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
17package com.android.volley;
18
19/**
20 * Default retry policy for requests.
21 */
22public class DefaultRetryPolicy implements RetryPolicy {
23    /** The current timeout in milliseconds. */
24    private int mCurrentTimeoutMs;
25
26    /** The current retry count. */
27    private int mCurrentRetryCount;
28
29    /** The maximum number of attempts. */
30    private final int mMaxNumRetries;
31
32    /** The backoff multiplier for for the policy. */
33    private final float mBackoffMultiplier;
34
35    /** The default socket timeout in milliseconds */
36    public static final int DEFAULT_TIMEOUT_MS = 2500;
37
38    /** The default number of retries */
39    public static final int DEFAULT_MAX_RETRIES = 1;
40
41    /** The default backoff multiplier */
42    public static final float DEFAULT_BACKOFF_MULT = 1f;
43
44    /**
45     * Constructs a new retry policy using the default timeouts.
46     */
47    public DefaultRetryPolicy() {
48        this(DEFAULT_TIMEOUT_MS, DEFAULT_MAX_RETRIES, DEFAULT_BACKOFF_MULT);
49    }
50
51    /**
52     * Constructs a new retry policy.
53     * @param initialTimeoutMs The initial timeout for the policy.
54     * @param maxNumRetries The maximum number of retries.
55     * @param backoffMultiplier Backoff multiplier for the policy.
56     */
57    public DefaultRetryPolicy(int initialTimeoutMs, int maxNumRetries, float backoffMultiplier) {
58        mCurrentTimeoutMs = initialTimeoutMs;
59        mMaxNumRetries = maxNumRetries;
60        mBackoffMultiplier = backoffMultiplier;
61    }
62
63    /**
64     * Returns the current timeout.
65     */
66    @Override
67    public int getCurrentTimeout() {
68        return mCurrentTimeoutMs;
69    }
70
71    /**
72     * Returns the current retry count.
73     */
74    @Override
75    public int getCurrentRetryCount() {
76        return mCurrentRetryCount;
77    }
78
79    /**
80     * Prepares for the next retry by applying a backoff to the timeout.
81     * @param error The error code of the last attempt.
82     */
83    @Override
84    public void retry(VolleyError error) throws VolleyError {
85        mCurrentRetryCount++;
86        mCurrentTimeoutMs += (mCurrentTimeoutMs * mBackoffMultiplier);
87        if (!hasAttemptRemaining()) {
88            throw error;
89        }
90    }
91
92    /**
93     * Returns true if this policy has attempts remaining, false otherwise.
94     */
95    protected boolean hasAttemptRemaining() {
96        return mCurrentRetryCount <= mMaxNumRetries;
97    }
98}
99