Exemplo n.º 1
0
 /** @return The previous page. */
 private <T> Page<T> queryPreviousPage(
     int rowsPerPage,
     String currentStartKey,
     String currentStartKeyDocId,
     String startKey,
     String startKeyDocId,
     Class<T> classOfT) {
   // set view query params
   limit(rowsPerPage + 1);
   includeDocs(true);
   descending(true); // read backward
   startKey(currentStartKey);
   startKeyDocId(currentStartKeyDocId);
   // init page, query view
   final Page<T> page = new Page<T>();
   final List<T> pageList = new ArrayList<T>();
   final ViewResult<String, String, T> vr = queryView(String.class, String.class, classOfT);
   final List<ViewResult<String, String, T>.Rows> rows = vr.getRows();
   final int resultRows = rows.size();
   final int offset = vr.getOffset();
   final long totalRows = vr.getTotalRows();
   Collections.reverse(rows); // fix order
   // holds page params
   final JsonObject currentKeys = new JsonObject();
   final JsonObject jsonNext = new JsonObject();
   final JsonObject jsonPrev = new JsonObject();
   currentKeys.addProperty(CURRENT_START_KEY, rows.get(0).getKey());
   currentKeys.addProperty(CURRENT_START_KEY_DOC_ID, rows.get(0).getId());
   for (int i = 0; i < resultRows; i++) {
     // set keys for the next page
     if (i == resultRows - 1) { // last element (i.e rowsPerPage + 1)
       if (resultRows >= rowsPerPage) { // if not last page
         page.setHasNext(true);
         jsonNext.addProperty(START_KEY, rows.get(i).getKey());
         jsonNext.addProperty(START_KEY_DOC_ID, rows.get(i).getId());
         jsonNext.add(CURRENT_KEYS, currentKeys);
         jsonNext.addProperty(ACTION, NEXT);
         page.setNextParam(Base64.encodeBase64URLSafeString(jsonNext.toString().getBytes()));
         continue;
       }
     }
     pageList.add(rows.get(i).getDoc());
   }
   // set keys for the previous page
   if (offset != (totalRows - rowsPerPage - 1)) { // if not first page
     page.setHasPrevious(true);
     jsonPrev.addProperty(START_KEY, currentStartKey);
     jsonPrev.addProperty(START_KEY_DOC_ID, currentStartKeyDocId);
     jsonPrev.add(CURRENT_KEYS, currentKeys);
     jsonPrev.addProperty(ACTION, PREVIOUS);
     page.setPreviousParam(Base64.encodeBase64URLSafeString(jsonPrev.toString().getBytes()));
   }
   // calculate paging display info
   page.setResultList(pageList);
   page.setTotalResults(totalRows);
   page.setResultFrom((int) totalRows - (offset + rowsPerPage));
   final int resultTo = (int) totalRows - offset - 1;
   page.setResultTo(resultTo);
   page.setPageNumber(resultTo / rowsPerPage);
   return page;
 }
Exemplo n.º 2
0
 /** @return The next page. */
 private <T> Page<T> queryNextPage(
     int rowsPerPage,
     String currentStartKey,
     String currentStartKeyDocId,
     String startKey,
     String startKeyDocId,
     Class<T> classOfT) {
   // set view query params
   limit(rowsPerPage + 1);
   includeDocs(true);
   if (startKey != null) {
     startKey(startKey);
     startKeyDocId(startKeyDocId);
   }
   // init page, query view
   final Page<T> page = new Page<T>();
   final List<T> pageList = new ArrayList<T>();
   final ViewResult<String, String, T> vr = queryView(String.class, String.class, classOfT);
   final List<ViewResult<String, String, T>.Rows> rows = vr.getRows();
   final int resultRows = rows.size();
   final int offset = vr.getOffset();
   final long totalRows = vr.getTotalRows();
   // holds page params
   final JsonObject currentKeys = new JsonObject();
   final JsonObject jsonNext = new JsonObject();
   final JsonObject jsonPrev = new JsonObject();
   currentKeys.addProperty(CURRENT_START_KEY, rows.get(0).getKey());
   currentKeys.addProperty(CURRENT_START_KEY_DOC_ID, rows.get(0).getId());
   for (int i = 0; i < resultRows; i++) {
     // set keys for the next page
     if (i == resultRows - 1) { // last element (i.e rowsPerPage + 1)
       if (resultRows > rowsPerPage) { // if not last page
         page.setHasNext(true);
         jsonNext.addProperty(START_KEY, rows.get(i).getKey());
         jsonNext.addProperty(START_KEY_DOC_ID, rows.get(i).getId());
         jsonNext.add(CURRENT_KEYS, currentKeys);
         jsonNext.addProperty(ACTION, NEXT);
         page.setNextParam(Base64.encodeBase64URLSafeString(jsonNext.toString().getBytes()));
         continue; // exclude
       }
     }
     pageList.add(rows.get(i).getDoc());
   }
   // set keys for the previous page
   if (offset != 0) { // if not first page
     page.setHasPrevious(true);
     jsonPrev.addProperty(START_KEY, currentStartKey);
     jsonPrev.addProperty(START_KEY_DOC_ID, currentStartKeyDocId);
     jsonPrev.add(CURRENT_KEYS, currentKeys);
     jsonPrev.addProperty(ACTION, PREVIOUS);
     page.setPreviousParam(Base64.encodeBase64URLSafeString(jsonPrev.toString().getBytes()));
   }
   // calculate paging display info
   page.setResultList(pageList);
   page.setTotalResults(totalRows);
   page.setResultFrom(offset + 1);
   final int resultTo =
       rowsPerPage > resultRows
           ? resultRows
           : rowsPerPage; // fix when rowsPerPage exceeds returned rows
   page.setResultTo(offset + resultTo);
   page.setPageNumber((int) Math.ceil(page.getResultFrom() / Double.valueOf(rowsPerPage)));
   return page;
 }