gitee.com/go-spring2/spring-base@v1.1.3/cache/result.go (about)

     1  /*
     2   * Copyright 2012-2019 the original author or authors.
     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   *      https://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  
    17  package cache
    18  
    19  import (
    20  	"errors"
    21  	"fmt"
    22  	"reflect"
    23  
    24  	"gitee.com/go-spring2/spring-base/json"
    25  )
    26  
    27  // Result stores a value.
    28  type Result interface {
    29  	JSON() (string, error)
    30  	Load(v interface{}) error
    31  }
    32  
    33  // ValueResult stores a `reflect.Value`.
    34  type ValueResult struct {
    35  	v reflect.Value
    36  	t reflect.Type
    37  }
    38  
    39  // NewValueResult returns a Result which stores a `reflect.Value`.
    40  func NewValueResult(v interface{}) Result {
    41  	return &ValueResult{
    42  		v: reflect.ValueOf(v),
    43  		t: reflect.TypeOf(v),
    44  	}
    45  }
    46  
    47  // JSON returns the JSON encoding of the stored value.
    48  func (r *ValueResult) JSON() (string, error) {
    49  	b, err := json.Marshal(r.v.Interface())
    50  	if err != nil {
    51  		return "", err
    52  	}
    53  	return string(b), nil
    54  }
    55  
    56  // Load injects the saved value to v.
    57  func (r *ValueResult) Load(v interface{}) error {
    58  	outVal := reflect.ValueOf(v)
    59  	if outVal.Kind() != reflect.Ptr || outVal.IsNil() {
    60  		return errors.New("value should be ptr and not nil")
    61  	}
    62  	if outVal.Type().Elem() != r.t {
    63  		return fmt.Errorf("load type (%s) but expect type (%s)", outVal.Elem().Type(), r.t.String())
    64  	}
    65  	outVal.Elem().Set(r.v)
    66  	return nil
    67  }
    68  
    69  // JSONResult stores a JSON string.
    70  type JSONResult struct {
    71  	v string
    72  }
    73  
    74  // NewJSONResult returns a Result which stores a JSON string.
    75  func NewJSONResult(v string) Result {
    76  	return &JSONResult{
    77  		v: v,
    78  	}
    79  }
    80  
    81  // JSON returns the JSON encoding of the stored value.
    82  func (r *JSONResult) JSON() (string, error) {
    83  	return r.v, nil
    84  }
    85  
    86  // Load injects the saved value to v.
    87  func (r *JSONResult) Load(v interface{}) error {
    88  	return json.Unmarshal([]byte(r.v), v)
    89  }