Tab.java

package ch.akuhn.util;

/**
 * Indents lines while printing them.
 * 
 * @author Adrian Kuhn, 2008/07/21
 * @author Thanks to Yossi Gil for suggesting better class and method names.
 */

public class Tab {

    private String s;
    private final String tab;

    public Tab() {
        this("\t");
    }

    public Tab(String tab) {
        this.tab = tab;
        this.s = "";
    }

    public String begin() {
        try {
            return toString();
        } finally {
            this.more();
        }
    }

    public String end() {
        return this.less().toString();
    }

    public boolean isEmpty() {
        return s.length() == 0;
    }

    public Tab less() {
        if (isEmpty()) throw new IllegalStateException();
        s = s.substring(0, s.length() - tab.length());
        return this;
    }

    public Tab more() {
        s += tab;
        return this;
    }

    public String toString() {
        return s;
    }

}