Skip to content

Issue 335: 8.4 listing #352

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
pearcej merged 7 commits into from
Aug 5, 2026
Merged

Issue 335: 8.4 listing #352

Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
ffaf7dd
added listing tags
habibasorour Aug 4, 2026
54e5c71
fixed pre tags, to add linking
habibasorour Aug 4, 2026
c0fb145
added listing to text
habibasorour Aug 4, 2026
79437de
fixed xml:id tag
habibasorour Aug 4, 2026
47d278a
added a missing listing
habibasorour Aug 4, 2026
13467a6
fixed a build error
habibasorour Aug 4, 2026
b56a824
fixed issue with datafile block
habibasorour Aug 4, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
116 changes: 79 additions & 37 deletions source/ch8_filehandling.ptx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -240,10 +240,11 @@ public class CreateFile {
</p>

<p>
Let us create the framework for a class that will write to a file. Let's call this class <c>WriteFile</c>:
<xref ref="write-file-class-java" text="type-global"/> shows the framework for a class that will write to a file. Let's call this class <c>WriteFile</c>.
</p>

<program xml:id="write-file-class-java" language="java">

<listing xml:id="write-file-class-java">
<program language="java">
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
Expand All @@ -254,39 +255,46 @@ public class CreateFile {
}
}
</program>
</listing>

<p>
Next, we will create a <c>FileWriter</c> object. Let's call it <c>myWriter</c>. The equivalent Python code to this operation is:
Next, we will create a <c>FileWriter</c> object. Let's call it <c>myWriter</c>. <xref ref="filerwriter-object-python" text="type-global"/> shows the code to create a <c>myWriter</c> object in Python.
</p>

<program xml:id="filerwriter-object-python" language="python">
<listing xml:id="filerwriter-object-python">
<program language="python">
with open("myfile.txt", "w") as myWriter:
</program>
</listing>

<p>
The Java code to create a <c>FileWriter</c> object is:
<xref ref="filerwriter-object-java" text="type-global"/> shows the Java code to create a <c>FileWriter</c> object. Note that the <c>FileWriter</c> object is created with the name of the file to write to as an argument. If the file does not exist, it will be created. If it does exist, it will be overwritten.:
</p>

<program xml:id="filerwriter-object-java" language="java">
<listing xml:id="filerwriter-object-java">
<program language="java">
FileWriter myWriter = new FileWriter("myfile.txt");
</program>
</listing>

<p>
In this next step, we will use the <c>write()</c> method from the FileWriter class. This method will take any data within the parenthesis and write that data to the file selected. The <c>write()</c> method takes most standard data types. First, how this step is completed with Python:
In this next step, we will use the <c>write()</c> method from the FileWriter class. This method will take any data within the parenthesis and write that data to the file selected. The <c>write()</c> method takes most standard data types. The <xref ref="write-and-close-python" text="type-global"/> shows the code to write to a file in Python.
</p>

<program xml:id="write-and-close-python" language="python">
<listing xml:id="write-and-close-python">
<program language="python">
my_writer.write("File successfully updated!")
</program>
</listing>

<p>
And the Java equivalent. This is almost completely identical except for the second line, which is very important!
<xref ref="write-and-close-java" text="type-global"/> shows the Java equivalent. This is almost completely identical except for the second line, which is very important!
</p>

<program xml:id="write-and-close-java" language="java">
<listing xml:id="write-and-close-java">
<program language="java">
myWriter.write("File successfully updated!");
myWriter.close();
</program>
</listing>

<note>
<p>
Expand All @@ -295,10 +303,11 @@ public class CreateFile {
</note>

<p>
Next, we will again add the required try/catch blocks utilizing the <c>IOException</c> class. Just like with creating files, the program will not compile without these crucial additions! We will also add some print statements to inform us of the success of the file write operation. First, a Python example:
Next, we will again add the required try/catch blocks utilizing the <c>IOException</c> class. Just like with creating files, the program will not compile without these crucial additions! We will also add some print statements to inform us of the success of the file write operation. <xref ref="file-try-catch-python" text="type-global"/> shows the code to write to a file in Python.
</p>

<program xml:id="file-try-catch-python" language="python" add-files = "my-file-8-4-2">
<listing xml:id="file-try-catch-python">
<program language="python" add-files = "my-file-8-4-2">
try:
with open("myfile.txt", "w") as my_writer:
my_writer.write("File successfully updated!")
Expand All @@ -308,12 +317,14 @@ public class CreateFile {
import traceback
traceback.print_exc()
</program>
</listing>

<p>
And the equivalent Java code:
<xref ref="file-try-catch-java" text="type-global"/> shows the Java equivalent.
</p>

<program language="java" xml:id="file-try-catch-java">
<listing xml:id="file-try-catch-java">
<program language="java">
try {
FileWriter myWriter = new FileWriter("myfile.txt");
myWriter.write("File successfully updated!");
Expand All @@ -324,16 +335,23 @@ public class CreateFile {
e.printStackTrace();
}
</program>
</listing>

<p>
And that's it! We will add our code to the foundational code for a complete program. First, an example of equivalent Python code:
And that's it! We will add our code to the foundational code for a complete program. First, <xref ref="file-write-full-python" text="type-global"/> shows the completed Python code.
</p>
<datafile label="my-file-8-4-4" filename="myfile.txt" xml:id= "my-file-8-4-4" editable="yes">

<data xml:id="listing-data-file-write-full-python">
<title>Data file for writing example</title>
<datafile xml:id="data-file-write-full-python" label="data-file-write-full-python" filename="myfile.txt" editable="yes">
<pre>

</pre>
</datafile>
<program xml:id="file-write-full-python" interactive="activecode" language="python" add-files="my-file-8-4-4">
</data>

<listing xml:id="file-write-full-python">
<program interactive="activecode" language="python" add-files="data-file-write-full-python">
<code>
try:
with open("myfile.txt", "w") as my_writer:
Expand All @@ -345,16 +363,22 @@ public class CreateFile {
traceback.print_exc()
</code>
</program>
</listing>

<p>
The completed Java code:
<xref ref="file-write-full-java" text="type-global"/> shows the completed Java code.
</p>
<datafile label="my-file-8-4-5" filename="myfile.txt" xml:id= "my-file-8-4-5" editable="yes">
<data xml:id="listing-data-file-write-full-java">
<title>Data file for writing example</title>
<datafile xml:id="data-file-write-full-java" label="data-file-write-full-java" filename="myfile.txt" editable="yes">
<pre>

</pre>
</datafile>
<program xml:id="file-write-full-java" interactive="activecode" language="java" add-files = "my-file-8-4-5">
</data>

<listing xml:id="file-write-full-java">
<program interactive="activecode" language="java" add-files = "data-file-write-full-java">
<code>
import java.io.FileWriter;
import java.io.IOException;
Expand All @@ -372,8 +396,10 @@ public class CreateFile {
}
}
}
</code>
</code> ~
</program>
</listing>


<note>
<p>
Expand All @@ -382,22 +408,30 @@ public class CreateFile {
</note>

<p>
Speaking of overwriting data, what if we want to append text to the end of any text already in <c>myfile.txt</c>? To accomplish this, we can pass a <c>boolean</c> argument along with the file name when creating a new data argument:
Speaking of overwriting data, what if we want to append text to the end of any text already in <c>myfile.txt</c>? To accomplish this, we can pass a <c>boolean</c> argument along with the file name when creating a new data argument as shown in <xref ref="append-true" text="type-global"/>.
</p>

<program xml:id="append-true" language="java">
<listing xml:id="append-true">
<program language="java">
FileWriter myWriter = new FileWriter("myfile.txt", true); // true enables append mode
</program>
</listing>

<p>
Now, when we use <c>write()</c> method like before, the text will be appended if there is already tSext in the document. If we were to update our code to include the <c>boolean</c> argument:
Now, when we use <c>write()</c> method like before, the text will be appended if there is already tSext in the document. If we were to update our code to include the <c>boolean</c> argument as shown in <xref ref="file-write-with-append" text="type-global"/>.
</p>
<datafile label="my-file-8-4-6" filename="myfile" xml:id= "my-file-8-4-6" editable="yes">

<data xml:id="listing-data-file-write-with-append">
<title>Data file for writing example</title>
<datafile xml:id="data-file-write-with-append" label="data-file-write-with-append" filename="myfile" editable="yes">
<pre>

</pre>
</datafile>
<program xml:id="file-write-with-append" interactive="activecode" language="java" add-files = "my-file-8-4-6">
</data>

<listing xml:id="file-write-with-append">
<program interactive="activecode" language="java" add-files = "data-file-write-with-append">
<code>
import java.io.FileWriter;
import java.io.IOException;
Expand All @@ -417,32 +451,40 @@ public class CreateFile {
}
</code>
</program>
</listing>

<p>
Then if we run the program twice, the contents of <c>myfile.txt</c> would be:
Then if we run the program twice, the contents of <c>myfile.txt</c> would be as <xref ref="file-write-with-append-output" text="type-global"/> shows.
</p>

<pre>
<listing xml:id="file-write-with-append-output">
<program>
File successfully updated!File successfully updated!
</pre>
</program>
</listing>

<p>
This doesn't look very good! If we want each additional write to appear on a new line? A simple solution is to use the <c>\n</c> newline character:
This doesn't look very good! If we want each additional write to appear on a new line? A simple solution is to use the <c>\n</c> newline character as <xref ref="file-write-with-newline" text="type-global"/> shows.
</p>

<program xml:id="newline" language="java">
<listing xml:id="file-write-with-newline">
<program language="java">
myWriter.write("File successfully updated!\n"); // Added newline character
myWriter.close();
</program>
</listing>

<p>
Running the code with the newline character twice will result in the following contents in myfile.txt:
Running the code with the newline character twice will result in the following contents in myfile.txt as <xref ref="file-write-with-newline-output" text="type-global"/> shows.
</p>

<pre>
<listing xml:id="file-write-with-newline-output">
<program>
File successfully updated!
File successfully updated!
</pre>
</program>
</listing>

</section>

<section xml:id="file-delete">
Expand Down