flink-core/src/main/java/org/apache/flink/configuration/description/Description.java

/*
 * 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;

import java.util.ArrayList;
import java.util.List;

/**
 * Description for {@link org.apache.flink.configuration.ConfigOption}. Allows providing multiple rich formats.
 */
public class Description {

	private final List<BlockElement> blocks;

	public static DescriptionBuilder builder() {
		return new DescriptionBuilder();
	}

	public List<BlockElement> getBlocks() {
		return blocks;
	}

	/**
	 * Builder for {@link Description}. Allows adding a rich formatting like lists, links, linebreaks etc.
	 * For example:
	 * <pre>{@code
	 * Description description = Description.builder()
	 * 	.text("This is some list: ")
	 * 	.list(
	 * 		text("this is first element of list"),
	 * 		text("this is second element of list with a %s", link("https://link")))
	 * 	.build();
	 * }</pre>
	 */
	public static class DescriptionBuilder {

		private final List<BlockElement> blocks = new ArrayList<>();

		/**
		 * Adds a block of text with placeholders ("%s") that will be replaced with proper string representation of
		 * given {@link InlineElement}. For example:
		 *
		 * <p>{@code text("This is a text with a link %s", link("https://somepage", "to here"))}
		 *
		 * @param format   text with placeholders for elements
		 * @param elements elements to be put in the text
		 * @return description with added block of text
		 */
		public DescriptionBuilder text(String format, InlineElement... elements) {
			blocks.add(TextElement.text(format, elements));
			return this;
		}

		/**
		 * Creates a simple block of text.
		 *
		 * @param text a simple block of text
		 * @return block of text
		 */
		public DescriptionBuilder text(String text) {
			blocks.add(TextElement.text(text));
			return this;
		}

		/**
		 * Block of description add.
		 *
		 * @param block block of description to add
		 * @return block of description
		 */
		public DescriptionBuilder add(BlockElement block) {
			blocks.add(block);
			return this;
		}

		/**
		 * Creates a line break in the description.
		 */
		public DescriptionBuilder linebreak() {
			blocks.add(LineBreakElement.linebreak());
			return this;
		}

		/**
		 * Adds a bulleted list to the description.
		 */
		public DescriptionBuilder list(InlineElement... elements) {
			blocks.add(ListElement.list(elements));
			return this;
		}

		/**
		 * Creates description representation.
		 */
		public Description build() {
			return new Description(blocks);
		}

	}

	private Description(List<BlockElement> blocks) {
		this.blocks = blocks;
	}
}