnmodifiableList());
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}
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/**
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* Recursively collects {@link PropertyDescriptor}s for all properties exposed by the given type and all its super
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* interfaces.
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*
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* @return
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*/
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private Stream<PropertyDescriptor> collectDescriptors() {
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Stream<PropertyDescriptor> allButDefaultGetters = Arrays.stream(BeanUtils.getPropertyDescriptors(type)) //
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.filter(it -> !hasDefaultGetter(it));
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Stream<PropertyDescriptor> ownDescriptors = metadata.map(it -> filterAndOrder(allButDefaultGetters, it))
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.orElse(allButDefaultGetters);
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Stream<PropertyDescriptor> superTypeDescriptors = metadata.map(this::fromMetadata) //
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.orElseGet(this::fromType) //
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.flatMap(it -> new PropertyDescriptorSource(it).collectDescriptors());
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return Stream.concat(ownDescriptors, superTypeDescriptors);
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}
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/**
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* Returns a Stream of {@link PropertyDescriptor} ordered following the given {@link MethodsMetadata} only returning
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* methods seen by the given {@link MethodsMetadata}.
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*
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* @param source must not be {@literal null}.
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* @param metadata must not be {@literal null}.
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* @return
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*/
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private static Stream<PropertyDescriptor> filterAndOrder(Stream<PropertyDescriptor> source,
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MethodsMetadata metadata) {
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Map<String, Integer> orderedMethods = getMethodOrder(metadata);
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if (orderedMethods.isEmpty()) {
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return source;
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}
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return source.filter(descriptor -> orderedMethods.containsKey(descriptor.getReadMethod().getName()))
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.sorted(Comparator.comparingInt(left -> orderedMethods.get(left.getReadMethod().getName())));
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}
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/**
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* Returns a {@link Stream} of interfaces using the given {@link MethodsMetadata} as primary source for ordering.
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*
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* @param metadata must not be {@literal null}.
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* @return
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*/
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private Stream<Class<?>> fromMetadata(MethodsMetadata metadata) {
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return Arrays.stream(metadata.getInterfaceNames()).map(it -> findType(it, type.getInterfaces()));
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}
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/**
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* Returns a Stream of interfaces using the given type as primary source for ordering.
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*
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* @return
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*/
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private Stream<Class<?>> fromType() {
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return Arrays.stream(type.getInterfaces());
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}
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/**
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* Attempts to obtain {@link MethodsMetadata} from {@link Class}. Returns {@link Optional} containing
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* {@link MethodsMetadata} if metadata was read successfully, {@link Optional#empty()} otherwise.
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*
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* @param type must not be {@literal null}.
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* @return the optional {@link MethodsMetadata}.
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*/
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private static Optional<MethodsMetadata> getMetadata(Class<?> type) {
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try {
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MethodsMetadataReaderFactory factory = new MethodsMetadataReaderFactory(type.getClassLoader());
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MethodsMetadataReader metadataReader = factory.getMetadataReader(ClassUtils.getQualifiedName(type));
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return Optional.of(metadataReader.getMethodsMetadata());
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} catch (IOException e) {
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LOG.info("Couldn't read class metadata for {}. Input property calculation might fail!", type);
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return Optional.empty();
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}
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}
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/**
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* Find the type with the given name in the given array of {@link Class}.
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*
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* @param name must not be {@literal null} or empty.
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* @param types must not be {@literal null}.
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* @return
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*/
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private static Class<?> findType(String name, Class<?>[] types) {
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return Arrays.stream(types) //
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.filter(it -> name.equals(it.getName())) //
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.findFirst()
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.orElseThrow(() -> new IllegalStateException(String.format("Did not find type %s in %s!", name, types)));
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}
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/**
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* Returns a {@link Map} containing method name to its positional index according to {@link MethodsMetadata}.
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*
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* @param metadata
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* @return
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*/
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private static Map<String, Integer> getMethodOrder(MethodsMetadata metadata) {
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List<String> methods = metadata.getMethods() //
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.stream() //
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.map(MethodMetadata::getMethodName) //
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.distinct() //
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.collect(Collectors.toList());
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return IntStream.range(0, methods.size()) //
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.boxed() //
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.collect(Collectors.toMap(methods::get, i -> i));
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}
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}
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}
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