Adds ObjectToJsonConverter interface implementation using Jackson to convert an Object to JSON.

Resolves gh-67.

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

@@ -0,0 +1,65 @@
+/*
+ * 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.support;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import org.springframework.core.convert.ConversionFailedException;
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.geode.data.json.converter.ObjectToJsonConverter;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+
+/**
+ * A {@link ObjectToJsonConverter} implementation using Jackson's {@link ObjectMapper} to convert
+ * from an {@link Object} to a {@literal JSON} {@link String}.
+ *
+ * @author John Blum
+ * @see com.fasterxml.jackson.databind.ObjectMapper
+ * @see org.springframework.geode.data.json.converter.ObjectToJsonConverter
+ * @since 1.3.0
+ */
+public class JacksonObjectToJsonConverter implements ObjectToJsonConverter {
+
+	/**
+	 * @inheritDoc
+	 */
+	@Nullable @Override
+	public String convert(Object source) {
+
+		try {
+
+			ObjectMapper objectMapper = newObjectMapper();
+
+			return objectMapper.writeValueAsString(source);
+		}
+		catch (JsonProcessingException cause) {
+			throw new ConversionFailedException(TypeDescriptor.forObject(source), TypeDescriptor.valueOf(String.class),
+				source, cause);
+		}
+	}
+
+	/**
+	 * Constructs a new instance of the Jackson {@link ObjectMapper} class.
+	 *
+	 * @return a new instance of the Jackson {@link ObjectMapper} class.
+	 * @see com.fasterxml.jackson.databind.ObjectMapper
+	 */
+	protected @NonNull ObjectMapper newObjectMapper() {
+		return new ObjectMapper();
+	}
+}

spring-geode/src/test/java/org/springframework/geode/data/json/converter/support/JacksonObjectToJsonConverterUnitTests.java

@@ -0,0 +1,96 @@
+/*
+ * 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.support;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import com.fasterxml.jackson.core.JsonGenerationException;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import org.junit.Test;
+
+import org.springframework.core.convert.ConversionFailedException;
+
+/**
+ * Unit Tests for {@link JacksonObjectToJsonConverter}.
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.mockito.Mockito
+ * @see org.springframework.geode.data.json.converter.support.JacksonObjectToJsonConverter
+ * @since 1.3.0
+ */
+public class JacksonObjectToJsonConverterUnitTests {
+
+	@Test
+	public void convertObjectToJson() throws JsonProcessingException {
+
+		String json = "{ \"name\": \"Jon Doe\" }";
+
+		Object source = new Object();
+
+		ObjectMapper mockObjectMapper = mock(ObjectMapper.class);
+
+		JacksonObjectToJsonConverter converter = spy(new JacksonObjectToJsonConverter());
+
+		doReturn(json).when(mockObjectMapper).writeValueAsString(eq(source));
+		doReturn(mockObjectMapper).when(converter).newObjectMapper();
+
+		assertThat(converter.convert(source)).isEqualTo(json);
+
+		verify(converter, times(1)).newObjectMapper();
+		verify(mockObjectMapper, times(1)).writeValueAsString(eq(source));
+	}
+
+	@Test(expected = ConversionFailedException.class)
+	public void convertHandlesJsonProcessingException() throws JsonProcessingException {
+
+		ObjectMapper mockObjectMapper = mock(ObjectMapper.class);
+
+		JacksonObjectToJsonConverter converter = spy(new JacksonObjectToJsonConverter());
+
+		doReturn(mockObjectMapper).when(converter).newObjectMapper();
+		doThrow(new JsonGenerationException("TEST", (JsonGenerator) null))
+			.when(mockObjectMapper).writeValueAsString(any());
+
+		try {
+			converter.convert(null);
+		}
+		catch (ConversionFailedException expected) {
+
+			assertThat(expected.getCause()).isInstanceOf(JsonProcessingException.class);
+			assertThat(expected.getCause()).hasMessage("TEST");
+			assertThat(expected.getCause()).hasNoCause();
+
+			throw expected;
+		}
+		finally {
+			verify(converter, times(1)).newObjectMapper();
+			verify(mockObjectMapper, times(1)).writeValueAsString(isNull());
+		}
+	}
+}