scg/ch12/AdventurePage

001 packagepackage is used to name the directory or folder a class is in scg.ch12;
002 
003 importimport means to make the classes and/or packages available in this program java.io.PrintWriter;
004 importimport means to make the classes and/or packages available in this program java.util.Scanner;
005 
006 publicpublic is used to indicate unrestricted access (any other class can have access) abstractAbstract means there is implementation missing. classclass is a group of fields and methods used for making objects AdventurePage {open braces start code blocks and must be matched with a close brace
007   /** index value used to indicate that there is no matching page */
008   publicpublic is used to indicate unrestricted access (any other class can have access) staticstatic means that an instance is not required for access (class level access) finalfinal means not changeable (often used for constants) intint is the type for whole numbers and it is short for integer NO_SUCH_PAGE =this assignment operator makes the left side equal to the right side -1;
009 
010   /**
011    * The format of the input file (as far as thisthis means the current object (the implicit parameter) method is concerned)
012    * is the name of a page type (subclass of {open braces start code blocks and must be matched with a close brace@link AdventurePage}close braces end code blocks and must match an earlier open brace)
013    * followed by the data forfor is a looping structure for repeatedly executing a block of code the content of that object. This method
014    * reads the line (containing "Answer" or "Question") and constructs
015    * the appropriate type of page, passing in a reference to thisthis means the current object (the implicit parameter) book
016    * and the scanner; the page constructor is responsible forfor is a looping structure for repeatedly executing a block of code consuming
017    * all necessary information and leaving the scanner set to read the
018    * next classclass is a group of fields and methods used for making objects naming line.
019    *
020    * @paramthis is the Javadoc tag for documenting the purpose of parameters   book     the {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace to which the newnew is used to create objects by calling the constructor page
021    *                   belongs
022    * @paramthis is the Javadoc tag for documenting the purpose of parameters   scanner  input {open braces start code blocks and must be matched with a close brace@link Scanner}close braces end code blocks and must match an earlier open brace attached to a proper input
023    *                   stream
024    *
025    * @returnnull  a newnew is used to create objects by calling the constructor page ({open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace or {open braces start code blocks and must be matched with a close brace@link Answer}close braces end code blocks and must match an earlier open brace)
026    */
027   publicpublic is used to indicate unrestricted access (any other class can have access) staticstatic means that an instance is not required for access (class level access) AdventurePage readPageFromFile(AdventureBook book,
028     Scanner scanner) {open braces start code blocks and must be matched with a close brace
029     String questionOrAnswer =this assignment operator makes the left side equal to the right side scanner.nextLine();
030     ifif executes the next statement only if the condition in parenthesis evaluates to true (questionOrAnswer.equals("Question")) {open braces start code blocks and must be matched with a close brace
031       returnreturn means to provide the result of the method and/or cease execution of the method immediately newnew is used to create objects by calling the constructor Question(book, scanner);
032     }close braces end code blocks and must match an earlier open brace elseelse is what happens when the if condition is false {open braces start code blocks and must be matched with a close brace
033       returnreturn means to provide the result of the method and/or cease execution of the method immediately newnew is used to create objects by calling the constructor Answer(book, scanner);
034     }close braces end code blocks and must match an earlier open brace
035   }close braces end code blocks and must match an earlier open brace
036 
037   /**
038    * Parallel with {open braces start code blocks and must be matched with a close brace@link #readPageFromFile(AdventureBook, Scanner)}close braces end code blocks and must match an earlier open brace,
039    * thisthis means the current object (the implicit parameter) method writes a given page out to the open text output file.
040    *
041    * @paramthis is the Javadoc tag for documenting the purpose of parameters   page  the page to write
042    * @paramthis is the Javadoc tag for documenting the purpose of parameters   out   the {open braces start code blocks and must be matched with a close brace@link PrintWriter}close braces end code blocks and must match an earlier open brace to which the page should be
043    *                saved
044    */
045   publicpublic is used to indicate unrestricted access (any other class can have access) staticstatic means that an instance is not required for access (class level access) voidvoid means the method does not return a value writePageToFile(AdventurePage page,
046     PrintWriter out) {open braces start code blocks and must be matched with a close brace
047     page.save(out);
048   }close braces end code blocks and must match an earlier open brace
049 
050   /** the book to which thisthis means the current object (the implicit parameter) page belongs */
051   privateprivate is used to restrict access to the current class only finalfinal means not changeable (often used for constants) AdventureBook book;
052 
053   /** the index of the parent node */
054   privateprivate is used to restrict access to the current class only intint is the type for whole numbers and it is short for integer parentNdx;
055 
056   /** thisthis means the current object (the implicit parameter) node's text value */
057   privateprivate is used to restrict access to the current class only finalfinal means not changeable (often used for constants) String text;
058 
059   /**
060    * Construct a newnew is used to create objects by calling the constructor {open braces start code blocks and must be matched with a close brace@link AdventurePage}close braces end code blocks and must match an earlier open brace. The page will have the given
061    * text as its content and will be added to the given {open braces start code blocks and must be matched with a close brace@link
062    * AdventureBook}close braces end code blocks and must match an earlier open brace.
063    *
064    * @paramthis is the Javadoc tag for documenting the purpose of parameters  book  the {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace to which thisthis means the current object (the implicit parameter) page should
065    *               belong
066    * @paramthis is the Javadoc tag for documenting the purpose of parameters  text  the page contents
067    */
068   protectedprotected is used to restrict access to the current class and subclasses only AdventurePage(AdventureBook book, String text,
069     intint is the type for whole numbers and it is short for integer parentNdx) {open braces start code blocks and must be matched with a close brace
070     thisthis means the current object (the implicit parameter).book =this assignment operator makes the left side equal to the right side book;
071     book.add(thisthis means the current object (the implicit parameter));
072     thisthis means the current object (the implicit parameter).text =this assignment operator makes the left side equal to the right side text;
073     setParentNdx(parentNdx);
074   }close braces end code blocks and must match an earlier open brace
075 
076   /**
077    * Get the page number of thisthis means the current object (the implicit parameter) page in the book to which it belongs.
078    *
079    * @returnnull  the 0-based page number (index) of thisthis means the current object (the implicit parameter) page
080    */
081   publicpublic is used to indicate unrestricted access (any other class can have access) intint is the type for whole numbers and it is short for integer getNdx() {open braces start code blocks and must be matched with a close brace
082     returnreturn means to provide the result of the method and/or cease execution of the method immediately book.indexOf(thisthis means the current object (the implicit parameter));
083   }close braces end code blocks and must match an earlier open brace
084 
085   /**
086    * Return the current text value forfor is a looping structure for repeatedly executing a block of code thisthis means the current object (the implicit parameter) node
087    *
088    * @returnnull  current text value
089    */
090   publicpublic is used to indicate unrestricted access (any other class can have access) String getText() {open braces start code blocks and must be matched with a close brace
091     returnreturn means to provide the result of the method and/or cease execution of the method immediately text;
092   }close braces end code blocks and must match an earlier open brace
093 
094   /**
095    * Play thisthis means the current object (the implicit parameter) page. A page is played by presenting some text to the
096    * user (through standard output) and accept some input from the user
097    * (through standard input). This method _must_ be provided by all
098    * subclasses of thisthis means the current object (the implicit parameter) classclass is a group of fields and methods used for making objects. It is provided here solely to describe
099    * the publicpublic is used to indicate unrestricted access (any other class can have access) interfaceinterface is a named collection of declared methods forfor is a looping structure for repeatedly executing a block of code users of {open braces start code blocks and must be matched with a close brace@link AdventurePage}close braces end code blocks and must match an earlier open brace objects.
100    *
101    * @returnnull  truetrue is the boolean value that is the opposite of false ifif executes the next statement only if the condition in parenthesis evaluates to true the computer won the game, falsefalse is a value for the boolean type and means not true otherwise.
102    */
103   publicpublic is used to indicate unrestricted access (any other class can have access) abstractAbstract means there is implementation missing. booleanboolean is a type that is either true or false play();
104 
105   /**
106    * Get the book to which thisthis means the current object (the implicit parameter) page belongs. This is protectedprotected is used to restrict access to the current class and subclasses only because
107    * the book is only of interest to thisthis means the current object (the implicit parameter) object and the pages which
108    * extend it.
109    *
110    * @returnnull  the {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace to which thisthis means the current object (the implicit parameter) page belongs
111    */
112   protectedprotected is used to restrict access to the current class and subclasses only AdventureBook getBook() {open braces start code blocks and must be matched with a close brace
113     returnreturn means to provide the result of the method and/or cease execution of the method immediately book;
114   }close braces end code blocks and must match an earlier open brace
115 
116   /**
117    * The parent of thisthis means the current object (the implicit parameter) node must be a {open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace (ifif executes the next statement only if the condition in parenthesis evaluates to true it exists).
118    * Thus the cast here is safe.
119    *
120    * @returnnull  reference to the {open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace which leads to thisthis means the current object (the implicit parameter) page
121    *          (ifif executes the next statement only if the condition in parenthesis evaluates to true there is one); nullnull is the value used to refer to a non-existant object ifif executes the next statement only if the condition in parenthesis evaluates to true the node is the root of the
122    *          tree
123    */
124   protectedprotected is used to restrict access to the current class and subclasses only Question getParent() {open braces start code blocks and must be matched with a close brace
125     ifif executes the next statement only if the condition in parenthesis evaluates to true (getParentNdx() !=this is the not equals operator which evaluates to true if both sides are different NO_SUCH_PAGE) {open braces start code blocks and must be matched with a close brace
126       returnreturn means to provide the result of the method and/or cease execution of the method immediately (Question) getBook().get(getParentNdx());
127     }close braces end code blocks and must match an earlier open brace elseelse is what happens when the if condition is false {open braces start code blocks and must be matched with a close brace
128       returnreturn means to provide the result of the method and/or cease execution of the method immediately nullnull is the value used to refer to a non-existant object;
129     }close braces end code blocks and must match an earlier open brace
130   }close braces end code blocks and must match an earlier open brace
131 
132   /**
133    * Get a reference to the {open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace (ifif executes the next statement only if the condition in parenthesis evaluates to true any) forfor is a looping structure for repeatedly executing a block of code which thisthis means the current object (the implicit parameter)
134    * question is an answer. Implementation detail must be visible to all
135    * {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace types.
136    *
137    * @returnnull  reference to {open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace (ifif executes the next statement only if the condition in parenthesis evaluates to true there is one) of which
138    *          thisthis means the current object (the implicit parameter) {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace is a child.
139    */
140   protectedprotected is used to restrict access to the current class and subclasses only intint is the type for whole numbers and it is short for integer getParentNdx() {open braces start code blocks and must be matched with a close brace
141     returnreturn means to provide the result of the method and/or cease execution of the method immediately parentNdx;
142   }close braces end code blocks and must match an earlier open brace
143 
144   /**
145    * Write the {open braces start code blocks and must be matched with a close brace@link AdventurePage}close braces end code blocks and must match an earlier open brace to the given text file so that it
146    * can be read back in by {open braces start code blocks and must be matched with a close brace@link #readPageFromFile(AdventureBook,
147    * Scanner)}close braces end code blocks and must match an earlier open brace. Overriding methods _must_ call thisthis means the current object (the implicit parameter) method before
148    * writing anything to the text file.
149    *
150    * @paramthis is the Javadoc tag for documenting the purpose of parameters  out  a {open braces start code blocks and must be matched with a close brace@link PrintWriter}close braces end code blocks and must match an earlier open brace, opened and attached to an
151    *              output text file. Where to save thisthis means the current object (the implicit parameter) page.
152    */
153   protectedprotected is used to restrict access to the current class and subclasses only voidvoid means the method does not return a value save(PrintWriter out) {open braces start code blocks and must be matched with a close brace
154     out.println(getClass().getName());
155     out.println(getText());
156     out.println(getParentNdx());
157   }close braces end code blocks and must match an earlier open brace
158 
159   /**
160    * Set the value of the parent of the current {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace.
161    * Implementation detail must be visible to all {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace
162    * types.
163    *
164    * @paramthis is the Javadoc tag for documenting the purpose of parameters  parent  reference to the {open braces start code blocks and must be matched with a close brace@link Question}close braces end code blocks and must match an earlier open brace of which thisthis means the current object (the implicit parameter)
165    *                 {open braces start code blocks and must be matched with a close brace@link AdventureBook}close braces end code blocks and must match an earlier open brace is a child.
166    */
167   protectedprotected is used to restrict access to the current class and subclasses only voidvoid means the method does not return a value setParentNdx(intint is the type for whole numbers and it is short for integer parentNdx) {open braces start code blocks and must be matched with a close brace
168     thisthis means the current object (the implicit parameter).parentNdx =this assignment operator makes the left side equal to the right side parentNdx;
169   }close braces end code blocks and must match an earlier open brace
170 }close braces end code blocks and must match an earlier open brace
171 
172 //Uploaded on Mon Mar 29 21:39:45 EDT 2010