Department of Civil and Environmental Engineering, Spring Semester, ENCE 688R: Final Exam: 2 Hours, Open Book and Open Notes

Transcription

1 Department of Civil and Environmental Engineering, Spring Semester, 2017 ENCE 688R: Final Exam: 2 Hours, Open Book and Open Notes Name : Question Points Score Total 100 1

2 Question 1: 50 points This question builds upon the many-to-many association example given in Chapter 11 of the class notes, and adds constraints on the number of entities that can participate in the student-department association relationship. Student TinyDepartment Figure 1: Association relationship between students and a tiny department. Figure 1 is a graphical representation of the constrained association relationship. The constraints are as follows: 1. A student can belong to at most 2 departments. 2. The minimum number of students that can be enrolled in a department is one. 3. The maximum number of students that can be enrolled in a department is three. Now let s suppose that you are experimenting with the following set of source code files: build.xml, Student.java, TinyDepartment.java, The test program is TestTinyUniversity.java. Details of the java source code files are as follows: File: Student.java source code /* * =========================================================== * Student.java: Students can enroll in up to two departments. * * Written by: Mark Austin May 2017 * =========================================================== */ package school; import java.util.collection; import java.util.arraylist; import java.util.iterator; public class Student { private int id; private String name; private int MaximumDepartments = 2; 2

3 // Collection of departments in which the student enrols. private Collection<TinyDepartment> departments; // Constuctor method... public Student() { departments = new ArrayList<TinyDepartment>(); // Setup student Ids... public int getid() { return id; public void setid(int id) { this.id = id; // Set student name... public String getname() { return name; public void setname(string name) { this.name = name; // Student enrols in a department... public void add( TinyDepartment department ) { // Check to see if enrollment limit has been reached... if ( getdepartments().size() == MaximumDepartments ) { System.out.println("*** Enrollment limit exceeded!! "); return; // Add new department to students resume.. if ( getdepartments().contains(department) == false ) { getdepartments().add(department); // Update list of students enrolled in the department.. if ( department.getstudents().contains(this) == false ) { department.getstudents().add(this); 3

4 // Student drops-out of a department... public void remove( TinyDepartment department ) { // Remove department from students resume.. if ( getdepartments().contains(department) == true ) { getdepartments().remove(department); // Update list of students enrolled in the department.. if ( department.getstudents().contains(this) == true ) { department.getstudents().remove(this); // Return collection of departments... public Collection<TinyDepartment> getdepartments() { return departments; public void setdepartment( Collection <TinyDepartment> departments) { this.departments = departments; // Create String representation of student object... public String tostring() { String s = "Student: " + name + "\n"; s = s + "Departments: "; if ( departments.size() == 0 ) s = s + " none \n"; else { Iterator iterator1 = departments.iterator(); while ( iterator1.hasnext()!= false ) { TinyDepartment dept = (TinyDepartment) iterator1.next(); s = s + dept.getname() + " "; s = s + "\n"; return s; File: TinyDepartment.java source code 4

5 /* * ================================================================= * TinyDepartment.java; Simple model of a small academic department. * * Written by: Mark Austin May 2017 * ================================================================= */ package school; import java.util.arraylist; import java.util.collection; import java.util.iterator; public class TinyDepartment { private int id; private String name; private int MinimumStudents = 1; private int MaximumStudents = 3; // Setup collection of students... private Collection<Student> students; // Constructor method... public TinyDepartment(){ students = new ArrayList<Student>(); // Set/get the department Id. public int getid() { return id; public void setid(int id) { this.id = id; // Methods to deal with the department name... public String getname() { return name; public void setname(string deptname) { this.name = deptname; // ========================================================= // Add a student to department... // ========================================================= public void add (Student student) { 5

6 // Department is full. Reject application... if ( students.size() == MaximumStudents ) { System.out.printf("*** Department %s is full... \n", getname() ); System.out.printf("*** Applicant rejected: %s... \n\n", student.getname() ); return; // Add student to department... if ( getstudents().contains(student) == false ) { System.out.printf("*** Adding student: %s to %s... \n\n", student.getname(), getname() ); getstudents().add(student); // Update departments on the student side... if ( student.getdepartments().contains(this) == false ) { student.getdepartments().add(this); // ========================================================= // Remove a student from department... // ========================================================= public void remove ( Student student ) { // Remove student from department... if ( getstudents().contains( student ) == true ) { getstudents().remove( student ); // Remove department from student s record... student.remove (this); public Collection<Student> getstudents() { return students; public void setstudent( Collection<Student> students ) { this.students = students; // Create a String representation for the department... public String tostring() { StringBuffer buf = new StringBuffer(); 6

7 buf.append( String.format("Academic Department: %s...\n", getname() ) ); buf.append( String.format("Current enrollment = %2d...\n", students.size() ) ); buf.append( String.format("Maximum enrollment = %2d...\n", MaximumStudents ) ); buf.append( "Students: " ); if ( students.size() == 0 ) buf.append( " none \n" ); else { Iterator iterator1 = students.iterator(); while ( iterator1.hasnext()!= false ) { Student student = (Student) iterator1.next(); buf.append( String.format(" %s ", student.getname() ) ); buf.append( "\n" ); return buf.tostring(); File: TestTinyUniversity.java source code /* * ====================================================================== * TestTinyUniversity.java: Simulate many-to-many relationships between * students and the departments in which they enroll in a tiny university. * * Two constraints are placed on the student-department association * relationship: * * 1. Students can only enrol in one department. * 2. AcademicDepartments must have a least one student, but no more * than three. * * Written by: Mark Austin May 2017 * ====================================================================== */ package demo; import school.*; public class TestTinyUniversity { public static void main( String[] args ) { System.out.println( "Part 1: Create academic departments and students" ); System.out.println( "================================================" ); // Create academic department objects... 7

8 TinyDepartment civil = new TinyDepartment(); civil.setname("cee"); TinyDepartment eecs = new TinyDepartment(); eecs.setname("ece"); // Create student objects... Student student01 = new Student(); student01.setname("arash"); Student student02 = new Student(); student02.setname("mingxi"); Student student03 = new Student(); student03.setname("linyu"); Student student04 = new Student(); student04.setname("xi"); Student student05 = new Student(); student05.setname("tingzhen"); System.out.println( "Part 2: Add students to engineering departments" ); System.out.println( "===============================================" ); // Add student to civil engineering... civil.add( student01 ); // Add students to electrical engineering... eecs.add( student02 ); eecs.add( student03 ); eecs.add( student04 ); eecs.add( student05 ); System.out.println( "Part 3: Plan B: Tingzhen applies to Civil Engineering..." ); System.out.println( "=========================================================" ); civil.add( student05 ); System.out.println( "Part 4: Summary of Department-Student Associations" ); System.out.println( "==================================================" ); System.out.println( civil ); System.out.println( eecs ); System.out.println( "Part 5: Linyu switches from Electrical to Civil..." ); System.out.println( "===================================================" ); student03.remove( eecs ); student03.add( civil ); 8

9 System.out.println( "Part 6: Validate Linyu s enrollment in CEE and ECE..." ); System.out.println( "======================================================" ); System.out.println( student03 ); System.out.println( civil ); System.out.println( eecs ); System.out.println( "Part 7: Linyu graduates, congratulations!!..." ); System.out.println( "======================================================" ); civil.remove( student03 ); System.out.println( civil ); System.out.println( "======================================================" ); System.out.println( "Finished!!..." ); The script of program input and output is as follows: prompt >> ant run05 Buildfile: /Users/austin/ence688r.d/exam-code.d/build.xml compile: run05: [java] Part 1: Create academic departments and students [java] ================================================ [java] Part 2: Add students to engineering departments [java] =============================================== [java] *** Adding student: Arash to CEE... [java] [java] *** Adding student: Mingxi to ECE... [java] [java] *** Adding student: Linyu to ECE... [java] [java] *** Adding student: Xi to ECE... [java] [java] *** Department ECE is full... [java] *** Applicant rejected: Tingzhen... [java] [java] Part 3: Plan B: Tingzhen applies to Civil Engineering... [java] ========================================================= [java] *** Adding student: Tingzhen to CEE... [java] [java] Part 4: Summary of Department-Student Associations [java] ================================================== [java] Academic Department: CEE... [java] Current enrollment = 2... [java] Maximum enrollment = 3... [java] Students: Arash Tingzhen 9

10 [java] [java] Academic Department: ECE... [java] Current enrollment = 3... [java] Maximum enrollment = 3... [java] Students: Mingxi Linyu Xi [java] [java] Part 5: Linyu switches from Electrical to Civil... [java] =================================================== [java] Part 6: Validate Linyu s enrollment in CEE and ECE... [java] ====================================================== [java] Student: Linyu [java] Departments: CEE [java] [java] Academic Department: CEE... [java] Current enrollment = 3... [java] Maximum enrollment = 3... [java] Students: Arash Tingzhen Linyu [java] [java] Academic Department: ECE... [java] Current enrollment = 2... [java] Maximum enrollment = 3... [java] Students: Mingxi Xi [java] [java] Part 7: Linyu graduates, congratulations!!... [java] ====================================================== [java] Academic Department: CEE... [java] Current enrollment = 2... [java] Maximum enrollment = 3... [java] Students: Arash Tingzhen [java] [java] ====================================================== [java] Finished!!... BUILD SUCCESSFUL Total time: 0 seconds prompt >> exit Please look at the source code carefully and answer the questions that follow: [1a] (5 pts). Draw and label a diagram that shows the organizational arrangement of java packages and user-defined java source code files. 10

11 [1b] (10 pts). Draw and label a diagram that shows the relationship among the Student, Tiny- Department and TestTinyUniversity classes. [1c] (10 pts). Draw and label a diagram showing the layout of memory generated by the statements: TinyDepartment civil = new TinyDepartment(); civil.setname("cee"); 11

12 [1d] (5 pts). In Part 02, the first student to be added to a department is Arash. Draw and label a diagram showing the layout of memory immediately after the statement: civil.add( student01 ); [1e] (5 pts). Draw and label a diagram showing the layout of memory immediately after the statements: // Add students to electrical engineering... eecs.add( student02 ); eecs.add( student03 ); eecs.add( student04 ); eecs.add( student05 ); 12

13 [1f] (5 pts). In Student.java, departments is declared; private Collection<TinyDepartment> departments; Briefly explain each term... [1g] (5 pts). Then, a little bit later on in Student.java, memory for departments is created with: public Student() { departments = new ArrayList<TinyDepartment>(); Briefly explain how the relationship between the classes Collection and ArrayList works. 13

14 [1h] (5 pts). Draw and label a diagram showing the layout of memory at the conclusion of Part 07 (i.e., after Linyu graduates). 14

15 Question 2: 30 points An alias is used to indicate that a named entity is also known by another specified name. For example, in Java, the full name for the math classes is java.lang.math. The short name (or alias) is Math. In this question we explore the use of aliases to access state capitals, first using the complete state name (e.g., Maryland), and then using a short name (e.g., MD). We will say that MD is an alias for Maryland, which in turn, will be mapped to the state capital (e.g. Annapolis). The source code is organized into two files: Alias.java and a test program TestAliasMap.java. File: Alias.java source code /* * ============================================================== * AliasMap.java * ============================================================== */ package alias; import java.util.*; public class AliasMap<T> { public class Key { private Map<T, Key> aliases = new HashMap<T, Key>(); public Key addkey(t alias) { Key key = new Key(); aliases.put(alias, key); return key; public void addalias(t orig, T alias) { aliases.put(alias, aliases.get(orig)); public Key lookup(t alias) { return aliases.get(alias); File: TestAliasMap.java 15

16 source code /** * ====================================================================== * TestAliasMap.java: * * Written by: Mark Austin May 2017 * ====================================================================== */ package demo; import java.util.*; import alias.*; public class TestAliasMap { Map<AliasMap<String>.Key, String> map01; AliasMap<String> aliaser; // ============================================================ // Constructor methods to store object map relationships... // ============================================================ public TestAliasMap() { map01 = new HashMap< AliasMap<String>.Key, String >(); aliaser = new AliasMap<String>(); // ============================================================ // Exercise alias map capabilities... // ============================================================ public static void main ( String args[] ) throws Exception { TestAliasMap test = new TestAliasMap(); // Part 01: Play with alias <String, String> map... System.out.println( "*** Part 01: Create <String, String> map for state capitals..."); System.out.println( "*** =========================================================== "); test.map01.put( test.aliaser.addkey("california"), "Sacramento"); test.map01.put( test.aliaser.addkey("maryland"), "Annapolis"); test.map01.put( test.aliaser.addkey("virginia"), "Richmond"); System.out.println( "*** Maryland -> " + test.map01.get( test.aliaser.lookup("maryland")) ); System.out.println( "*** Virginia -> " + test.map01.get( test.aliaser.lookup("virginia")) ); System.out.println( "*** California -> " + test.map01.get( test.aliaser.lookup("california")) ); // Create and print alias map entries... System.out.println( "*** "); 16

17 System.out.println( "*** Part 02: Add aliases for states..."); System.out.println( "*** =========================================================== "); System.out.println( "*** Alias MD for Maryland, VA for Virginia, etc..."); test.aliaser.addalias( "California", "CA" ); test.aliaser.addalias( "Maryland", "MD" ); test.aliaser.addalias( "Virginia", "VA" ); System.out.printf( "*** State Capital of CA is: %s... \n", test.map01.get( test.aliaser.lookup("ca") ) ); System.out.printf( "*** State Capital of MD is: %s... \n", test.map01.get( test.aliaser.lookup("md") ) ); System.out.printf( "*** State Capital of VA is: %s... \n", test.map01.get( test.aliaser.lookup("va") ) ); System.out.println( "*** =========================================================== "); The script of program input and output is as follows: Buildfile: /Users/austin/ence688r.d/exam-code.d/build.xml compile: run04: [java] *** Part 01: Create <String, String> map for state capitals... [java] *** =========================================================== [java] *** Maryland -> Annapolis [java] *** Virginia -> Richmond [java] *** California -> Sacramento [java] *** [java] *** Part 02: Add aliases for states... [java] *** =========================================================== [java] *** Alias MD for Maryland, VA for Virginia, etc... [java] *** State Capital of CA is: Sacramento... [java] *** State Capital of MD is: Annapolis... [java] *** State Capital of VA is: Richmond... [java] *** =========================================================== BUILD SUCCESSFUL Total time: 0 seconds 17

18 [2a]. (5 pts). Briefly explain the purpose of the Java Generics in: private Map<T, Key> aliases = new HashMap<T, Key>(); [2b]. (10 pts). Draw and label a diagram for the layout of memory at the conclusion of Part

19 [2c]. (10 pts). Draw and label a diagram for the layout of memory generated by the fragment of code test.aliaser.addalias( "California", "CA" ); test.aliaser.addalias( "Maryland", "MD" ); test.aliaser.addalias( "Virginia", "VA" ); All reasonable answers will be accepted. [2d]. (5 pts). Briefly explain what is happening in the statement: System.out.printf( "*** State Capital of CA is: %s... \n", test.map01.get( test.aliaser.lookup("ca") ) ); 19

20 Question 3: 20 points This question covers use of the Java collections framework and software design patterns for the implementation of a two-dimensional plotting library. To see the kinds of features that such a library might support, consider the two-dimensional plot of voltage measurements (Volts) versus time (sec) shown in Figure 2. Figure 2: A simple matlab-like plot. Thetwo dimensinal plot contains multiple curves, a title, and labels for the x- andy- axes, labels for individual curves, and a dashed-line grid. Standard optional features would include the ability to draw curves in specific colors (e.g., blue, green, red) and a legend of symbols displayed in the figure (not shown in Figure 2). An advanced implementation would allow for multiple plots, automatically relabel the plot when the figure is resized and/or provide users with the ability to zoom in on a small portion of a figure. 20

21 [3a] (10 pts.) Draw and label a diagram (or series of diagrams) that shows how you would use the composite design pattern to layout the contents of Figure 2. Clearly indicate the various types of leaf node that will be supported in your plotting package. 21

22 [3b] (10 pts.) Develop a few ideas for how HashSets and HashMaps might beused in your plotting application. All reasonable answers will be accepted. 22