Added SQL command "EXISTS" and "NOT EXISTS" to Ebean (ExpressionFactory,

ExpressionList).

src/main/java/com/avaje/ebean/ExpressionFactory.java

@@ -169,6 +169,16 @@ public interface ExpressionFactory {
    * In - property has a value in the collection of values.
    */
   public Expression in(String propertyName, Collection<?> values);
+  
+  /**
+   * Exists expression
+   */
+  public Expression exists(Query<?> subQuery);
+  
+  /**
+   * Not exists expression
+   */
+  public Expression notExists(Query<?> subQuery);
 
   /**
    * Id Equal to - ID property is equal to the value.

src/main/java/com/avaje/ebean/ExpressionList.java

@@ -473,6 +473,16 @@ public interface ExpressionList<T> extends Serializable {
    * In - property has a value in the collection of values.
    */
   public ExpressionList<T> in(String propertyName, Collection<?> values);
+  
+  /**
+   * Exists expression
+   */
+  public ExpressionList<T> exists(Query<?> subQuery);
+  
+  /**
+   * Not exists expression
+   */
+  public ExpressionList<T> notExists(Query<?> subQuery);
 
   /**
    * Id IN a list of id values.

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

@@ -241,6 +241,23 @@ public class DefaultExpressionFactory implements SpiExpressionFactory {
   public Expression in(String propertyName, Collection<?> values) {
     return new InExpression(propertyName, values);
   }
+  
+  /**
+   * Exists subquery 
+   */
+  @Override
+  public Expression exists(Query<?> subQuery) {
+	return new ExistsExpression((SpiQuery<?>) subQuery, false);
+  }
+  
+  /**
+   * Not exists subquery 
+   */
+  @Override
+  public Expression notExists(Query<?> subQuery) {
+	return new ExistsExpression((SpiQuery<?>) subQuery, true);
+  }
+
 
   /**
    * Id Equal to - ID property is equal to the value.

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

@@ -0,0 +1,87 @@
+package com.avaje.ebeaninternal.server.expression;
+
+import java.util.List;
+
+import com.avaje.ebean.event.BeanQueryRequest;
+import com.avaje.ebeaninternal.api.HashQueryPlanBuilder;
+import com.avaje.ebeaninternal.api.ManyWhereJoins;
+import com.avaje.ebeaninternal.api.SpiEbeanServer;
+import com.avaje.ebeaninternal.api.SpiExpression;
+import com.avaje.ebeaninternal.api.SpiExpressionRequest;
+import com.avaje.ebeaninternal.api.SpiQuery;
+import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
+import com.avaje.ebeaninternal.server.query.CQuery;
+
+public class ExistsExpression implements SpiExpression {
+
+	  private static final long serialVersionUID = 666990277309851644L;
+
+	  private final boolean not;
+	  private final SpiQuery<?> subQuery;
+
+	  private transient CQuery<?> compiledSubQuery;
+
+	  public ExistsExpression(SpiQuery<?> subQuery, boolean not) {
+	    this.subQuery = subQuery;
+	    this.not=not;
+	  }
+
+	  public void queryAutoFetchHash(HashQueryPlanBuilder builder) {
+	    builder.add(ExistsExpression.class).add(not);
+	    
+	    subQuery.queryAutofetchHash(builder);
+	  }
+
+	  public void queryPlanHash(BeanQueryRequest<?> request, HashQueryPlanBuilder builder) {
+
+	    // queryPlanHash executes prior to addSql() or addBindValues()
+	    // ... so compiledQuery will exist
+	    compiledSubQuery = compileSubQuery(request);
+
+	    queryAutoFetchHash(builder);
+	  }
+
+	  /**
+	   * Compile/build the sub query.
+	   */
+	  private CQuery<?> compileSubQuery(BeanQueryRequest<?> queryRequest) {
+
+	    SpiEbeanServer ebeanServer = (SpiEbeanServer) queryRequest.getEbeanServer();
+	    return ebeanServer.compileQuery(subQuery, queryRequest.getTransaction());
+	  }
+
+	  public int queryBindHash() {
+	    return subQuery.queryBindHash();
+	  }
+
+	  public void addSql(SpiExpressionRequest request) {
+
+	    String subSelect = compiledSubQuery.getGeneratedSql();
+	    subSelect = subSelect.replace('\n', ' ');
+
+
+	    if(not) request.append(" not");
+	    request.append(" exists (");
+	    request.append(subSelect);
+	    request.append(") ");
+	  }
+
+	  public void addBindValues(SpiExpressionRequest request) {
+
+	    List<Object> bindParams = compiledSubQuery.getPredicates().getWhereExprBindValues();
+
+	    if (bindParams == null) {
+	      return;
+	    }
+
+	    for (int i = 0; i < bindParams.size(); i++) {
+	      request.addBindValue(bindParams.get(i));
+	    }
+	  }
+
+	@Override
+	public void containsMany(BeanDescriptor<?> desc, ManyWhereJoins whereManyJoins) {
+		// TODO Auto-generated method stub
+		
+	}
+}

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

@@ -361,6 +361,16 @@ abstract class JunctionExpression<T> implements Junction<T>, SpiExpression, Expr
   public ExpressionList<T> in(String propertyName, com.avaje.ebean.Query<?> subQuery) {
     return exprList.in(propertyName, subQuery);
   }
+  
+  @Override
+  public ExpressionList<T> exists(Query<?> subQuery) {
+	return exprList.exists(subQuery);
+  }
+  
+  @Override
+  public ExpressionList<T> notExists(Query<?> subQuery) {
+	return exprList.exists(subQuery);
+  }
 
   @Override
   public ExpressionList<T> isNotNull(String propertyName) {

src/main/java/com/avaje/ebeaninternal/util/DefaultExpressionList.java

@@ -468,6 +468,19 @@ public class DefaultExpressionList<T> implements SpiExpressionList<T> {
     add(expr.in(propertyName, values));
     return this;
   }
+  
+  @Override
+  public ExpressionList<T> exists(Query<?> subQuery) {
+	add(expr.exists(subQuery));
+	return this;
+  }
+  
+  @Override
+  public ExpressionList<T> notExists(Query<?> subQuery) {
+	add(expr.notExists(subQuery));
+	return this;
+  }
+
 
   @Override
   public ExpressionList<T> isNotNull(String propertyName) {

src/test/java/com/avaje/tests/query/TestQueryExists.java

@@ -0,0 +1,41 @@
+package com.avaje.tests.query;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.avaje.ebean.BaseTestCase;
+import com.avaje.ebean.Ebean;
+import com.avaje.ebean.Query;
+import com.avaje.tests.model.basic.Customer;
+import com.avaje.tests.model.basic.Order;
+import com.avaje.tests.model.basic.ResetBasicData;
+
+public class TestQueryExists extends BaseTestCase {
+	@Test
+	public void testExists() {
+		ResetBasicData.reset();
+
+		Query<Order> subQuery=Ebean.find(Order.class).alias("sq").select("id").where().raw("sq.kcustomer_id = qt.id")
+				.query();
+		Query<Customer> query=Ebean.find(Customer.class).alias("qt").where().exists(subQuery).query();
+
+		query.findList();
+		String sql=query.getGeneratedSql();
+
+		Assert.assertTrue(sql.indexOf("exists (")>0);
+	}
+
+	@Test
+	public void testNotExists() {
+		ResetBasicData.reset();
+
+		Query<Order> subQuery=Ebean.find(Order.class).alias("sq").select("id").where().raw("sq.kcustomer_id = qt.id")
+				.query();
+		Query<Customer> query=Ebean.find(Customer.class).alias("qt").where().notExists(subQuery).query();
+
+		query.findList();
+		String sql=query.getGeneratedSql();
+
+		Assert.assertTrue(sql.indexOf("not exists (")>0);
+	}
+}