1. A method for searching a plurality of objects of a document, the method comprising: generating a query expression for searching the document, the query expression comprising one or more attributes related to attributes of a target object of the document; parsing attributes of the query expression into one or more attribute groups based on logical operators between the attributes, each attribute group comprising at least one attribute; weighting each one or more attribute group based on an order priority of the attributes; and searching for the target object in the document based on the weighted one or more attribute groups.