iSharkFly-Docs/java-tutorials
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

pagination work

Browse Source
This commit is contained in:
eugenp 2014-01-05 14:17:38 +02:00
parent 1af3eb4b1f
commit 33fee76a32
4 changed files with 182 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
spring-security-rest-full/src/main/java/org/baeldung/web/controller/FooController.java
View File

@ -9,6 +9,7 @@ import javax.servlet.http.HttpServletResponse;
import org.baeldung.persistence.model.Foo;
import org.baeldung.persistence.service.IFooService;
import org.baeldung.web.exception.MyResourceNotFoundException;
import org.baeldung.web.hateoas.PaginatedResultsRetrievedEvent;
import org.baeldung.web.util.LinkUtil;
import org.baeldung.web.util.ResourceCreated;
import org.baeldung.web.util.RestPreconditions;
@ -72,7 +73,7 @@ public class FooController {
if (page > resultPage.getTotalPages()) {
throw new MyResourceNotFoundException();
}
// eventPublisher.publishEvent(new PaginatedResultsRetrievedEvent<Foo>(Foo.class, uriBuilder, response, page, resultPage.getTotalPages(), size));
eventPublisher.publishEvent(new PaginatedResultsRetrievedEvent<Foo>(Foo.class, uriBuilder, response, page, resultPage.getTotalPages(), size));
return resultPage.getContent();
}

107
spring-security-rest-full/src/main/java/org/baeldung/web/hateoas/PaginatedResultsRetrievedDiscoverabilityListener.java Normal file
View File

@ -0,0 +1,107 @@
package org.baeldung.web.hateoas;
import javax.servlet.http.HttpServletResponse;
import org.baeldung.web.util.LinkUtil;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;
import org.springframework.web.util.UriComponentsBuilder;
import com.google.common.base.Preconditions;
import com.google.common.net.HttpHeaders;
@SuppressWarnings({ "rawtypes" })
@Component
class PaginatedResultsRetrievedDiscoverabilityListener implements ApplicationListener<PaginatedResultsRetrievedEvent> {
private static final String PAGE = "page";
public PaginatedResultsRetrievedDiscoverabilityListener() {
super();
}
// API
@Override
public final void onApplicationEvent(final PaginatedResultsRetrievedEvent ev) {
Preconditions.checkNotNull(ev);
addLinkHeaderOnPagedResourceRetrieval(ev.getUriBuilder(), ev.getResponse(), ev.getClazz(), ev.getPage(), ev.getTotalPages(), ev.getPageSize());
}
// - note: at this point, the URI is transformed into plural (added `s`) in a hardcoded way - this will change in the future
final void addLinkHeaderOnPagedResourceRetrieval(final UriComponentsBuilder uriBuilder, final HttpServletResponse response, final Class clazz, final int page, final int totalPages, final int pageSize) {
plural(uriBuilder, clazz);
final StringBuilder linkHeader = new StringBuilder();
if (hasNextPage(page, totalPages)) {
final String uriForNextPage = constructNextPageUri(uriBuilder, page, pageSize);
linkHeader.append(LinkUtil.createLinkHeader(uriForNextPage, LinkUtil.REL_NEXT));
}
if (hasPreviousPage(page)) {
final String uriForPrevPage = constructPrevPageUri(uriBuilder, page, pageSize);
appendCommaIfNecessary(linkHeader);
linkHeader.append(LinkUtil.createLinkHeader(uriForPrevPage, LinkUtil.REL_PREV));
}
if (hasFirstPage(page)) {
final String uriForFirstPage = constructFirstPageUri(uriBuilder, pageSize);
appendCommaIfNecessary(linkHeader);
linkHeader.append(LinkUtil.createLinkHeader(uriForFirstPage, LinkUtil.REL_FIRST));
}
if (hasLastPage(page, totalPages)) {
final String uriForLastPage = constructLastPageUri(uriBuilder, totalPages, pageSize);
appendCommaIfNecessary(linkHeader);
linkHeader.append(LinkUtil.createLinkHeader(uriForLastPage, LinkUtil.REL_LAST));
}
if (linkHeader.length() > 0) {
response.addHeader(HttpHeaders.LINK, linkHeader.toString());
}
}
final String constructNextPageUri(final UriComponentsBuilder uriBuilder, final int page, final int size) {
return uriBuilder.replaceQueryParam(PAGE, page + 1).replaceQueryParam("size", size).build().encode().toUriString();
}
final String constructPrevPageUri(final UriComponentsBuilder uriBuilder, final int page, final int size) {
return uriBuilder.replaceQueryParam(PAGE, page - 1).replaceQueryParam("size", size).build().encode().toUriString();
}
final String constructFirstPageUri(final UriComponentsBuilder uriBuilder, final int size) {
return uriBuilder.replaceQueryParam(PAGE, 0).replaceQueryParam("size", size).build().encode().toUriString();
}
final String constructLastPageUri(final UriComponentsBuilder uriBuilder, final int totalPages, final int size) {
return uriBuilder.replaceQueryParam(PAGE, totalPages).replaceQueryParam("size", size).build().encode().toUriString();
}
final boolean hasNextPage(final int page, final int totalPages) {
return page < totalPages - 1;
}
final boolean hasPreviousPage(final int page) {
return page > 0;
}
final boolean hasFirstPage(final int page) {
return hasPreviousPage(page);
}
final boolean hasLastPage(final int page, final int totalPages) {
return totalPages > 1 && hasNextPage(page, totalPages);
}
final void appendCommaIfNecessary(final StringBuilder linkHeader) {
if (linkHeader.length() > 0) {
linkHeader.append(", ");
}
}
// template
protected void plural(final UriComponentsBuilder uriBuilder, final Class clazz) {
final String resourceName = clazz.getSimpleName() + "s";
uriBuilder.path("/" + resourceName);
}
}

67
spring-security-rest-full/src/main/java/org/baeldung/web/hateoas/PaginatedResultsRetrievedEvent.java Normal file
View File

@ -0,0 +1,67 @@
package org.baeldung.web.hateoas;
import java.io.Serializable;
import javax.servlet.http.HttpServletResponse;
import org.springframework.context.ApplicationEvent;
import org.springframework.web.util.UriComponentsBuilder;
/**
* Event that is fired when a paginated search is performed.
* <p/>
* This event object contains all the information needed to create the URL for the paginated results
*
* @param <T>
* Type of the result that is being handled (commonly Entities).
*/
public final class PaginatedResultsRetrievedEvent<T extends Serializable> extends ApplicationEvent {
private final UriComponentsBuilder uriBuilder;
private final HttpServletResponse response;
private final int page;
private final int totalPages;
private final int pageSize;
public PaginatedResultsRetrievedEvent(final Class<T> clazz, final UriComponentsBuilder uriBuilderToSet, final HttpServletResponse responseToSet, final int pageToSet, final int totalPagesToSet, final int pageSizeToSet) {
super(clazz);
uriBuilder = uriBuilderToSet;
response = responseToSet;
page = pageToSet;
totalPages = totalPagesToSet;
pageSize = pageSizeToSet;
}
// API
public final UriComponentsBuilder getUriBuilder() {
return uriBuilder;
}
public final HttpServletResponse getResponse() {
return response;
}
public final int getPage() {
return page;
}
public final int getTotalPages() {
return totalPages;
}
public final int getPageSize() {
return pageSize;
}
/**
* The object on which the Event initially occurred.
*
* @return The object on which the Event initially occurred.
*/
@SuppressWarnings("unchecked")
public final Class<T> getClazz() {
return (Class<T>) getSource();
}
}

6
spring-security-rest-full/src/main/java/org/baeldung/web/util/LinkUtil.java
View File

@ -7,6 +7,12 @@ import javax.servlet.http.HttpServletResponse;
*/
public final class LinkUtil {
public static final String REL_COLLECTION = "collection";
public static final String REL_NEXT = "next";
public static final String REL_PREV = "prev";
public static final String REL_FIRST = "first";
public static final String REL_LAST = "last";
private LinkUtil() {
throw new AssertionError();
}