public String toString() {
        StringBuilder builder = new StringBuilder();
        builder.append(type).append(" ").append(target);
        if (condition != null) {
            builder.append(" on ").append(condition);
        }
        return builder.toString();
    }
Create a new JoinExpression instance

@param type type of join
@param target target of join
@param condition join condition or null, if none is used
@param flags join flags
querydsl-core/src/main/java/com/querydsl/core/JoinExpression.java