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package cn.enilu.flash.core.db;

import cn.enilu.flash.core.lang.Strings;
import com.google.common.base.Joiner;

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

public class GenericSQLBuilder implements ISQLBuilder {
	protected String table;
    protected String tag;

	protected List columns = new ArrayList();
	protected List joins = new ArrayList();
	protected List conditions = new ArrayList();
	protected List groupBys = new ArrayList();
	protected List havings = new ArrayList();
	protected List orderBys = new ArrayList();

	protected boolean lockForUpdate;

	protected Integer offset;
	protected Integer rowCount;

	protected List parameters = new ArrayList();

	@Override
	public ISQLBuilder clone() {
		try {
			GenericSQLBuilder clone = (GenericSQLBuilder) super.clone();

			clone.columns = new ArrayList(columns);
			clone.joins = new ArrayList(joins);
			clone.conditions = new ArrayList(conditions);
			clone.groupBys = new ArrayList(groupBys);
			clone.havings = new ArrayList(havings);
			clone.orderBys = new ArrayList(orderBys);
			clone.parameters = new ArrayList(parameters);
			clone.lockForUpdate = lockForUpdate;

			return clone;
		} catch (CloneNotSupportedException e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public void setTable(String table) {
		this.table = table;
	}

	@Override
	public Object[] getParameters() {
		return parameters.toArray();
	}

	@Override
	public String toCountSQL() {
		if (groupBys.isEmpty()) {
			StringBuilder sql = new StringBuilder("select ");
            fillTag(sql);
            sql.append(" count(*) from ");
			sql.append(table).append(toJoinSQL());
			if (!conditions.isEmpty()) {
				sql.append(" where ");
				for (int i = 0; i < conditions.size(); i++) {
					if (i > 0) {
						sql.append(" and ");
					}
					sql.append(conditions.get(i));
				}
			}

			return sql.toString();
		} else {
			return "select count(*) from (" + toSQL0(true, false, false)
					+ ") a";
		}
	}

	@Override
	public String toSQL() {
		return toSQL0(true, true, true);
	}

	protected String toSQL0(boolean withGroup, boolean withOrderBy,
			boolean withLimit) {
		StringBuilder sql = new StringBuilder("select ");
        fillTag(sql);
        sql.append(toSelectColumns()).append(" from ").append(table)
				.append(toJoinSQL());
		if (!conditions.isEmpty()) {
			sql.append(" where ");
			for (int i = 0; i < conditions.size(); i++) {
				if (i > 0) {
					sql.append(" and ");
				}
				sql.append(conditions.get(i));
			}
		}

		if (withGroup) {
			sql.append(toGroupBySQL()).append(toHavingSQL());
		}
		if (withOrderBy) {
			sql.append(toOrderBySQL());
		}
		if (withLimit) {
			sql.append(toLimitSQL());
		}

		if (lockForUpdate) {
			sql.append(" for update");
		}

		return sql.toString();
	}

    private void fillTag(StringBuilder sql) {
        if (!Strings.isBlank(tag)) {
            sql.append("/* tag: ").append(tag).append(" */ ");
        }
    }

    protected String toSelectColumns() {
		if (columns.isEmpty()) {
			return "*";
		}
		return Joiner.on(", ").join(columns);
	}

	protected String toJoinSQL() {
		if (joins.isEmpty()) {
			return "";
		}
		return "\n" + Joiner.on("\n").join(joins);
	}

	protected String toGroupBySQL() {
		if (groupBys.isEmpty()) {
			return "";
		}

		return " group by " + Joiner.on(", ").join(groupBys);
	}

	protected String toHavingSQL() {
		if (havings.isEmpty()) {
			return "";
		}
		return " having " + Joiner.on(" and ").join(havings);
	}

	protected String toOrderBySQL() {
		if (orderBys.isEmpty()) {
			return "";
		}

		return " order by " + Joiner.on(", ").join(orderBys);
	}

	protected String toLimitSQL() {
		if (offset == null) {
			return "";
		}
		return " limit " + offset + ", " + rowCount;
	}

	@Override
	public String escapeColumn(String column) {
		return column;
	}

    @Override
    public void tag(String tag) {
        this.tag = tag;
    }

	@Override
	public void where(String condition, Object... params) {
		conditions.add(condition);

		for (Object param : params) {
			parameters.add(param);
		}
	}

	@Override
	public void select(String... columns) {
		this.columns.addAll(Arrays.asList(columns));
	}

	@Override
	public void clearSelect() {
		this.columns.clear();
	}

	@Override
	public void join(String joinSql) {
		joins.add(joinSql);
	}

	@Override
	public void groupBy(String groupBy) {
		groupBys.add(groupBy);
	}

	@Override
	public void having(String having) {
		havings.add(having);
	}

	@Override
	public void orderBy(String orderBy) {
		orderBys.add(orderBy);
	}

	@Override
	public void limit(Integer offset, Integer rowCount) {
		this.offset = offset;
		this.rowCount = rowCount;
	}

	@Override
	public boolean hasLimit() {
		return offset != null;
	}

	public void lock() {
		lockForUpdate = true;
	}

	@Override
	public String getLastInsertIdSQL() {
		return null;
	}

} 















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