diff --git a/src/main/java/org/springframework/data/elasticsearch/Document.java b/src/main/java/org/springframework/data/elasticsearch/Document.java
new file mode 100644
index 000000000..703e40c25
--- /dev/null
+++ b/src/main/java/org/springframework/data/elasticsearch/Document.java
@@ -0,0 +1,388 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch;
+
+import java.io.IOException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.BooleanSupplier;
+import java.util.function.Function;
+import java.util.function.IntSupplier;
+import java.util.function.LongSupplier;
+import java.util.function.Supplier;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * A representation of a Elasticsearch document as extended {@link Map} with {@link String} keys. All iterators preserve
+ * original insertion order.
+ * <p>
+ * Document does not allow {@code null} keys. It allows {@literal null} values.
+ * <p>
+ * Implementing classes can bei either mutable or immutable. In case a subclass is immutable, its methods may throw
+ * {@link UnsupportedOperationException} when calling modifying methods.
+ *
+ * @author Mark Paluch
+ * @since 4.0
+ */
+public interface Document extends Map<String, Object> {
+
+	/**
+	 * Create a new mutable {@link Document}.
+	 *
+	 * @return a new {@link Document}.
+	 */
+	static Document create() {
+		return new MapDocument();
+	}
+
+	/**
+	 * Create a {@link Document} from a {@link Map} containing key-value pairs and sub-documents.
+	 *
+	 * @param map source map containing key-value pairs and sub-documents.
+	 * @return a new {@link Document}.
+	 */
+	static Document from(Map<String, Object> map) {
+
+		Assert.notNull(map, "Map must not be null");
+
+		if (map instanceof LinkedHashMap) {
+			return new MapDocument(map);
+		}
+
+		return new MapDocument(new LinkedHashMap<>(map));
+	}
+
+	/**
+	 * Parse JSON to {@link Document}.
+	 *
+	 * @param json must not be {@literal null}.
+	 * @return the parsed {@link Document}.
+	 */
+	static Document parse(String json) {
+		try {
+			return new MapDocument(MapDocument.OBJECT_MAPPER.readerFor(Map.class).readValue(json));
+		} catch (IOException e) {
+			throw new ElasticsearchException("Cannot parse JSON", e);
+		}
+	}
+
+	/**
+	 * {@link #put(Object, Object)} the {@code key}/{@code value} tuple and return {@code this} {@link Document}.
+	 *
+	 * @param key key with which the specified value is to be associated.
+	 * @param value value to be associated with the specified key.
+	 * @return {@code this} {@link Document}.
+	 */
+	default Document append(String key, Object value) {
+		put(key, value);
+		return this;
+	}
+
+	/**
+	 * Return {@literal true} if this {@link Document} is associated with an identifier.
+	 *
+	 * @return {@literal true} if this {@link Document} is associated with an identifier, {@literal false} otherwise.
+	 */
+	default boolean hasId() {
+		return false;
+	}
+
+	/**
+	 * Retrieve the identifier associated with this {@link Document}.
+	 * <p>
+	 * The default implementation throws {@link UnsupportedOperationException}. It's recommended to check {@link #hasId()}
+	 * prior to calling this method.
+	 *
+	 * @return the identifier associated with this {@link Document}.
+	 * @throws IllegalStateException if the underlying implementation supports Id's but no Id was yet associated with the
+	 *           document.
+	 */
+	default String getId() {
+		throw new UnsupportedOperationException();
+	}
+
+	/**
+	 * Set the identifier for this {@link Document}.
+	 * <p>
+	 * The default implementation throws {@link UnsupportedOperationException}.
+	 */
+	default void setId(String id) {
+		throw new UnsupportedOperationException();
+	}
+
+	/**
+	 * Return {@literal true} if this {@link Document} is associated with a version.
+	 *
+	 * @return {@literal true} if this {@link Document} is associated with a version, {@literal false} otherwise.
+	 */
+	default boolean hasVersion() {
+		return false;
+	}
+
+	/**
+	 * Retrieve the version associated with this {@link Document}.
+	 * <p>
+	 * The default implementation throws {@link UnsupportedOperationException}. It's recommended to check
+	 * {@link #hasVersion()} prior to calling this method.
+	 *
+	 * @return the version associated with this {@link Document}.
+	 * @throws IllegalStateException if the underlying implementation supports Id's but no Id was yet associated with the
+	 *           document.
+	 */
+	default long getVersion() {
+		throw new UnsupportedOperationException();
+	}
+
+	/**
+	 * Set the version for this {@link Document}.
+	 * <p>
+	 * The default implementation throws {@link UnsupportedOperationException}.
+	 */
+	default void setVersion(long version) {
+		throw new UnsupportedOperationException();
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped, or {@literal null} if this document contains no
+	 * mapping for the key. The value is casted within the method which makes it useful for calling code as it does not
+	 * require casting on the calling side. If the value type is not assignable to {@code type}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @param type the expected return value type.
+	 * @param <T> expected return type.
+	 * @return the value to which the specified key is mapped, or {@literal null} if this document contains no mapping for
+	 *         the key.
+	 * @throws ClassCastException if the value of the given key is not of {@code type T}.
+	 */
+	@Nullable
+	default <T> T get(Object key, Class<T> type) {
+
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(type, "Type must not be null");
+
+		return type.cast(get(key));
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped, or {@literal null} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Boolean}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped, or {@literal null} if this document contains no mapping for
+	 *         the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Boolean}.
+	 */
+	@Nullable
+	default Boolean getBoolean(String key) {
+		return get(key, Boolean.class);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or {@code defaultValue} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Boolean}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or {@code defaultValue} if this document contains no mapping
+	 *         for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Boolean}.
+	 */
+	default boolean getBooleanOrDefault(String key, boolean defaultValue) {
+		return getBooleanOrDefault(key, () -> defaultValue);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or the value from {@code defaultValue} if this
+	 * document contains no mapping for the key. If the value type is not a {@link Boolean}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or the value from {@code defaultValue} if this document
+	 *         contains no mapping for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Boolean}.
+	 * @see BooleanSupplier
+	 */
+	default boolean getBooleanOrDefault(String key, BooleanSupplier defaultValue) {
+
+		Boolean value = getBoolean(key);
+
+		return value == null ? defaultValue.getAsBoolean() : value;
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped, or {@literal null} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Integer}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped, or {@literal null} if this document contains no mapping for
+	 *         the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Integer}.
+	 */
+	@Nullable
+	default Integer getInt(String key) {
+		return get(key, Integer.class);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or {@code defaultValue} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Integer}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or {@code defaultValue} if this document contains no mapping
+	 *         for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Integer}.
+	 */
+	default int getIntOrDefault(String key, int defaultValue) {
+		return getIntOrDefault(key, () -> defaultValue);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or the value from {@code defaultValue} if this
+	 * document contains no mapping for the key. If the value type is not a {@link Integer}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or the value from {@code defaultValue} if this document
+	 *         contains no mapping for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Integer}.
+	 * @see IntSupplier
+	 */
+	default int getIntOrDefault(String key, IntSupplier defaultValue) {
+
+		Integer value = getInt(key);
+
+		return value == null ? defaultValue.getAsInt() : value;
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped, or {@literal null} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Long}, then this method throws {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped, or {@literal null} if this document contains no mapping for
+	 *         the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Long}.
+	 */
+	@Nullable
+	default Long getLong(String key) {
+		return get(key, Long.class);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or {@code defaultValue} if this document contains no
+	 * mapping for the key. If the value type is not a {@link Long}, then this method throws {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or {@code defaultValue} if this document contains no mapping
+	 *         for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Long}.
+	 */
+	default long getLongOrDefault(String key, long defaultValue) {
+		return getLongOrDefault(key, () -> defaultValue);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or the value from {@code defaultValue} if this
+	 * document contains no mapping for the key. If the value type is not a {@link Long}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or the value from {@code defaultValue} if this document
+	 *         contains no mapping for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link Long}.
+	 * @see LongSupplier
+	 */
+	default long getLongOrDefault(String key, LongSupplier defaultValue) {
+
+		Long value = getLong(key);
+
+		return value == null ? defaultValue.getAsLong() : value;
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped, or {@literal null} if this document contains no
+	 * mapping for the key. If the value type is not a {@link String}, then this method throws {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped, or {@literal null} if this document contains no mapping for
+	 *         the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link String}.
+	 */
+	@Nullable
+	default String getString(String key) {
+		return get(key, String.class);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or {@code defaultValue} if this document contains no
+	 * mapping for the key. If the value type is not a {@link String}, then this method throws {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or {@code defaultValue} if this document contains no mapping
+	 *         for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link String}.
+	 */
+	default String getStringOrDefault(String key, String defaultValue) {
+		return getStringOrDefault(key, () -> defaultValue);
+	}
+
+	/**
+	 * Returns the value to which the specified {@code key} is mapped or the value from {@code defaultValue} if this
+	 * document contains no mapping for the key. If the value type is not a {@link String}, then this method throws
+	 * {@link ClassCastException}.
+	 *
+	 * @param key the key whose associated value is to be returned
+	 * @return the value to which the specified key is mapped or the value from {@code defaultValue} if this document
+	 *         contains no mapping for the key.
+	 * @throws ClassCastException if the value of the given key is not a {@link String}.
+	 * @see Supplier
+	 */
+	default String getStringOrDefault(String key, Supplier<String> defaultValue) {
+
+		String value = getString(key);
+
+		return value == null ? defaultValue.get() : value;
+	}
+
+	/**
+	 * This method allows the application of a function to {@code this} {@link Document}. The function should expect a
+	 * single {@link Document} argument and produce an {@code R} result.
+	 * <p>
+	 * Any exception thrown by the function will be propagated to the caller.
+	 *
+	 * @param transformer functional interface to a apply
+	 * @param <R> class of the result
+	 * @return the result of applying the function to this string
+	 * @see java.util.function.Function
+	 */
+	default <R> R transform(Function<? super Document, ? extends R> transformer) {
+		return transformer.apply(this);
+	}
+
+	/**
+	 * Render this {@link Document} to JSON. Auxiliary values such as Id and version are not considered within the JSON
+	 * representation.
+	 *
+	 * @return a JSON representation of this document.
+	 */
+	String toJson();
+}
diff --git a/src/main/java/org/springframework/data/elasticsearch/MapDocument.java b/src/main/java/org/springframework/data/elasticsearch/MapDocument.java
new file mode 100644
index 000000000..317a1894d
--- /dev/null
+++ b/src/main/java/org/springframework/data/elasticsearch/MapDocument.java
@@ -0,0 +1,285 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.BiConsumer;
+
+import org.springframework.lang.Nullable;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * {@link Document} implementation backed by a {@link LinkedHashMap}.
+ *
+ * @author Mark Paluch
+ * @since 4.0
+ */
+class MapDocument implements Document {
+
+	static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
+	private final LinkedHashMap<String, Object> documentAsMap;
+
+	private @Nullable String id;
+	private @Nullable Long version;
+
+	MapDocument() {
+		this(new LinkedHashMap<>());
+	}
+
+	MapDocument(Map<String, Object> documentAsMap) {
+		this.documentAsMap = new LinkedHashMap<>(documentAsMap);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#hasId()
+	 */
+	@Override
+	public boolean hasId() {
+		return this.id != null;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#getId()
+	 */
+	@Override
+	public String getId() {
+
+		if (!hasId()) {
+			throw new IllegalStateException("No Id associated with this Document");
+		}
+
+		return this.id;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#setId(java.lang.String)
+	 */
+	@Override
+	public void setId(String id) {
+		this.id = id;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#hasVersion()
+	 */
+	@Override
+	public boolean hasVersion() {
+		return this.version != null;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#getVersion()
+	 */
+	@Override
+	public long getVersion() {
+
+		if (!hasVersion()) {
+			throw new IllegalStateException("No version associated with this Document");
+		}
+
+		return this.version;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#setVersion(long)
+	 */
+	@Override
+	public void setVersion(long version) {
+		this.version = version;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#size()
+	 */
+	@Override
+	public int size() {
+		return documentAsMap.size();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#isEmpty()
+	 */
+	@Override
+	public boolean isEmpty() {
+		return documentAsMap.isEmpty();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#containsKey(java.lang.Object)
+	 */
+	@Override
+	public boolean containsKey(Object key) {
+		return documentAsMap.containsKey(key);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#containsValue(java.lang.Object)
+	 */
+	@Override
+	public boolean containsValue(Object value) {
+		return documentAsMap.containsValue(value);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#get(java.lang.Object)
+	 */
+	@Override
+	public Object get(Object key) {
+		return documentAsMap.get(key);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#getOrDefault(java.lang.Object, java.lang.Object)
+	 */
+	@Override
+	public Object getOrDefault(Object key, Object defaultValue) {
+		return documentAsMap.getOrDefault(key, defaultValue);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#put(java.lang.Object, java.lang.Object)
+	 */
+	@Override
+	public Object put(String key, Object value) {
+		return documentAsMap.put(key, value);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#remove(java.lang.Object)
+	 */
+	@Override
+	public Object remove(Object key) {
+		return documentAsMap.remove(key);
+	}
+
+	/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#putAll(Map)
+		 */
+	@Override
+	public void putAll(Map<? extends String, ?> m) {
+		documentAsMap.putAll(m);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#clear()
+	 */
+	@Override
+	public void clear() {
+		documentAsMap.clear();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#keySet()
+	 */
+	@Override
+	public Set<String> keySet() {
+		return documentAsMap.keySet();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#values()
+	 */
+	@Override
+	public Collection<Object> values() {
+		return documentAsMap.values();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#entrySet()
+	 */
+	@Override
+	public Set<Entry<String, Object>> entrySet() {
+		return documentAsMap.entrySet();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object o) {
+		return documentAsMap.equals(o);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		return documentAsMap.hashCode();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.util.Map#forEach(java.util.function.BiConsumer)
+	 */
+	@Override
+	public void forEach(BiConsumer<? super String, ? super Object> action) {
+		documentAsMap.forEach(action);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.Document#toJson()
+	 */
+	@Override
+	public String toJson() {
+		try {
+			return OBJECT_MAPPER.writeValueAsString(this);
+		} catch (JsonProcessingException e) {
+			throw new ElasticsearchException("Cannot render document to JSON", e);
+		}
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+
+		String id = hasId() ? getId() : "?";
+		String version = hasVersion() ? Long.toString(getVersion()) : "?";
+
+		return getClass().getSimpleName() + "@" + id + "#" + version + " " + toJson();
+	}
+}
diff --git a/src/main/java/org/springframework/data/elasticsearch/SearchDocument.java b/src/main/java/org/springframework/data/elasticsearch/SearchDocument.java
new file mode 100644
index 000000000..3ac4b9eb4
--- /dev/null
+++ b/src/main/java/org/springframework/data/elasticsearch/SearchDocument.java
@@ -0,0 +1,33 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch;
+
+/**
+ * Extension to {@link Document} exposing a search {@link #getScore() score}.
+ *
+ * @author Mark Paluch
+ * @since 4.0
+ * @see Document
+ */
+public interface SearchDocument extends Document {
+
+	/**
+	 * Return the search {@code score}.
+	 *
+	 * @return the search {@code score}.
+	 */
+	float getScore();
+}
diff --git a/src/main/java/org/springframework/data/elasticsearch/core/DocumentAdapters.java b/src/main/java/org/springframework/data/elasticsearch/core/DocumentAdapters.java
new file mode 100644
index 000000000..dd44763d6
--- /dev/null
+++ b/src/main/java/org/springframework/data/elasticsearch/core/DocumentAdapters.java
@@ -0,0 +1,674 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch.core;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.stream.Collectors;
+
+import org.elasticsearch.action.get.GetResponse;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.document.DocumentField;
+import org.elasticsearch.index.get.GetResult;
+import org.elasticsearch.search.SearchHit;
+import org.springframework.data.elasticsearch.Document;
+import org.springframework.data.elasticsearch.ElasticsearchException;
+import org.springframework.data.elasticsearch.SearchDocument;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+import com.fasterxml.jackson.core.JsonEncoding;
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonGenerator;
+
+/**
+ * Utility class to adapt {@link org.elasticsearch.common.document.DocumentField} to
+ * {@link org.springframework.data.elasticsearch.Document}.
+ *
+ * @author Mark Paluch
+ * @since 4.0
+ */
+class DocumentAdapters {
+
+	/**
+	 * Create a {@link Document} from {@link GetResponse}.
+	 * <p>
+	 * Returns a {@link Document} using the source if available.
+	 *
+	 * @param source the source {@link GetResponse}.
+	 * @return the adapted {@link Document}.
+	 */
+	public static Document from(GetResponse source) {
+
+		Assert.notNull(source, "GetResponse must not be null");
+
+		if (source.isSourceEmpty()) {
+			return fromDocumentFields(source, source.getId(), source.getVersion());
+		}
+
+		Document document = Document.from(source.getSourceAsMap());
+		document.setId(source.getId());
+		document.setVersion(source.getVersion());
+
+		return document;
+	}
+
+	/**
+	 * Create a {@link Document} from {@link GetResult}.
+	 * <p>
+	 * Returns a {@link Document} using the source if available.
+	 *
+	 * @param source the source {@link GetResult}.
+	 * @return the adapted {@link Document}.
+	 */
+	public static Document from(GetResult source) {
+
+		Assert.notNull(source, "GetResult must not be null");
+
+		if (source.isSourceEmpty()) {
+			return fromDocumentFields(source, source.getId(), source.getVersion());
+		}
+
+		Document document = Document.from(source.getSource());
+		document.setId(source.getId());
+		document.setVersion(source.getVersion());
+
+		return document;
+	}
+
+	/**
+	 * Create a {@link SearchDocument} from {@link SearchHit}.
+	 * <p>
+	 * Returns a {@link SearchDocument} using the source if available.
+	 *
+	 * @param source the source {@link SearchHit}.
+	 * @return the adapted {@link SearchDocument}.
+	 */
+	public static SearchDocument from(SearchHit source) {
+
+		Assert.notNull(source, "SearchHit must not be null");
+
+		BytesReference sourceRef = source.getSourceRef();
+
+		if (sourceRef == null || sourceRef.length() == 0) {
+			return new SearchDocumentAdapter(source.getScore(),
+					fromDocumentFields(source, source.getId(), source.getVersion()));
+		}
+
+		Document document = Document.from(source.getSourceAsMap());
+		document.setId(source.getId());
+
+		if (source.getVersion() >= 0) {
+			document.setVersion(source.getVersion());
+		}
+
+		return new SearchDocumentAdapter(source.getScore(), document);
+	}
+
+	/**
+	 * Create an unmodifiable {@link Document} from {@link Iterable} of {@link DocumentField}s.
+	 *
+	 * @param documentFields the {@link DocumentField}s backing the {@link Document}.
+	 * @return the adapted {@link Document}.
+	 */
+	public static Document fromDocumentFields(Iterable<DocumentField> documentFields, String id, long version) {
+
+		if (documentFields instanceof Collection) {
+			return new DocumentFieldAdapter((Collection<DocumentField>) documentFields, id, version);
+		}
+
+		List<DocumentField> fields = new ArrayList<>();
+		for (DocumentField documentField : documentFields) {
+			fields.add(documentField);
+		}
+
+		return new DocumentFieldAdapter(fields, id, version);
+	}
+
+	// TODO: Performance regarding keys/values/entry-set
+	static class DocumentFieldAdapter implements Document {
+
+		private final Collection<DocumentField> documentFields;
+		private final String id;
+		private final long version;
+
+		DocumentFieldAdapter(Collection<DocumentField> documentFields, String id, long version) {
+			this.documentFields = documentFields;
+			this.id = id;
+			this.version = version;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#hasId()
+		 */
+		@Override
+		public boolean hasId() {
+			return id != null;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#getId()
+		 */
+		@Override
+		public String getId() {
+			return this.id;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#hasVersion()
+		 */
+		@Override
+		public boolean hasVersion() {
+			return this.version >= 0;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#getVersion()
+		 */
+		@Override
+		public long getVersion() {
+
+			if (!hasVersion()) {
+				throw new IllegalStateException("No version associated with this Document");
+			}
+
+			return this.version;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#size()
+		 */
+		@Override
+		public int size() {
+			return documentFields.size();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#isEmpty()
+		 */
+		@Override
+		public boolean isEmpty() {
+			return documentFields.isEmpty();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#containsKey(java.lang.Object)
+		 */
+		@Override
+		public boolean containsKey(Object key) {
+
+			for (DocumentField documentField : documentFields) {
+				if (documentField.getName().equals(key)) {
+					return true;
+				}
+			}
+
+			return false;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#containsValue(java.lang.Object)
+		 */
+		@Override
+		public boolean containsValue(Object value) {
+
+			for (DocumentField documentField : documentFields) {
+
+				Object fieldValue = getValue(documentField);
+				if (fieldValue != null && fieldValue.equals(value) || value == fieldValue) {
+					return true;
+				}
+			}
+
+			return false;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#get(java.lang.Object)
+		 */
+		@Override
+		public Object get(Object key) {
+
+			for (DocumentField documentField : documentFields) {
+				if (documentField.getName().equals(key)) {
+
+					return getValue(documentField);
+				}
+			}
+
+			return null;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#put(java.lang.Object, java.lang.Object)
+		 */
+		@Override
+		public Object put(String key, Object value) {
+			throw new UnsupportedOperationException();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#remove(java.lang.Object)
+		 */
+		@Override
+		public Object remove(Object key) {
+			throw new UnsupportedOperationException();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#putAll(Map)
+		 */
+		@Override
+		public void putAll(Map<? extends String, ?> m) {
+			throw new UnsupportedOperationException();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#clear()
+		 */
+		@Override
+		public void clear() {
+			throw new UnsupportedOperationException();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#keySet()
+		 */
+		@Override
+		public Set<String> keySet() {
+			return documentFields.stream().map(DocumentField::getName).collect(Collectors.toCollection(LinkedHashSet::new));
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#values()
+		 */
+		@Override
+		public Collection<Object> values() {
+			return documentFields.stream().map(DocumentFieldAdapter::getValue).collect(Collectors.toList());
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#entrySet()
+		 */
+		@Override
+		public Set<Entry<String, Object>> entrySet() {
+			return documentFields.stream().collect(Collectors.toMap(DocumentField::getName, DocumentFieldAdapter::getValue))
+					.entrySet();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#forEach(java.util.function.BiConsumer)
+		 */
+		@Override
+		public void forEach(BiConsumer<? super String, ? super Object> action) {
+
+			Objects.requireNonNull(action);
+
+			documentFields.forEach(field -> {
+				action.accept(field.getName(), getValue(field));
+			});
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#toJson()
+		 */
+		@Override
+		public String toJson() {
+
+			JsonFactory nodeFactory = new JsonFactory();
+			try {
+				ByteArrayOutputStream stream = new ByteArrayOutputStream();
+				JsonGenerator generator = nodeFactory.createGenerator(stream, JsonEncoding.UTF8);
+				generator.writeStartObject();
+				for (DocumentField value : documentFields) {
+					if (value.getValues().size() > 1) {
+						generator.writeArrayFieldStart(value.getName());
+						for (Object val : value.getValues()) {
+							generator.writeObject(val);
+						}
+						generator.writeEndArray();
+					} else {
+						generator.writeObjectField(value.getName(), value.getValue());
+					}
+				}
+				generator.writeEndObject();
+				generator.flush();
+				return new String(stream.toByteArray(), StandardCharsets.UTF_8);
+			} catch (IOException e) {
+				throw new ElasticsearchException("Cannot render JSON", e);
+			}
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+			return getClass().getSimpleName() + "@" + this.id + "#" + this.version + " " + toJson();
+		}
+
+		@Nullable
+		private static Object getValue(DocumentField documentField) {
+
+			if (documentField.getValues().isEmpty()) {
+				return null;
+			}
+
+			if (documentField.getValues().size() == 1) {
+				return documentField.getValue();
+			}
+
+			return documentField.getValues();
+		}
+	}
+
+	/**
+	 * Adapter for a {@link SearchDocument}.
+	 */
+	static class SearchDocumentAdapter implements SearchDocument {
+
+		private final float score;
+		private final Document delegate;
+
+		SearchDocumentAdapter(float score, Document delegate) {
+			this.score = score;
+			this.delegate = delegate;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#append(java.lang.String, java.lang.Object)
+		 */
+		@Override
+		public SearchDocument append(String key, Object value) {
+			delegate.append(key, value);
+
+			return this;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.SearchDocument#getScore()
+		 */
+		@Override
+		public float getScore() {
+			return score;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#hasId()
+		 */
+		@Override
+		public boolean hasId() {
+			return delegate.hasId();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#getId()
+		 */
+		@Override
+		public String getId() {
+			return delegate.getId();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#setId(java.lang.String)
+		 */
+		@Override
+		public void setId(String id) {
+			delegate.setId(id);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#hasVersion()
+		 */
+		@Override
+		public boolean hasVersion() {
+			return delegate.hasVersion();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#getVersion()
+		 */
+		@Override
+		public long getVersion() {
+			return delegate.getVersion();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#setVersion(long)
+		 */
+		@Override
+		public void setVersion(long version) {
+			delegate.setVersion(version);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#get(java.lang.Object, java.lang.Class)
+		 */
+		@Override
+		@Nullable
+		public <T> T get(Object key, Class<T> type) {
+			return delegate.get(key, type);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.elasticsearch.Document#toJson()
+		 */
+		@Override
+		public String toJson() {
+			return delegate.toJson();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#size()
+		 */
+		@Override
+		public int size() {
+			return delegate.size();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#isEmpty()
+		 */
+		@Override
+		public boolean isEmpty() {
+			return delegate.isEmpty();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#containsKey(java.lang.Object)
+		 */
+		@Override
+		public boolean containsKey(Object key) {
+			return delegate.containsKey(key);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#containsValue(java.lang.Object)
+		 */
+		@Override
+		public boolean containsValue(Object value) {
+			return delegate.containsValue(value);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#get(java.lang.Object)
+		 */
+		@Override
+		public Object get(Object key) {
+			return delegate.get(key);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#put(java.lang.Object, java.lang.Object)
+		 */
+		@Override
+		public Object put(String key, Object value) {
+			return delegate.put(key, value);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#remove(java.lang.Object)
+		 */
+		@Override
+		public Object remove(Object key) {
+			return delegate.remove(key);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#putAll(Map)
+		 */
+		@Override
+		public void putAll(Map<? extends String, ?> m) {
+			delegate.putAll(m);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#clear()
+		 */
+		@Override
+		public void clear() {
+			delegate.clear();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#keySet()
+		 */
+		@Override
+		public Set<String> keySet() {
+			return delegate.keySet();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#values()
+		 */
+		@Override
+		public Collection<Object> values() {
+			return delegate.values();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#entrySet()
+		 */
+		@Override
+		public Set<Entry<String, Object>> entrySet() {
+			return delegate.entrySet();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#equals(java.lang.Object)
+		 */
+		@Override
+		public boolean equals(Object o) {
+			if (this == o)
+				return true;
+			if (!(o instanceof SearchDocumentAdapter))
+				return false;
+			SearchDocumentAdapter that = (SearchDocumentAdapter) o;
+			return Float.compare(that.score, score) == 0 && delegate.equals(that.delegate);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#hashCode()
+		 */
+		@Override
+		public int hashCode() {
+			return delegate.hashCode();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#forEach(java.util.function.BiConsumer)
+		 */
+		@Override
+		public void forEach(BiConsumer<? super String, ? super Object> action) {
+			delegate.forEach(action);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.util.Map#remove(java.lang.Object, java.lang.Object)
+		 */
+		@Override
+		public boolean remove(Object key, Object value) {
+			return delegate.remove(key, value);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+
+			String id = hasId() ? getId() : "?";
+			String version = hasVersion() ? Long.toString(getVersion()) : "?";
+
+			return getClass().getSimpleName() + "@" + id + "#" + version + " " + toJson();
+		}
+	}
+}
diff --git a/src/test/java/org/springframework/data/elasticsearch/DocumentUnitTests.java b/src/test/java/org/springframework/data/elasticsearch/DocumentUnitTests.java
new file mode 100644
index 000000000..eb2717a32
--- /dev/null
+++ b/src/test/java/org/springframework/data/elasticsearch/DocumentUnitTests.java
@@ -0,0 +1,196 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link Document}.
+ *
+ * @author Mark Paluch
+ */
+public class DocumentUnitTests {
+
+	@Test // DATAES-628
+	public void shouldCreateNewDocument() {
+
+		Document document = Document.create().append("key", "value");
+
+		assertThat(document).containsEntry("key", "value");
+	}
+
+	@Test // DATAES-628
+	public void shouldCreateNewDocumentFromMap() {
+
+		Document document = Document.from(Collections.singletonMap("key", "value"));
+
+		assertThat(document).containsEntry("key", "value");
+	}
+
+	@Test // DATAES-628
+	public void shouldRenderDocumentToJson() {
+
+		Document document = Document.from(Collections.singletonMap("key", "value"));
+
+		assertThat(document.toJson()).isEqualTo("{\"key\":\"value\"}");
+	}
+
+	@Test // DATAES-628
+	public void shouldParseDocumentFromJson() {
+
+		Document document = Document.parse("{\"key\":\"value\"}");
+
+		assertThat(document).containsEntry("key", "value");
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnContainsKey() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.containsKey("string")).isTrue();
+		assertThat(document.containsKey("not-set")).isFalse();
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnContainsValue() {
+
+		Document document = Document.create().append("string", "value").append("bool", Arrays.asList(true, true, false))
+				.append("int", 43).append("long", 42L);
+
+		assertThat(document.containsValue("value")).isTrue();
+		assertThat(document.containsValue(43)).isTrue();
+		assertThat(document.containsValue(44)).isFalse();
+		assertThat(document.containsValue(Arrays.asList(true, true, false))).isTrue();
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnTypedValue() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.get("string")).isEqualTo("value");
+		assertThat(document.getString("string")).isEqualTo("value");
+
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.get("long", String.class));
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnTypedValueString() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.getString("string")).isEqualTo("value");
+		assertThat(document.getStringOrDefault("not-set", "default")).isEqualTo("default");
+		assertThat(document.getStringOrDefault("not-set", () -> "default")).isEqualTo("default");
+
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.getString("long"));
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.get("long", String.class));
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnTypedValueBoolean() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.getBoolean("bool")).isTrue();
+		assertThat(document.getBooleanOrDefault("not-set", true)).isTrue();
+		assertThat(document.getBooleanOrDefault("not-set", () -> true)).isTrue();
+
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.getString("bool"));
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.get("bool", String.class));
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnTypedValueInt() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.getInt("int")).isEqualTo(43);
+		assertThat(document.getIntOrDefault("not-set", 44)).isEqualTo(44);
+		assertThat(document.getIntOrDefault("not-set", () -> 44)).isEqualTo(44);
+
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.getString("int"));
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.get("int", String.class));
+	}
+
+	@Test // DATAES-628
+	public void shouldReturnTypedValueLong() {
+
+		Document document = Document.create().append("string", "value").append("bool", true).append("int", 43)
+				.append("long", 42L);
+
+		assertThat(document.getLong("long")).isEqualTo(42);
+		assertThat(document.getLongOrDefault("not-set", 44)).isEqualTo(44);
+		assertThat(document.getLongOrDefault("not-set", () -> 44)).isEqualTo(44);
+
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.getString("long"));
+		assertThatExceptionOfType(ClassCastException.class).isThrownBy(() -> document.get("long", String.class));
+	}
+
+	@Test // DATAES-628
+	public void shouldApplyTransformer() {
+
+		Document document = Document.create();
+		document.setId("value");
+
+		assertThat(document.transform(Document::getId)).isEqualTo("value");
+	}
+
+	@Test // DATAES-628
+	public void shouldSetId() {
+
+		Document document = Document.create();
+
+		assertThat(document.hasId()).isFalse();
+		assertThatIllegalStateException().isThrownBy(document::getId);
+
+		document.setId("foo");
+		assertThat(document.getId()).isEqualTo("foo");
+	}
+
+	@Test // DATAES-628
+	public void shouldSetVersion() {
+
+		Document document = Document.create();
+
+		assertThat(document.hasVersion()).isFalse();
+		assertThatIllegalStateException().isThrownBy(document::getVersion);
+
+		document.setVersion(14);
+		assertThat(document.getVersion()).isEqualTo(14);
+	}
+
+	@Test // DATAES-628
+	public void shouldRenderToString() {
+
+		Document document = Document.from(Collections.singletonMap("key", "value"));
+		document.setId("123");
+		document.setVersion(42);
+
+		assertThat(document).hasToString("MapDocument@123#42 {\"key\":\"value\"}");
+	}
+}
diff --git a/src/test/java/org/springframework/data/elasticsearch/core/DocumentAdaptersUnitTests.java b/src/test/java/org/springframework/data/elasticsearch/core/DocumentAdaptersUnitTests.java
new file mode 100644
index 000000000..77804f211
--- /dev/null
+++ b/src/test/java/org/springframework/data/elasticsearch/core/DocumentAdaptersUnitTests.java
@@ -0,0 +1,163 @@
+/*
+ * 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
+ *
+ *      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.elasticsearch.core;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.elasticsearch.action.get.GetResponse;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.document.DocumentField;
+import org.elasticsearch.common.text.Text;
+import org.elasticsearch.index.get.GetResult;
+import org.elasticsearch.search.SearchHit;
+import org.junit.Test;
+
+import org.springframework.data.elasticsearch.Document;
+import org.springframework.data.elasticsearch.SearchDocument;
+
+/**
+ * Unit tests for {@link DocumentAdapters}.
+ *
+ * @author Mark Paluch
+ */
+public class DocumentAdaptersUnitTests {
+
+	@Test // DATAES-628
+	public void shouldAdaptGetResponse() {
+
+		Map<String, DocumentField> fields = Collections.singletonMap("field",
+				new DocumentField("field", Arrays.asList("value")));
+
+		GetResult getResult = new GetResult("index", "type", "my-id", 1, 0, 42, true, null, fields);
+		GetResponse response = new GetResponse(getResult);
+
+		Document document = DocumentAdapters.from(response);
+
+		assertThat(document.hasId()).isTrue();
+		assertThat(document.getId()).isEqualTo("my-id");
+		assertThat(document.hasVersion()).isTrue();
+		assertThat(document.getVersion()).isEqualTo(42);
+		assertThat(document.get("field")).isEqualTo("value");
+	}
+
+	@Test // DATAES-628
+	public void shouldAdaptGetResponseSource() {
+
+		BytesArray source = new BytesArray("{\"field\":\"value\"}");
+
+		GetResult getResult = new GetResult("index", "type", "my-id", 1, 0, 42, true, source, Collections.emptyMap());
+		GetResponse response = new GetResponse(getResult);
+
+		Document document = DocumentAdapters.from(response);
+
+		assertThat(document.hasId()).isTrue();
+		assertThat(document.getId()).isEqualTo("my-id");
+		assertThat(document.hasVersion()).isTrue();
+		assertThat(document.getVersion()).isEqualTo(42);
+		assertThat(document.get("field")).isEqualTo("value");
+	}
+
+	@Test // DATAES-628
+	public void shouldAdaptSearchResponse() {
+
+		Map<String, DocumentField> fields = Collections.singletonMap("field",
+				new DocumentField("field", Arrays.asList("value")));
+
+		SearchHit searchHit = new SearchHit(123, "my-id", new Text("type"), fields);
+		searchHit.score(42);
+
+		SearchDocument document = DocumentAdapters.from(searchHit);
+
+		assertThat(document.hasId()).isTrue();
+		assertThat(document.getId()).isEqualTo("my-id");
+		assertThat(document.hasVersion()).isFalse();
+		assertThat(document.getScore()).isBetween(42f, 42f);
+		assertThat(document.get("field")).isEqualTo("value");
+	}
+
+	@Test // DATAES-628
+	public void searchResponseShouldReturnContainsKey() {
+
+		Map<String, DocumentField> fields = new LinkedHashMap<>();
+
+		fields.put("string", new DocumentField("string", Arrays.asList("value")));
+		fields.put("bool", new DocumentField("bool", Arrays.asList(true, true, false)));
+
+		SearchHit searchHit = new SearchHit(123, "my-id", new Text("type"), fields);
+
+		SearchDocument document = DocumentAdapters.from(searchHit);
+
+		assertThat(document.containsKey("string")).isTrue();
+		assertThat(document.containsKey("not-set")).isFalse();
+	}
+
+	@Test // DATAES-628
+	public void searchResponseShouldReturnContainsValue() {
+
+		Map<String, DocumentField> fields = new LinkedHashMap<>();
+
+		fields.put("string", new DocumentField("string", Arrays.asList("value")));
+		fields.put("bool", new DocumentField("bool", Arrays.asList(true, true, false)));
+		fields.put("null", new DocumentField("null", Collections.emptyList()));
+
+		SearchHit searchHit = new SearchHit(123, "my-id", new Text("type"), fields);
+
+		SearchDocument document = DocumentAdapters.from(searchHit);
+
+		assertThat(document.containsValue("value")).isTrue();
+		assertThat(document.containsValue(Arrays.asList(true, true, false))).isTrue();
+		assertThat(document.containsValue(null)).isTrue();
+	}
+
+	@Test // DATAES-628
+	public void shouldRenderToJson() {
+
+		Map<String, DocumentField> fields = new LinkedHashMap<>();
+
+		fields.put("string", new DocumentField("string", Arrays.asList("value")));
+		fields.put("bool", new DocumentField("bool", Arrays.asList(true, true, false)));
+
+		SearchHit searchHit = new SearchHit(123, "my-id", new Text("type"), fields);
+
+		SearchDocument document = DocumentAdapters.from(searchHit);
+
+		assertThat(document.toJson()).isEqualTo("{\"string\":\"value\",\"bool\":[true,true,false]}");
+	}
+
+	@Test // DATAES-628
+	public void shouldAdaptSearchResponseSource() {
+
+		BytesArray source = new BytesArray("{\"field\":\"value\"}");
+
+		SearchHit searchHit = new SearchHit(123, "my-id", new Text("type"), Collections.emptyMap());
+		searchHit.sourceRef(source).score(42);
+		searchHit.version(22);
+
+		SearchDocument document = DocumentAdapters.from(searchHit);
+
+		assertThat(document.hasId()).isTrue();
+		assertThat(document.getId()).isEqualTo("my-id");
+		assertThat(document.hasVersion()).isTrue();
+		assertThat(document.getVersion()).isEqualTo(22);
+		assertThat(document.getScore()).isBetween(42f, 42f);
+		assertThat(document.get("field")).isEqualTo("value");
+	}
+}