#919 - io.ebean package initial

src/main/java/io/ebeaninternal/server/expression/NullExpression.java

@@ -0,0 +1,104 @@
+package io.ebeaninternal.server.expression;
+
+import io.ebeaninternal.api.HashQueryPlanBuilder;
+import io.ebeaninternal.api.ManyWhereJoins;
+import io.ebeaninternal.api.SpiExpression;
+import io.ebeaninternal.api.SpiExpressionRequest;
+import io.ebeaninternal.server.deploy.BeanDescriptor;
+import io.ebeaninternal.server.el.ElPropertyValue;
+import io.ebeaninternal.server.query.SplitName;
+
+import java.io.IOException;
+
+
+/**
+ * Null / Not Null expression.
+ * <p>
+ * Note that for OneToMany/ManyToMany this effectively gets translated into isEmpty()/isNotEmpty().
+ * </p>
+ */
+class NullExpression extends AbstractExpression {
+
+  private final boolean notNull;
+
+  private ElPropertyValue elProperty;
+
+  private boolean assocMany;
+
+  private String propertyPath;
+
+  NullExpression(String propertyName, boolean notNull) {
+    super(propertyName);
+    this.notNull = notNull;
+  }
+
+  @Override
+  public void containsMany(BeanDescriptor<?> desc, ManyWhereJoins manyWhereJoin) {
+    elProperty = desc.getElGetValue(propName);
+    if (elProperty != null && elProperty.isAssocMany()) {
+      // it is OneToMany or ManyToMany so going to be treated as isEmpty() expression
+      assocMany = true;
+      propertyPath = SplitName.split(propName)[0];
+      propertyContainsMany(propertyPath, desc, manyWhereJoin);
+    } else {
+      propertyContainsMany(propName, desc, manyWhereJoin);
+    }
+  }
+
+  @Override
+  public void writeDocQuery(DocQueryContext context) throws IOException {
+    context.writeExists(notNull, propName);
+  }
+
+  @Override
+  public void addBindValues(SpiExpressionRequest request) {
+
+  }
+
+  @Override
+  public void addSql(SpiExpressionRequest request) {
+
+    if (assocMany) {
+      // translate to exists subquery
+      IsEmptyExpression.isEmptySql(request, elProperty, !notNull, propertyPath);
+      return;
+    }
+
+    String nullExpr = notNull ? " is not null " : " is null ";
+    if (elProperty != null && elProperty.isAssocId()) {
+      request.append(elProperty.getAssocIdExpression(propName, nullExpr));
+    } else {
+      request.append(propName).append(nullExpr);
+    }
+  }
+
+  @Override
+  public boolean isSameByPlan(SpiExpression other) {
+    if (!(other instanceof NullExpression)) {
+      return false;
+    }
+
+    NullExpression that = (NullExpression) other;
+    return this.propName.equals(that.propName)
+      && this.notNull == that.notNull;
+  }
+
+  @Override
+  public boolean isSameByBind(SpiExpression other) {
+    // no bind values so always true
+    return true;
+  }
+
+  /**
+   * Based on notNull flag and the propertyName.
+   */
+  @Override
+  public void queryPlanHash(HashQueryPlanBuilder builder) {
+    builder.add(NullExpression.class).add(notNull).add(propName);
+  }
+
+  @Override
+  public int queryBindHash() {
+    return (notNull ? 1 : 0);
+  }
+}