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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package android.hardware.camera2.marshal;
     17 
     18 import android.hardware.camera2.utils.TypeReference;
     19 
     20 /**
     21  * Query if a marshaler can marshal to/from a particular native and managed type; if it supports
     22  * the combination, allow creating a marshaler instance to do the serialization.
     23  *
     24  * <p>Not all queryable instances will support exactly one combination. Some, such as the
     25  * primitive queryable will support all primitive to/from managed mappings (as long as they are
     26  * 1:1). Others, such as the rectangle queryable will only support integer to rectangle mappings.
     27  * </p>
     28  *
     29  * <p>Yet some others are codependent on other queryables; e.g. array queryables might only support
     30  * a type map for {@code T[]} if another queryable exists with support for the component type
     31  * {@code T}.</p>
     32  */
     33 public interface MarshalQueryable<T> {
     34     /**
     35      * Create a marshaler between the selected managed and native type.
     36      *
     37      * <p>This marshaler instance is only good for that specific type mapping; and will refuse
     38      * to map other managed types, other native types, or an other combination that isn't
     39      * this exact one.</p>
     40      *
     41      * @param managedType a managed type reference
     42      * @param nativeType the native type, e.g.
     43      *          {@link android.hardware.camera2.impl.CameraMetadataNative#TYPE_BYTE TYPE_BYTE}
     44      * @return
     45      *
     46      * @throws UnsupportedOperationException
     47      *          if {@link #isTypeMappingSupported} returns {@code false}
     48      */
     49     public Marshaler<T> createMarshaler(
     50             TypeReference<T> managedType, int nativeType);
     51 
     52     /**
     53      * Determine whether or not this query marshal is able to create a marshaler that will
     54      * support the managed type and native type mapping.
     55      *
     56      * <p>If this returns {@code true}, then a marshaler can be instantiated by
     57      * {@link #createMarshaler} that will marshal data to/from the native type
     58      * from/to the managed type.</p>
     59      *
     60      * <p>Most marshalers are likely to only support one type map.</p>
     61      */
     62     public boolean isTypeMappingSupported(TypeReference<T> managedType, int nativeType);
     63 }
     64