hydra1983/wildcard_matcher.java

## wildcard_matcher.java
public class Main {
	public static void main(String[] args) {
		test("<html*", "<html></html>");
		test("12*?", "12345");
		test("12*4?", "12345");
	}

	private static void test(String pattern, String input) {
		Pattern p = Pattern.compile(pattern);
		System.out.println(pattern + " : " + input + " matches? "
				+ p.match(input));
	}
}


public final class Pattern {
	private static final char ESCAPES[] = { '$', '^', '[', ']', '(', ')', '{',
			'|', '+', '\\', '.', '<', '>' };

	public static Pattern compile(String pattern) {
		return new Pattern(pattern);
	}

	private Pattern(String pattern) {
		regexp = wildcardToRegexp(pattern);
	}

	private String regexp;

	public boolean match(String input) {
		if (input == null) {
			return false;
		}
		return input.matches(this.regexp);
	}

	private String wildcardToRegexp(String pattern) {
		String result = "^";

		for (int i = 0; i < pattern.length(); i++) {
			char ch = pattern.charAt(i);
			boolean isEscaped = false;
			for (int j = 0; j < ESCAPES.length; j++) {
				if (ch == ESCAPES[j]) {
					result += "\\" + ch;
					isEscaped = true;
					break;
				}
			}

			if (!isEscaped) {
				if (ch == '*') {
					result += ".*";
				} else if (ch == '?') {
					result += ".";
				} else {
					result += ch;
				}
			}
		}
		result += "$";
		return result;
	}
}
	public class Main {
	public static void main(String[] args) {
	test("<html*", "<html></html>");
	test("12*?", "12345");
	test("12*4?", "12345");
	}

	private static void test(String pattern, String input) {
	Pattern p = Pattern.compile(pattern);
	System.out.println(pattern + " : " + input + " matches? "
	+ p.match(input));
	}
	}


	public final class Pattern {
	private static final char ESCAPES[] = { '$', '^', '[', ']', '(', ')', '{',
	'\|', '+', '\\', '.', '<', '>' };

	public static Pattern compile(String pattern) {
	return new Pattern(pattern);
	}

	private Pattern(String pattern) {
	regexp = wildcardToRegexp(pattern);
	}

	private String regexp;

	public boolean match(String input) {
	if (input == null) {
	return false;
	}
	return input.matches(this.regexp);
	}

	private String wildcardToRegexp(String pattern) {
	String result = "^";

	for (int i = 0; i < pattern.length(); i++) {
	char ch = pattern.charAt(i);
	boolean isEscaped = false;
	for (int j = 0; j < ESCAPES.length; j++) {
	if (ch == ESCAPES[j]) {
	result += "\\" + ch;
	isEscaped = true;
	break;
	}
	}

	if (!isEscaped) {
	if (ch == '*') {
	result += ".*";
	} else if (ch == '?') {
	result += ".";
	} else {
	result += ch;
	}
	}
	}
	result += "$";
	return result;
	}
	}