#11 - refactoring count query

9tigerio · Jan 19, 2024 · 6719dba · 6719dba
1 parent 0a1cdb7
commit 6719dba
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Showing 7 changed files with 106 additions and 25 deletions.
diff --git a/src/main/java/com/homihq/db2rest/rest/read/CountQueryController.java b/src/main/java/com/homihq/db2rest/rest/read/CountQueryController.java
@@ -0,0 +1,22 @@
+package com.homihq.db2rest.rest.read;
+
+import com.homihq.db2rest.rest.read.model.CountResponse;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@Slf4j
+@RequiredArgsConstructor
+public class CountQueryController {
+    private final CountQueryService countQueryService;
+    @GetMapping("/{tableName}/count")
+    public CountResponse count(@PathVariable String tableName
+                                    , @RequestParam(name = "filter", required = false, defaultValue = "") String filter) {
+
+        log.info("tableName - {}", tableName);
+        log.info("filter - {}", filter);
+
+        return countQueryService.count(tableName, filter);
+    }
+}
diff --git a/src/main/java/com/homihq/db2rest/rest/read/CountQueryService.java b/src/main/java/com/homihq/db2rest/rest/read/CountQueryService.java
@@ -0,0 +1,45 @@
+package com.homihq.db2rest.rest.read;
+
+import com.homihq.db2rest.rest.read.helper.*;
+
+import com.homihq.db2rest.rest.read.model.CountResponse;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
+import org.springframework.stereotype.Service;
+
+import java.util.Map;
+
+
+@Service
+@Slf4j
+@RequiredArgsConstructor
+public class CountQueryService {
+
+    private final SelectBuilder selectBuilder;
+    private final WhereBuilder whereBuilder;
+    private final NamedParameterJdbcTemplate namedParameterJdbcTemplate;
+
+
+    public CountResponse count(String tableName, String filter) {
+        ReadContext ctx = ReadContext.builder()
+                .select("count(*)")
+                .tableName(tableName)
+                .filter(filter)
+                .build();
+        selectBuilder.build(ctx);
+        whereBuilder.build(ctx);
+
+        String sql = ctx.prepareSQL();
+        Map<String, Object> bindValues = ctx.prepareParameters();
+
+        log.info("SQL count - {}", sql);
+        log.info("Bind variables - {}", bindValues);
+
+        Long itemCount = namedParameterJdbcTemplate.queryForObject(sql, bindValues, Long.class);
+
+        return new CountResponse(itemCount);
+    }
+
+
+}
diff --git a/src/main/java/com/homihq/db2rest/rest/read/ReadController.java b/src/main/java/com/homihq/db2rest/rest/read/ReadController.java
@@ -51,9 +51,5 @@ public ResponseEntity<Object> findByCustomQuery(@RequestBody @Valid QueryRequest
         return ResponseEntity.ok(readService.findByCustomQuery(queryRequest));
     }
 
-    @GetMapping(value = "/query/{tableName}/count", produces = MediaType.APPLICATION_JSON_VALUE)
-    public ResponseEntity<Integer> getCount(@PathVariable String tableName) {
-        return ResponseEntity.ok(readService.findCount(tableName));
-    }
 
 }
diff --git a/src/main/java/com/homihq/db2rest/rest/read/ReadService.java b/src/main/java/com/homihq/db2rest/rest/read/ReadService.java
@@ -47,21 +47,6 @@ public Object findAll(String schemaName, String tableName, String select, String
 
     }
 
-    public int findCount(String tableName) {
-        ReadContext ctx = ReadContext.builder()
-                .tableName(tableName)
-                .select("*")
-                .build();
-        selectBuilder.build(ctx);
-
-        String sql = ctx.prepareSQL();
-        Map<String, Object> bindValues = ctx.prepareParameters();
-
-        log.info("SQL count - {}", sql);
-        log.info("Bind variables - {}", bindValues);
-
-        return namedParameterJdbcTemplate.queryForList(sql, bindValues).size();
-    }
 
     Object findByCustomQuery(QueryRequest queryRequest) {
         return queryRequest.isSingle() ?

diff --git a/src/main/java/com/homihq/db2rest/rest/read/helper/ReadContext.java b/src/main/java/com/homihq/db2rest/rest/read/helper/ReadContext.java
@@ -3,6 +3,7 @@
 import com.homihq.db2rest.exception.GenericDataAccessException;
 import com.homihq.db2rest.mybatis.MyBatisTable;
 import lombok.*;
+import org.apache.commons.lang3.StringUtils;
 import org.mybatis.dynamic.sql.BasicColumn;
 import org.mybatis.dynamic.sql.SqlColumn;
 import org.mybatis.dynamic.sql.SqlCriterion;
@@ -20,6 +21,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import static org.mybatis.dynamic.sql.SqlBuilder.count;
 import static org.mybatis.dynamic.sql.select.SelectDSL.select;
 
 
@@ -48,7 +50,9 @@ public void addWhereClause(SqlCriterion condition) {
         queryExpressionDSL.where(condition);
     }
 
-
+    public boolean isCountQuery() {
+        return StringUtils.equals(select, "count(*)");
+    }
 
     public SqlColumn<?> getSortColumn(String columnName) {
         //for now just support root table
@@ -65,6 +69,10 @@ public void createSelect() {
         if(union) {
             createUnionQuery();
         }
+        else if(isCountQuery()) {
+            from = getRootTable();
+            queryExpressionDSL = select(count()).from(from, from.getAlias());
+        }
         else{
             from = getRootTable();
             queryExpressionDSL = select(columns).from(from, from.getAlias());

diff --git a/src/main/java/com/homihq/db2rest/rest/read/helper/SelectBuilder.java b/src/main/java/com/homihq/db2rest/rest/read/helper/SelectBuilder.java
@@ -20,18 +20,35 @@ public class SelectBuilder{
     private final Db2RestConfigProperties db2RestConfigProperties;
 
     public void build(ReadContext context) {
-        context.setTables(createTables(context));
+        context.setTables(prepareTables(context));
         context.createSelect();
 
     }
 
-    private List<MyBatisTable> createTables(ReadContext context) {
+    private List<MyBatisTable> prepareTables(ReadContext context) {
         List<MyBatisTable> tables = new ArrayList<>();
+        int counter = 0;
+
+        if(context.isCountQuery()) {
+            tables = createTables(
+                    context.schemaName,
+                    context.tableName, null, counter);
+
+            for(MyBatisTable table : tables) {
+                table.setRoot(true);
+            }
+
+            return tables;
+        }
+
+
+
         log.info("context.select - {}", context.select);
+
         //split to get all fragments
         String [] tabCols = context.select.split(";");
 
-        int counter = 0;
+
 
         log.info("tabCols - {}", tabCols.length);
 
@@ -90,15 +107,19 @@ private List<MyBatisTable> createTables(String schemaName, String tableName,  St
         if(StringUtils.isNotBlank(sName)) {
             MyBatisTable table = schemaManager.findTable(sName, tName, counter);
 
-            addColumns(table, colStr);
+            if(StringUtils.isNotBlank(colStr)) {
+                addColumns(table, colStr);
+            }
 
             return List.of(table);
         }
         else {
             List<MyBatisTable> tables = schemaManager.findTables(tName);
 
             for(MyBatisTable table : tables) {
-                addColumns(table, colStr);
+                if(StringUtils.isNotBlank(colStr)) {
+                    addColumns(table, colStr);
+                }
             }
 
             return tables;

diff --git a/src/main/java/com/homihq/db2rest/rest/read/model/CountResponse.java b/src/main/java/com/homihq/db2rest/rest/read/model/CountResponse.java
@@ -0,0 +1,4 @@
+package com.homihq.db2rest.rest.read.model;
+
+public record CountResponse(long count) {
+}