implement validations of pagination URLs

java/org/chromium/distiller/PageLinkInfo.java

+// Copyright 2015 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.distiller;
+
+/**
+ * This class stores information about the link (anchor) after PageParameterDetector has detected
+ * the page parameter:
+ * - the page number (as represented by the original plain text) for the link
+ * - the original page parameter numeric component in the URL (this component would be replaced
+ *   by PageParameterDetector.PAGE_PARAM_PLACEHOLDER in the URL pattern)
+ * - the position of this link in the list of ascending numbers.
+ */
+class PageLinkInfo {
+    int mPageNum;
+    int mPageParamValue;
+    int mPosInAscendingList;

[cjhopman, 2015/04/22 00:35:35]

Does a PageLinkInfo always correspond to a PageParamInfo.PageInfo? If so, why is
the information split into two classes with just this implicit connection?

[kuan, 2015/04/22 13:39:38]

no it doesn't.
1) a PageParamInfo.PageInfo can have no mUrl, in which case, there'd be no
PageLinkInfo.
2) a PageParamInfo.PageInfo can emit multiple different PageLinkInfo's,
depending on the number of groups of consecutive digits in the url, as explained
in PageParameterDetector.java lines 127 and 157.

+
+    PageLinkInfo(int pageNum, int pageParamValue, int posInAscendingList) {
+        mPageNum = pageNum;
+        mPageParamValue = pageParamValue;
+        mPosInAscendingList = posInAscendingList;
+    }
+}