Query does not implement Expression

criteria/common/src/org/immutables/criteria/Criterias.java

@@ -16,8 +16,10 @@
 
 package org.immutables.criteria;
 
+import com.google.common.base.Preconditions;
 import org.immutables.criteria.expression.Expression;
-import org.immutables.criteria.expression.Expressional;
+import org.immutables.criteria.expression.Query;
+import org.immutables.criteria.expression.Queryable;
 
 import java.util.Objects;
 
@@ -26,19 +28,22 @@ public final class Criterias {
   private Criterias() {}
 
   /**
-   * Extracts {@link Expressional} interface from a criteria. Any criteria implements
-   * {@code Expressional} interface at runtime.
+   * Extracts {@link Query} from a criteria. Any criteria implements
+   * {@code Queryable} interface at runtime.
    */
-  public static Expressional toExpressional(DocumentCriteria<?> criteria) {
+  public static Query toQuery(DocumentCriteria<?> criteria) {
     Objects.requireNonNull(criteria, "criteria");
-    return (Expressional) criteria;
+    Preconditions.checkArgument(criteria instanceof Queryable, "%s should implement %s",
+            criteria.getClass().getName(), Queryable.class.getName());
+
+    return ((Queryable) criteria).query();
   }
 
   /**
-   * Extract directly expression from a criteria
+   * Extract directly filter from a criteria
    */
-  public static Expression toExpression(DocumentCriteria<?> criteria) {
-    return toExpressional(criteria).expression();
+  public static Expression toFilterExpression(DocumentCriteria<?> criteria) {
+    return toQuery(criteria).filter().orElseThrow(() -> new IllegalArgumentException("no defined filter for " + criteria));
   }
 
 }

criteria/common/src/org/immutables/criteria/expression/AbstractExpressionVisitor.java

@@ -50,8 +50,4 @@ public T visit(Path path) {
     return mapper.apply(path);
   }
 
-  @Override
-  public T visit(Query query) {
-    return query.filter().map(e -> e.accept(this)).orElseGet(() -> mapper.apply(query));
-  }
 }

criteria/common/src/org/immutables/criteria/expression/DebugExpressionVisitor.java

@@ -61,8 +61,4 @@ public Void visit(Path path) {
     return null;
   }
 
-  @Override
-  public Void visit(Query query) {
-    return query.filter().map(e -> e.accept(this)).orElse(null);
-  }
 }

criteria/common/src/org/immutables/criteria/expression/DnfExpression.java

@@ -18,7 +18,6 @@
 
 import com.google.common.collect.ImmutableList;
 
-import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -30,7 +29,7 @@
  *
  *  <p>Example: {@code (A and B or C and D or E)}
  */
-public class DnfExpression implements Expressional, Expression {
+public class DnfExpression implements Queryable {
 
   private final Query root;
   private final List<Expression> conjunctions;
@@ -46,18 +45,12 @@ public static DnfExpression create(Query root) {
     return new DnfExpression(root, Collections.emptyList(), Collections.emptyList());
   }
 
-  @Nullable
   @Override
-  public <R, C> R accept(ExpressionBiVisitor<R, C> visitor, @Nullable C context) {
-    return expression().accept(visitor, context);
-  }
-
-  @Override
-  public Expression expression() {
+  public Query query() {
     return simplify();
   }
 
-  private Expression simplify() {
+  private Query simplify() {
     final List<Expression> expressions = new ArrayList<>(disjunctions);
     if (!conjunctions.isEmpty()) {
       expressions.add(Expressions.and(conjunctions));

criteria/common/src/org/immutables/criteria/expression/ExpressionBiVisitor.java

@@ -32,6 +32,4 @@ public interface ExpressionBiVisitor<V, C> {
 
   V visit(Path path, @Nullable C context);
 
-  V visit(Query root, @Nullable C context);
-
 }

criteria/common/src/org/immutables/criteria/expression/ExpressionVisitor.java

@@ -31,6 +31,4 @@ public interface ExpressionVisitor<V> {
 
   V visit(Path path);
 
-  V visit(Query query);
-
 }

criteria/common/src/org/immutables/criteria/expression/Expressions.java

@@ -22,7 +22,6 @@
 import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Optional;
 
 /**
  * A set of predefined utilities and factories for expressions like {@link Constant} or {@link Call}
@@ -87,25 +86,10 @@ public V visit(Path path, @Nullable Void context) {
         return visitor.visit(path);
       }
 
-      @Override
-      public V visit(Query root, @Nullable Void context) {
-        return visitor.visit(root);
-      }
     };
   }
 
-  public static Optional<Expression> extractPredicate(Expression expression) {
-    if (expression instanceof Query) {
-      return ((Query) expression).filter();
-    }
-
-    return Optional.of(expression);
-  }
-
   public static Expression not(Expression call) {
-    if (call instanceof Query) {
-      return ((Query) call).transform(e -> call(Operators.NOT, e));
-    }
     return Expressions.call(Operators.NOT, call);
   }
 

criteria/common/src/org/immutables/criteria/expression/Query.java

@@ -16,15 +16,14 @@
 
 package org.immutables.criteria.expression;
 
-import javax.annotation.Nullable;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.UnaryOperator;
 
 /**
  * Query which is composed of predicates, projections, group by and order by expressions.
  */
-public final class Query implements Expression {
+public final class Query  {
 
   private final EntityPath entityPath;
   private final Expression filter;
@@ -34,16 +33,10 @@ private Query(EntityPath entityPath, Expression filter) {
     this.filter = filter;
   }
 
-  @Nullable
-  @Override
-  public <R, C> R accept(ExpressionBiVisitor<R, C> visitor, @Nullable C context) {
-    return visitor.visit(this, context);
-  }
-
   public EntityPath entityPath() {
     return this.entityPath;
   }
-  
+
   public Optional<Expression> filter() {
     return Optional.ofNullable(filter);
   }

criteria/common/src/org/immutables/criteria/expression/Expressional.java → criteria/common/src/org/immutables/criteria/expression/Queryable.java

@@ -18,13 +18,13 @@
 
 
 /**
- * Means an object can be expressed as Abstract Syntax Tree (AST).
+ * Allows to expose current query
  */
-public interface Expressional {
+public interface Queryable {
 
   /**
    * Expose expression used by an object.
    */
-  Expression expression();
+  Query query();
 
 }

criteria/common/src/org/immutables/criteria/matcher/CriteriaContext.java

@@ -20,11 +20,12 @@
 import com.google.common.collect.ImmutableList;
 import org.immutables.criteria.expression.DnfExpression;
 import org.immutables.criteria.expression.Expression;
-import org.immutables.criteria.expression.Expressional;
 import org.immutables.criteria.expression.Expressions;
 import org.immutables.criteria.expression.Operator;
 import org.immutables.criteria.expression.Operators;
 import org.immutables.criteria.expression.Path;
+import org.immutables.criteria.expression.Query;
+import org.immutables.criteria.expression.Queryable;
 
 import java.lang.reflect.Member;
 import java.util.List;
@@ -35,7 +36,7 @@
  * Link between front-end (Criteria DSL) and <a href="https://cs.lmu.edu/~ray/notes/ir/">Intermediate Representation</a>
  * (internally known as {@link Expression}).
  */
-public final class CriteriaContext implements Expressional {
+public final class CriteriaContext implements Queryable {
 
   private final List<CriteriaCreator<?>> creators;
   private final DnfExpression expression;
@@ -159,8 +160,8 @@ public CriteriaContext or() {
   }
 
   @Override
-  public Expression expression() {
-    return this.expression.expression();
+  public Query query() {
+    return this.expression.query();
   }
 
   public CriteriaContext withOperator(UnaryOperator<Expression> operator) {

criteria/common/src/org/immutables/criteria/matcher/Matchers.java

@@ -139,7 +139,7 @@ private static <T> T createWithReflection(Class<T> type, CriteriaContext context
 
   /**
    * Hacky (and temporary) reflection until we define proper sub-classes for criterias
-   * (to hide Expressional implementation).
+   * (to hide Queryable implementation).
    */
   static CriteriaContext extract(Object object) {
     Objects.requireNonNull(object, "object");
@@ -156,7 +156,7 @@ static <C> UnaryOperator<Expression> toExpressionOperator(Supplier<C> supplier,
     return expression -> {
       final C initial = supplier.get();
       final C changed = expr.apply(initial);
-      return Matchers.extract(changed).expression();
+      return Matchers.extract(changed).query().filter().orElseThrow(() -> new IllegalStateException("filter should be set"));
     };
   }
 
@@ -168,7 +168,7 @@ static <C> UnaryOperator<Expression> toExpressionOperator3(CriteriaContext conte
       final CriteriaCreator.TriFactory<?, ?, C> factory = context.factory3();
       final C initial = (C) context.withCreators(factory.creator3(), factory.creator2(), factory.creator3()).factory3().create3();
       final C changed = expr.apply(initial);
-      return Matchers.extract(changed).expression();
+      return Matchers.extract(changed).query().filter().orElseThrow(() -> new IllegalStateException("filter should be set"));
     };
   }
 

criteria/common/test/org/immutables/criteria/ExpressionAsStringTest.java

@@ -69,7 +69,7 @@ public void not() {
 
   private static void assertExpressional(DocumentCriteria<?> crit, String ... expectedLines) {
     final StringWriter out = new StringWriter();
-    Criterias.toExpressional(crit).expression().accept(new DebugExpressionVisitor<>(new PrintWriter(out)));
+    Criterias.toFilterExpression(crit).accept(new DebugExpressionVisitor<>(new PrintWriter(out)));
     final String expected = Arrays.stream(expectedLines).collect(Collectors.joining(System.lineSeparator()));
     Assert.assertEquals(expected, out.toString().trim());
   }

criteria/elasticsearch/src/org/immutables/criteria/elasticsearch/Elasticsearch.java

@@ -18,12 +18,9 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
-import org.immutables.criteria.expression.Expression;
 import org.immutables.criteria.expression.ExpressionConverter;
-import org.immutables.criteria.expression.Expressions;
 
 import java.util.Objects;
-import java.util.Optional;
 
 final class Elasticsearch {
 
@@ -33,15 +30,9 @@ static ExpressionConverter<ObjectNode> converter(ObjectMapper mapper) {
     Objects.requireNonNull(mapper, "expression");
 
     return expression -> {
-      Optional<Expression> predicate = Expressions.extractPredicate(expression);
-
-      if (!predicate.isPresent()) {
-        return mapper.createObjectNode();
-      }
-
       final ObjectNode query = mapper.createObjectNode();
       final ElasticsearchQueryVisitor visitor = new ElasticsearchQueryVisitor();
-      final QueryBuilders.QueryBuilder builder = predicate.get().accept(visitor);
+      final QueryBuilders.QueryBuilder builder = expression.accept(visitor);
       query.set("query", QueryBuilders.constantScoreQuery(builder).toJson(mapper));
       return query;
     };

criteria/elasticsearch/src/org/immutables/criteria/elasticsearch/ElasticsearchBackend.java

@@ -30,6 +30,7 @@
 import org.immutables.criteria.adapter.Backend;
 import org.immutables.criteria.adapter.Operations;
 import org.immutables.criteria.expression.Expression;
+import org.immutables.criteria.expression.Query;
 import org.reactivestreams.Publisher;
 
 import java.io.IOException;
@@ -68,12 +69,12 @@ public <T> Publisher<T> execute(Operation<T> query) {
     return queryInternal((Operations.Query<T>) query);
   }
 
-  private <T> Flowable<T> queryInternal(Operations.Query<T> query) {
+  private <T> Flowable<T> queryInternal(Operations.Query<T> op) {
     final Request request = new Request("POST", String.format("/%s/_search", index));
-    final Expression expression = Criterias.toExpression(query.criteria());
-    final ObjectNode json = Elasticsearch.converter(mapper).convert(expression);
-    query.limit().ifPresent(limit -> json.put("size", limit));
-    query.offset().ifPresent(offset -> json.put("start", offset));
+    final Query query = Criterias.toQuery(op.criteria());
+    final ObjectNode json = query.filter().map(f -> Elasticsearch.converter(mapper).convert(f)).orElseGet(mapper::createObjectNode);
+    op.limit().ifPresent(limit -> json.put("size", limit));
+    op.offset().ifPresent(offset -> json.put("start", offset));
     request.setEntity(new StringEntity(json.toString(), ContentType.APPLICATION_JSON));
     return Flowable.fromPublisher(new AsyncRestPublisher(restClient, request))
             .map(r -> converter((Class<T>) type).apply(r))

criteria/geode/src/org/immutables/criteria/geode/GeodeBackend.java

@@ -25,6 +25,7 @@
 import org.immutables.criteria.Repository;
 import org.immutables.criteria.adapter.Backend;
 import org.immutables.criteria.adapter.Operations;
+import org.immutables.criteria.expression.Query;
 import org.reactivestreams.Publisher;
 
 import java.util.Collection;
@@ -33,7 +34,7 @@
 import java.util.Optional;
 
 /**
- * Backend for
+ * Backend for <a href="https://geode.apache.org/">Apache Geode</a>
  */
 public class GeodeBackend implements Backend {
 
@@ -58,19 +59,17 @@ public <T> Publisher<T> execute(Operation<T> operation) {
   }
 
   private <T> Flowable<T> query(Operations.Query<T> op) {
-    final StringBuilder query = new StringBuilder();
+    final StringBuilder oql = new StringBuilder();
+    final Query query = Criterias.toQuery(op.criteria());
 
-    query.append("SELECT * FROM ").append(region.getFullPath());
+    oql.append("SELECT * FROM ").append(region.getFullPath());
 
-    final String predicate = Geodes.converter().convert(Criterias.toExpression(op.criteria()));
-    if (!predicate.isEmpty()) {
-      query.append(" WHERE ").append(predicate);
-    }
+    query.filter().ifPresent(e -> oql.append(" WHERE ").append(Geodes.converter().convert(e)));
 
-    op.limit().ifPresent(limit -> query.append(" LIMIT ").append(limit));
-    op.offset().ifPresent(offset -> query.append(" OFFSET ").append(offset));
+    op.limit().ifPresent(limit -> oql.append(" LIMIT ").append(limit));
+    op.offset().ifPresent(offset -> oql.append(" OFFSET ").append(offset));
 
-    return Flowable.<Collection<T>>fromCallable(() -> region.query(query.toString()))
+    return Flowable.<Collection<T>>fromCallable(() -> region.query(oql.toString()))
             .flatMapIterable(x -> x);
   }
 
@@ -89,7 +88,7 @@ private <T> Flowable<Repository.Success> insert(Operations.Insert<T> op) {
   }
 
   private <T> Flowable<Repository.Success> delete(Operations.Delete op) {
-    if (!Geodes.hasPredicate(op.criteria())) {
+    if (!Criterias.toQuery(op.criteria()).filter().isPresent()) {
       // means delete all (ie clear whole region)
       return Completable.fromRunnable(region::clear)
               .toSingleDefault(Repository.Success.SUCCESS)
@@ -106,7 +105,7 @@ private <T> Flowable<Repository.Success> delete(Operations.Delete op) {
     }
 
 
-    final String predicate = Criterias.toExpression(op.criteria())
+    final String predicate = Criterias.toFilterExpression(op.criteria())
             .accept(new GeodeQueryVisitor(path -> String.format("e.value.%s", path.toStringPath())));
 
     final String query = String.format("select distinct e.key from %s.entries e where %s", region.getFullPath(), predicate);