/*
 * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.management;



/**
 * This class is used by the query-building mechanism to represent binary
 * relations.
 * @serial include
 *
 * @since 1.5
 */
class MatchQueryExp extends QueryEval implements QueryExp {

    /* Serial version */
    private static final long serialVersionUID = -7156603696948215014L;

    /**
     * @serial The attribute value to be matched
     */
    private AttributeValueExp exp;

    /**
     * @serial The pattern to be matched
     */
    private String pattern;


    /**
     * Basic Constructor.
     */
    public MatchQueryExp() {
    }

    /**
     * Creates a new MatchQueryExp where the specified AttributeValueExp matches
     * the specified pattern StringValueExp.
     */
    public MatchQueryExp(AttributeValueExp a, StringValueExp s) {
        exp     = a;
        pattern = s.getValue();
    }


    /**
     * Returns the attribute of the query.
     */
    public AttributeValueExp getAttribute()  {
        return exp;
    }

    /**
     * Returns the pattern of the query.
     */
    public String getPattern()  {
        return pattern;
    }

    /**
     * Applies the MatchQueryExp on a MBean.
     *
     * @param name The name of the MBean on which the MatchQueryExp will be applied.
     *
     * @return  True if the query was successfully applied to the MBean, false otherwise.
     *
     * @exception BadStringOperationException
     * @exception BadBinaryOpValueExpException
     * @exception BadAttributeValueExpException
     * @exception InvalidApplicationException
     */
    public boolean apply(ObjectName name) throws
        BadStringOperationException,
        BadBinaryOpValueExpException,
        BadAttributeValueExpException,
        InvalidApplicationException {

        ValueExp val = exp.apply(name);
        if (!(val instanceof StringValueExp)) {
            return false;
        }
        return wildmatch(((StringValueExp)val).getValue(), pattern);
    }

    /**
     * Returns the string representing the object
     */
    public String toString()  {
        return exp + " like " + new StringValueExp(pattern);
    }

    /*
     * Tests whether string s is matched by pattern p.
     * Supports "?", "*", "[", each of which may be escaped with "\";
     * character classes may use "!" for negation and "-" for range.
     * Not yet supported: internationalization; "\" inside brackets.<P>
     * Wildcard matching routine by Karl Heuer.  Public Domain.<P>
     */
    private static boolean wildmatch(String s, String p) {
        char c;
        int si = 0, pi = 0;
        int slen = s.length();
        int plen = p.length();

        while (pi < plen) { // While still string
            c = p.charAt(pi++);
            if (c == '?') {
                if (++si > slen)
                    return false;
            } else if (c == '[') { // Start of choice
                if (si >= slen)
                    return false;
                boolean wantit = true;
                boolean seenit = false;
                if (p.charAt(pi) == '!') {
                    wantit = false;
                    ++pi;
                }
                while ((c = p.charAt(pi)) != ']' && ++pi < plen) {
                    if (p.charAt(pi) == '-' &&
                        pi+1 < plen &&
                        p.charAt(pi+1) != ']') {
                        if (s.charAt(si) >= p.charAt(pi-1) &&
                            s.charAt(si) <= p.charAt(pi+1)) {
                            seenit = true;
                        }
                        ++pi;
                    } else {
                        if (c == s.charAt(si)) {
                            seenit = true;
                        }
                    }
                }
                if ((pi >= plen) || (wantit != seenit)) {
                    return false;
                }
                ++pi;
                ++si;
            } else if (c == '*') { // Wildcard
                if (pi >= plen)
                    return true;
                do {
                    if (wildmatch(s.substring(si), p.substring(pi)))
                        return true;
                } while (++si < slen);
                return false;
            } else if (c == '\\') {
                if (pi >= plen || si >= slen ||
                    p.charAt(pi++) != s.charAt(si++))
                    return false;
            } else {
                if (si >= slen || c != s.charAt(si++)) {
                    return false;
                }
            }
        }
        return (si == slen);
    }
 }