xml writer api

XMLStringBuilder.java

class Main {
    public static class XMLStringBuilder {
        public static final String OPEN_BRACE = "<";
        public static final String CLOSE_BRACE = ">";

        public static final String CLOSE_SUFFIX = " />";

        public static final String OPEN_CLOSE_TAG = "</";

        public static final String ATTR_PREFIX = "=\"";
        public static final String ATTR_SUFFIX = "\"";


        protected StringBuilder stringBuilder = new StringBuilder();

        protected boolean openingTag = false;

        public XMLStringBuilder open(String tag, String... attributes) {
            if (openingTag) {
                throw new IllegalArgumentException("Tag have been already opened");
            }

            openingTag = true;

            stringBuilder
                .append(OPEN_BRACE)
                .append(tag);

            attributes(attributes);

            return this;
        }

        public XMLStringBuilder tag(String tag, String body, String...attributes) {
            open(tag, attributes);
            body(body);
            close(tag);

            return this;
        }

        public XMLStringBuilder body(String body) {
            if (openingTag) {
                stringBuilder.append(CLOSE_BRACE);

                openingTag = false;
            }

            stringBuilder.append(body);

            return this;
        }

        public XMLStringBuilder close(String tag) {
            if (openingTag) {
                stringBuilder.append(CLOSE_SUFFIX);

                openingTag = false;
            } else {
                stringBuilder.append(OPEN_CLOSE_TAG).append(tag).append(CLOSE_BRACE);
            }

            return this;
        }

        public XMLStringBuilder attributes(String... attributes) {
            if (!openingTag) {
                throw new IllegalArgumentException("Tag not open");
            }

            if (attributes!=null && attributes.length>0) {
                for (int i = 0; i < attributes.length; i++) {
                    if (i % 2 == 0) {
                        stringBuilder
                            .append(" ")
                            .append(attributes[i]);
                    } else {
                        stringBuilder
                            .append(ATTR_PREFIX)
                            .append(attributes[i])
                            .append(ATTR_SUFFIX);
                    }
                }
            }

            return this;
        }

        @Override
        public String toString() {
            return stringBuilder.toString();
        }
    }

    public static void main(String... args) {
        final XMLStringBuilder sb = new XMLStringBuilder();

        sb.open("a","href", "http://yandex.ru");

        sb.body("Click me");

        sb.close("a");

        System.out.println(sb.toString());

        final XMLStringBuilder sb2 = new XMLStringBuilder();

        sb2.open("a","href", "http://yandex.ru");
        sb2.close("a");

        System.out.println(sb2.toString());

        final XMLStringBuilder sb3 = new XMLStringBuilder();

        sb3.tag("a","Click me","href", "http://yandex.ru");

        System.out.println(sb3.toString());

        final XMLStringBuilder sb4 = new XMLStringBuilder();

        sb4.close("div");

        sb4.close("a");

        System.out.println(sb4.toString());
    }
}

xmlwriter.md

final XMLStringBuilder wr = new XMLStringBuilder();

wr.opening("tag", "attr1", "attrvalue1");

wr.body("Tag body");

wr.close("tag");

wr.toString();

<tag attr1="attrvalue1">Tag body</tag>

wr.opening("tag", "attr1", "attrvalue1");
wr.close("tag");

wr.toString();

<tag attr1="attrvalue1" />

wr.tag("tag","Body","attr1","attrvalue1");

wr.toString();

<tag attr1="attrvalue1">Body</tag>