Update the paging calculation, to correctly handle requests from the …

…Scroller plugin Fix #23
darrachequesne · Aug 18, 2016 · 5aefdde · 5aefdde
1 parent 73db1d6
commit 5aefdde
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Showing 4 changed files with 84 additions and 4 deletions.
diff --git a/...n/java/org/springframework/data/jpa/datatables/qrepository/QDataTablesRepositoryImpl.java b/...n/java/org/springframework/data/jpa/datatables/qrepository/QDataTablesRepositoryImpl.java
@@ -73,6 +73,10 @@ public <R> DataTablesOutput<R> findAll(DataTablesInput input, Predicate addition
       Predicate preFilteringPredicate, Converter<T, R> converter) {
     DataTablesOutput<R> output = new DataTablesOutput<R>();
     output.setDraw(input.getDraw());
+    if (input.getLength() == 0) {
+      return output;
+    }
+
     try {
       long recordsTotal = preFilteringPredicate == null ? count() : count(preFilteringPredicate);
       if (recordsTotal == 0) {

diff --git a/...ain/java/org/springframework/data/jpa/datatables/repository/DataTablesRepositoryImpl.java b/...ain/java/org/springframework/data/jpa/datatables/repository/DataTablesRepositoryImpl.java
@@ -58,6 +58,9 @@ public <R> DataTablesOutput<R> findAll(DataTablesInput input,
       Converter<T, R> converter) {
     DataTablesOutput<R> output = new DataTablesOutput<R>();
     output.setDraw(input.getDraw());
+    if (input.getLength() == 0) {
+      return output;
+    }
 
     try {
       long recordsTotal =

diff --git a/src/main/java/org/springframework/data/jpa/datatables/repository/DataTablesUtils.java b/src/main/java/org/springframework/data/jpa/datatables/repository/DataTablesUtils.java
@@ -3,7 +3,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
@@ -42,7 +41,7 @@ public static Pageable getPageable(DataTablesInput input) {
       input.setStart(0);
       input.setLength(Integer.MAX_VALUE);
     }
-    return new PageRequest(input.getStart() / input.getLength(), input.getLength(), sort);
+    return new DataTablesPageRequest(input.getStart(), input.getLength(), sort);
   }
 
   public static boolean isBoolean(String filterValue) {
@@ -55,4 +54,57 @@ public static String getLikeFilterValue(String filterValue) {
         + "%";
   }
 
+  private static class DataTablesPageRequest implements Pageable {
+
+    private final int offset;
+    private final int pageSize;
+    private final Sort sort;
+
+    public DataTablesPageRequest(int offset, int pageSize, Sort sort) {
+      this.offset = offset;
+      this.pageSize = pageSize;
+      this.sort = sort;
+    }
+
+    @Override
+    public int getOffset() {
+      return offset;
+    }
+
+    @Override
+    public int getPageSize() {
+      return pageSize;
+    }
+
+    @Override
+    public Sort getSort() {
+      return sort;
+    }
+
+    @Override
+    public Pageable next() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Pageable previousOrFirst() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Pageable first() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean hasPrevious() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getPageNumber() {
+      throw new UnsupportedOperationException();
+    }
+  }
+
 }
diff --git a/src/test/java/org/springframework/data/jpa/datatables/repository/UserRepositoryTest.java b/src/test/java/org/springframework/data/jpa/datatables/repository/UserRepositoryTest.java
@@ -241,8 +241,8 @@ public void testWithZeroLength() {
     input.setLength(0);
     DataTablesOutput<User> output = userRepository.findAll(input);
     assertNotNull(output);
-    assertNotNull(output.getError());
-    assertEquals(output.getError(), "java.lang.ArithmeticException: / by zero");
+    assertEquals(0, output.getData().size());
+    assertEquals(0, output.getRecordsFiltered());
   }
 
   @Test
@@ -278,6 +278,27 @@ public UserDto convert(User user) {
     assertEquals("BLOCKED", user.getStatus());
   }
 
+  @Test
+  public void testWithFancyPaging() {
+    DataTablesInput input = getBasicInput();
+
+    input.setLength(5);
+    input.setStart(7);
+    DataTablesOutput<User> output = userRepository.findAll(input);
+    assertNotNull(output);
+    assertNull(output.getError());
+    assertEquals(5, output.getData().size());
+    assertEquals(8, (int) output.getData().get(0).getId());
+    assertEquals(8 + 5 - 1, (int) output.getData().get(4).getId());
+
+    input.setLength(7);
+    input.setStart(22);
+    output = userRepository.findAll(input);
+    assertNotNull(output);
+    assertEquals(2, output.getData().size());
+    assertEquals(23, (int) output.getData().get(0).getId());
+  }
+
   /**
    * 
    * @return basic input parameters