ServerParseShow.java

/*
 * Copyright 1999-2012 Alibaba Group.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.cobar.server.parser;

import com.alibaba.cobar.parser.util.ParseUtil;

/**
 * @author xianmao.hexm 2011-5-7 下午01:23:06
 */
public final class ServerParseShow {

    public static final int OTHER = -1;
    public static final int DATABASES = 1;
    public static final int DATASOURCES = 2;
    public static final int COBAR_STATUS = 3;
    public static final int COBAR_CLUSTER = 4;

    public static int parse(String stmt, int offset) {
        int i = offset;
        for (; i < stmt.length(); i++) {
            switch (stmt.charAt(i)) {
            case ' ':
                continue;
            case '/':
            case '#':
                i = ParseUtil.comment(stmt, i);
                continue;
            case 'C':
            case 'c':
                return cobarCheck(stmt, i);
            case 'D':
            case 'd':
                return dataCheck(stmt, i);
            default:
                return OTHER;
            }
        }
        return OTHER;
    }

    // SHOW COBAR_
    static int cobarCheck(String stmt, int offset) {
        if (stmt.length() > offset + "obar_?".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            if ((c1 == 'O' || c1 == 'o') && (c2 == 'B' || c2 == 'b') && (c3 == 'A' || c3 == 'a')
                    && (c4 == 'R' || c4 == 'r') && (c5 == '_')) {
                switch (stmt.charAt(++offset)) {
                case 'S':
                case 's':
                    return showCobarStatus(stmt, offset);
                case 'C':
                case 'c':
                    return showCobarCluster(stmt, offset);
                default:
                    return OTHER;
                }
            }
        }
        return OTHER;
    }

    // SHOW COBAR_STATUS
    static int showCobarStatus(String stmt, int offset) {
        if (stmt.length() > offset + "tatus".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            if ((c1 == 't' || c1 == 'T') && (c2 == 'a' || c2 == 'A') && (c3 == 't' || c3 == 'T')
                    && (c4 == 'u' || c4 == 'U') && (c5 == 's' || c5 == 'S')
                    && (stmt.length() == ++offset || ParseUtil.isEOF(stmt.charAt(offset)))) {
                return COBAR_STATUS;
            }
        }
        return OTHER;
    }

    // SHOW COBAR_CLUSTER
    static int showCobarCluster(String stmt, int offset) {
        if (stmt.length() > offset + "luster".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            char c6 = stmt.charAt(++offset);
            if ((c1 == 'L' || c1 == 'l') && (c2 == 'U' || c2 == 'u') && (c3 == 'S' || c3 == 's')
                    && (c4 == 'T' || c4 == 't') && (c5 == 'E' || c5 == 'e') && (c6 == 'R' || c6 == 'r')
                    && (stmt.length() == ++offset || ParseUtil.isEOF(stmt.charAt(offset)))) {
                return COBAR_CLUSTER;
            }
        }
        return OTHER;
    }

    // SHOW DATA
    static int dataCheck(String stmt, int offset) {
        if (stmt.length() > offset + "ata?".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            if ((c1 == 'A' || c1 == 'a') && (c2 == 'T' || c2 == 't') && (c3 == 'A' || c3 == 'a')) {
                switch (stmt.charAt(++offset)) {
                case 'B':
                case 'b':
                    return showDatabases(stmt, offset);
                case 'S':
                case 's':
                    return showDataSources(stmt, offset);
                default:
                    return OTHER;
                }
            }
        }
        return OTHER;
    }

    // SHOW DATABASES
    static int showDatabases(String stmt, int offset) {
        if (stmt.length() > offset + "ases".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            if ((c1 == 'A' || c1 == 'a') && (c2 == 'S' || c2 == 's') && (c3 == 'E' || c3 == 'e')
                    && (c4 == 'S' || c4 == 's') && (stmt.length() == ++offset || ParseUtil.isEOF(stmt.charAt(offset)))) {
                return DATABASES;
            }
        }
        return OTHER;
    }

    // SHOW DATASOURCES
    static int showDataSources(String stmt, int offset) {
        if (stmt.length() > offset + "ources".length()) {
            char c1 = stmt.charAt(++offset);
            char c2 = stmt.charAt(++offset);
            char c3 = stmt.charAt(++offset);
            char c4 = stmt.charAt(++offset);
            char c5 = stmt.charAt(++offset);
            char c6 = stmt.charAt(++offset);
            if ((c1 == 'O' || c1 == 'o') && (c2 == 'U' || c2 == 'u') && (c3 == 'R' || c3 == 'r')
                    && (c4 == 'C' || c4 == 'c') && (c5 == 'E' || c5 == 'e') && (c6 == 'S' || c6 == 's')
                    && (stmt.length() == ++offset || ParseUtil.isEOF(stmt.charAt(offset)))) {
                return DATASOURCES;
            }
        }
        return OTHER;
    }

}