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#1335 - Added HalModelBuilder.embed(Stream<?> …).

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HalModelBuilder is now able to take Stream instances directly immediately resolving them so that clients don't have to call ….collect(Collectors.toList()) all the time. Some internal rearrangements and stricter null guarantees in EmbeddedWrappers.
This commit is contained in:
Oliver Drotbohm
2020-07-28 16:42:26 +02:00
parent a5ccafc4da
commit 035b742a1f
3 changed files with 162 additions and 49 deletions
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99
src/main/java/org/springframework/hateoas/mediatype/hal/HalModelBuilder.java
View File

@@ -18,6 +18,8 @@ package org.springframework.hateoas.mediatype.hal;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.springframework.hateoas.CollectionModel;
import org.springframework.hateoas.EntityModel;
@@ -26,7 +28,6 @@ import org.springframework.hateoas.LinkRelation;
import org.springframework.hateoas.Links;
import org.springframework.hateoas.MediaTypes;
import org.springframework.hateoas.RepresentationModel;
import org.springframework.hateoas.server.core.EmbeddedWrapper;
import org.springframework.hateoas.server.core.EmbeddedWrappers;
import org.springframework.lang.Nullable;
import org.springframework.ui.Model;
@@ -147,44 +148,105 @@ public class HalModelBuilder {
return this;
}
/**
* Embeds the given collection in the {@link RepresentationModel}. If the collection is empty nothing will be added to
* the {@link RepresentationModel}.
*
* @param collection must not be {@literal null}.
* @return will never be {@literal null}.
*/
public HalModelBuilder embed(Collection<?> collection) {
return embed(collection, Void.class);
}
/**
* Embeds the given collection in the {@link RepresentationModel} and the {@link LinkRelation} derived from the given
* type. If the collection is empty nothing will be added to the {@link RepresentationModel} an empty embed for the
* derived {@link LinkRelation} will be added.
*
* @param collection must not be {@literal null}.
* @param type the type to derive the {@link LinkRelation} to be used, must not be {@literal null}.
* @return will never be {@literal null}.
* @see #embed(Collection, LinkRelation)
*/
public HalModelBuilder embed(Collection<?> collection, Class<?> type) {
Assert.notNull(collection, "Collection must not be null!");
Assert.notNull(type, "Type must not be null!");
if (!collection.isEmpty()) {
EmbeddedWrapper wrapper = wrappers.wrap(collection);
return wrapper == null ? this : embed(wrapper);
return embed(wrappers.wrap(collection));
}
if (Void.class.equals(type)) {
return this;
}
return embed(wrappers.emptyCollectionOf(type));
return Void.class.equals(type) ? this : embed(wrappers.emptyCollectionOf(type));
}
/**
* Embeds the given collection in the {@link RepresentationModel} for the given {@link LinkRelation}. If the
* collection is empty nothing will be added to the {@link RepresentationModel}.
* collection is empty nothing will be added to the {@link RepresentationModel} an empty embed for the derived
* {@link LinkRelation} will be added.
*
* @param collection must not be {@literal null}.
* @param relation must not be {@literal null}.
* @return will never be {@literal null}.
* @see #embed(Collection, LinkRelation, Class)
*/
public HalModelBuilder embed(Collection<?> collection, LinkRelation relation) {
Assert.notNull(collection, "Collection must not be null!");
Assert.notNull(relation, "Link relation must not be null!");
EmbeddedWrapper wrapper = wrappers.wrap(collection, relation);
return embed(wrappers.wrap(collection, relation));
}
return wrapper == null ? this : embed(wrapper);
/**
* Embeds the given {@link Stream} in the {@link RepresentationModel}. The given {@link Stream} will be resolved
* immediately, i.e. the method acts as mere syntactic sugar to avoid clients having to collect the {@link Stream}
* into a {@link Collection} beforehand. If the {@link Stream} is empty nothing will be added to the
* {@link RepresentationModel}.
*
* @param stream must not be {@literal null}.
* @return will never be {@literal null}.
*/
public HalModelBuilder embed(Stream<?> stream) {
return embed(stream, Void.class);
}
/**
* Embeds the given {@link Stream} in the {@link RepresentationModel} and the {@link LinkRelation} derived from the
* given type. The given {@link Stream} will be resolved immediately, i.e. the method acts as mere syntactic sugar to
* avoid clients having to collect the {@link Stream} into a {@link Collection} beforehand. If the {@link Stream} is
* empty nothing will be added to the {@link RepresentationModel} an empty embed for the derived {@link LinkRelation}
* will be added.
*
* @param stream must not be {@literal null}.
* @param type the type to derive the {@link LinkRelation} to be used, must not be {@literal null}.
* @return will never be {@literal null}.
* @see #embed(Collection, LinkRelation)
*/
public HalModelBuilder embed(Stream<?> stream, Class<?> type) {
Assert.notNull(stream, "Stream must not be null!");
Assert.notNull(type, "Type must not be null!");
return embed(stream.collect(Collectors.toList()), type);
}
/**
* Embeds the given {@link Stream} in the {@link RepresentationModel} for the given {@link LinkRelation}. The given
* {@link Stream} will be resolved immediately, i.e. the method acts as mere syntactic sugar to avoid clients having
* to collect the {@link Stream} into a {@link Collection} beforehand. If the {@link Stream} is empty nothing will be
* added to the {@link RepresentationModel} an empty embed for the derived {@link LinkRelation} will be added.
*
* @param stream must not be {@literal null}.
* @param relation must not be {@literal null}.
* @return will never be {@literal null}.
*/
public HalModelBuilder embed(Stream<?> stream, LinkRelation relation) {
Assert.notNull(stream, "Stream must not be null!");
Assert.notNull(relation, "Link relation must not be null!");
return embed(stream.collect(Collectors.toList()), relation);
}
/**
@@ -295,6 +357,7 @@ public class HalModelBuilder {
*
* @return will never be {@literal null}.
*/
@SuppressWarnings("unchecked")
public <T extends RepresentationModel<T>> RepresentationModel<T> build() {
return (T) new HalRepresentationModel<>(model, CollectionModel.of(embeddeds), links);
}
@@ -317,7 +380,7 @@ public class HalModelBuilder {
private static class HalRepresentationModel<T> extends EntityModel<T> {
private final T entity;
private final @Nullable T entity;
private final CollectionModel<?> embeddeds;
public HalRepresentationModel(@Nullable T entity, CollectionModel<T> embeddeds, Links links) {
@@ -327,7 +390,9 @@ public class HalModelBuilder {
add(links);
}
public HalRepresentationModel(T entity, CollectionModel<?> embeddeds) {
private HalRepresentationModel(@Nullable T entity, CollectionModel<?> embeddeds) {
Assert.notNull(embeddeds, "Embedds must not be null!");
this.entity = entity;
this.embeddeds = embeddeds;

49
src/main/java/org/springframework/hateoas/server/core/EmbeddedWrappers.java
View File

@@ -15,9 +15,12 @@
*/
package org.springframework.hateoas.server.core;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.springframework.aop.support.AopUtils;
import org.springframework.hateoas.EntityModel;
@@ -47,11 +50,10 @@ public class EmbeddedWrappers {
/**
* Creates a new {@link EmbeddedWrapper} that
*
* @param source
* @return
* @param source must not be {@literal null}.
* @return will never be {@literal null}.
*/
@Nullable
public EmbeddedWrapper wrap(@Nullable Object source) {
public EmbeddedWrapper wrap(Object source) {
return wrap(source, AbstractEmbeddedWrapper.NO_REL);
}
@@ -68,31 +70,44 @@ public class EmbeddedWrappers {
/**
* Creates a new {@link EmbeddedWrapper} with the given rel.
*
* @param source can be {@literal null}, will return {@literal null} if so.
* @param source must not be {@literal null}.
* @param rel must not be {@literal null} or empty.
* @return
* @return will never be {@literal null}.
*/
@SuppressWarnings("unchecked")
@Nullable
public EmbeddedWrapper wrap(@Nullable Object source, LinkRelation rel) {
public EmbeddedWrapper wrap(Object source, LinkRelation rel) {
if (source == null) {
return null;
}
Assert.notNull(source, "Source must not be null!");
Assert.notNull(rel, "Link relation must not be null!");
if (source instanceof EmbeddedWrapper) {
return (EmbeddedWrapper) source;
}
if (source instanceof Collection) {
return new EmbeddedCollection((Collection<Object>) source, rel);
return source instanceof Collection || source instanceof Stream || preferCollections
? new EmbeddedCollection(asCollection(source), rel)
: new EmbeddedElement(source, rel);
}
@SuppressWarnings("unchecked")
private static Collection<Object> asCollection(@Nullable Object source) {
if (source == null) {
return Collections.emptyList();
}
if (preferCollections) {
return new EmbeddedCollection(Collections.singleton(source), rel);
if (Collection.class.isInstance(source)) {
return Collection.class.cast(source);
}
return new EmbeddedElement(source, rel);
if (Stream.class.isInstance(source)) {
return (Collection<Object>) Stream.class.cast(source).collect(Collectors.toList());
}
if (source.getClass().isArray()) {
return Arrays.asList((Object[]) source);
}
return Collections.singleton(source);
}
private static abstract class AbstractEmbeddedWrapper implements EmbeddedWrapper {