Merged in support for derived properties.

1 files changed, 62 insertions, 0 deletions

diff --git a/src/main/java/com/amazon/carbonado/Derived.java b/src/main/java/com/amazon/carbonado/Derived.java
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+++ b/src/main/java/com/amazon/carbonado/Derived.java
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+/*

+ * Copyright 2007 Amazon Technologies, Inc. or its affiliates.

+ * Amazon, Amazon.com and Carbonado are trademarks or registered trademarks

+ * of Amazon Technologies, Inc. or its affiliates.  All rights reserved.

+ *

+ * 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 com.amazon.carbonado;

+

+import java.lang.annotation.*;

+

+/**

+ * Identifies a {@link Storable} property which is not directly persisted, but

+ * is instead derived from other property values. A derived property cannot be

+ * abstract, and a "set" method is optional.

+ *

+ * <p>Derived properties can be used just like a normal property in most

+ * cases. They can be used in query filters, indexes, alternate keys, and they

+ * can also be used to define a {@link Version} property.

+ *

+ * <p>If the derived property depends on {@link Join} properties and is also

+ * used in an index or alternate key, dependencies must be listed in order for

+ * the index to be properly updated.

+ *

+ * <p>Example:<pre>

+ * &#64;Indexes(&#64;Index("uppercaseName"))

+ * public abstract class UserInfo implements Storable&lt;UserInfo&gt; {

+ *     /**

+ *      * Derive an uppercase name for case-insensitive searches.

+ *      *&#47;

+ *     <b>&#64;Derived</b>

+ *     public String getUppercaseName() {

+ *         String name = getName();

+ *         return name == null ? null : name.toUpperCase();

+ *     }

+ *

+ *     ...

+ * }

+ * </pre>

+ *

+ * @author Brian S O'Neill

+ */

+@Documented

+@Retention(RetentionPolicy.RUNTIME)

+@Target(ElementType.METHOD)

+public @interface Derived {

+    /**

+     * List of properties that this property is derived from.

+     */

+    String[] from() default {};

+}