Add JsonToPdxArrayConverter interface and Spring Converter extension specifying a contract to convert JSON into PDX, as an array of PdxInstance objects.

Resolves gh-69.

spring-geode/src/main/java/org/springframework/geode/data/json/converter/JsonToPdxArrayConverter.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 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.geode.data.json.converter;
+
+import org.apache.geode.pdx.PdxInstance;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.lang.NonNull;
+
+/**
+ * A Spring {@link Converter} interface extension defining a contract to convert
+ * from {@link String JSON} to an array of {@link PdxInstance} objects.
+ *
+ * @author John Blum
+ * @see java.lang.FunctionalInterface
+ * @see java.lang.String
+ * @see org.apache.geode.pdx.PdxInstance
+ * @see org.springframework.core.convert.converter.Converter
+ * @since 1.3.0
+ */
+@FunctionalInterface
+public interface JsonToPdxArrayConverter extends Converter<String, PdxInstance[]> {
+
+	/**
+	 * Converts the array of {@link Byte#TYPE bytes} containing {@link String JSON}
+	 * into an array of {@link PdxInstance} objects.
+	 *
+	 * @param json array of {@link Byte#TYPE bytes} containing the {@link String JSON};
+	 * must not be {@literal null}.
+	 * @return an array of {@link PdxInstance} objects for the given {@link String JSON}.
+	 * @see org.apache.geode.pdx.PdxInstance
+	 * @see #convert(Object)
+	 */
+	default @NonNull PdxInstance[] convert(@NonNull byte[] json) {
+		return convert(new String(json));
+	}
+}