net.weweave.commerce.DomainList Maven / Gradle / Ivy

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package net.weweave.commerce;

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

/**
 * A {@link DomainList} object represents a list of domain names.
 * 
 * It can be used to transform a list of domain names into a regular expression
 * string which can be used as a {@code subject} in a {@link LicenseKeyEncoder}
 * object.
 * 

 * On the other hand, it can be constructed from a regular expression,
 * transforming the domain names of the regular expression into user-
 * readable string items.
 * 
 * See the documentation of weweave Commerce for more details at:
 * weweave.net
 *
 * @author weweave GbR
 * @see LicenseKeyEncoder
 */
public class DomainList {
    private static final String DOMAIN_PREFIX = "(.*\\.)?";

    private final List domains;

    /**
     * Constructs a domain list from a regular expression which is formatted
     * in a way that is generated by this class.
     *
     * @param regex the regular expression to be parsed
     */
    public DomainList(String regex) {
        this();
        this.domains.addAll(extractDomains(regex));
    }

    /**
     * Constructs an empty domain list.
     */
    public DomainList() {
        this.domains = new ArrayList<>();
    }

    /**
     * @return the number of domain names
     */
    public int getNumDomains() {
        return domains.size();
    }

    /**
     * @return the actual domain names
     */
    public List getDomains() {
        return new ArrayList<>(this.domains);
    }

    /**
     * Adds a domain name to the list.
     *
     * @param domain the domain name to be added
     * @param assureIncludeDot if true, an {@link IllegalArgumentException}
     *                         will be thrown if no dot is included in the
     *                         domain name (default: true)
     * @param assureSingleDot if true, an {@link IllegalArgumentException}
     *                        will be thrown if there is more than one dot
     *                        in the domain name (default: true)
     */
    public void addDomain(String domain, boolean assureIncludeDot, boolean assureSingleDot) {
        if (GenericValidator.isBlankOrNull(domain)) {
            throw new IllegalArgumentException("Domain must not be null or empty");
        }
        if (assureIncludeDot && !domain.contains(".")) {
            throw new IllegalArgumentException("Domain must consist of top and second level domain");
        }
        if (assureSingleDot && domain.indexOf(".") != domain.lastIndexOf(".")) {
            throw new IllegalArgumentException("There must be exactly one dot (.) in the domain name");
        }
        if (domain.matches(".*[\\*\\[\\]\\{\\}\\(\\)\\?\\+].*")) {
            throw new IllegalArgumentException("Invalid characters in domain name");
        }
        this.domains.add(domain);
    }

    public void addDomain(String domain, boolean assureIncludeDot) {
        this.addDomain(domain, assureIncludeDot, true);
    }

    public void addDomain(String domain) {
        this.addDomain(domain, true, true);
    }

    /**
     * @return a regular expression of domain names which i.e. can be used as
     *         the subject in a {@link LicenseKeyEncoder} object
     */
    public String getRegEx() {
        StringBuilder sb = new StringBuilder();
        sb.append("^(");
        int i = 0;
        for (String domain : this.domains) {
            if (i > 0) {
                sb.append("|");
            }
            sb.append(DOMAIN_PREFIX + domain.replace(".", "\\."));
            i++;
        }
        sb.append(")$");
        return sb.toString();
    }

    private List extractDomains(String regex) {
        List result = new ArrayList<>();
        if (regex.endsWith(")$")) {
            regex = regex.substring(0, regex.length()-2);
            regex = regex.substring(2);
        } else if (regex.endsWith("$")) {
            regex = regex.substring(0, regex.length()-1);
            regex = regex.substring(1);
        }
        String[] tokens = regex.split("\\|");
        for (String token : tokens) {
            if (!GenericValidator.isBlankOrNull(token)) {
                if (token.startsWith(DOMAIN_PREFIX)) {
                    token = token.substring(DOMAIN_PREFIX.length());
                }
                String domain = "*."+token.replace("\\.", ".");
                result.add(domain);
            }
        }
        return result;
    }

    /**
     * Extracts the top level domain (TLD) from a domain name.
     *
     * @param domain the domain name
     * @return the top level domain (TLD)
     */
    public static String getTldFromDomain(String domain) {
        int start = domain.indexOf(".");
        if (start == -1) {
            return "";
        }
        String tld = domain.substring(start+1);
        return tld;
    }
}