DATAKV-103 - Add KeyValueStore abstraction.

The KeyValueStore abstraction allows more direct interaction with the underlying adapter through a simple keyspace bound interface. This allows to bypass keyspace and id lookup performed by the template.

Original pull request: #9.

src/main/java/org/springframework/data/keyvalue/core/AdapterBackedKeyValueStore.java

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2015 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.keyvalue.core;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+
+/**
+ * @author Christoph Strobl
+ * @param <K>
+ * @param <V>
+ */
+public class AdapterBackedKeyValueStore<K extends Serializable, V> implements KeyValueStore<K, V> {
+
+	private final Serializable keyspace;
+	private final KeyValueAdapter adapter;
+
+	public AdapterBackedKeyValueStore(KeyValueAdapter adapter, Serializable keyspace) {
+
+		Assert.notNull(adapter, "Adapter must not be null!");
+		Assert.notNull(keyspace, "Keyspace must not be null!");
+		this.adapter = adapter;
+		this.keyspace = keyspace;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#put(java.io.Serializable, java.lang.Object)
+	 */
+	@Override
+	@SuppressWarnings("unchecked")
+	public V put(K id, V item) {
+		return (V) adapter.put(id, item, keyspace);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#contains(java.io.Serializable)
+	 */
+	@Override
+	public boolean contains(K id) {
+		return adapter.contains(id, keyspace);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#get(java.io.Serializable)
+	 */
+	@Override
+	@SuppressWarnings("unchecked")
+	public V get(K id) {
+		return (V) adapter.get(id, keyspace);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#getAll(java.util.Collection)
+	 */
+	@Override
+	public Iterable<V> getAll(Collection<K> keys) {
+
+		if (CollectionUtils.isEmpty(keys)) {
+			return Collections.emptySet();
+		}
+
+		List<V> result = new ArrayList<V>(keys.size());
+		for (K key : keys) {
+			result.add(get(key));
+		}
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#delete(java.io.Serializable)
+	 */
+	@Override
+	@SuppressWarnings("unchecked")
+	public V remove(K id) {
+		return (V) adapter.delete(id, keyspace);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#removeAll(java.util.Collection)
+	 */
+	@Override
+	public Iterable<V> removeAll(Collection<K> keys) {
+
+		if (CollectionUtils.isEmpty(keys)) {
+			return Collections.emptySet();
+		}
+
+		List<V> result = new ArrayList<V>(keys.size());
+		for (K key : keys) {
+			result.add(remove(key));
+		}
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#size()
+	 */
+	@Override
+	public long size() {
+		return adapter.count(keyspace);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueStore#clear()
+	 */
+	@Override
+	public void clear() {
+		adapter.deleteAllOf(keyspace);
+	}
+
+}

src/main/java/org/springframework/data/keyvalue/core/KeyValueOperations.java

@@ -169,6 +169,14 @@ public interface KeyValueOperations extends DisposableBean {
 	 */
 	long count(KeyValueQuery<?> query, Class<?> type);
 
+	/**
+	 * Returns a {@link KeyValueStore} scoped to the given {@code keyspace}.
+	 * 
+	 * @param keyspace must not be {@literal null}.
+	 * @return
+	 */
+	<K extends Serializable, V> KeyValueStore<K, V> getKeyValueStore(Serializable keyspace);
+
 	/**
 	 * @return mapping context in use.
 	 */

src/main/java/org/springframework/data/keyvalue/core/KeyValueStore.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2015 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.keyvalue.core;
+
+import java.io.Serializable;
+import java.util.Collection;
+
+/**
+ * @author Christoph Strobl
+ * @param <K>
+ * @param <V>
+ */
+public interface KeyValueStore<K extends Serializable, V> {
+
+	/**
+	 * Add object with given key.
+	 * 
+	 * @param key must not be {@literal null}.
+	 * @return the item previously associated with the key.
+	 */
+	V put(K key, V item);
+
+	/**
+	 * Check if given key is present in KeyValue store.
+	 * 
+	 * @param key must not be {@literal null}.
+	 * @return
+	 */
+	boolean contains(K key);
+
+	/**
+	 * Get the Object associated with the given key.
+	 * 
+	 * @param key must not be {@literal null}.
+	 * @return {@literal null} if key not available.
+	 */
+	V get(K key);
+
+	/**
+	 * Get all Objects associated with the given keys.
+	 * 
+	 * @param keys must not be {@literal null}.
+	 * @return an empty {@link Iterable} if no matching key found.
+	 */
+	Iterable<V> getAll(Collection<K> keys);
+
+	/**
+	 * Delete and return the element associated with the given key.
+	 * 
+	 * @param key must not be {@literal null}.
+	 * @return
+	 */
+	V remove(K key);
+
+	/**
+	 * Delete and return all elements associated with the given keys.
+	 * 
+	 * @param keys must not be {@literal null}.
+	 * @return
+	 */
+	Iterable<V> removeAll(Collection<K> keys);
+
+	/**
+	 * Get the number of total elements contained.
+	 * 
+	 * @return
+	 */
+	long size();
+
+	/**
+	 * Removes all elements. The {@link KeyValueStore} will be empty after this call returns.
+	 */
+	void clear();
+
+}

src/main/java/org/springframework/data/keyvalue/core/KeyValueTemplate.java

@@ -428,6 +428,15 @@ public Long doInKeyValue(KeyValueAdapter adapter) {
 		});
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.keyvalue.core.KeyValueOperations#getKeyValueStore(java.io.Serializable)
+	 */
+	@Override
+	public <K extends Serializable, V> KeyValueStore<K, V> getKeyValueStore(Serializable keyspace) {
+		return new AdapterBackedKeyValueStore<K, V>(this.adapter, keyspace);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.keyvalue.core.KeyValueOperations#getMappingContext()