ShowTables.java

package io.mycat.server.response;

import com.google.common.base.Strings;
import io.mycat.MycatServer;
import io.mycat.net.BufferArray;
import io.mycat.net.NetSystem;
import io.mycat.server.ErrorCode;
import io.mycat.server.Fields;
import io.mycat.server.MySQLFrontConnection;
import io.mycat.server.config.node.MycatConfig;
import io.mycat.server.config.node.SchemaConfig;
import io.mycat.server.config.node.UserConfig;
import io.mycat.server.packet.EOFPacket;
import io.mycat.server.packet.FieldPacket;
import io.mycat.server.packet.ResultSetHeaderPacket;
import io.mycat.server.packet.RowDataPacket;
import io.mycat.server.packet.util.PacketUtil;
import io.mycat.server.parser.ServerParse;
import io.mycat.util.StringUtil;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * show tables impl
 * 
 * @author yanglixue
 * 
 */
public class ShowTables {

	private static final int FIELD_COUNT = 1;
	private static final ResultSetHeaderPacket header = PacketUtil
			.getHeader(FIELD_COUNT);
	private static final FieldPacket[] fields = new FieldPacket[FIELD_COUNT];
	private static final EOFPacket eof = new EOFPacket();

	private static final String SCHEMA_KEY = "schemaName";
	private static final Pattern pattern = Pattern
			.compile(
					"^\\s*(SHOW)\\s+(TABLES)(\\s+(FROM)\\s+([a-zA-Z_0-9]+))?(\\s+(LIKE\\s+'(.*)'))?\\s*",
					Pattern.CASE_INSENSITIVE);

	/**
	 * response method.
	 * 
	 * @param c
	 */
	public static void response(MySQLFrontConnection c, String stmt, int type) {
		SchemaConfig schema = MycatServer.getInstance().getConfig()
				.getSchemas().get(c.getSchema());
		if (schema != null) {
            //不分库的schema，show tables从后端 mysql中查
            String node = schema.getDataNode();
            if(!Strings.isNullOrEmpty(node)) {
                c.execute(stmt, ServerParse.SHOW);
                return;
            }
		} else {
			c.writeErrMessage(ErrorCode.ER_NO_DB_ERROR, "No database selected");
		}

		// 分库的schema，直接从SchemaConfig中获取所有表名
		Map<String, String> parm = buildFields(c, stmt);
		BufferArray bufferArray = NetSystem.getInstance().getBufferPool()
				.allocateArray();



        int i = 0;
        byte packetId = 0;
        header.packetId = ++packetId;
        fields[i] = PacketUtil.getField("Tables in " + parm.get(SCHEMA_KEY),
                Fields.FIELD_TYPE_VAR_STRING);
        fields[i++].packetId = ++packetId;
        eof.packetId = ++packetId;
		// write header
		header.write(bufferArray);

		// write fields
		for (FieldPacket field : fields) {
			field.write(bufferArray);
		}

		// write eof
		eof.write(bufferArray);

		// write rows
		 packetId = eof.packetId;

        TreeSet<String> tableSet = getTables(c, parm);
        for (String name : tableSet) {
            RowDataPacket row = new RowDataPacket(FIELD_COUNT);
            row.add(StringUtil.encode(name.toLowerCase(), c.getCharset()));
            row.packetId = ++packetId;
            row.write(bufferArray);
        }
		// write last eof
		EOFPacket lastEof = new EOFPacket();
		lastEof.packetId = ++packetId;
		lastEof.write(bufferArray);

		// post write
		c.write(bufferArray);

	}
    public static Set<String> getTableSet(MySQLFrontConnection c, String stmt)
    {
        Map<String,String> parm = buildFields(c,stmt);
        return getTables(c, parm);

    }

    private static TreeSet<String> getTables(MySQLFrontConnection c, Map<String, String> parm)
    {
        TreeSet<String> tableSet = new TreeSet<String>();

        MycatConfig conf = MycatServer.getInstance().getConfig();

        Map<String, UserConfig> users = conf.getUsers();
        UserConfig user = users == null ? null : users.get(c.getUser());
        if (user != null) {


            Map<String, SchemaConfig> schemas = conf.getSchemas();
            for (String name : schemas.keySet()) {
                if (null != parm.get(SCHEMA_KEY)
                        && parm.get(SCHEMA_KEY).toUpperCase()
                                .equals(name.toUpperCase())) {

                    if (null == parm.get("LIKE_KEY")) {
                        tableSet.addAll(schemas.get(name).getTables().keySet());
                    } else {
                        String p = "^"
                                + parm.get("LIKE_KEY").replaceAll("%", ".*");
                        Pattern pattern = Pattern.compile(p,
                                Pattern.CASE_INSENSITIVE);
                        Matcher ma;

                        for (String tname : schemas.get(name).getTables()
                                .keySet()) {
                            ma = pattern.matcher(tname);
                            if (ma.matches()) {
                                tableSet.add(tname);
                            }
                        }

                    }

                }
            }



        }
        return tableSet;
    }

    /**
	 * build fields
	 * 
	 * @param c
	 * @param stmt
	 */
	private static Map<String, String> buildFields(MySQLFrontConnection c,
			String stmt) {

		Map<String, String> map = new HashMap<String, String>();

		Matcher ma = pattern.matcher(stmt);

		if (ma.find()) {
			String schemaName = ma.group(5);
			if (null != schemaName && (!"".equals(schemaName))
					&& (!"null".equals(schemaName))) {
				map.put(SCHEMA_KEY, schemaName);
			}

			String like = ma.group(8);
			if (null != like && (!"".equals(like)) && (!"null".equals(like))) {
				map.put("LIKE_KEY", like);
			}
		}

		if (null == map.get(SCHEMA_KEY)) {
			map.put(SCHEMA_KEY, c.getSchema());
		}



		return map;

	}

}