What is the difference between SAX and DOM I will provide general Q A oriented answer for this question Answer to Questions. Dragon Ball Z Mugen For Mac more. Why do we need XML parserIn computing, the Java API for XML Processing, or JAXP d k s p i JAKSpee, one of the Java XML Application programming interfaces APIs, provides the. Apache Ant is a software tool for automating software build processes, which originated from the Apache Tomcat project in early 2000. It was a replacement for the. Pollinator Education Resources. Xerces Society Schools Site. Sample of statebased program. Jakarta_jmeter_screenshot.png' alt='Xerces Sample Programs' title='Xerces Sample Programs' />We need XML parser because we do not want to do everything in our application from scratch, and we need some helper programs or libraries to do something very low level but very necessary to us. These low level but necessary things include checking the well formedness, validating the document against its DTD or schema just for validating parsers, resolving character reference, understanding CDATA sections, and so on. XML parsers are just such helper programs and they will do all these jobs. With XML parser, we are shielded from a lot of these complexities and we could concentrate ourselves on just programming at high level through the APIs implemented by the parsers, and thus gain programming efficiency. Which one is better, SAX or DOM Both SAX and DOM parser have their advantages and disadvantages. Which one is better should depend on the characteristics of your application please refer to some questions below. Which parser can get better speed, DOM or SAX parsers SAX parser can get better speed. Whats the difference between tree based API and event based API A tree based API is centered around a tree structure and therefore provides interfaces on components of a tree which is a DOM document such as Document interface,Node interface, Node. List interface, Element interface, Attr interface and so on. By contrast, however, an event based API provides interfaces on handlers. There are four handler interfaces, Content. Xerces Sample Programs' title='Xerces Sample Programs' />Handler interface, DTDHandler interface, Entity. Resolver interface and Error. Handler interface. What is the difference between a DOM Parser and a SAX Parser DOM parsers and SAX parsers work in different ways A DOM parser creates a tree structure in memory from the input. But a SAX parser. Instead, it takes the. ADOM parser always serves the client application with the entire. But a. SAX parser serves the client application always only with pieces of. With DOM parser, method calls in. But. with SAX, some certain methods usually overriden by the cient will. These methods do not have. How do we decide on which parser is good Ideally a good parser should be fast time efficient,space efficient, rich in functionality and easy to use. But in reality, none of the main parsers have all these features at the same time. For example, a DOM Parser is rich in functionality because it creates a DOM tree in memory and allows you to access any part of the document repeatedly and allows you to modify the DOM tree, but it is space inefficient when the document is huge, and it takes a little bit long to learn how to work with it. A SAX Parser, however, is much more space efficient in case of big input document because it creates no internal structure. Whats more, it runs faster and is easier to learn than DOM Parser because its API is really simple. But from the functionality point of view, it provides less functions which mean that the users themselves have to take care of more, such as creating their own data structures. By the way, what is a good parser I think the answer really depends on the characteristics of your application. What are some real world applications where using SAX parser is. DOM parser and vice versa What are the usual. DOM parser and for a SAX parser In the following cases, using SAX parser is advantageous than using DOM parser. The input document is too big for available memory actually in this case SAX is your only choiceYou can process the document in small contiguous chunks of input. You do not need the entire document before you can do useful work. You just want to use the parser to extract the information of interest, and all your computation will be completely based on the data structures created by yourself. Actually in most of our applications, we create data structures of our own which are usually not as complicated as the DOM tree. From this sense, I think, the chance of using a DOM parser is less than that of using a SAX parser. In the following cases, using DOM parser is advantageous than using SAX parser. Your application needs to access widely separately parts of the document at the same time. Your application may probably use a internal data structure which is almost as complicated as the document itself. Your application has to modify the document repeatedly. Your application has to store the document for a significant amount of time through many method calls. Example Use a DOM parser or a SAX parser Assume that an instructor has an XML document containing all the personal information of the students as well as the points his students made in his class, and he is now assigning final grades for the students using an application. What he wants to produce, is a list with the SSN and the grades. Also we assume that in his application, the instructor use no data structure such as arrays to store the student personal information and the points. If the instructor decides to give As to those who earned the class average or above, and give Bs to the others, then hed better to use a DOM parser in his application. The reason is that he has no way to know how much is the class average before the entire document gets processed. What he probably need to do in his application, is first to look through all the students points and compute the average, and then look through the document again and assign the final grade to each student by comparing the points he earned to the class average. If, however, the instructor adopts such a grading policy that the students who got 9. As and the others are assigned Bs, then probably hed better use a SAX parser. The reason is, to assign each student a final grade, he do not need to wait for the entire document to be processed. He could immediately assign a grade to a student once the SAX parser reads the grade of this student. In the above analysis, we assumed that the instructor created no data structure of his own. What if he creates his own data structure, such as an array of strings to store the SSN and an array of integers to sto re the points In this case, I think SAX is a better choice, before this could save both memory and time as well, yet get the job done. Well, one more consideration on this example. What if what the instructor wants to do is not to print a list, but to save the original document back with the grade of each student updated In this case, a DOM parser should be a better choice no matter what grading policy he is adopting. He does not need to create any data structure of his own. What he needs to do is to first modify the DOM tree i. If he choose to use a SAX parser instead of a DOM parser, then in this case he has to create a data structure which is almost as complicated as a DOM tree before he could get the job done. Problem statement Write a Java program to extract all the. XML document. We assume that each circle element has three child elementsi. A sample document is given. DOCTYPE shapes. ELEMENT shapes circle. ELEMENT circle x,y,radius. ELEMENT x PCDATA. ELEMENT y PCDATA. ELEMENT radius PCDATA. ATTLIST circle color CDATA IMPLIED. BLUE. lt x 2. RED. Program with DOMparserimport java. DOMParser. public class shapesDOM. Of. Circles 0 total number of circles seen. X coordinates of the centers. Y coordinates of the centers. String color new String1.