first commit

2024-01-15 20:14:10 +00:00
commit 8c81ee28b7
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--- a/1/Java/examples/projects/chapter07/weblog-analyzer/LogEntry.java
+++ b/1/Java/examples/projects/chapter07/weblog-analyzer/LogEntry.java
@@ -0,0 +1,140 @@
+import java.util.Calendar;
+
+/**
+ * Store the data from a single line of a
+ * web-server log file.
+ * Individual fields are made available via
+ * accessors such as getHour() and getMinute().
+ * 
+ * @author David J. Barnes and Michael Kölling.
+ * @version    2016.02.29
+ */
+public class LogEntry implements Comparable<LogEntry>
+{
+    // Where the data values extracted from a single
+    // log line are stored.
+    private int[] dataValues;
+    // The equivalent Calendar object for the log time.
+    private Calendar when;
+    
+    // At which index in dataValues the different fields
+    // from a log line are stored.
+    private static final int YEAR = 0, MONTH = 1, DAY = 2,
+                             HOUR = 3, MINUTE = 4;
+    // The number of fields. If more fields are added, e.g. for
+    // seconds or a status code, then this value must be increased
+    // to match.
+    private static final int NUMBER_OF_FIELDS = 5;
+                      
+    /**
+     * Decompose a log line so that the individual fields
+     * are available.
+     * @param logline A single line from the log.
+     *                This should be in the format:
+     *                year month day hour minute etc.
+     */
+    public LogEntry(String logline)
+    {
+        // The array to store the data for a single line.
+        dataValues = new int[NUMBER_OF_FIELDS];
+        // Break up the log line.
+        LoglineTokenizer tokenizer = new LoglineTokenizer();
+        tokenizer.tokenize(logline,dataValues);
+        setWhen();
+    }
+    
+    /**
+     * Create a LogEntry from the individual components.
+     * @param year The year
+     * @param month The month (1-12)
+     * @param day The day (1-31)
+     * @param hour The hour (0-23)
+     * @param minute The minute (0-59)
+     */
+    public LogEntry(int year, int month, int day, int hour, int minute)
+    {
+        // The array to store the data for a single line.
+        dataValues = new int[NUMBER_OF_FIELDS];
+        dataValues[YEAR] = year;
+        dataValues[MONTH] = month;
+        dataValues[DAY] = day;
+        dataValues[HOUR] = hour;
+        dataValues[MINUTE] = minute;
+        setWhen();
+    }
+    
+    /**
+     * Return the hour.
+     * @return The hour field from the log line.
+     */
+    public int getHour()
+    {
+        return dataValues[HOUR];
+    }
+
+    /**
+     * Return the minute.
+     * @return The minute field from the log line.
+     */
+    public int getMinute()
+    {
+        return dataValues[MINUTE];
+    }
+    
+    /**
+     * Create a string representation of the data.
+     * This is not necessarily identical with the
+     * text of the original log line.
+     * @return A string representing the data of this entry.
+     */
+    public String toString()
+    {
+        StringBuffer buffer = new StringBuffer();
+        for(int value : dataValues) {
+           // Prefix a leading zero on single digit numbers.
+            if(value < 10) {
+                buffer.append('0');
+            }
+            buffer.append(value);
+            buffer.append(' ');
+        }
+        // Drop any trailing space.
+        return buffer.toString().trim();
+    }
+    
+    /**
+     * Compare the date/time combination of this log entry
+     * with another.
+     * @param otherEntry The other entry to compare against.
+     * @return A negative value if this entry comes before the other.
+     *         A positive value if this entry comes after the other.
+     *         Zero if the entries are the same.
+     */
+    public int compareTo(LogEntry otherEntry)
+    {
+        // Use the equivalent Calendars comparison method.
+        return when.compareTo(otherEntry.getWhen());
+    }
+    
+    /**
+     * Return the Calendar object representing this event.
+     * @return The Calendar for this event.
+     */
+    private Calendar getWhen()
+    {
+        return when;
+    }
+
+    /**
+     * Create an equivalent Calendar object from the data values.
+     */
+    private void setWhen()
+    {
+        when = Calendar.getInstance();
+        // Adjust from 1-based month and day to 0-based.
+        when.set(dataValues[YEAR],
+                 dataValues[MONTH] - 1, dataValues[DAY] - 1,
+                 dataValues[HOUR], dataValues[MINUTE]);
+    }
+    
+}