Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/6312#discussion_r202644607
--- Diff:
flink-core/src/main/java/org/apache/flink/configuration/description/LineBreakElement.java
---
@@ -0,0 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.flink.configuration.description;
+
+/**
+ * Represents a line break in the {@link Description}.
+ */
+public class LineBreakElement implements BlockElement {
+
+ /**
+ * Creates a line break in the description.
+ */
+ public static LineBreakElement linebreak() {
+ return new LineBreakElement();
+ }
+
+ private LineBreakElement() {
+ }
+
+ @Override
+ public String format(Formatter formatter) {
--- End diff --
hmm... i think we can do this with internal state. I gave it a shot and
came up with 2 versions:
1) internal state kept in `HtmlFormatter`
The internal state is a simple Stringbuilder. The only tricky part is the
format string for `text()`, for this i create a new `HtmlFormatter` for each
individual element, and then add them to the actual state.
Changes are isolated to `HtmlFormatter`.
2) internal state kept in `Formatter`, main formatting logic now resides in
`Formatter` with hooks for specific elements (like List prefixes) that
subclasses implement.
Same approach for dealing with `text()` as for 1), solved with
`Formatter#duplicate()` method.
## 1)
```
public abstract class Formatter {
/**
* Formats the description into a String using format specific tags.
*
* @param description description to be formatted
* @return string representation of the description
*/
public String format(Description description) {
description.getBlocks().forEach(b -> b.format(this));
return finalizeFormatting();
}
public abstract String finalizeFormatting();
public abstract void format(LinkElement element);
public abstract void format(TextElement element);
public abstract void format(LineBreakElement element);
public abstract void format(ListElement element);
}
public class HtmlFormatter extends Formatter {
private final StringBuilder state = new StringBuilder();
public String finalizeFormatting() {
return state.toString();
//TODO: clean state
}
@Override
public void format(LinkElement element) {
state.append(String.format("<a href=\"%s\">%s</a>",
element.getLink(), element.getText()));
}
@Override
public void format(TextElement element) {
String format = escapeCharacters(element.getFormat());
final List<InlineElement> inlineElements =
element.getElements();
if (inlineElements.isEmpty()) {
state.append(format);
} else {
Object[] formattedInlineElements = new
String[inlineElements.size()];
for (int x = 0; x < formattedInlineElements.length;
x++) {
HtmlFormatter innerFormatter = new
HtmlFormatter();
inlineElements.get(x).format(innerFormatter);
formattedInlineElements[x] =
innerFormatter.finalizeFormatting();
}
state.append(String.format(format,
formattedInlineElements));
}
}
@Override
public void format(LineBreakElement element) {
state.append("<br/>");
}
@Override
public void format(ListElement element) {
state.append("<ul>");
for (InlineElement item : element.getEntries()) {
state.append("<li>");
item.format(this);
state.append("</li>");
}
state.append("</ul>");
}
private static String escapeCharacters(String value) {
return value
.replaceAll("<", "<")
.replaceAll(">", ">");
}
}
## 2)
```
public abstract class Formatter {
private final StringBuilder state = new StringBuilder();
/**
* Formats the description into a String using format specific tags.
*
* @param description description to be formatted
* @return string representation of the description
*/
public String format(Description description) {
description.getBlocks().forEach(b -> b.format(this));
return finalizeFormatting();
}
public String finalizeFormatting() {
return state.toString();
}
public void format(LinkElement element) {
state.append(getLinkPrefix() + element.getLink() +
getLinkInfix() + element.getText() + getLinkSuffix());
}
public abstract String getLinkPrefix();
public abstract String getLinkInfix();
public abstract String getLinkSuffix();
public void format(TextElement element) {
String format = escapeTextCharacters(element.getFormat());
final List<InlineElement> inlineElements =
element.getElements();
if (inlineElements.isEmpty()) {
state.append(format);
} else {
Object[] formattedInlineElements = new
String[inlineElements.size()];
for (int x = 0; x < formattedInlineElements.length;
x++) {
Formatter innerFormatter = duplicate();
inlineElements.get(x).format(innerFormatter);
formattedInlineElements[x] =
innerFormatter.finalizeFormatting();
}
state.append(String.format(format,
formattedInlineElements));
}
}
public void format(LineBreakElement element) {
state.append(createLineBreak());
}
public abstract String createLineBreak();
public void format(ListElement element) {
state.append(getListPrefix());
for (InlineElement item : element.getEntries()) {
state.append(getListItemPrefix());
item.format(this);
state.append(getListItemSuffix());
}
state.append(getListSuffix());
}
public abstract String getListPrefix();
public abstract String getListSuffix();
public abstract String getListItemPrefix();
public abstract String getListItemSuffix();
public abstract Formatter duplicate();
protected abstract String escapeTextCharacters(String value);
}
public class HtmlFormatter extends Formatter {
@Override
public String getLinkPrefix() {
return "<a href=\"";
}
@Override
public String getLinkInfix() {
return "\">";
}
@Override
public String getLinkSuffix() {
return "</a>";
}
@Override
public String createLineBreak() {
return "<br/>";
}
@Override
public String getListPrefix() {
return "<ul>";
}
@Override
public String getListSuffix() {
return "</ul>";
}
@Override
public String getListItemPrefix() {
return "<li>";
}
@Override
public String getListItemSuffix() {
return "</li>";
}
protected String escapeTextCharacters(String value) {
return value
.replaceAll("<", "<")
.replaceAll(">", ">");
}
@Override
public Formatter duplicate() {
return new HtmlFormatter();
}
}
```
---
