added find string methods and reset() to PropertyQuery

Author: greenrobot

objectbox-java/src/main/java/io/objectbox/query/PropertyQuery.java

@@ -44,6 +44,18 @@ public class PropertyQuery {
         this.property = property;
     }
 
+    /** Clears all values (e.g. distinct and null value). */
+    public PropertyQuery reset() {
+        distinct = false;
+        noCaseIfDistinct = true;
+        enableNull = false;
+        nullValueDouble = 0;
+        nullValueFloat = 0;
+        nullValueString = null;
+        nullValueLong = 0;
+        return this;
+    }
+
     /**
      * Only distinct values should be returned (e.g. 1,2,3 instead of 1,1,2,3,3,3).
      * <p>
@@ -251,6 +263,24 @@ public double[] call() {
         });
     }
 
+    private String findString(final boolean unique) {
+        return (String) query.callInReadTx(new Callable<String>() {
+            @Override
+            public String call() {
+                return query.nativeFindString(query.handle, query.cursorHandle(), property.id, unique,
+                        enableNull, nullValueString);
+            }
+        });
+    }
+
+    public String findFirstString() {
+        return findString(false);
+    }
+
+    public String findUniqueString() {
+        return findString(true);
+    }
+
     private Object findNumber(final boolean unique) {
         return query.callInReadTx(new Callable<Object>() {
             @Override
@@ -269,7 +299,6 @@ public Long findUniqueLong() {
         return (Long) findNumber(true);
     }
 
-
     public Integer findFirstInt() {
         return (Integer) findNumber(false);
     }

objectbox-java/src/main/java/io/objectbox/query/Query.java

@@ -86,6 +86,9 @@ native double[] nativeFindDoubles(long handle, long cursorHandle, int propertyId
     native Object nativeFindNumber(long handle, long cursorHandle, int propertyId, boolean unique, boolean enableNull,
                                    long nullValue, float nullValueFloat, double nullValueDouble);
 
+    native String nativeFindString(long handle, long cursorHandle, int propertyId, boolean unique, boolean enableNull,
+                                   String nullValue);
+
     native long nativeCount(long handle, long cursorHandle);
 
     native long nativeSum(long handle, long cursorHandle, int propertyId);

tests/objectbox-java-test/src/main/java/io/objectbox/query/PropertyQueryTest.java

@@ -131,6 +131,32 @@ public void testFindStrings_wrongPropertyType() {
         box.query().build().property(simpleInt).findStrings();
     }
 
+    @Test
+    public void testFindString() {
+        Query<TestEntity> query = box.query().greater(simpleLong, 1002).build();
+        PropertyQuery propertyQuery = query.property(simpleString);
+        assertNull(propertyQuery.findFirstString());
+        assertNull(propertyQuery.reset().findUniqueString());
+        putTestEntities(5);
+        assertEquals("foo3", propertyQuery.reset().findFirstString());
+
+        query = box.query().greater(simpleLong, 1004).build();
+        propertyQuery = query.property(simpleString);
+        assertEquals("foo5", propertyQuery.reset().findUniqueString());
+
+        putTestEntity(null, 6);
+        // TODO XXX enable me after fixing combination of unique and distinct: putTestEntity(null, 7);
+        query.setParameter(simpleLong, 1005);
+        assertEquals("nope", propertyQuery.reset().distinct().nullValue("nope").findUniqueString());
+    }
+
+    @Test(expected = DbException.class)
+    public void testFindString_uniqueFails() {
+        putTestEntity("foo", 1);
+        putTestEntity("foo", 2);
+        box.query().build().property(simpleString).findUniqueString();
+    }
+
     @Test
     public void testFindLongs() {
         putTestEntities(5);