Introduce Vector abstraction

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-commons</artifactId>
-	<version>3.5.0-SNAPSHOT</version>
+	<version>3.5.0-GH-3193-SNAPSHOT</version>
 
 	<name>Spring Data Core</name>
 	<description>Core Spring concepts underpinning every Spring Data module.</description>

src/main/java/org/springframework/data/domain/DoubleVector.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2025 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
+ *
+ *      https://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.domain;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import org.springframework.util.ObjectUtils;
+
+/**
+ * {@link Vector} implementation based on {@code double} array.
+ *
+ * @author Mark Paluch
+ * @since 3.5
+ */
+class DoubleVector implements Vector {
+
+	private final double[] v;
+
+	DoubleVector(double[] v) {
+		this.v = v;
+	}
+
+	/**
+	 * Copy the given {@code double} array and wrap it within a Vector.
+	 */
+	static Vector copy(double[] v) {
+
+		if (v.length == 0) {
+			return new DoubleVector(new double[0]);
+		}
+
+		return new DoubleVector(Arrays.copyOf(v, v.length));
+	}
+
+	/**
+	 * Copy the given numeric values and wrap within a Vector.
+	 */
+	static Vector copy(Collection<? extends Number> v) {
+
+		if (v.isEmpty()) {
+			return new DoubleVector(new double[0]);
+		}
+
+		double[] copy = new double[v.size()];
+		int i = 0;
+		for (Number number : v) {
+			copy[i++] = number.doubleValue();
+		}
+
+		return new DoubleVector(copy);
+	}
+
+	@Override
+	public Class<Double> getType() {
+		return Double.TYPE;
+	}
+
+	@Override
+	public Object getSource() {
+		return v;
+	}
+
+	@Override
+	public int size() {
+		return v.length;
+	}
+
+	@Override
+	public float[] toFloatArray() {
+
+		float[] copy = new float[this.v.length];
+		for (int i = 0; i < this.v.length; i++) {
+			copy[i] = (float) this.v[i];
+		}
+
+		return copy;
+	}
+
+	@Override
+	public double[] toDoubleArray() {
+		return Arrays.copyOf(this.v, this.v.length);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof DoubleVector that)) {
+			return false;
+		}
+		return ObjectUtils.nullSafeEquals(v, that.v);
+	}
+
+	@Override
+	public int hashCode() {
+		return Arrays.hashCode(v);
+	}
+
+	@Override
+	public String toString() {
+		return "D" + Arrays.toString(v);
+	}
+}

src/main/java/org/springframework/data/domain/FloatVector.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2025 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
+ *
+ *      https://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.domain;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import org.springframework.util.ObjectUtils;
+
+/**
+ * {@link Vector} implementation based on {@code float} array.
+ *
+ * @author Mark Paluch
+ * @since 3.5
+ */
+class FloatVector implements Vector {
+
+	private final float[] v;
+
+	FloatVector(float[] v) {
+		this.v = v;
+	}
+
+	/**
+	 * Copy the given {@code float} array and wrap it within a Vector.
+	 */
+	static Vector copy(float[] v) {
+
+		if (v.length == 0) {
+			return new FloatVector(new float[0]);
+		}
+
+		return new FloatVector(Arrays.copyOf(v, v.length));
+	}
+
+	/**
+	 * Copy the given numeric values and wrap within a Vector.
+	 */
+	static Vector copy(Collection<? extends Number> v) {
+
+		if (v.isEmpty()) {
+			return new FloatVector(new float[0]);
+		}
+
+		float[] copy = new float[v.size()];
+		int i = 0;
+		for (Number number : v) {
+			copy[i++] = number.floatValue();
+		}
+
+		return new FloatVector(copy);
+	}
+
+	@Override
+	public Class<Float> getType() {
+		return Float.TYPE;
+	}
+
+	@Override
+	public Object getSource() {
+		return v;
+	}
+
+	@Override
+	public int size() {
+		return v.length;
+	}
+
+	@Override
+	public float[] toFloatArray() {
+		return Arrays.copyOf(this.v, this.v.length);
+	}
+
+	@Override
+	public double[] toDoubleArray() {
+
+		double[] copy = new double[this.v.length];
+		for (int i = 0; i < this.v.length; i++) {
+			copy[i] = this.v[i];
+		}
+
+		return copy;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof FloatVector that)) {
+			return false;
+		}
+		return ObjectUtils.nullSafeEquals(v, that.v);
+	}
+
+	@Override
+	public int hashCode() {
+		return Arrays.hashCode(v);
+	}
+
+	@Override
+	public String toString() {
+		return "F" + Arrays.toString(v);
+	}
+}

src/main/java/org/springframework/data/domain/NumberVector.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright 2025 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
+ *
+ *      https://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.domain;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+
+/**
+ * {@link Vector} implementation based on {@link Number} array.
+ *
+ * @author Mark Paluch
+ * @since 3.5
+ */
+class NumberVector implements Vector {
+
+	private final Number[] v;
+
+	NumberVector(Number[] v) {
+
+		Assert.noNullElements(v, "Vector [v] must not contain null elements");
+		this.v = v;
+	}
+
+	/**
+	 * Copy the given {@link Number} array and wrap it within a Vector.
+	 */
+	static Vector copy(Number[] v) {
+
+		if (v.length == 0) {
+			return new NumberVector(new Number[0]);
+		}
+
+		return new NumberVector(Arrays.copyOf(v, v.length));
+	}
+
+	/**
+	 * Copy the given {@link Number} and wrap it within a Vector.
+	 */
+	static Vector copy(Collection<? extends Number> v) {
+
+		if (v.isEmpty()) {
+			return new NumberVector(new Number[0]);
+		}
+
+		return new NumberVector(v.toArray(Number[]::new));
+	}
+
+	@Override
+	public Class<? extends Number> getType() {
+
+		if (this.v.length == 0) {
+			return Number.class;
+		}
+
+		Class<? extends Number> candidate = this.v[0].getClass();
+		for (int i = 1; i < this.v.length; i++) {
+			if (candidate != this.v[i].getClass()) {
+				return Number.class;
+			}
+		}
+		return candidate;
+	}
+
+	@Override
+	public Object getSource() {
+		return v;
+	}
+
+	@Override
+	public int size() {
+		return v.length;
+	}
+
+	@Override
+	public float[] toFloatArray() {
+
+		float[] copy = new float[this.v.length];
+		for (int i = 0; i < this.v.length; i++) {
+			copy[i] = this.v[i].floatValue();
+		}
+
+		return copy;
+	}
+
+	@Override
+	public double[] toDoubleArray() {
+
+		double[] copy = new double[this.v.length];
+		for (int i = 0; i < this.v.length; i++) {
+			copy[i] = this.v[i].doubleValue();
+		}
+
+		return copy;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof NumberVector that)) {
+			return false;
+		}
+		return ObjectUtils.nullSafeEquals(v, that.v);
+	}
+
+	@Override
+	public int hashCode() {
+		return Arrays.hashCode(v);
+	}
+
+	@Override
+	public String toString() {
+		return "N" + Arrays.toString(v);
+	}
+}