#68 - ENH: Add delegate methods for findStream / findLargeStream

Author: rbygrave

pom.xml

@@ -8,8 +8,8 @@
 
   <parent>
     <groupId>org.avaje</groupId>
-    <artifactId>java8-parent</artifactId>
-    <version>1.4</version>
+    <artifactId>java8-oss</artifactId>
+    <version>2.1</version>
   </parent>
 
   <scm>

src/main/java/io/ebean/typequery/TQRootBean.java

@@ -38,6 +38,7 @@
 import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
+import java.util.stream.Stream;
 
 /**
  * Base root query bean.
@@ -1600,6 +1601,52 @@ public List<T> findList() {
     return query.findList();
   }
 
+  /**
+   * Execute the query returning the result as a Stream.
+   * <p>
+   * Note that this will hold all resulting beans in memory using a single
+   * persistence context. Use findLargeStream() for queries that expect to
+   * return a large number of results.
+   * </p>
+   * <pre>{@code
+   *
+   *  // use try with resources to ensure Stream is closed
+   *
+   *  try (Stream<Customer> stream = query.findStream()) {
+   *    stream
+   *    .map(...)
+   *    .collect(...);
+   *  }
+   *
+   * }</pre>
+   */
+  @Nonnull
+  public Stream<T> findSteam() {
+    return query.findStream();
+  }
+
+  /**
+   * Execute the query returning the result as a Stream.
+   * <p>
+   * Note that this uses multiple persistence contexts such that we can use
+   * it with a large number of results.
+   * </p>
+   * <pre>{@code
+   *
+   *  // use try with resources to ensure Stream is closed
+   *
+   *  try (Stream<Customer> stream = query.findLargeStream()) {
+   *    stream
+   *    .map(...)
+   *    .collect(...);
+   *  }
+   *
+   * }</pre>
+   */
+  public Stream<T> findLargeStream() {
+    return query.findLargeStream();
+  }
+
   /**
    * Execute the query returning the set of objects.
    * <p>

src/test/java/org/example/domain/SomePojo.java

@@ -1,25 +1,19 @@
 package org.example.domain;
 
-import javax.validation.constraints.AssertTrue;
-import javax.xml.ws.Action;
-import javax.xml.ws.soap.Addressing;
 import java.util.ArrayList;
 
-@Addressing
 public class SomePojo {
 
-  @AssertTrue
   String name;
 
   ArrayList<String> foos = new ArrayList<>();
-  
-  @Action
+
   public String getName() {
     return name;
   }
 
   public void setName(String name) {
     this.name = name;
   }
-  
+
 }

src/test/java/org/querytest/QCustomerTest.java

@@ -32,6 +32,8 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.StringJoiner;
+import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.example.domain.query.QAddress.Alias.country;
@@ -289,6 +291,48 @@ public void testFindOne() {
       .findList();
   }
 
+  private void insertCustomer(String name) {
+    Customer cust = new Customer();
+    cust.setName(name);
+    cust.setStatus(Customer.Status.GOOD);
+    cust.save();
+  }
+
+  @Test
+  public void testFindStream() {
+    insertCustomer("stream1");
+    insertCustomer("stream2");
+
+    StringJoiner sb = new StringJoiner("|");
+    try (Stream<Customer> stream = new QCustomer()
+      .name.startsWith("stream")
+      .id.asc()
+      .findSteam()) {
+
+      stream.forEach(it -> sb.add(it.getName()));
+    }
+
+    assertThat(sb.toString()).isEqualTo("stream1|stream2");
+  }
+
+  @Test
+  public void testFindLargeStream() {
+    insertCustomer("largeStream1");
+    insertCustomer("largeStream2");
+    insertCustomer("largeStream3");
+
+    StringJoiner sb = new StringJoiner("|");
+    try (Stream<Customer> stream = new QCustomer()
+      .name.startsWith("largeStream")
+      .id.asc()
+      .findSteam()) {
+
+      stream.forEach(it -> sb.add(it.getName()));
+    }
+
+    assertThat(sb.toString()).isEqualTo("largeStream1|largeStream2|largeStream3");
+  }
+
   @Test
   public void testFilterMany() {