#361 - ENH: Add ServerConfig expressionEqualsWithNullAsNoop - Can eq ne gt ... methods in ExpressionList treat null value as 1=1 ?

src/main/java/com/avaje/ebean/config/ServerConfig.java

@@ -324,6 +324,11 @@ public class ServerConfig {
   private Object objectMapper;
   private boolean diffFlatMode;
 
+  /**
+   * Set to true if you want eq("someProperty", null) to generate 1=1 rather than "is null" sql expression.
+   */
+  private boolean expressionEqualsWithNullAsNoop;
+
   /**
    * Construct a Server Configuration for programmatically creating an EbeanServer.
    */
@@ -1902,6 +1907,7 @@ public class ServerConfig {
 
     persistenceContextScope = PersistenceContextScope.valueOf(p.get("persistenceContextScope", "TRANSACTION"));
 
+    expressionEqualsWithNullAsNoop = p.getBoolean("expressionEqualsWithNullAsNoop", expressionEqualsWithNullAsNoop);
     diffFlatMode = p.getBoolean("diffFlatMode", diffFlatMode);
     asOfViewSuffix = p.get("asOfViewSuffix", asOfViewSuffix);
     asOfSysPeriod = p.get("asOfSysPeriod", asOfSysPeriod);
@@ -2029,4 +2035,23 @@ public class ServerConfig {
   public void setDiffFlatMode(boolean diffFlatMode) {
     this.diffFlatMode = diffFlatMode;
   }
+
+  /**
+   * Return true if eq("someProperty", null) should to generate "1=1" rather than "is null" sql expression.
+   */
+  public boolean isExpressionEqualsWithNullAsNoop() {
+    return expressionEqualsWithNullAsNoop;
+  }
+
+  /**
+   * Set to true if you want eq("someProperty", null) to generate "1=1" rather than "is null" sql expression.
+   * <p>
+   *   Setting this to true has the effect that eq(propertyName, value), ieq(propertyName, value) and
+   *   ne(propertyName, value) have no effect when the value is null. The expression factory adds a NoopExpression
+   *   which will add "1=1" into the SQL rather than "is null".
+   * </p>
+   */
+  public void setExpressionEqualsWithNullAsNoop(boolean expressionEqualsWithNullAsNoop) {
+    this.expressionEqualsWithNullAsNoop = expressionEqualsWithNullAsNoop;
+  }
 }

src/main/java/com/avaje/ebeaninternal/server/core/InternalConfiguration.java

@@ -106,7 +106,7 @@ public class InternalConfiguration {
     this.cacheManager = cacheManager;
     this.serverConfig = serverConfig;
     this.bootupClasses = bootupClasses;
-    this.expressionFactory = new DefaultExpressionFactory();
+    this.expressionFactory = new DefaultExpressionFactory(serverConfig.isExpressionEqualsWithNullAsNoop());
 
     this.typeManager = new DefaultTypeManager(serverConfig, bootupClasses);
     this.binder = new Binder(typeManager);

src/main/java/com/avaje/ebeaninternal/server/expression/DefaultExpressionFactory.java

@@ -22,8 +22,10 @@ public class DefaultExpressionFactory implements SpiExpressionFactory {
 
   private static final Object[] EMPTY_ARRAY = new Object[] {};
 
+  private final boolean equalsWithNullAsNoop;
 
-  public DefaultExpressionFactory() {
+  public DefaultExpressionFactory(boolean equalsWithNullAsNoop) {
+    this.equalsWithNullAsNoop = equalsWithNullAsNoop;
   }
 
   public ExpressionFactory createExpressionFactory(){
@@ -39,7 +41,7 @@ public class DefaultExpressionFactory implements SpiExpressionFactory {
    */
   public Expression eq(String propertyName, Object value) {
     if (value == null) {
-      return isNull(propertyName);
+      return equalsWithNullAsNoop ? NoopExpression.INSTANCE : isNull(propertyName);
     }
     return new SimpleExpression(propertyName, SimpleExpression.Op.EQ, value);
   }
@@ -49,7 +51,7 @@ public class DefaultExpressionFactory implements SpiExpressionFactory {
    */
   public Expression ne(String propertyName, Object value) {
     if (value == null) {
-      return isNotNull(propertyName);
+      return equalsWithNullAsNoop ? NoopExpression.INSTANCE : isNotNull(propertyName);
     }
     return new SimpleExpression(propertyName, SimpleExpression.Op.NOT_EQ, value);
   }
@@ -60,7 +62,7 @@ public class DefaultExpressionFactory implements SpiExpressionFactory {
    */
   public Expression ieq(String propertyName, String value) {
     if (value == null) {
-      return isNull(propertyName);
+      return equalsWithNullAsNoop ? NoopExpression.INSTANCE : isNull(propertyName);
     }
     return new CaseInsensitiveEqualExpression(propertyName, value);
   }

src/main/java/com/avaje/ebeaninternal/server/expression/NoopExpression.java

@@ -0,0 +1,47 @@
+package com.avaje.ebeaninternal.server.expression;
+
+import com.avaje.ebean.event.BeanQueryRequest;
+import com.avaje.ebeaninternal.api.HashQueryPlanBuilder;
+import com.avaje.ebeaninternal.api.ManyWhereJoins;
+import com.avaje.ebeaninternal.api.SpiExpression;
+import com.avaje.ebeaninternal.api.SpiExpressionRequest;
+import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
+
+/**
+ * Effectively an expression that has no effect.
+ */
+class NoopExpression implements SpiExpression {
+
+  protected static final NoopExpression INSTANCE = new NoopExpression();
+
+  @Override
+  public void containsMany(BeanDescriptor<?> desc, ManyWhereJoins whereManyJoins) {
+    // nothing to do
+  }
+
+  @Override
+  public void queryAutoFetchHash(HashQueryPlanBuilder builder) {
+    builder.add(NoopExpression.class);
+  }
+
+  @Override
+  public void queryPlanHash(BeanQueryRequest<?> request, HashQueryPlanBuilder builder) {
+    queryAutoFetchHash(builder);
+  }
+
+  @Override
+  public int queryBindHash() {
+    // no bind values
+    return 0;
+  }
+
+  @Override
+  public void addSql(SpiExpressionRequest request) {
+    request.append("1=1");
+  }
+
+  @Override
+  public void addBindValues(SpiExpressionRequest request) {
+    // nothing to do
+  }
+}