initial add of EbeanORM server based on v2.8.1

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

@@ -0,0 +1,58 @@
+package com.avaje.ebeaninternal.server.expression;
+
+import com.avaje.ebean.event.BeanQueryRequest;
+import com.avaje.ebeaninternal.api.SpiExpressionRequest;
+import com.avaje.ebeaninternal.server.el.ElPropertyValue;
+
+
+/**
+ * Slightly redundant as Query.setId() ultimately also does the same job.
+ */
+class NullExpression extends AbstractExpression {
+
+	private static final long serialVersionUID = 4246991057451128269L;
+	
+	private final boolean notNull;
+	
+	NullExpression(FilterExprPath pathPrefix, String propertyName, boolean notNull) {
+		super(pathPrefix, propertyName);
+		this.notNull = notNull;
+	}
+    
+	public void addBindValues(SpiExpressionRequest request) {
+		
+	}
+	
+	public void addSql(SpiExpressionRequest request) {
+		
+        String propertyName = getPropertyName();
+
+	    String nullExpr = notNull ? " is not null " : " is null ";
+	    
+	    ElPropertyValue prop = getElProp(request);
+        if (prop != null && prop.isAssocId()){
+            request.append(prop.getAssocOneIdExpr(propertyName, nullExpr));
+            return;
+        }
+	    
+		request.append(propertyName).append(nullExpr);
+	}
+	
+	/**
+	 * Based on notNull flag and the propertyName.
+	 */
+	public int queryAutoFetchHash() {
+		int hc = NullExpression.class.getName().hashCode();
+		hc = hc * 31 + (notNull ? 1 : 0);
+		hc = hc * 31 + propName.hashCode();
+		return hc;
+	}
+
+	public int queryPlanHash(BeanQueryRequest<?> request) {
+		return queryAutoFetchHash();
+	}
+	
+	public int queryBindHash() {
+		return (notNull ? 1 : 0);
+	}
+}