#75 - Add anonymous indexed bind markers.

Anonymous indexed bind markers come with a static placeholder symbol for all parameter occurrences and they are bound by index.

Original pull request: #84.

Author: mp911de

src/main/java/org/springframework/data/r2dbc/dialect/AnonymousBindMarkers.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.r2dbc.dialect;
+
+import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
+
+/**
+ * Anonymous, index-based bind marker using a static placeholder. Instances are bound by the ordinal position ordered by
+ * the appearance of the placeholder. This implementation creates indexed bind markers using an anonymous placeholder
+ * that correlates with an index.
+ *
+ * @author Mark Paluch
+ */
+class AnonymousBindMarkers implements BindMarkers {
+
+	private static final AtomicIntegerFieldUpdater<AnonymousBindMarkers> COUNTER_INCREMENTER = AtomicIntegerFieldUpdater
+			.newUpdater(AnonymousBindMarkers.class, "counter");
+
+	// access via COUNTER_INCREMENTER
+	@SuppressWarnings("unused") private volatile int counter;
+
+	private final String placeholder;
+
+	/**
+	 * Creates a new {@link AnonymousBindMarkers} instance given {@code placeholder}.
+	 *
+	 * @param placeholder parameter bind marker.
+	 */
+	AnonymousBindMarkers(String placeholder) {
+		this.counter = 0;
+		this.placeholder = placeholder;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.r2dbc.dialect.BindMarkers#next()
+	 */
+	@Override
+	public BindMarker next() {
+
+		int index = COUNTER_INCREMENTER.getAndIncrement(this);
+
+		return new IndexedBindMarker(placeholder, index);
+	}
+
+}

src/main/java/org/springframework/data/r2dbc/dialect/BindMarkersFactory.java

@@ -43,6 +43,22 @@ static BindMarkersFactory indexed(String prefix, int beginWith) {
 		return () -> new IndexedBindMarkers(prefix, beginWith);
 	}
 
+	/**
+	 * Creates anonymous, index-based bind marker using a static placeholder. Instances are bound by the ordinal position
+	 * ordered by the appearance of the placeholder. This implementation creates indexed bind markers using an anonymous
+	 * placeholder that correlates with an index.
+	 *
+	 * @param placeholder parameter placeholder.
+	 * @return a {@link BindMarkersFactory} using {@code placeholder}.
+	 * @see io.r2dbc.spi.Statement#bindNull(int, Class)
+	 * @see io.r2dbc.spi.Statement#bind(int, Object)
+	 */
+	static BindMarkersFactory anonymous(String placeholder) {
+
+		Assert.hasText(placeholder, "Placeholder must not be empty!");
+		return () -> new AnonymousBindMarkers(placeholder);
+	}
+
 	/**
 	 * Create named {@link BindMarkers} using identifiers to bind parameters. Named bind markers can support
 	 * {@link BindMarkers#next(String) name hints}. If no {@link BindMarkers#next(String) hint} is given, named bind

src/main/java/org/springframework/data/r2dbc/dialect/IndexedBindMarker.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.r2dbc.dialect;
+
+import io.r2dbc.spi.Statement;
+
+/**
+ * A single indexed bind marker.
+ */
+class IndexedBindMarker implements BindMarker {
+
+	private final String placeholder;
+
+	private int index;
+
+	IndexedBindMarker(String placeholder, int index) {
+		this.placeholder = placeholder;
+		this.index = index;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.r2dbc.dialect.BindMarker#getPlaceholder()
+	 */
+	@Override
+	public String getPlaceholder() {
+		return placeholder;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.r2dbc.dialect.BindMarker#bindValue(io.r2dbc.spi.Statement, java.lang.Object)
+	 */
+	@Override
+	public void bind(Statement statement, Object value) {
+		statement.bind(this.index, value);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.r2dbc.dialect.BindMarker#bindNull(io.r2dbc.spi.Statement, java.lang.Class)
+	 */
+	@Override
+	public void bindNull(Statement statement, Class<?> valueType) {
+		statement.bindNull(this.index, valueType);
+	}
+}

src/main/java/org/springframework/data/r2dbc/dialect/IndexedBindMarkers.java

@@ -1,7 +1,5 @@
 package org.springframework.data.r2dbc.dialect;
 
-import io.r2dbc.spi.Statement;
-
 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
 
 /**
@@ -45,46 +43,4 @@ public BindMarker next() {
 
 		return new IndexedBindMarker(prefix + "" + (index + offset), index);
 	}
-
-	/**
-	 * A single indexed bind marker.
-	 */
-	static class IndexedBindMarker implements BindMarker {
-
-		private final String placeholder;
-
-		private int index;
-
-		IndexedBindMarker(String placeholder, int index) {
-			this.placeholder = placeholder;
-			this.index = index;
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.r2dbc.dialect.BindMarker#getPlaceholder()
-		 */
-		@Override
-		public String getPlaceholder() {
-			return placeholder;
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.r2dbc.dialect.BindMarker#bindValue(io.r2dbc.spi.Statement, java.lang.Object)
-		 */
-		@Override
-		public void bind(Statement statement, Object value) {
-			statement.bind(this.index, value);
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.r2dbc.dialect.BindMarker#bindNull(io.r2dbc.spi.Statement, java.lang.Class)
-		 */
-		@Override
-		public void bindNull(Statement statement, Class<?> valueType) {
-			statement.bindNull(this.index, valueType);
-		}
-	}
 }

src/test/java/org/springframework/data/r2dbc/dialect/AnonymousBindMarkersUnitTests.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.r2dbc.dialect;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import io.r2dbc.spi.Statement;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link AnonymousBindMarkers}.
+ *
+ * @author Mark Paluch
+ */
+public class AnonymousBindMarkersUnitTests {
+
+	@Test // gh-75
+	public void shouldCreateNewBindMarkers() {
+
+		BindMarkersFactory factory = BindMarkersFactory.anonymous("?");
+
+		BindMarkers bindMarkers1 = factory.create();
+		BindMarkers bindMarkers2 = factory.create();
+
+		assertThat(bindMarkers1.next().getPlaceholder()).isEqualTo("?");
+		assertThat(bindMarkers2.next().getPlaceholder()).isEqualTo("?");
+	}
+
+	@Test // gh-75
+	public void shouldBindByIndex() {
+
+		Statement statement = mock(Statement.class);
+
+		BindMarkers bindMarkers = BindMarkersFactory.anonymous("?").create();
+
+		BindMarker first = bindMarkers.next();
+		BindMarker second = bindMarkers.next();
+
+		second.bind(statement, "foo");
+		first.bindNull(statement, Object.class);
+
+		verify(statement).bindNull(0, Object.class);
+		verify(statement).bind(1, "foo");
+	}
+}