Merge pull request #29 from Karumi/use-page-object-for-pagination

Replace offset + limit by Page class

README.md

@@ -318,9 +318,9 @@ PaginatedRosieRepository<Key, Value> repository = /*...*/;
 // Get a value by its key just as with a regular repoitory
 Value value = repository.getByKey(key);
 // Get a page
-page = repository.getPage(offset, limit);
+page = repository.getPage(Page.withOffsetAndLimit(offset, limit));
 // Get a page using only the cache data source
-page = repository.getPage(offset, limit, ReadPolicy.CACHE_ONLY);
+page = repository.getPage(Page.withOffsetAndLimit(offset, limit), ReadPolicy.CACHE_ONLY);
 ```
 
 

rosie/src/main/java/com/karumi/rosie/repository/PaginatedCollection.java

@@ -16,6 +16,7 @@
 
 package com.karumi.rosie.repository;
 
+import com.karumi.rosie.repository.datasource.paginated.Page;
 import java.util.Collection;
 import java.util.Collections;
 
@@ -27,8 +28,7 @@ public class PaginatedCollection<T> {
 
   private Collection<T> items;
   private boolean hasMore;
-  private int offset;
-  private int limit;
+  private Page page;
 
   public PaginatedCollection() {
     this(Collections.<T>emptyList());
@@ -43,13 +43,8 @@ public PaginatedCollection setHasMore(boolean hasMore) {
     return this;
   }
 
-  public PaginatedCollection setOffset(int offset) {
-    this.offset = offset;
-    return this;
-  }
-
-  public PaginatedCollection setLimit(int limit) {
-    this.limit = limit;
+  public PaginatedCollection setPage(Page page) {
+    this.page = page;
     return this;
   }
 
@@ -61,11 +56,7 @@ public boolean hasMore() {
     return hasMore;
   }
 
-  public int getOffset() {
-    return offset;
-  }
-
-  public int getLimit() {
-    return limit;
+  public Page getPage() {
+    return page;
   }
 }

rosie/src/main/java/com/karumi/rosie/repository/PaginatedRosieRepository.java

@@ -17,6 +17,7 @@
 package com.karumi.rosie.repository;
 
 import com.karumi.rosie.repository.datasource.Identifiable;
+import com.karumi.rosie.repository.datasource.paginated.Page;
 import com.karumi.rosie.repository.datasource.paginated.PaginatedCacheDataSource;
 import com.karumi.rosie.repository.datasource.paginated.PaginatedReadableDataSource;
 import com.karumi.rosie.repository.policy.ReadPolicy;
@@ -47,43 +48,43 @@ protected final <R extends PaginatedCacheDataSource<K, V>> void addPaginatedCach
   }
 
   /**
-   * Returns a page of values bounded by the offset and limit values.
-   * @param offset Index of the first item to be retrieved
-   * @param limit Number of elements that will be retrieved
+   * Returns a page of values bounded by the provided page.
+   *
+   * @param page Page to be retrieved
    */
-  public PaginatedCollection<V> getPage(int offset, int limit) {
-    return getPage(offset, limit, ReadPolicy.READ_ALL);
+  public PaginatedCollection<V> getPage(Page page) {
+    return getPage(page, ReadPolicy.READ_ALL);
   }
 
   /**
-   * Returns a page of values bounded by the offset and limit values.
-   * @param offset Index of the first item to be retrieved
-   * @param limit Number of elements that will be retrieved
+   * Returns a page of values bounded by the provided page.
+   *
+   * @param page Page to be retrieved
    * @param policy Specifies how the value is going to be retrieved.
    */
-  public PaginatedCollection<V> getPage(int offset, int limit, ReadPolicy policy) {
+  public PaginatedCollection<V> getPage(Page page, ReadPolicy policy) {
     PaginatedCollection<V> values = null;
 
     if (policy.useCache()) {
-      values = getPaginatedValuesFromCaches(offset, limit);
+      values = getPaginatedValuesFromCaches(page);
     }
 
     if (values == null && policy.useReadable()) {
-      values = getPaginatedValuesFromReadables(offset, limit);
+      values = getPaginatedValuesFromReadables(page);
     }
 
     if (values != null) {
-      populatePaginatedCaches(offset, limit, values);
+      populatePaginatedCaches(page, values);
     }
 
     return values;
   }
 
-  protected PaginatedCollection<V> getPaginatedValuesFromCaches(int offset, int limit) {
+  protected PaginatedCollection<V> getPaginatedValuesFromCaches(Page page) {
     PaginatedCollection<V> values = null;
 
     for (PaginatedCacheDataSource<K, V> cacheDataSource : paginatedCacheDataSources) {
-      values = cacheDataSource.getPage(offset, limit);
+      values = cacheDataSource.getPage(page);
 
       if (values != null) {
         if (areValidValues(values, cacheDataSource)) {
@@ -98,11 +99,11 @@ protected PaginatedCollection<V> getPaginatedValuesFromCaches(int offset, int li
     return values;
   }
 
-  protected PaginatedCollection<V> getPaginatedValuesFromReadables(int offset, int limit) {
+  protected PaginatedCollection<V> getPaginatedValuesFromReadables(Page page) {
     PaginatedCollection<V> values = null;
 
     for (PaginatedReadableDataSource<V> readable : paginatedReadableDataSources) {
-      values = readable.getPage(offset, limit);
+      values = readable.getPage(page);
 
       if (values != null) {
         break;
@@ -112,9 +113,9 @@ protected PaginatedCollection<V> getPaginatedValuesFromReadables(int offset, int
     return values;
   }
 
-  protected void populatePaginatedCaches(int offset, int limit, PaginatedCollection<V> values) {
+  protected void populatePaginatedCaches(Page page, PaginatedCollection<V> values) {
     for (PaginatedCacheDataSource<K, V> cacheDataSource : paginatedCacheDataSources) {
-      cacheDataSource.addOrUpdatePage(offset, limit, values.getItems(), values.hasMore());
+      cacheDataSource.addOrUpdatePage(page, values.getItems(), values.hasMore());
     }
   }
 

rosie/src/main/java/com/karumi/rosie/repository/datasource/paginated/EmptyPaginatedCacheDataSource.java

@@ -27,13 +27,12 @@ public class EmptyPaginatedCacheDataSource<K, V extends Identifiable<K>>
     return false;
   }
 
-  @Override public PaginatedCollection<V> getPage(int offset, int limit) {
+  @Override public PaginatedCollection<V> getPage(Page page) {
     return null;
   }
 
   @Override
-  public PaginatedCollection<V> addOrUpdatePage(int offset, int limit, Collection<V> values,
-      boolean hasMore) {
+  public PaginatedCollection<V> addOrUpdatePage(Page page, Collection<V> values, boolean hasMore) {
     return null;
   }
 

rosie/src/main/java/com/karumi/rosie/repository/datasource/paginated/InMemoryPaginatedCacheDataSource.java

@@ -40,27 +40,28 @@ public InMemoryPaginatedCacheDataSource(TimeProvider timeProvider, long ttlInMil
     this.items = new ArrayList<>();
   }
 
-  @Override public PaginatedCollection<V> getPage(int offset, int limit) {
+  @Override public PaginatedCollection<V> getPage(Page page) {
     List<V> result = new LinkedList<>();
+
+    int offset = page.getOffset();
+    int limit = page.getLimit();
+
     for (int i = offset; i < items.size() && i < offset + limit; i++) {
       V value = items.get(i);
       result.add(value);
     }
     PaginatedCollection<V> paginatedCollection = new PaginatedCollection<>(result);
-    paginatedCollection.setOffset(offset);
-    paginatedCollection.setLimit(limit);
+    paginatedCollection.setPage(page);
     paginatedCollection.setHasMore(offset + limit < items.size() || this.hasMore);
     return paginatedCollection;
   }
 
   @Override
-  public PaginatedCollection<V> addOrUpdatePage(int offset, int limit, Collection<V> values,
-      boolean hasMore) {
+  public PaginatedCollection<V> addOrUpdatePage(Page page, Collection<V> values, boolean hasMore) {
     this.items.addAll(values);
     this.hasMore = hasMore;
     PaginatedCollection<V> paginatedCollection = new PaginatedCollection<>(values);
-    paginatedCollection.setOffset(offset);
-    paginatedCollection.setLimit(limit);
+    paginatedCollection.setPage(page);
     paginatedCollection.setHasMore(hasMore);
     lastItemsUpdate = timeProvider.currentTimeMillis();
     return paginatedCollection;

rosie/src/main/java/com/karumi/rosie/repository/datasource/paginated/Page.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2015 Karumi.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.karumi.rosie.repository.datasource.paginated;
+
+public final class Page {
+
+  private final int offset;
+  private final int limit;
+
+  private Page(int offset, int limit) {
+    this.offset = offset;
+    this.limit = limit;
+  }
+
+  public static Page withOffsetAndLimit(int offset, int limit) {
+    return new Page(offset, limit);
+  }
+
+  public int getOffset() {
+    return offset;
+  }
+
+  public int getLimit() {
+    return limit;
+  }
+}

rosie/src/main/java/com/karumi/rosie/repository/datasource/paginated/PaginatedReadableDataSource.java

@@ -25,9 +25,9 @@
  */
 public interface PaginatedReadableDataSource<V> {
   /**
-   * Returns a page of values bounded by the offset and limit values.
-   * @param offset Index of the first item to be retrieved
-   * @param limit Number of elements that will be retrieved
+   * Returns a page of values bounded by the provided page.
+   *
+   * @param page page to be retrieved
    */
-  PaginatedCollection<V> getPage(int offset, int limit);
+  PaginatedCollection<V> getPage(Page page);
 }

rosie/src/main/java/com/karumi/rosie/repository/datasource/paginated/PaginatedWriteableDataSource.java

@@ -30,13 +30,11 @@ public interface PaginatedWriteableDataSource<K, V extends Identifiable<K>> {
   /**
    * Adds or update a page of values into this data source.
    *
-   * @param offset Index of the first item to be retrieved
-   * @param limit Number of elements that will be retrieved
+   * @param page Page to be stored
    * @param values Collection of values to be stored
    * @param hasMore True whether the persisted page has more elements
    */
-  PaginatedCollection<V> addOrUpdatePage(int offset, int limit, Collection<V> values,
-      boolean hasMore);
+  PaginatedCollection<V> addOrUpdatePage(Page page, Collection<V> values, boolean hasMore);
 
   /**
    * Deletes all the pages stored in this data source.