Merge pull request #3776 from ebean-orm/feature/PString_eqIfNotBlank

Add PString eqIfNotBlank() helper query expression

ebean-querybean/src/main/java/io/ebean/typequery/PString.java

@@ -26,6 +26,35 @@ public final class PString<R> extends PBaseComparable<R, String> {
     super(name, root, prefix);
   }
 
+  /**
+   * Is equal to if the value is non-null and not blank, otherwise no expression is added to the query.
+   * <p>
+   * This is like {@code eqIfPresent()} but additionally treats an empty or whitespace-only value as
+   * "not present". When present, the value is trimmed before being used in the equal to expression.
+   * <p>
+   * This is a helper for building queries in fluid style where a String predicate is effectively
+   * optional, avoiding a separate {@code if} block and {@code trimToNull()} style helper.
+   *
+   * <pre>{@code
+   *   List<Customer> customers = new QCustomer()
+   *     .name.eqIfNotBlank(nameFilter)
+   *     .status.eqIfPresent(statusFilter)
+   *     .findList();
+   * }</pre>
+   *
+   * @param value the value which can be null or blank
+   * @return the root query bean instance
+   */
+  public R eqIfNotBlank(@Nullable String value) {
+    if (value != null) {
+      String trimmed = value.trim();
+      if (!trimmed.isEmpty()) {
+        expr().eq(_name, trimmed);
+      }
+    }
+    return _root;
+  }
+
   /**
    * Case insensitive is equal to.
    *

ebean-querybean/src/test/java/org/querytest/QStringEqIfNotBlankTest.java

@@ -0,0 +1,79 @@
+package org.querytest;
+
+import io.ebean.DB;
+import io.ebean.Database;
+import org.example.domain.Customer;
+import org.example.domain.query.QCustomer;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.example.domain.query.QCustomer.Alias.name;
+
+class QStringEqIfNotBlankTest {
+
+  @Test
+  void present_addsEqPredicate() {
+    var q = new QCustomer()
+      .select(name)
+      .name.eqIfNotBlank("rob")
+      .query();
+
+    q.findList();
+    assertThat(q.getGeneratedSql()).contains("where t0.name = ?");
+  }
+
+  @Test
+  void null_skipsPredicate() {
+    var q = new QCustomer()
+      .select(name)
+      .name.isNotNull()
+      .name.eqIfNotBlank(null)
+      .query();
+
+    q.findList();
+    assertThat(q.getGeneratedSql()).doesNotContain("t0.name = ?");
+  }
+
+  @Test
+  void blankWhitespace_skipsPredicate() {
+    var q = new QCustomer()
+      .select(name)
+      .name.isNotNull()
+      .name.eqIfNotBlank("   ")
+      .query();
+
+    q.findList();
+    assertThat(q.getGeneratedSql()).doesNotContain("t0.name = ?");
+  }
+
+  @Test
+  void empty_skipsPredicate() {
+    var q = new QCustomer()
+      .select(name)
+      .name.isNotNull()
+      .name.eqIfNotBlank("")
+      .query();
+
+    q.findList();
+    assertThat(q.getGeneratedSql()).doesNotContain("t0.name = ?");
+  }
+
+  @Test
+  void present_trimsBoundValue() {
+    Database db = DB.getDefault();
+    String unique = "eqIfNotBlank-" + System.nanoTime();
+
+    Customer customer = new Customer();
+    customer.name = unique;
+    db.save(customer);
+
+    Customer found = new QCustomer(db)
+      .name.eqIfNotBlank("  " + unique + "  ")
+      .findOne();
+
+    assertThat(found).isNotNull();
+    assertThat(found.name).isEqualTo(unique);
+
+    db.delete(customer);
+  }
+}

ebean-querybean/src/test/java/org/querytest/QueryAlsoIfTest.java

@@ -24,7 +24,7 @@ class QueryAlsoIfTest {
       .query();
 
     q.findList();
-    assertThat(q.getGeneratedSql()).isEqualTo("select /* QueryAlsoIfTest.also */ t0.id, t0.name from be_customer t0 where t0.name is not null and t0.email is not null");
+    assertThat(q.getGeneratedSql()).contains("from be_customer t0 where t0.name is not null and t0.email is not null");
   }
 
   @Test
@@ -61,7 +61,7 @@ class QueryAlsoIfTest {
       .query();
 
     q.findList();
-    assertThat(q.getGeneratedSql()).isEqualTo("select /* QueryAlsoIfTest.applyIfPresent */ t0.id, t0.name from be_customer t0 where t0.name is not null and t0.status = ?");
+    assertThat(q.getGeneratedSql()).contains("from be_customer t0 where t0.name is not null and t0.status = ?");
   }
 
   @Test
@@ -74,7 +74,7 @@ class QueryAlsoIfTest {
       .query();
 
     q.findList();
-    assertThat(q.getGeneratedSql()).isEqualTo("select /* QueryAlsoIfTest.notApplyIfPresent */ t0.id, t0.name from be_customer t0 where t0.name is not null");
+    assertThat(q.getGeneratedSql()).contains("from be_customer t0 where t0.name is not null");
   }
 
   @Test