Move Cronet metrics-related classes into their own files

components/cronet/android/api/src/org/chromium/net/RequestFinishedInfo.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.net;
+
+import android.support.annotation.Nullable;
+
+import java.util.Collection;
+import java.util.concurrent.Executor;
+
+/**
+ * Information about a finished request. Passed to {@link RequestFinishedInfo.Listener}.
+ *
+ * {@hide} as it's a prototype.
+ */
+public final class RequestFinishedInfo {
+    /**
+     * Listens for finished requests for the purpose of collecting metrics.
+     *
+     * {@hide} as it's a prototype.
+     */
+    public abstract static class Listener {
+        private final Executor mExecutor;
+
+        public Listener(Executor executor) {
+            if (executor == null) {
+                throw new IllegalStateException("Executor must not be null");
+            }
+            mExecutor = executor;
+        }
+
+        /**
+         * Invoked with request info. Will be called in a task submitted to the
+         * {@link java.util.concurrent.Executor} returned by {@link #getExecutor}.
+         * @param requestInfo {@link RequestFinishedInfo} for finished request.
+         */
+        public abstract void onRequestFinished(RequestFinishedInfo requestInfo);
+
+        /**
+         * Returns this listener's executor. Can be called on any thread.
+         * @return this listener's {@link java.util.concurrent.Executor}
+         */
+        public Executor getExecutor() {
+            return mExecutor;
+        }
+    }
+
+    /**
+     * Metrics collected for a single request.
+     *
+     * {@hide} as it's a prototype.
+     */
+    public static class Metrics {
+        @Nullable
+        private final Long mTtfbMs;
+        @Nullable
+        private final Long mTotalTimeMs;
+        @Nullable
+        private final Long mSentBytesCount;
+        @Nullable
+        private final Long mReceivedBytesCount;
+
+        public Metrics(@Nullable Long ttfbMs, @Nullable Long totalTimeMs,
+                @Nullable Long sentBytesCount, @Nullable Long receivedBytesCount) {
+            mTtfbMs = ttfbMs;
+            mTotalTimeMs = totalTimeMs;
+            mSentBytesCount = sentBytesCount;
+            mReceivedBytesCount = receivedBytesCount;
+        }
+
+        /**
+         * Returns milliseconds between request initiation and first byte of response headers,
+         * or null if not collected.
+         */
+        @Nullable
+        public Long getTtfbMs() {
+            return mTtfbMs;
+        }
+
+        /**
+         * Returns milliseconds between request initiation and finish,
+         * including a failure or cancellation, or null if not collected.
+         */
+        @Nullable
+        public Long getTotalTimeMs() {
+            return mTotalTimeMs;
+        }
+
+        /**
+         * Returns total bytes sent over the network transport layer, or null if not collected.
+         */
+        @Nullable
+        public Long getSentBytesCount() {
+            return mSentBytesCount;
+        }
+
+        /**
+         * Returns total bytes received over the network transport layer, or null if not collected.
+         */
+        @Nullable
+        public Long getReceivedBytesCount() {
+            return mReceivedBytesCount;
+        }
+    }
+
+    private final String mUrl;
+    private final Collection<Object> mAnnotations;
+    private final Metrics mMetrics;
+    @Nullable
+    private final UrlResponseInfo mResponseInfo;
+
+    /**
+     * @hide only used by internal implementation.
+     */
+    public RequestFinishedInfo(String url, Collection<Object> annotations, Metrics metrics,
+            @Nullable UrlResponseInfo responseInfo) {
+        mUrl = url;
+        mAnnotations = annotations;
+        mMetrics = metrics;
+        mResponseInfo = responseInfo;
+    }
+
+    /** Returns the request's original URL. */
+    public String getUrl() {
+        return mUrl;
+    }
+
+    /** Returns the objects that the caller has supplied when initiating the request. */
+    public Collection<Object> getAnnotations() {
+        return mAnnotations;
+    }
+
+    // TODO(klm): Collect and return a chain of Metrics objects for redirect responses.
+    /**
+     * Returns metrics collected for this request.
+     *
+     * <p>The reported times and bytes account for all redirects, i.e.
+     * the TTFB is from the start of the original request to the ultimate response headers,
+     * the TTLB is from the start of the original request to the end of the ultimate response,
+     * the received byte count is for all redirects and the ultimate response combined.
+     * These cumulative metric definitions are debatable, but are chosen to make sense
+     * for user-facing latency analysis.
+     *
+     * @return metrics collected for this request.
+     */
+    public Metrics getMetrics() {
+        return mMetrics;
+    }
+
+    /**
+     * Returns a {@link UrlResponseInfo} for the request, if its response had started.
+     * @return {@link UrlResponseInfo} for the request, if its response had started.
+     */
+    @Nullable
+    public UrlResponseInfo getResponseInfo() {
+        return mResponseInfo;
+    }
+}