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

ExpressionList).

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
+		
+	}
+}