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
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+++ b/core/src/main/java/com/android/volley/Cache.java
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+/*
+ * 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;
+        }
+    }
+}