pagination work

spring-security-rest-full/src/main/java/org/baeldung/persistence/IOperations.java

@@ -3,12 +3,22 @@
 import java.io.Serializable;
 import java.util.List;
 
+import org.springframework.data.domain.Page;
+
 public interface IOperations<T extends Serializable> {
 
+    // read - one
+
     T findOne(final long id);
 
+    // read - all
+
     List<T> findAll();
 
+    Page<T> findPaginated(int page, int size);
+
+    // write
+
     T create(final T entity);
 
     T update(final T entity);

spring-security-rest-full/src/main/java/org/baeldung/persistence/service/common/AbstractService.java

@@ -4,6 +4,8 @@
 import java.util.List;
 
 import org.baeldung.persistence.IOperations;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
 import org.springframework.data.repository.PagingAndSortingRepository;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -12,18 +14,29 @@
 @Transactional
 public abstract class AbstractService<T extends Serializable> implements IOperations<T> {
 
+    // read - one
+
     @Override
     @Transactional(readOnly = true)
     public T findOne(final long id) {
         return getDao().findOne(id);
     }
 
+    // read - all
+
     @Override
     @Transactional(readOnly = true)
     public List<T> findAll() {
         return Lists.newArrayList(getDao().findAll());
     }
 
+    @Override
+    public Page<T> findPaginated(final int page, final int size) {
+        return getDao().findAll(new PageRequest(page, size));
+    }
+
+    // write
+
     @Override
     public T create(final T entity) {
         return getDao().save(entity);

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

@@ -8,17 +8,21 @@
 
 import org.baeldung.persistence.model.Foo;
 import org.baeldung.persistence.service.IFooService;
+import org.baeldung.web.exception.MyResourceNotFoundException;
 import org.baeldung.web.util.LinkUtil;
 import org.baeldung.web.util.ResourceCreated;
+import org.baeldung.web.util.RestPreconditions;
 import org.baeldung.web.util.SingleResourceRetrieved;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.data.domain.Page;
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.util.UriComponentsBuilder;
@@ -42,29 +46,39 @@ public FooController() {
 
     // API
 
-    // read
+    // read - one
 
     @RequestMapping(value = "/{id}", method = RequestMethod.GET)
     @ResponseBody
-    public Foo findOne(@PathVariable("id") final Long id, final UriComponentsBuilder uriBuilder, final HttpServletResponse response) {
-        return service.findOne(id);
+    public Foo findOne(@PathVariable("id") final Long id, final UriComponentsBuilder uriBuilder, final HttpServletRequest request, final HttpServletResponse response) {
+        final Foo resourceById = RestPreconditions.checkFound(service.findOne(id));
+        eventPublisher.publishEvent(new SingleResourceRetrieved(this, request, response));
+        return resourceById;
     }
 
+    // read - all
+
     @RequestMapping(method = RequestMethod.GET)
     @ResponseBody
     public List<Foo> findAll() {
         return service.findAll();
     }
 
-    @RequestMapping(value = "admin/foo/{id}", method = RequestMethod.GET)
+    @RequestMapping(params = { "page", "size" }, method = RequestMethod.GET)
     @ResponseBody
-    public Foo get(@PathVariable("id") final Long id, final HttpServletRequest request, final HttpServletResponse response) {
-        final Foo resourceById = Preconditions.checkNotNull(service.findOne(id));
+    public List<Foo> findPaginated(@RequestParam("page") final int page, @RequestParam("size") final int size, final UriComponentsBuilder uriBuilder, final HttpServletResponse response) {
 
-        eventPublisher.publishEvent(new SingleResourceRetrieved(this, request, response));
-        return resourceById;
+        final Page<Foo> resultPage = service.findPaginated(page, size);
+        if (page > resultPage.getTotalPages()) {
+            throw new MyResourceNotFoundException();
+        }
+        // eventPublisher.publishEvent(new PaginatedResultsRetrievedEvent<Foo>(Foo.class, uriBuilder, response, page, resultPage.getTotalPages(), size));
+
+        return resultPage.getContent();
     }
 
+    // discover
+
     @RequestMapping(value = "admin", method = RequestMethod.GET)
     @ResponseStatus(value = HttpStatus.NO_CONTENT)
     public void adminRoot(final HttpServletRequest request, final HttpServletResponse response) {

spring-security-rest-full/src/main/java/org/baeldung/web/error/RestResponseEntityExceptionHandler.java

@@ -2,6 +2,7 @@
 
 import javax.persistence.EntityNotFoundException;
 
+import org.baeldung.web.exception.MyResourceNotFoundException;
 import org.hibernate.exception.ConstraintViolationException;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.DataIntegrityViolationException;
@@ -50,7 +51,7 @@ protected ResponseEntity<Object> handleMethodArgumentNotValid(final MethodArgume
 
     // 404
 
-    @ExceptionHandler(value = { EntityNotFoundException.class })
+    @ExceptionHandler(value = { EntityNotFoundException.class, MyResourceNotFoundException.class })
     protected ResponseEntity<Object> handleBadRequest(final EntityNotFoundException ex, final WebRequest request) {
         final String bodyOfResponse = "This should be application specific";
         return handleExceptionInternal(ex, bodyOfResponse, new HttpHeaders(), HttpStatus.NOT_FOUND, request);

spring-security-rest-full/src/main/java/org/baeldung/web/exception/MyResourceNotFoundException.java

@@ -0,0 +1,21 @@
+package org.baeldung.web.exception;
+
+public final class MyResourceNotFoundException extends RuntimeException {
+
+    public MyResourceNotFoundException() {
+        super();
+    }
+
+    public MyResourceNotFoundException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+
+    public MyResourceNotFoundException(final String message) {
+        super(message);
+    }
+
+    public MyResourceNotFoundException(final Throwable cause) {
+        super(cause);
+    }
+
+}

spring-security-rest-full/src/main/java/org/baeldung/web/util/RestPreconditions.java

@@ -0,0 +1,47 @@
+package org.baeldung.web.util;
+
+import org.baeldung.web.exception.MyResourceNotFoundException;
+import org.springframework.http.HttpStatus;
+
+/**
+ * Simple static methods to be called at the start of your own methods to verify correct arguments and state. If the Precondition fails, an {@link HttpStatus} code is thrown
+ */
+public final class RestPreconditions {
+
+    private RestPreconditions() {
+        throw new AssertionError();
+    }
+
+    // API
+
+    /**
+     * Check if some value was found, otherwise throw exception.
+     * 
+     * @param expression
+     *            has value true if found, otherwise false
+     * @throws MyResourceNotFoundException
+     *             if expression is false, means value not found.
+     */
+    public static void checkFound(final boolean expression) {
+        if (!expression) {
+            throw new MyResourceNotFoundException();
+        }
+    }
+
+    /**
+     * Check if some value was found, otherwise throw exception.
+     * 
+     * @param expression
+     *            has value true if found, otherwise false
+     * @throws MyResourceNotFoundException
+     *             if expression is false, means value not found.
+     */
+    public static <T> T checkFound(final T resource) {
+        if (resource == null) {
+            throw new MyResourceNotFoundException();
+        }
+
+        return resource;
+    }
+
+}