EQL - Simplify nested query where expressions after parsing

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

@@ -21,6 +21,11 @@ public abstract class AbstractExpression implements SpiExpression {
     this.propName = propName;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public Object getIdEqualTo(String idName) {
     // override on SimpleExpression

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

@@ -88,6 +88,11 @@ public class DefaultExampleExpression implements SpiExpression, ExampleExpressio
     }
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
     if (!list.isEmpty()) {

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

@@ -97,6 +97,16 @@ public class DefaultExpressionList<T> implements SpiExpressionList<T> {
     }
   }
 
+  void simplifyEntries() {
+    for (SpiExpression element : list) {
+      element.simplify();
+    }
+  }
+
+  public void simplify() {
+    simplifyEntries();
+  }
+
   /**
    * Write being aware if it is the Top level "text" expressions.
    * <p>

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

@@ -36,6 +36,11 @@ class ExistsQueryExpression implements SpiExpression, UnsupportedDocStoreExpress
     this.subQuery = null;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
     throw new IllegalStateException("Not supported");

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

@@ -38,6 +38,11 @@ class InQueryExpression extends AbstractExpression implements UnsupportedDocStor
     this.bindParams = bindParams;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
     throw new IllegalStateException("Not supported");

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

@@ -39,9 +39,9 @@ import java.util.Set;
  */
 class JunctionExpression<T> implements SpiJunction<T>, SpiExpression, ExpressionList<T> {
 
-  protected final DefaultExpressionList<T> exprList;
+  protected DefaultExpressionList<T> exprList;
 
-  protected final Junction.Type type;
+  protected Junction.Type type;
 
   JunctionExpression(Junction.Type type, Query<T> query, ExpressionList<T> parent) {
     this.type = type;
@@ -56,6 +56,31 @@ class JunctionExpression<T> implements SpiJunction<T>, SpiExpression, Expression
     this.exprList = exprList;
   }
 
+  /**
+   * Simplify nested expressions where possible.
+   * <p>
+   * This is expected to only used after expressions are built via query language parsing.
+   * </p>
+   */
+  public void simplify() {
+    exprList.simplifyEntries();
+
+    List<SpiExpression> list = exprList.list;
+    if (list.size() == 1 && list.get(0) instanceof JunctionExpression) {
+      JunctionExpression nested = (JunctionExpression)list.get(0);
+      if (type == Type.AND && !nested.type.isText()) {
+        // and (and (a, b, c)) -> and (a, b, c)
+        // and (not (a, b, c)) -> not (a, b, c)
+        // and (or  (a, b, c)) -> or  (a, b, c)
+        this.exprList = nested.exprList;
+        this.type = nested.type;
+      } else if (type == Type.NOT && nested.type == Type.AND) {
+        // not (and (a, b, c)) -> not (a, b, c)
+        this.exprList = nested.exprList;
+      }
+    }
+  }
+
   public SpiExpression copyForPlanKey() {
     return new JunctionExpression<T>(type, exprList.copyForPlanKey());
   }

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

@@ -57,6 +57,11 @@ abstract class LogicExpression implements SpiExpression {
     this.expTwo = (SpiExpression) expTwo;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
 

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

@@ -24,6 +24,11 @@ class NestedPathWrapperExpression implements SpiExpression {
     this.delegate = delegate;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
     context.startNested(nestedPath);

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

@@ -8,6 +8,11 @@ import com.avaje.ebeaninternal.api.SpiExpression;
  */
 abstract class NonPrepareExpression implements SpiExpression {
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void prepareExpression(BeanQueryRequest<?> request) {
     // do nothing

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

@@ -17,6 +17,11 @@ class NoopExpression implements SpiExpression {
 
   protected static final NoopExpression INSTANCE = new NoopExpression();
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public SpiExpression copyForPlanKey() {
     return this;

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

@@ -22,6 +22,11 @@ final class NotExpression implements SpiExpression {
     this.exp = (SpiExpression) exp;
   }
 
+  @Override
+  public void simplify() {
+    // do nothing
+  }
+
   @Override
   public void writeDocQuery(DocQueryContext context) throws IOException {
     context.startBoolMustNot();

src/main/java/com/avaje/ebeaninternal/server/grammer/EqlAdapter.java

@@ -27,8 +27,8 @@ class EqlAdapter<T> extends EQLBaseListener {
 
   private boolean textMode;
 
-  public EqlAdapter(Query<T> query) {
-    this.query = (SpiQuery<T>)query;
+  public EqlAdapter(SpiQuery<T> query) {
+    this.query = query;
     this.helper = new EqlAdapterHelper(this);
   }
 

src/main/java/com/avaje/ebeaninternal/server/grammer/EqlParser.java

@@ -1,6 +1,6 @@
 package com.avaje.ebeaninternal.server.grammer;
 
-import com.avaje.ebean.Query;
+import com.avaje.ebeaninternal.api.SpiQuery;
 import com.avaje.ebeaninternal.server.grammer.antlr.EQLLexer;
 import com.avaje.ebeaninternal.server.grammer.antlr.EQLParser;
 import org.antlr.v4.runtime.ANTLRInputStream;
@@ -9,7 +9,7 @@ import org.antlr.v4.runtime.tree.ParseTreeWalker;
 
 public class EqlParser {
 
-  public static <T> void parse(String raw, Query<T> query) {
+  public static <T> void parse(String raw, SpiQuery<T> query) {
 
     EQLLexer lexer = new EQLLexer(new ANTLRInputStream(raw));
     CommonTokenStream tokens = new CommonTokenStream(lexer);
@@ -20,5 +20,7 @@ public class EqlParser {
 
     ParseTreeWalker walker = new ParseTreeWalker();
     walker.walk(adapter, context);
+
+    query.simplifyExpressions();
   }
 }

src/main/java/com/avaje/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -1349,6 +1349,13 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
     return whereExpressions;
   }
 
+  @Override
+  public void simplifyExpressions() {
+    if (whereExpressions != null) {
+      whereExpressions.simplify();
+    }
+  }
+
   @Override
   public DefaultOrmQuery<T> having(Expression expression) {
     having().add(expression);