com.github.antelopeframework.mybatis.criterion.CriteriaQueryTranslator Maven / Gradle / Ivy

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package com.github.antelopeframework.mybatis.criterion;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.session.SqlSession;

import lombok.Getter;
import lombok.extern.slf4j.Slf4j;

/**
 * 
 * @author yangzhi.yzh
 *
 */
@Slf4j
@Getter
public class CriteriaQueryTranslator implements CriteriaQuery {
	private final Criteria rootCriteria;
	private final SqlSession sqlSession;
	
	private final String queryCondition;
	private final TypedValue[] queryParams;
	
	public CriteriaQueryTranslator(SqlSession sqlSession, Criteria rootCriteria) {
		this.sqlSession = sqlSession;
		this.rootCriteria = rootCriteria;

		this.queryCondition = buildQueryCondition();
		this.queryParams = getQueryParameters();
	}
	
	private String buildQueryCondition() {
		String whereCondition = getWhereCondition();
		String orderBy = getOrderBy();
		
		StringBuilder sqlBuffer = new StringBuilder();
		if (StringUtils.isNotBlank(whereCondition)) {
			sqlBuffer.append(" where ").append(whereCondition);
		}
		
		if (StringUtils.isNotBlank(orderBy)) {
			sqlBuffer.append(" order by ").append(orderBy);
		}
		
		if (rootCriteria.getMaxResults() != 0) {
			sqlBuffer.append(" limit " + rootCriteria.getMaxResults());
		}
		
		if (rootCriteria.getFirstResult() != 0) {
			sqlBuffer.append(" offset " + rootCriteria.getFirstResult());
		}
		
		return sqlBuffer.toString();
	}
	
	private String getWhereCondition() {
		StringBuilder condition = new StringBuilder(30);
		Iterator criterionIterator = rootCriteria.iterateExpressionEntries();
		while (criterionIterator.hasNext()) {
			Criteria.CriterionEntry entry = criterionIterator.next();
			String sqlString = entry.getCriterion().toSqlString(this);
			condition.append(sqlString);
			if (criterionIterator.hasNext()) {
				condition.append(" and ");
			}
		}

		return condition.toString();
	}
	
	private String getOrderBy() {
		StringBuilder orderBy = new StringBuilder(30);
		Iterator criterionIterator = rootCriteria.iterateOrderings();
		while (criterionIterator.hasNext()) {
			Criteria.OrderEntry oe = criterionIterator.next();
			orderBy.append(oe.getOrder().toSqlString(this));
			if (criterionIterator.hasNext()) {
				orderBy.append(", ");
			}
		}
		
		return orderBy.toString();
	}
	
	private TypedValue[] getQueryParameters() {
		final List values = new ArrayList<>();
		final Iterator iter = rootCriteria.iterateExpressionEntries();
		while (iter.hasNext()) {
			final Criteria.CriterionEntry ce = iter.next();
			final TypedValue[] tv = ce.getCriterion().getTypedValues(this);
			for (TypedValue aTv : tv) {
				values.add(aTv);
			}
		}
		
		return values.toArray(new TypedValue[0]);
	}
}