draft implementation of server side pagination for retriveOne

mifosng-provider/src/main/java/org/mifosplatform/portfolio/client/api/ClientsApiResource.java

@@ -5,6 +5,7 @@
  */
 package org.mifosplatform.portfolio.client.api;
 
+import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -41,6 +42,7 @@ import org.mifosplatform.portfolio.client.data.ClientAccountSummaryCollectionDat
 import org.mifosplatform.portfolio.client.data.ClientData;
 import org.mifosplatform.portfolio.client.service.ClientReadPlatformService;
 import org.mifosplatform.portfolio.group.service.SearchParameters;
+import org.mifosplatform.portfolio.pagination.Page;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Component;
@@ -124,6 +126,17 @@ public class ClientsApiResource {
         return this.toApiJsonSerializer.serialize(settings, clientData, ClientApiConstants.CLIENT_RESPONSE_DATA_PARAMETERS);
     }
     
+    @GET
+    @Path("/paginated")
+    @Consumes({ MediaType.APPLICATION_JSON })
+    @Produces({ MediaType.APPLICATION_JSON })
+    public String retrieveOnePaginated(@QueryParam("pageNo") final int pageNo, @QueryParam("pageSize") final int pageSize,
+            @Context final UriInfo uriInfo) throws SQLException {
+        context.authenticatedUser().validateHasReadPermission(ClientApiConstants.CLIENT_RESOURCE_NAME);
+        Page<ClientData> clientData = this.clientReadPlatformService.retrieveOnePaginated(pageNo, pageSize);
+        return clientData.toString();
+    }
+
     @POST
     @Consumes({ MediaType.APPLICATION_JSON })
     @Produces({ MediaType.APPLICATION_JSON })

mifosng-provider/src/main/java/org/mifosplatform/portfolio/client/service/ClientReadPlatformService.java

@@ -11,6 +11,7 @@ import org.mifosplatform.portfolio.client.data.ClientAccountSummaryCollectionDat
 import org.mifosplatform.portfolio.client.data.ClientAccountSummaryData;
 import org.mifosplatform.portfolio.client.data.ClientData;
 import org.mifosplatform.portfolio.group.service.SearchParameters;
+import org.mifosplatform.portfolio.pagination.Page;
 
 public interface ClientReadPlatformService {
 
@@ -18,6 +19,8 @@ public interface ClientReadPlatformService {
 
     Collection<ClientData> retrieveAll(SearchParameters searchParameters);
     
+    Page<ClientData> retrieveOnePaginated(int pageNo, int pageSize);
+
     ClientData retrieveOne(Long clientId);
 
     Collection<ClientData> retrieveAllForLookup(String extraCriteria);

mifosng-provider/src/main/java/org/mifosplatform/portfolio/client/service/ClientReadPlatformServiceImpl.java

@@ -29,11 +29,14 @@ import org.mifosplatform.portfolio.group.data.GroupGeneralData;
 import org.mifosplatform.portfolio.group.service.SearchParameters;
 import org.mifosplatform.portfolio.loanaccount.data.LoanStatusEnumData;
 import org.mifosplatform.portfolio.loanproduct.service.LoanEnumerations;
+import org.mifosplatform.portfolio.pagination.Page;
+import org.mifosplatform.portfolio.pagination.PaginationHelper;
 import org.mifosplatform.useradministration.domain.AppUser;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
+import org.springframework.jdbc.core.simple.ParameterizedRowMapper;
 import org.springframework.stereotype.Service;
 
 @Service
@@ -87,6 +90,35 @@ public class ClientReadPlatformServiceImpl implements ClientReadPlatformService
         return this.jdbcTemplate.query(sql, clientMapper, new Object[] { hierarchySearchString });
     }
 
+    @Override
+    public Page<ClientData> retrieveOnePaginated(final int pageNo, final int pageSize) {
+        PaginationHelper<ClientData> ph = new PaginationHelper<ClientData>();
+        return ph.fetchPage(jdbcTemplate, "SELECT count(*) FROM m_client ORDER BY firstname", "SELECT * FROM m_client ORDER BY firstname",
+                null, pageNo, pageSize, new ParameterizedRowMapper<ClientData>() {
+
+                    @Override
+                    public ClientData mapRow(ResultSet rs, int rowNum) throws SQLException {
+                        final String accountNo = rs.getString("account_no");
+                        final EnumOptionData status = null;
+                        final Long officeId = JdbcSupport.getLong(rs, "office_id");
+                        final Long id = JdbcSupport.getLong(rs, "id");
+                        final String firstname = rs.getString("firstname");
+                        final String middlename = rs.getString("middlename");
+                        final String lastname = rs.getString("lastname");
+                        final String fullname = rs.getString("fullname");
+                        final String displayName = rs.getString("display_name");
+                        final String externalId = rs.getString("external_Id");
+                        final LocalDate activationDate = JdbcSupport.getLocalDate(rs, "activation_date");
+                        final String imageKey = rs.getString("image_key");
+                        final String officeName = null;
+
+                        return ClientData.instance(accountNo, status, officeId, officeName, id, firstname, middlename, lastname, fullname,
+                                displayName, externalId, activationDate, imageKey);
+                    }
+                });
+
+    }
+    
     private String buildSqlStringFromClientCriteria(final SearchParameters searchParameters) {
 
         final String sqlSearch = searchParameters.getSqlSearch();

mifosng-provider/src/main/java/org/mifosplatform/portfolio/pagination/Page.java

@@ -0,0 +1,42 @@
+package org.mifosplatform.portfolio.pagination;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.google.gson.Gson;
+
+public class Page<E> {
+
+    private int pageNumber;
+    private int pagesAvailable;
+    private List<E> pageItems = new ArrayList<E>();
+
+    public void setPageNumber(int pageNumber) {
+        this.pageNumber = pageNumber;
+    }
+
+    public void setPagesAvailable(int pagesAvailable) {
+        this.pagesAvailable = pagesAvailable;
+    }
+
+    public void setPageItems(List<E> pageItems) {
+        this.pageItems = pageItems;
+    }
+
+    public int getPageNumber() {
+        return pageNumber;
+    }
+
+    public int getPagesAvailable() {
+        return pagesAvailable;
+    }
+
+    public List<E> getPageItems() {
+        return pageItems;
+    }
+
+    @Override
+    public String toString() {
+        return new Gson().toJson(this);
+    }
+}

mifosng-provider/src/main/java/org/mifosplatform/portfolio/pagination/PaginationHelper.java

@@ -0,0 +1,51 @@
+package org.mifosplatform.portfolio.pagination;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
+
+import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.ResultSetExtractor;
+import org.springframework.jdbc.core.simple.ParameterizedRowMapper;
+
+public class PaginationHelper<E> {
+
+    public Page<E> fetchPage(final JdbcTemplate jt, final String sqlCountRows, final String sqlFetchRows, final Object args[],
+            final int pageNo, final int pageSize, final ParameterizedRowMapper<E> rowMapper) {
+
+        // determine how many rows are available
+        final int rowCount = jt.queryForInt(sqlCountRows, args);
+
+        // calculate the number of pages
+        int pageCount = rowCount / pageSize;
+        if (rowCount > pageSize * pageCount) {
+            pageCount++;
+        }
+
+        // create the page object
+        final Page<E> page = new Page<E>();
+        page.setPageNumber(pageNo);
+        page.setPagesAvailable(pageCount);
+
+        // fetch a single page of results
+        final int startRow = (pageNo - 1) * pageSize;
+        jt.query(sqlFetchRows, new ResultSetExtractor<E>() {
+
+            @Override
+            public E extractData(ResultSet rs) throws SQLException, DataAccessException {
+                final List<E> pageItems = page.getPageItems();
+                int currentRow = 0;
+                while (rs.next() && currentRow < startRow + pageSize) {
+                    if (currentRow >= startRow) {
+                        pageItems.add(rowMapper.mapRow(rs, currentRow));
+                    }
+                    currentRow++;
+                }
+                return (E) page;
+            }
+        });
+        return page;
+    }
+
+}