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      1 /*
      2  * Copyright (C) 2011 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 
     17 package com.android.volley.toolbox;
     18 
     19 import com.android.volley.NetworkResponse;
     20 import com.android.volley.Request;
     21 import com.android.volley.Response;
     22 import com.android.volley.Response.ErrorListener;
     23 import com.android.volley.Response.Listener;
     24 import com.android.volley.VolleyLog;
     25 
     26 import java.io.UnsupportedEncodingException;
     27 
     28 /**
     29  * A request for retrieving a T type response body at a given URL that also
     30  * optionally sends along a JSON body in the request specified.
     31  *
     32  * @param <T> JSON type of response expected
     33  */
     34 public abstract class JsonRequest<T> extends Request<T> {
     35     /** Default charset for JSON request. */
     36     protected static final String PROTOCOL_CHARSET = "utf-8";
     37 
     38     /** Content type for request. */
     39     private static final String PROTOCOL_CONTENT_TYPE =
     40         String.format("application/json; charset=%s", PROTOCOL_CHARSET);
     41 
     42     /** Lock to guard mListener as it is cleared on cancel() and read on delivery. */
     43     private final Object mLock = new Object();
     44 
     45     // @GuardedBy("mLock")
     46     private Listener<T> mListener;
     47     private final String mRequestBody;
     48 
     49     /**
     50      * Deprecated constructor for a JsonRequest which defaults to GET unless {@link #getPostBody()}
     51      * or {@link #getPostParams()} is overridden (which defaults to POST).
     52      *
     53      * @deprecated Use {@link #JsonRequest(int, String, String, Listener, ErrorListener)}.
     54      */
     55     @Deprecated
     56     public JsonRequest(String url, String requestBody, Listener<T> listener,
     57             ErrorListener errorListener) {
     58         this(Method.DEPRECATED_GET_OR_POST, url, requestBody, listener, errorListener);
     59     }
     60 
     61     public JsonRequest(int method, String url, String requestBody, Listener<T> listener,
     62             ErrorListener errorListener) {
     63         super(method, url, errorListener);
     64         mListener = listener;
     65         mRequestBody = requestBody;
     66     }
     67 
     68     @Override
     69     public void cancel() {
     70         super.cancel();
     71         synchronized (mLock) {
     72             mListener = null;
     73         }
     74     }
     75 
     76     @Override
     77     protected void deliverResponse(T response) {
     78         Response.Listener<T> listener;
     79         synchronized (mLock) {
     80             listener = mListener;
     81         }
     82         if (listener != null) {
     83             listener.onResponse(response);
     84         }
     85     }
     86 
     87     @Override
     88     abstract protected Response<T> parseNetworkResponse(NetworkResponse response);
     89 
     90     /**
     91      * @deprecated Use {@link #getBodyContentType()}.
     92      */
     93     @Deprecated
     94     @Override
     95     public String getPostBodyContentType() {
     96         return getBodyContentType();
     97     }
     98 
     99     /**
    100      * @deprecated Use {@link #getBody()}.
    101      */
    102     @Deprecated
    103     @Override
    104     public byte[] getPostBody() {
    105         return getBody();
    106     }
    107 
    108     @Override
    109     public String getBodyContentType() {
    110         return PROTOCOL_CONTENT_TYPE;
    111     }
    112 
    113     @Override
    114     public byte[] getBody() {
    115         try {
    116             return mRequestBody == null ? null : mRequestBody.getBytes(PROTOCOL_CHARSET);
    117         } catch (UnsupportedEncodingException uee) {
    118             VolleyLog.wtf("Unsupported Encoding while trying to get the bytes of %s using %s",
    119                     mRequestBody, PROTOCOL_CHARSET);
    120             return null;
    121         }
    122     }
    123 }
    124