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package javax.json;

/**
 * This interface represents an implementation of a JSON Merge Patch
 * as defined by
 * <a target=_blank href="http://tools.ietf.org/html/rfc7396">RFC 7396</a>.
 *
 * <EMBED CLASS='external-html' DATA-FILE-ID=LICENSE DATA-CIETName=JsonMergePatch>
 * 
 * <BR /><BR />A {@code JsonMergePatch} can be instantiated with
 * {@link Json#createMergePatch(JsonValue)} by specifying the patch operations in a JSON Merge
 * Patch or using {@link Json#createMergeDiff(JsonValue, JsonValue)} to create a JSON Merge Patch
 * based on the difference between two {@code JsonValue}s.
 * 
 * <BR /><BR />The following illustrates both approaches.
 * 
 * <BR /><BR />1. Construct a JsonMergePatch with an existing JSON Merge Patch.
 * 
 * <BR /><DIV CLASS=SNIP>{@code
 * JsonValue        contacts    = ... ;     // The target to be patched
 * JsonValue        patch       = ...  ;    // JSON Merge Patch
 * JsonMergePatch   mergePatch  = Json.createMergePatch(patch);
 * JsonValue        result      = mergePatch.apply(contacts);
 * }</DIV>
 * 
 * <BR /><BR />2. Construct a JsonMergePatch from a difference between two {@code JsonValue}s.
 * 
 * <BR /><DIV CLASS=SNIP>{@code
 * JsonValue      source      = ... ; // The source object
 * JsonValue      target      = ... ; // The modified object
 * JsonMergePatch mergePatch  = Json.createMergeDiff(source, target);
 *  // The diff between source and target in a Json Merge Patch format
 * }</DIV>
 *
 * @see <a target=_blank href="http://tools.ietf.org/html/rfc7396">RFC 7396</a>
 *
 * @since 1.1
 */
public interface JsonMergePatch {

    /**
     * Applies the JSON Merge Patch to the specified {@code target}.
     * The target is not modified by the patch.
     *
     * @param target the target to apply the merge patch
     * @return the transformed target after the patch
     */
    JsonValue apply(JsonValue target);

    /**
     * Returns the {@code JsonMergePatch} as {@code JsonValue}.
     *
     * @return this {@code JsonMergePatch} as {@code JsonValue}
     */
    JsonValue toJsonValue();
}