src/main/java/com/android/volley/Request.java - platform/frameworks/volley - Git at Google

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * 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.android.volley;

 import android.net.TrafficStats;
 import android.net.Uri;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.SystemClock;
 import android.text.TextUtils;

 import com.android.volley.VolleyLog.MarkerLog;

 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.util.Collections;
 import java.util.Map;

 /**
  * Base class for all network requests.
  *
  * @param <T> The type of parsed response this request expects.
  */
 public abstract class Request<T> implements Comparable<Request<T>> {

     /**
      * Default encoding for POST or PUT parameters. See {@link #getParamsEncoding()}.
      */
     private static final String DEFAULT_PARAMS_ENCODING = "UTF-8";

     /**
      * Supported request methods.
      */
     public interface Method {
         int DEPRECATED_GET_OR_POST = -1;
         int GET = 0;
         int POST = 1;
         int PUT = 2;
         int DELETE = 3;
         int HEAD = 4;
         int OPTIONS = 5;
         int TRACE = 6;
         int PATCH = 7;
     }

     /** An event log tracing the lifetime of this request; for debugging. */
     private final MarkerLog mEventLog = MarkerLog.ENABLED ? new MarkerLog() : null;

     /**
      * Request method of this request.  Currently supports GET, POST, PUT, DELETE, HEAD, OPTIONS,
      * TRACE, and PATCH.
      */
     private final int mMethod;

     /** URL of this request. */
     private final String mUrl;

     /** Default tag for {@link TrafficStats}. */
     private final int mDefaultTrafficStatsTag;

     /** Listener interface for errors. */
     private final Response.ErrorListener mErrorListener;

     /** Sequence number of this request, used to enforce FIFO ordering. */
     private Integer mSequence;

     /** The request queue this request is associated with. */
     private RequestQueue mRequestQueue;

     /** Whether or not responses to this request should be cached. */
     private boolean mShouldCache = true;

     /** Whether or not this request has been canceled. */
     private boolean mCanceled = false;

     /** Whether or not a response has been delivered for this request yet. */
     private boolean mResponseDelivered = false;

     /** The retry policy for this request. */
     private RetryPolicy mRetryPolicy;

     /**
      * When a request can be retrieved from cache but must be refreshed from
      * the network, the cache entry will be stored here so that in the event of
      * a "Not Modified" response, we can be sure it hasn't been evicted from cache.
      */
     private Cache.Entry mCacheEntry = null;

     /** An opaque token tagging this request; used for bulk cancellation. */
     private Object mTag;

     /**
      * Creates a new request with the given URL and error listener.  Note that
      * the normal response listener is not provided here as delivery of responses
      * is provided by subclasses, who have a better idea of how to deliver an
      * already-parsed response.
      *
      * @deprecated Use {@link #Request(int, String, com.android.volley.Response.ErrorListener)}.
      */
     @Deprecated
     public Request(String url, Response.ErrorListener listener) {
         this(Method.DEPRECATED_GET_OR_POST, url, listener);
     }

     /**
      * Creates a new request with the given method (one of the values from {@link Method}),
      * URL, and error listener.  Note that the normal response listener is not provided here as
      * delivery of responses is provided by subclasses, who have a better idea of how to deliver
      * an already-parsed response.
      */
     public Request(int method, String url, Response.ErrorListener listener) {
         mMethod = method;
         mUrl = url;
         mErrorListener = listener;
         setRetryPolicy(new DefaultRetryPolicy());

         mDefaultTrafficStatsTag = findDefaultTrafficStatsTag(url);
     }

     /**
      * Return the method for this request.  Can be one of the values in {@link Method}.
      */
     public int getMethod() {
         return mMethod;
     }

     /**
      * Set a tag on this request. Can be used to cancel all requests with this
      * tag by {@link RequestQueue#cancelAll(Object)}.
      *
      * @return This Request object to allow for chaining.
      */
     public Request<?> setTag(Object tag) {
         mTag = tag;
         return this;
     }

     /**
      * Returns this request's tag.
      * @see Request#setTag(Object)
      */
     public Object getTag() {
         return mTag;
     }

     /**
      * @return this request's {@link com.android.volley.Response.ErrorListener}.
      */
     public Response.ErrorListener getErrorListener() {
         return mErrorListener;
     }

     /**
      * @return A tag for use with {@link TrafficStats#setThreadStatsTag(int)}
      */
     public int getTrafficStatsTag() {
         return mDefaultTrafficStatsTag;
     }

     /**
      * @return The hashcode of the URL's host component, or 0 if there is none.
      */
     private static int findDefaultTrafficStatsTag(String url) {
         if (!TextUtils.isEmpty(url)) {
             Uri uri = Uri.parse(url);
             if (uri != null) {
                 String host = uri.getHost();
                 if (host != null) {
                     return host.hashCode();
                 }
             }
         }
         return 0;
     }

     /**
      * Sets the retry policy for this request.
      *
      * @return This Request object to allow for chaining.
      */
     public Request<?> setRetryPolicy(RetryPolicy retryPolicy) {
         mRetryPolicy = retryPolicy;
         return this;
     }

     /**
      * Adds an event to this request's event log; for debugging.
      */
     public void addMarker(String tag) {
         if (MarkerLog.ENABLED) {
             mEventLog.add(tag, Thread.currentThread().getId());
         }
     }

     /**
      * Notifies the request queue that this request has finished (successfully or with error).
      *
      * <p>Also dumps all events from this request's event log; for debugging.</p>
      */
     void finish(final String tag) {
         if (mRequestQueue != null) {
             mRequestQueue.finish(this);
         }
         if (MarkerLog.ENABLED) {
             final long threadId = Thread.currentThread().getId();
             if (Looper.myLooper() != Looper.getMainLooper()) {
                 // If we finish marking off of the main thread, we need to
                 // actually do it on the main thread to ensure correct ordering.
                 Handler mainThread = new Handler(Looper.getMainLooper());
                 mainThread.post(new Runnable() {
                     @Override
                     public void run() {
                         mEventLog.add(tag, threadId);
                         mEventLog.finish(this.toString());
                     }
                 });
                 return;
             }

             mEventLog.add(tag, threadId);
             mEventLog.finish(this.toString());
         }
     }

     /**
      * Associates this request with the given queue. The request queue will be notified when this
      * request has finished.
      *
      * @return This Request object to allow for chaining.
      */
     public Request<?> setRequestQueue(RequestQueue requestQueue) {
         mRequestQueue = requestQueue;
         return this;
     }

     /**
      * Sets the sequence number of this request.  Used by {@link RequestQueue}.
      *
      * @return This Request object to allow for chaining.
      */
     public final Request<?> setSequence(int sequence) {
         mSequence = sequence;
         return this;
     }

     /**
      * Returns the sequence number of this request.
      */
     public final int getSequence() {
         if (mSequence == null) {
             throw new IllegalStateException("getSequence called before setSequence");
         }
         return mSequence;
     }

     /**
      * Returns the URL of this request.
      */
     public String getUrl() {
         return mUrl;
     }

     /**
      * Returns the cache key for this request.  By default, this is the URL.
      */
     public String getCacheKey() {
         return getUrl();
     }

     /**
      * Annotates this request with an entry retrieved for it from cache.
      * Used for cache coherency support.
      *
      * @return This Request object to allow for chaining.
      */
     public Request<?> setCacheEntry(Cache.Entry entry) {
         mCacheEntry = entry;
         return this;
     }

     /**
      * Returns the annotated cache entry, or null if there isn't one.
      */
     public Cache.Entry getCacheEntry() {
         return mCacheEntry;
     }

     /**
      * Mark this request as canceled.  No callback will be delivered.
      */
     public void cancel() {
         mCanceled = true;
     }

     /**
      * Returns true if this request has been canceled.
      */
     public boolean isCanceled() {
         return mCanceled;
     }

     /**
      * Returns a list of extra HTTP headers to go along with this request. Can
      * throw {@link AuthFailureError} as authentication may be required to
      * provide these values.
      * @throws AuthFailureError In the event of auth failure
      */
     public Map<String, String> getHeaders() throws AuthFailureError {
         return Collections.emptyMap();
     }

     /**
      * Returns a Map of POST parameters to be used for this request, or null if
      * a simple GET should be used.  Can throw {@link AuthFailureError} as
      * authentication may be required to provide these values.
      *
      * <p>Note that only one of getPostParams() and getPostBody() can return a non-null
      * value.</p>
      * @throws AuthFailureError In the event of auth failure
      *
      * @deprecated Use {@link #getParams()} instead.
      */
     @Deprecated
     protected Map<String, String> getPostParams() throws AuthFailureError {
         return getParams();
     }

     /**
      * Returns which encoding should be used when converting POST parameters returned by
      * {@link #getPostParams()} into a raw POST body.
      *
      * <p>This controls both encodings:
      * <ol>
      *     <li>The string encoding used when converting parameter names and values into bytes prior
      *         to URL encoding them.</li>
      *     <li>The string encoding used when converting the URL encoded parameters into a raw
      *         byte array.</li>
      * </ol>
      *
      * @deprecated Use {@link #getParamsEncoding()} instead.
      */
     @Deprecated
     protected String getPostParamsEncoding() {
         return getParamsEncoding();
     }

     /**
      * @deprecated Use {@link #getBodyContentType()} instead.
      */
     @Deprecated
     public String getPostBodyContentType() {
         return getBodyContentType();
     }

     /**
      * Returns the raw POST body to be sent.
      *
      * @throws AuthFailureError In the event of auth failure
      *
      * @deprecated Use {@link #getBody()} instead.
      */
     @Deprecated
     public byte[] getPostBody() throws AuthFailureError {
         // Note: For compatibility with legacy clients of volley, this implementation must remain
         // here instead of simply calling the getBody() function because this function must
         // call getPostParams() and getPostParamsEncoding() since legacy clients would have
         // overridden these two member functions for POST requests.
         Map<String, String> postParams = getPostParams();
         if (postParams != null && postParams.size() > 0) {
             return encodeParameters(postParams, getPostParamsEncoding());
         }
         return null;
     }

     /**
      * Returns a Map of parameters to be used for a POST or PUT request.  Can throw
      * {@link AuthFailureError} as authentication may be required to provide these values.
      *
      * <p>Note that you can directly override {@link #getBody()} for custom data.</p>
      *
      * @throws AuthFailureError in the event of auth failure
      */
     protected Map<String, String> getParams() throws AuthFailureError {
         return null;
     }

     /**
      * Returns which encoding should be used when converting POST or PUT parameters returned by
      * {@link #getParams()} into a raw POST or PUT body.
      *
      * <p>This controls both encodings:
      * <ol>
      *     <li>The string encoding used when converting parameter names and values into bytes prior
      *         to URL encoding them.</li>
      *     <li>The string encoding used when converting the URL encoded parameters into a raw
      *         byte array.</li>
      * </ol>
      */
     protected String getParamsEncoding() {
         return DEFAULT_PARAMS_ENCODING;
     }

     /**
      * Returns the content type of the POST or PUT body.
      */
     public String getBodyContentType() {
         return "application/x-www-form-urlencoded; charset=" + getParamsEncoding();
     }

     /**
      * Returns the raw POST or PUT body to be sent.
      *
      * <p>By default, the body consists of the request parameters in
      * application/x-www-form-urlencoded format. When overriding this method, consider overriding
      * {@link #getBodyContentType()} as well to match the new body format.
      *
      * @throws AuthFailureError in the event of auth failure
      */
     public byte[] getBody() throws AuthFailureError {
         Map<String, String> params = getParams();
         if (params != null && params.size() > 0) {
             return encodeParameters(params, getParamsEncoding());
         }
         return null;
     }

     /**
      * Converts <code>params</code> into an application/x-www-form-urlencoded encoded string.
      */
     private byte[] encodeParameters(Map<String, String> params, String paramsEncoding) {
         StringBuilder encodedParams = new StringBuilder();
         try {
             for (Map.Entry<String, String> entry : params.entrySet()) {
                 encodedParams.append(URLEncoder.encode(entry.getKey(), paramsEncoding));
                 encodedParams.append('=');
                 encodedParams.append(URLEncoder.encode(entry.getValue(), paramsEncoding));
                 encodedParams.append('&');
             }
             return encodedParams.toString().getBytes(paramsEncoding);
         } catch (UnsupportedEncodingException uee) {
             throw new RuntimeException("Encoding not supported: " + paramsEncoding, uee);
         }
     }

     /**
      * Set whether or not responses to this request should be cached.
      *
      * @return This Request object to allow for chaining.
      */
     public final Request<?> setShouldCache(boolean shouldCache) {
         mShouldCache = shouldCache;
         return this;
     }

     /**
      * Returns true if responses to this request should be cached.
      */
     public final boolean shouldCache() {
         return mShouldCache;
     }

     /**
      * Priority values.  Requests will be processed from higher priorities to
      * lower priorities, in FIFO order.
      */
     public enum Priority {
         LOW,
         NORMAL,
         HIGH,
         IMMEDIATE
     }

     /**
      * Returns the {@link Priority} of this request; {@link Priority#NORMAL} by default.
      */
     public Priority getPriority() {
         return Priority.NORMAL;
     }

     /**
      * Returns the socket timeout in milliseconds per retry attempt. (This value can be changed
      * per retry attempt if a backoff is specified via backoffTimeout()). If there are no retry
      * attempts remaining, this will cause delivery of a {@link TimeoutError} error.
      */
     public final int getTimeoutMs() {
         return mRetryPolicy.getCurrentTimeout();
     }

     /**
      * Returns the retry policy that should be used  for this request.
      */
     public RetryPolicy getRetryPolicy() {
         return mRetryPolicy;
     }

     /**
      * Mark this request as having a response delivered on it.  This can be used
      * later in the request's lifetime for suppressing identical responses.
      */
     public void markDelivered() {
         mResponseDelivered = true;
     }

     /**
      * Returns true if this request has had a response delivered for it.
      */
     public boolean hasHadResponseDelivered() {
         return mResponseDelivered;
     }

     /**
      * Subclasses must implement this to parse the raw network response
      * and return an appropriate response type. This method will be
      * called from a worker thread.  The response will not be delivered
      * if you return null.
      * @param response Response from the network
      * @return The parsed response, or null in the case of an error
      */
     abstract protected Response<T> parseNetworkResponse(NetworkResponse response);

     /**
      * Subclasses can override this method to parse 'networkError' and return a more specific error.
      *
      * <p>The default implementation just returns the passed 'networkError'.</p>
      *
      * @param volleyError the error retrieved from the network
      * @return an NetworkError augmented with additional information
      */
     protected VolleyError parseNetworkError(VolleyError volleyError) {
         return volleyError;
     }

     /**
      * Subclasses must implement this to perform delivery of the parsed
      * response to their listeners.  The given response is guaranteed to
      * be non-null; responses that fail to parse are not delivered.
      * @param response The parsed response returned by
      * {@link #parseNetworkResponse(NetworkResponse)}
      */
     abstract protected void deliverResponse(T response);

     /**
      * Delivers error message to the ErrorListener that the Request was
      * initialized with.
      *
      * @param error Error details
      */
     public void deliverError(VolleyError error) {
         if (mErrorListener != null) {
             mErrorListener.onErrorResponse(error);
         }
     }

     /**
      * Our comparator sorts from high to low priority, and secondarily by
      * sequence number to provide FIFO ordering.
      */
     @Override
     public int compareTo(Request<T> other) {
         Priority left = this.getPriority();
         Priority right = other.getPriority();

         // High-priority requests are "lesser" so they are sorted to the front.
         // Equal priorities are sorted by sequence number to provide FIFO ordering.
         return left == right ?
                 this.mSequence - other.mSequence :
                 right.ordinal() - left.ordinal();
     }

     @Override
     public String toString() {
         String trafficStatsTag = "0x" + Integer.toHexString(getTrafficStatsTag());
         return (mCanceled ? "[X] " : "[ ] ") + getUrl() + " " + trafficStatsTag + " "
                 + getPriority() + " " + mSequence;
     }
 }
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* 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.android.volley;

	import android.net.TrafficStats;
	import android.net.Uri;
	import android.os.Handler;
	import android.os.Looper;
	import android.os.SystemClock;
	import android.text.TextUtils;

	import com.android.volley.VolleyLog.MarkerLog;

	import java.io.UnsupportedEncodingException;
	import java.net.URLEncoder;
	import java.util.Collections;
	import java.util.Map;

	/**
	* Base class for all network requests.
	*
	* @param <T> The type of parsed response this request expects.
	*/
	public abstract class Request<T> implements Comparable<Request<T>> {

	/**
	* Default encoding for POST or PUT parameters. See {@link #getParamsEncoding()}.
	*/
	private static final String DEFAULT_PARAMS_ENCODING = "UTF-8";

	/**
	* Supported request methods.
	*/
	public interface Method {
	int DEPRECATED_GET_OR_POST = -1;
	int GET = 0;
	int POST = 1;
	int PUT = 2;
	int DELETE = 3;
	int HEAD = 4;
	int OPTIONS = 5;
	int TRACE = 6;
	int PATCH = 7;
	}

	/** An event log tracing the lifetime of this request; for debugging. */
	private final MarkerLog mEventLog = MarkerLog.ENABLED ? new MarkerLog() : null;

	/**
	* Request method of this request. Currently supports GET, POST, PUT, DELETE, HEAD, OPTIONS,
	* TRACE, and PATCH.
	*/
	private final int mMethod;

	/** URL of this request. */
	private final String mUrl;

	/** Default tag for {@link TrafficStats}. */
	private final int mDefaultTrafficStatsTag;

	/** Listener interface for errors. */
	private final Response.ErrorListener mErrorListener;

	/** Sequence number of this request, used to enforce FIFO ordering. */
	private Integer mSequence;

	/** The request queue this request is associated with. */
	private RequestQueue mRequestQueue;

	/** Whether or not responses to this request should be cached. */
	private boolean mShouldCache = true;

	/** Whether or not this request has been canceled. */
	private boolean mCanceled = false;

	/** Whether or not a response has been delivered for this request yet. */
	private boolean mResponseDelivered = false;

	/** The retry policy for this request. */
	private RetryPolicy mRetryPolicy;

	/**
	* When a request can be retrieved from cache but must be refreshed from
	* the network, the cache entry will be stored here so that in the event of
	* a "Not Modified" response, we can be sure it hasn't been evicted from cache.
	*/
	private Cache.Entry mCacheEntry = null;

	/** An opaque token tagging this request; used for bulk cancellation. */
	private Object mTag;

	/**
	* Creates a new request with the given URL and error listener. Note that
	* the normal response listener is not provided here as delivery of responses
	* is provided by subclasses, who have a better idea of how to deliver an
	* already-parsed response.
	*
	* @deprecated Use {@link #Request(int, String, com.android.volley.Response.ErrorListener)}.
	*/
	@Deprecated
	public Request(String url, Response.ErrorListener listener) {
	this(Method.DEPRECATED_GET_OR_POST, url, listener);
	}

	/**
	* Creates a new request with the given method (one of the values from {@link Method}),
	* URL, and error listener. Note that the normal response listener is not provided here as
	* delivery of responses is provided by subclasses, who have a better idea of how to deliver
	* an already-parsed response.
	*/
	public Request(int method, String url, Response.ErrorListener listener) {
	mMethod = method;
	mUrl = url;
	mErrorListener = listener;
	setRetryPolicy(new DefaultRetryPolicy());

	mDefaultTrafficStatsTag = findDefaultTrafficStatsTag(url);
	}

	/**
	* Return the method for this request. Can be one of the values in {@link Method}.
	*/
	public int getMethod() {
	return mMethod;
	}

	/**
	* Set a tag on this request. Can be used to cancel all requests with this
	* tag by {@link RequestQueue#cancelAll(Object)}.
	*
	* @return This Request object to allow for chaining.
	*/
	public Request<?> setTag(Object tag) {
	mTag = tag;
	return this;
	}

	/**
	* Returns this request's tag.
	* @see Request#setTag(Object)
	*/
	public Object getTag() {
	return mTag;
	}

	/**
	* @return this request's {@link com.android.volley.Response.ErrorListener}.
	*/
	public Response.ErrorListener getErrorListener() {
	return mErrorListener;
	}

	/**
	* @return A tag for use with {@link TrafficStats#setThreadStatsTag(int)}
	*/
	public int getTrafficStatsTag() {
	return mDefaultTrafficStatsTag;
	}

	/**
	* @return The hashcode of the URL's host component, or 0 if there is none.
	*/
	private static int findDefaultTrafficStatsTag(String url) {
	if (!TextUtils.isEmpty(url)) {
	Uri uri = Uri.parse(url);
	if (uri != null) {
	String host = uri.getHost();
	if (host != null) {
	return host.hashCode();
	}
	}
	}
	return 0;
	}

	/**
	* Sets the retry policy for this request.
	*
	* @return This Request object to allow for chaining.
	*/
	public Request<?> setRetryPolicy(RetryPolicy retryPolicy) {
	mRetryPolicy = retryPolicy;
	return this;
	}

	/**
	* Adds an event to this request's event log; for debugging.
	*/
	public void addMarker(String tag) {
	if (MarkerLog.ENABLED) {
	mEventLog.add(tag, Thread.currentThread().getId());
	}
	}

	/**
	* Notifies the request queue that this request has finished (successfully or with error).
	*
	* <p>Also dumps all events from this request's event log; for debugging.</p>
	*/
	void finish(final String tag) {
	if (mRequestQueue != null) {
	mRequestQueue.finish(this);
	}
	if (MarkerLog.ENABLED) {
	final long threadId = Thread.currentThread().getId();
	if (Looper.myLooper() != Looper.getMainLooper()) {
	// If we finish marking off of the main thread, we need to
	// actually do it on the main thread to ensure correct ordering.
	Handler mainThread = new Handler(Looper.getMainLooper());
	mainThread.post(new Runnable() {
	@Override
	public void run() {
	mEventLog.add(tag, threadId);
	mEventLog.finish(this.toString());
	}
	});
	return;
	}

	mEventLog.add(tag, threadId);
	mEventLog.finish(this.toString());
	}
	}

	/**
	* Associates this request with the given queue. The request queue will be notified when this
	* request has finished.
	*
	* @return This Request object to allow for chaining.
	*/
	public Request<?> setRequestQueue(RequestQueue requestQueue) {
	mRequestQueue = requestQueue;
	return this;
	}

	/**
	* Sets the sequence number of this request. Used by {@link RequestQueue}.
	*
	* @return This Request object to allow for chaining.
	*/
	public final Request<?> setSequence(int sequence) {
	mSequence = sequence;
	return this;
	}

	/**
	* Returns the sequence number of this request.
	*/
	public final int getSequence() {
	if (mSequence == null) {
	throw new IllegalStateException("getSequence called before setSequence");
	}
	return mSequence;
	}

	/**
	* Returns the URL of this request.
	*/
	public String getUrl() {
	return mUrl;
	}

	/**
	* Returns the cache key for this request. By default, this is the URL.
	*/
	public String getCacheKey() {
	return getUrl();
	}

	/**
	* Annotates this request with an entry retrieved for it from cache.
	* Used for cache coherency support.
	*
	* @return This Request object to allow for chaining.
	*/
	public Request<?> setCacheEntry(Cache.Entry entry) {
	mCacheEntry = entry;
	return this;
	}

	/**
	* Returns the annotated cache entry, or null if there isn't one.
	*/
	public Cache.Entry getCacheEntry() {
	return mCacheEntry;
	}

	/**
	* Mark this request as canceled. No callback will be delivered.
	*/
	public void cancel() {
	mCanceled = true;
	}

	/**
	* Returns true if this request has been canceled.
	*/
	public boolean isCanceled() {
	return mCanceled;
	}

	/**
	* Returns a list of extra HTTP headers to go along with this request. Can
	* throw {@link AuthFailureError} as authentication may be required to
	* provide these values.
	* @throws AuthFailureError In the event of auth failure
	*/
	public Map<String, String> getHeaders() throws AuthFailureError {
	return Collections.emptyMap();
	}

	/**
	* Returns a Map of POST parameters to be used for this request, or null if
	* a simple GET should be used. Can throw {@link AuthFailureError} as
	* authentication may be required to provide these values.
	*
	* <p>Note that only one of getPostParams() and getPostBody() can return a non-null
	* value.</p>
	* @throws AuthFailureError In the event of auth failure
	*
	* @deprecated Use {@link #getParams()} instead.
	*/
	@Deprecated
	protected Map<String, String> getPostParams() throws AuthFailureError {
	return getParams();
	}

	/**
	* Returns which encoding should be used when converting POST parameters returned by
	* {@link #getPostParams()} into a raw POST body.
	*
	* <p>This controls both encodings:
	* <ol>
	* <li>The string encoding used when converting parameter names and values into bytes prior
	* to URL encoding them.</li>
	* <li>The string encoding used when converting the URL encoded parameters into a raw
	* byte array.</li>
	* </ol>
	*
	* @deprecated Use {@link #getParamsEncoding()} instead.
	*/
	@Deprecated
	protected String getPostParamsEncoding() {
	return getParamsEncoding();
	}

	/**
	* @deprecated Use {@link #getBodyContentType()} instead.
	*/
	@Deprecated
	public String getPostBodyContentType() {
	return getBodyContentType();
	}

	/**
	* Returns the raw POST body to be sent.
	*
	* @throws AuthFailureError In the event of auth failure
	*
	* @deprecated Use {@link #getBody()} instead.
	*/
	@Deprecated
	public byte[] getPostBody() throws AuthFailureError {
	// Note: For compatibility with legacy clients of volley, this implementation must remain
	// here instead of simply calling the getBody() function because this function must
	// call getPostParams() and getPostParamsEncoding() since legacy clients would have
	// overridden these two member functions for POST requests.
	Map<String, String> postParams = getPostParams();
	if (postParams != null && postParams.size() > 0) {
	return encodeParameters(postParams, getPostParamsEncoding());
	}
	return null;
	}

	/**
	* Returns a Map of parameters to be used for a POST or PUT request. Can throw
	* {@link AuthFailureError} as authentication may be required to provide these values.
	*
	* <p>Note that you can directly override {@link #getBody()} for custom data.</p>
	*
	* @throws AuthFailureError in the event of auth failure
	*/
	protected Map<String, String> getParams() throws AuthFailureError {
	return null;
	}

	/**
	* Returns which encoding should be used when converting POST or PUT parameters returned by
	* {@link #getParams()} into a raw POST or PUT body.
	*
	* <p>This controls both encodings:
	* <ol>
	* <li>The string encoding used when converting parameter names and values into bytes prior
	* to URL encoding them.</li>
	* <li>The string encoding used when converting the URL encoded parameters into a raw
	* byte array.</li>
	* </ol>
	*/
	protected String getParamsEncoding() {
	return DEFAULT_PARAMS_ENCODING;
	}

	/**
	* Returns the content type of the POST or PUT body.
	*/
	public String getBodyContentType() {
	return "application/x-www-form-urlencoded; charset=" + getParamsEncoding();
	}

	/**
	* Returns the raw POST or PUT body to be sent.
	*
	* <p>By default, the body consists of the request parameters in
	* application/x-www-form-urlencoded format. When overriding this method, consider overriding
	* {@link #getBodyContentType()} as well to match the new body format.
	*
	* @throws AuthFailureError in the event of auth failure
	*/
	public byte[] getBody() throws AuthFailureError {
	Map<String, String> params = getParams();
	if (params != null && params.size() > 0) {
	return encodeParameters(params, getParamsEncoding());
	}
	return null;
	}

	/**
	* Converts <code>params</code> into an application/x-www-form-urlencoded encoded string.
	*/
	private byte[] encodeParameters(Map<String, String> params, String paramsEncoding) {
	StringBuilder encodedParams = new StringBuilder();
	try {
	for (Map.Entry<String, String> entry : params.entrySet()) {
	encodedParams.append(URLEncoder.encode(entry.getKey(), paramsEncoding));
	encodedParams.append('=');
	encodedParams.append(URLEncoder.encode(entry.getValue(), paramsEncoding));
	encodedParams.append('&');
	}
	return encodedParams.toString().getBytes(paramsEncoding);
	} catch (UnsupportedEncodingException uee) {
	throw new RuntimeException("Encoding not supported: " + paramsEncoding, uee);
	}
	}

	/**
	* Set whether or not responses to this request should be cached.
	*
	* @return This Request object to allow for chaining.
	*/
	public final Request<?> setShouldCache(boolean shouldCache) {
	mShouldCache = shouldCache;
	return this;
	}

	/**
	* Returns true if responses to this request should be cached.
	*/
	public final boolean shouldCache() {
	return mShouldCache;
	}

	/**
	* Priority values. Requests will be processed from higher priorities to
	* lower priorities, in FIFO order.
	*/
	public enum Priority {
	LOW,
	NORMAL,
	HIGH,
	IMMEDIATE
	}

	/**
	* Returns the {@link Priority} of this request; {@link Priority#NORMAL} by default.
	*/
	public Priority getPriority() {
	return Priority.NORMAL;
	}

	/**
	* Returns the socket timeout in milliseconds per retry attempt. (This value can be changed
	* per retry attempt if a backoff is specified via backoffTimeout()). If there are no retry
	* attempts remaining, this will cause delivery of a {@link TimeoutError} error.
	*/
	public final int getTimeoutMs() {
	return mRetryPolicy.getCurrentTimeout();
	}

	/**
	* Returns the retry policy that should be used for this request.
	*/
	public RetryPolicy getRetryPolicy() {
	return mRetryPolicy;
	}

	/**
	* Mark this request as having a response delivered on it. This can be used
	* later in the request's lifetime for suppressing identical responses.
	*/
	public void markDelivered() {
	mResponseDelivered = true;
	}

	/**
	* Returns true if this request has had a response delivered for it.
	*/
	public boolean hasHadResponseDelivered() {
	return mResponseDelivered;
	}

	/**
	* Subclasses must implement this to parse the raw network response
	* and return an appropriate response type. This method will be
	* called from a worker thread. The response will not be delivered
	* if you return null.
	* @param response Response from the network
	* @return The parsed response, or null in the case of an error
	*/
	abstract protected Response<T> parseNetworkResponse(NetworkResponse response);

	/**
	* Subclasses can override this method to parse 'networkError' and return a more specific error.
	*
	* <p>The default implementation just returns the passed 'networkError'.</p>
	*
	* @param volleyError the error retrieved from the network
	* @return an NetworkError augmented with additional information
	*/
	protected VolleyError parseNetworkError(VolleyError volleyError) {
	return volleyError;
	}

	/**
	* Subclasses must implement this to perform delivery of the parsed
	* response to their listeners. The given response is guaranteed to
	* be non-null; responses that fail to parse are not delivered.
	* @param response The parsed response returned by
	* {@link #parseNetworkResponse(NetworkResponse)}
	*/
	abstract protected void deliverResponse(T response);

	/**
	* Delivers error message to the ErrorListener that the Request was
	* initialized with.
	*
	* @param error Error details
	*/
	public void deliverError(VolleyError error) {
	if (mErrorListener != null) {
	mErrorListener.onErrorResponse(error);
	}
	}

	/**
	* Our comparator sorts from high to low priority, and secondarily by
	* sequence number to provide FIFO ordering.
	*/
	@Override
	public int compareTo(Request<T> other) {
	Priority left = this.getPriority();
	Priority right = other.getPriority();

	// High-priority requests are "lesser" so they are sorted to the front.
	// Equal priorities are sorted by sequence number to provide FIFO ordering.
	return left == right ?
	this.mSequence - other.mSequence :
	right.ordinal() - left.ordinal();
	}

	@Override
	public String toString() {
	String trafficStatsTag = "0x" + Integer.toHexString(getTrafficStatsTag());
	return (mCanceled ? "[X] " : "[ ] ") + getUrl() + " " + trafficStatsTag + " "
	+ getPriority() + " " + mSequence;
	}
	}