Merge pull request #861 from jeffgbutler/rework-spring-batch

Improve Spring Batch Support

Author: jeffgbutler

CHANGELOG.md

@@ -12,6 +12,10 @@ worked to make these changes as minimal as possible.
 
 **Potentially Breaking Changes:**
 
+- If you use this library with MyBatis' Spring Batch integration, you will need to make changes as we have
+  refactored that support to be more flexible. Please see the
+  [Spring Batch](https://mybatis.org/mybatis-dynamic-sql/docs/springBatch.html) documentation page to see the new usage
+  details.
 - If you have created any custom implementations of `SortSpecification`, you will need to update those
   implementations due to a new rendering strategy for ORDER BY phrases. The old methods `isDescending` and `orderByName`
   are removed in favor of a new method `renderForOrderBy` 

pom.xml

@@ -58,6 +58,8 @@
   <properties>
     <java.version>17</java.version>
     <java.release.version>17</java.release.version>
+    <java.test.version>17</java.test.version>
+    <java.test.release.version>17</java.test.release.version>
     <junit.jupiter.version>5.11.3</junit.jupiter.version>
     <spring.batch.version>5.1.2</spring.batch.version>
 

src/main/java/org/mybatis/dynamic/sql/delete/render/DeleteRenderer.java

@@ -84,7 +84,7 @@ private Optional<FragmentAndParameters> calculateLimitClause() {
     }
 
     private FragmentAndParameters renderLimitClause(Long limit) {
-        RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo();
+        RenderedParameterInfo parameterInfo = renderingContext.calculateLimitParameterInfo();
 
         return FragmentAndParameters.withFragment("limit " + parameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
                 .withParameter(parameterInfo.parameterMapKey(), limit)

src/main/java/org/mybatis/dynamic/sql/render/RenderingContext.java

@@ -57,18 +57,27 @@ private String nextMapKey() {
         return renderingStrategy.formatParameterMapKey(sequence);
     }
 
-    private String renderedPlaceHolder(String mapKey) {
-        return renderingStrategy.getFormattedJdbcPlaceholder(calculatedParameterName, mapKey);
-    }
-
     private <T> String renderedPlaceHolder(String mapKey, BindableColumn<T> column) {
         return  column.renderingStrategy().orElse(renderingStrategy)
                 .getFormattedJdbcPlaceholder(column, calculatedParameterName, mapKey);
     }
 
-    public RenderedParameterInfo calculateParameterInfo() {
-        String mapKey = nextMapKey();
-        return new RenderedParameterInfo(mapKey, renderedPlaceHolder(mapKey));
+    public RenderedParameterInfo calculateFetchFirstRowsParameterInfo() {
+        String mapKey = renderingStrategy.formatParameterMapKeyForFetchFirstRows(sequence);
+        return new RenderedParameterInfo(mapKey,
+                renderingStrategy.getFormattedJdbcPlaceholderForPagingParameters(calculatedParameterName, mapKey));
+    }
+
+    public RenderedParameterInfo calculateLimitParameterInfo() {
+        String mapKey = renderingStrategy.formatParameterMapKeyForLimit(sequence);
+        return new RenderedParameterInfo(mapKey,
+                renderingStrategy.getFormattedJdbcPlaceholderForPagingParameters(calculatedParameterName, mapKey));
+    }
+
+    public RenderedParameterInfo calculateOffsetParameterInfo() {
+        String mapKey = renderingStrategy.formatParameterMapKeyForOffset(sequence);
+        return new RenderedParameterInfo(mapKey,
+                renderingStrategy.getFormattedJdbcPlaceholderForPagingParameters(calculatedParameterName, mapKey));
     }
 
     public <T> RenderedParameterInfo calculateParameterInfo(BindableColumn<T> column) {

src/main/java/org/mybatis/dynamic/sql/render/RenderingStrategy.java

@@ -36,10 +36,55 @@
 public abstract class RenderingStrategy {
     public static final String DEFAULT_PARAMETER_PREFIX = "parameters"; //$NON-NLS-1$
 
+    /**
+     * Generate a unique key that can be used to place a parameter value in the parameter map.
+     *
+     * @param sequence a sequence for calculating a unique value
+     * @return a key used to place the parameter value in the parameter map
+     */
     public String formatParameterMapKey(AtomicInteger sequence) {
         return "p" + sequence.getAndIncrement(); //$NON-NLS-1$
     }
 
+    /**
+     * Return a parameter map key intended as a parameter for a fetch first query.
+     *
+     * <p>By default, this parameter is treated the same as any other. This method is a hook to support
+     * MyBatis Spring Batch.
+     *
+     * @param sequence a sequence for calculating a unique value
+     * @return a key used to place the parameter value in the parameter map
+     */
+    public String formatParameterMapKeyForFetchFirstRows(AtomicInteger sequence) {
+        return formatParameterMapKey(sequence);
+    }
+
+    /**
+     * Return a parameter map key intended as a parameter for a limit query.
+     *
+     * <p>By default, this parameter is treated the same as any other. This method is a hook to support
+     * MyBatis Spring Batch.
+     *
+     * @param sequence a sequence for calculating a unique value
+     * @return a key used to place the parameter value in the parameter map
+     */
+    public String formatParameterMapKeyForLimit(AtomicInteger sequence) {
+        return formatParameterMapKey(sequence);
+    }
+
+    /**
+     * Return a parameter map key intended as a parameter for a query offset.
+     *
+     * <p>By default, this parameter is treated the same as any other. This method is a hook to support
+     * MyBatis Spring Batch.
+     *
+     * @param sequence a sequence for calculating a unique value
+     * @return a key used to place the parameter value in the parameter map
+     */
+    public String formatParameterMapKeyForOffset(AtomicInteger sequence) {
+        return formatParameterMapKey(sequence);
+    }
+
     /**
      * This method generates a binding for a parameter to a placeholder in a generated SQL statement.
      *
@@ -78,6 +123,23 @@ public String formatParameterMapKey(AtomicInteger sequence) {
      */
     public abstract String getFormattedJdbcPlaceholder(String prefix, String parameterName);
 
+    /**
+     * This method generates a binding for a parameter to a placeholder in a generated SQL statement.
+     *
+     * <p>This method is used to generate bindings for limit, offset, and fetch first parameters. By default, these
+     * parameters are treated the same as any other. This method supports MyBatis Spring Batch integration where the
+     * parameter keys have predefined values and need special handling.
+     *
+     * @param prefix parameter prefix used for locating the parameters in a SQL provider object. Typically, will be
+     *               {@link RenderingStrategy#DEFAULT_PARAMETER_PREFIX}. This is ignored for Spring.
+     * @param parameterName name of the parameter. Typically generated by calling
+     *     {@link RenderingStrategy#formatParameterMapKey(AtomicInteger)}
+     * @return the generated binding
+     */
+    public String getFormattedJdbcPlaceholderForPagingParameters(String prefix, String parameterName) {
+        return getFormattedJdbcPlaceholder(prefix, parameterName);
+    }
+
     /**
      * This method generates a binding for a parameter to a placeholder in a row based insert statement.
      *

src/main/java/org/mybatis/dynamic/sql/select/render/FetchFirstPagingModelRenderer.java

@@ -51,30 +51,30 @@ private FragmentAndParameters renderFetchFirstRowsOnly() {
     }
 
     private FragmentAndParameters renderFetchFirstRowsOnly(Long fetchFirstRows) {
-        RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo();
+        RenderedParameterInfo fetchFirstParameterInfo = renderingContext.calculateFetchFirstRowsParameterInfo();
         return FragmentAndParameters
-                .withFragment("fetch first " + parameterInfo.renderedPlaceHolder() //$NON-NLS-1$
+                .withFragment("fetch first " + fetchFirstParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
                     + " rows only") //$NON-NLS-1$
-                .withParameter(parameterInfo.parameterMapKey(), fetchFirstRows)
+                .withParameter(fetchFirstParameterInfo.parameterMapKey(), fetchFirstRows)
                 .build();
     }
 
     private FragmentAndParameters renderOffsetOnly(Long offset) {
-        RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo();
-        return FragmentAndParameters.withFragment("offset " + parameterInfo.renderedPlaceHolder() //$NON-NLS-1$
+        RenderedParameterInfo offsetParameterInfo = renderingContext.calculateOffsetParameterInfo();
+        return FragmentAndParameters.withFragment("offset " + offsetParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
                 + " rows") //$NON-NLS-1$
-                .withParameter(parameterInfo.parameterMapKey(), offset)
+                .withParameter(offsetParameterInfo.parameterMapKey(), offset)
                 .build();
     }
 
     private FragmentAndParameters renderOffsetAndFetchFirstRows(Long offset, Long fetchFirstRows) {
-        RenderedParameterInfo parameterInfo1 = renderingContext.calculateParameterInfo();
-        RenderedParameterInfo parameterInfo2 = renderingContext.calculateParameterInfo();
-        return FragmentAndParameters.withFragment("offset " + parameterInfo1.renderedPlaceHolder() //$NON-NLS-1$
-                + " rows fetch first " + parameterInfo2.renderedPlaceHolder() //$NON-NLS-1$
+        RenderedParameterInfo offsetParameterInfo = renderingContext.calculateOffsetParameterInfo();
+        RenderedParameterInfo fetchFirstParameterInfo = renderingContext.calculateFetchFirstRowsParameterInfo();
+        return FragmentAndParameters.withFragment("offset " + offsetParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
+                + " rows fetch first " + fetchFirstParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
                 + " rows only") //$NON-NLS-1$
-                .withParameter(parameterInfo1.parameterMapKey(), offset)
-                .withParameter(parameterInfo2.parameterMapKey(), fetchFirstRows)
+                .withParameter(offsetParameterInfo.parameterMapKey(), offset)
+                .withParameter(fetchFirstParameterInfo.parameterMapKey(), fetchFirstRows)
                 .build();
     }
 }

src/main/java/org/mybatis/dynamic/sql/select/render/LimitAndOffsetPagingModelRenderer.java

@@ -40,19 +40,19 @@ public FragmentAndParameters render() {
     }
 
     private FragmentAndParameters renderLimitOnly() {
-        RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo();
-        return FragmentAndParameters.withFragment("limit " + parameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
-                .withParameter(parameterInfo.parameterMapKey(), limit)
+        RenderedParameterInfo limitParameterInfo = renderingContext.calculateLimitParameterInfo();
+        return FragmentAndParameters.withFragment("limit " + limitParameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
+                .withParameter(limitParameterInfo.parameterMapKey(), limit)
                 .build();
     }
 
     private FragmentAndParameters renderLimitAndOffset(Long offset) {
-        RenderedParameterInfo parameterInfo1 = renderingContext.calculateParameterInfo();
-        RenderedParameterInfo parameterInfo2 = renderingContext.calculateParameterInfo();
-        return FragmentAndParameters.withFragment("limit " + parameterInfo1.renderedPlaceHolder() //$NON-NLS-1$
-                    + " offset " + parameterInfo2.renderedPlaceHolder()) //$NON-NLS-1$
-                .withParameter(parameterInfo1.parameterMapKey(), limit)
-                .withParameter(parameterInfo2.parameterMapKey(), offset)
+        RenderedParameterInfo limitParameterInfo = renderingContext.calculateLimitParameterInfo();
+        RenderedParameterInfo offsetParameterInfo = renderingContext.calculateOffsetParameterInfo();
+        return FragmentAndParameters.withFragment("limit " + limitParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
+                    + " offset " + offsetParameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
+                .withParameter(limitParameterInfo.parameterMapKey(), limit)
+                .withParameter(offsetParameterInfo.parameterMapKey(), offset)
                 .build();
     }
 }

src/main/java/org/mybatis/dynamic/sql/update/render/UpdateRenderer.java

@@ -109,7 +109,7 @@ private Optional<FragmentAndParameters> calculateLimitClause() {
     }
 
     private FragmentAndParameters renderLimitClause(Long limit) {
-        RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo();
+        RenderedParameterInfo parameterInfo = renderingContext.calculateLimitParameterInfo();
 
         return FragmentAndParameters.withFragment("limit " + parameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
                 .withParameter(parameterInfo.parameterMapKey(), limit)

src/main/java/org/mybatis/dynamic/sql/util/springbatch/SpringBatchCursorReaderSelectModel.java

@@ -0,0 +1,50 @@
+/*
+ *    Copyright 2016-2024 the original author or authors.
+ *
+ *    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
+ *
+ *       https://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 org.mybatis.dynamic.sql.util.springbatch;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.mybatis.dynamic.sql.render.MyBatis3RenderingStrategy;
+
+/**
+ * This rendering strategy should be used for MyBatis3 statements using the
+ * MyBatisPagingItemReader supplied by mybatis-spring integration
+ * (<a href="http://www.mybatis.org/spring/">http://www.mybatis.org/spring/</a>).
+ */
+public class SpringBatchPagingItemReaderRenderingStrategy extends MyBatis3RenderingStrategy {
+
+    @Override
+    public String getFormattedJdbcPlaceholderForPagingParameters(String prefix, String parameterName) {
+        return "#{" //$NON-NLS-1$
+                + parameterName
+                + "}"; //$NON-NLS-1$
+    }
+
+    @Override
+    public String formatParameterMapKeyForFetchFirstRows(AtomicInteger sequence) {
+        return "_pagesize"; //$NON-NLS-1$
+    }
+
+    @Override
+    public String formatParameterMapKeyForLimit(AtomicInteger sequence) {
+        return "_pagesize"; //$NON-NLS-1$
+    }
+
+    @Override
+    public String formatParameterMapKeyForOffset(AtomicInteger sequence) {
+        return "_skiprows"; //$NON-NLS-1$
+    }
+}

src/main/java/org/mybatis/dynamic/sql/util/springbatch/SpringBatchPagingItemReaderRenderingStrategy.java

@@ -17,13 +17,9 @@
 
 import java.util.Map;
 
-import org.mybatis.dynamic.sql.select.render.SelectStatementProvider;
-
 public class SpringBatchProviderAdapter {
 
     public String select(Map<String, Object> parameterValues) {
-        SelectStatementProvider selectStatement =
-                (SelectStatementProvider) parameterValues.get(SpringBatchUtility.PARAMETER_KEY);
-        return selectStatement.getSelectStatement();
+        return (String) parameterValues.get(SpringBatchUtility.PARAMETER_KEY);
     }
 }