Add utility class for building HTML

This utility class is useful for formmatters that need to build custom
HTML.

Change-Id: I84f891de4b49c5fef177679ac339ae5c1d359cac
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java
new file mode 100644
index 0000000..c971df5
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/HtmlBuilder.java
@@ -0,0 +1,121 @@
+// Copyright (C) 2014 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.googlesource.gerrit.plugins.xdocs.formatter;
+
+import static org.apache.commons.lang.StringEscapeUtils.escapeHtml;
+
+import com.google.gerrit.server.GerritPersonIdent;
+import com.google.inject.Inject;
+
+import org.eclipse.jgit.lib.PersonIdent;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.Locale;
+
+public class HtmlBuilder {
+  private final DateFormat rfc2822DateFormatter;
+  private final StringBuilder html = new StringBuilder();
+
+  @Inject
+  HtmlBuilder(@GerritPersonIdent PersonIdent gerritIdent) {
+    rfc2822DateFormatter =
+        new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.US);
+    rfc2822DateFormatter.setCalendar(Calendar.getInstance(
+        gerritIdent.getTimeZone(), Locale.US));
+  }
+
+  public HtmlBuilder startDocument() {
+    return open("html");
+  }
+
+  public HtmlBuilder endDocument() {
+    return close("html");
+  }
+
+  public HtmlBuilder openBody() {
+    return open("body");
+  }
+
+  public HtmlBuilder closeBody() {
+    return close("body");
+  }
+
+  public HtmlBuilder openHead() {
+    return open("head");
+  }
+
+  public HtmlBuilder closeHead() {
+    return close("head");
+  }
+
+  public HtmlBuilder openTable() {
+    return open("table");
+  }
+
+  public HtmlBuilder closeTable() {
+    return close("table");
+  }
+
+  public HtmlBuilder openRow() {
+    return open("tr");
+  }
+
+  public HtmlBuilder closeRow() {
+    return close("tr");
+  }
+
+  public HtmlBuilder appendCellHeader(String s) {
+    return open("th").append(s).close("th");
+  }
+
+  public HtmlBuilder appendCell(String s) {
+    return open("td").append(s).close("td");
+  }
+
+  public HtmlBuilder appendCell() {
+    return appendCell("");
+  }
+
+  public HtmlBuilder appendDateCell(long date) {
+    return open("td").appendDate(date).close("td");
+  }
+
+  public HtmlBuilder open(String tag) {
+    html.append("<").append(tag).append(">");
+    return this;
+  }
+
+  public HtmlBuilder close(String tag) {
+    html.append("</").append(tag).append(">");
+    return this;
+  }
+
+  public HtmlBuilder append(String s) {
+    html.append(escapeHtml(s));
+    return this;
+  }
+
+  public HtmlBuilder appendDate(long date) {
+    html.append(rfc2822DateFormatter.format(new Date(date)));
+    return this;
+  }
+
+  public String toString() {
+    return html.toString();
+  }
+}