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Diffstat (limited to 'core/src/main/java/com/android/volley/Cache.java')
-rw-r--r-- | core/src/main/java/com/android/volley/Cache.java | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/core/src/main/java/com/android/volley/Cache.java b/core/src/main/java/com/android/volley/Cache.java new file mode 100644 index 0000000..7348d0f --- /dev/null +++ b/core/src/main/java/com/android/volley/Cache.java @@ -0,0 +1,121 @@ +/* + * 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 androidx.annotation.Nullable; +import java.util.Collections; +import java.util.List; +import java.util.Map; + +/** An interface for a cache keyed by a String with a byte array as data. */ +public interface Cache { + /** + * Retrieves an entry from the cache. + * + * @param key Cache key + * @return An {@link Entry} or null in the event of a cache miss + */ + @Nullable + Entry get(String key); + + /** + * Adds or replaces an entry to the cache. + * + * @param key Cache key + * @param entry Data to store and metadata for cache coherency, TTL, etc. + */ + void put(String key, Entry entry); + + /** + * Performs any potentially long-running actions needed to initialize the cache; will be called + * from a worker thread. + */ + void initialize(); + + /** + * Invalidates an entry in the cache. + * + * @param key Cache key + * @param fullExpire True to fully expire the entry, false to soft expire + */ + void invalidate(String key, boolean fullExpire); + + /** + * Removes an entry from the cache. + * + * @param key Cache key + */ + void remove(String key); + + /** Empties the cache. */ + void clear(); + + /** Data and metadata for an entry returned by the cache. */ + class Entry { + /** The data returned from cache. */ + public byte[] data; + + /** ETag for cache coherency. */ + public String etag; + + /** Date of this response as reported by the server. */ + public long serverDate; + + /** The last modified date for the requested object. */ + public long lastModified; + + /** TTL for this record. */ + public long ttl; + + /** Soft TTL for this record. */ + public long softTtl; + + /** + * Response headers as received from server; must be non-null. Should not be mutated + * directly. + * + * <p>Note that if the server returns two headers with the same (case-insensitive) name, + * this map will only contain the one of them. {@link #allResponseHeaders} may contain all + * headers if the {@link Cache} implementation supports it. + */ + public Map<String, String> responseHeaders = Collections.emptyMap(); + + /** + * All response headers. May be null depending on the {@link Cache} implementation. Should + * not be mutated directly. + */ + public List<Header> allResponseHeaders; + + /** True if the entry is expired. */ + public boolean isExpired() { + return isExpired(System.currentTimeMillis()); + } + + boolean isExpired(long currentTimeMillis) { + return this.ttl < currentTimeMillis; + } + + /** True if a refresh is needed from the original data source. */ + public boolean refreshNeeded() { + return refreshNeeded(System.currentTimeMillis()); + } + + boolean refreshNeeded(long currentTimeMillis) { + return this.softTtl < currentTimeMillis; + } + } +} |