- * Accepts int, long, char or Object values. New values added must be comparable to
- * those that have been added, otherwise the add method will throw an IllegalArgumentException.
- * The values are ordered using the default (natural order), unless a Comparator
- * is supplied in the constructor.
+ * Accepts int, long, char or Object values. New values added must be
+ * comparable to those that have been added, otherwise the add method will
+ * throw an IllegalArgumentException.
+ *
+ * Integer values (int, long, Integer, Long) are not distinguished by type --
+ * i.e. addValue(new Long(2)), addValue(2), addValue(2l) all have
+ * the same effect (similarly for arguments to getCount, etc.).
+ *
+ * The values are ordered using the default (natural order), unless a
+ * Comparatoris supplied in the constructor.
*
- * @version $Revision: 1.22 $ $Date: 2004/06/02 00:24:52 $
+ * @version $Revision: 1.23 $ $Date: 2004/06/20 16:53:17 $
*/
public class Frequency implements Serializable {
@@ -40,33 +43,35 @@ public class Frequency implements Serializable {
static final long serialVersionUID = -3845586908418844111L;
/** underlying collection */
- private SortedBag freqTable = null;
+ private TreeMap freqTable = null;
/**
* Default constructor.
*/
public Frequency() {
- freqTable = new TreeBag();
+ freqTable = new TreeMap();
}
/**
* Constructor allowing values Comparator to be specified.
+ *
* @param comparator Comparator used to order values
*/
public Frequency(Comparator comparator) {
- freqTable = new TreeBag(comparator);
+ freqTable = new TreeMap(comparator);
}
/**
* Return a string representation of this frequency
* distribution.
+ *
* @return a string representation.
*/
public String toString() {
NumberFormat nf = NumberFormat.getPercentInstance();
StringBuffer outBuffer = new StringBuffer();
outBuffer.append("Value \t Freq. \t Pct. \t Cum Pct. \n");
- Iterator iter = freqTable.uniqueSet().iterator();
+ Iterator iter = freqTable.keySet().iterator();
while (iter.hasNext()) {
Object value = iter.next();
outBuffer.append(value);
@@ -82,21 +87,28 @@ public class Frequency implements Serializable {
}
/**
- * Adds 1 to the frequency count for v
+ * Adds 1 to the frequency count for v.
+ *
* @param v the value to add.
* @throws IllegalArgumentException if v is not comparable.
*/
public void addValue(Object v) {
try {
- freqTable.add(v);
+ Long count = (Long) freqTable.get(v);
+ if (count == null) {
+ freqTable.put(v, new Long(1));
+ } else {
+ freqTable.put(v, new Long(count.longValue() + 1));
+ }
} catch (ClassCastException ex) {
- //TreeBag will throw ClassCastException if v is not comparable
+ //TreeMap will throw ClassCastException if v is not comparable
throw new IllegalArgumentException("Value not comparable to existing values.");
}
}
/**
- * Adds 1 to the frequency count for v
+ * Adds 1 to the frequency count for v.
+ *
* @param v the value to add.
*/
public void addValue(int v) {
@@ -105,6 +117,7 @@ public class Frequency implements Serializable {
/**
* Adds 1 to the frequency count for v.
+ *
* @param v the value to add.
*/
public void addValue(long v) {
@@ -113,6 +126,7 @@ public class Frequency implements Serializable {
/**
* Adds 1 to the frequency count for v.
+ *
* @param v the value to add.
*/
public void addValue(char v) {
@@ -126,31 +140,42 @@ public class Frequency implements Serializable {
/**
* Returns an Iterator over the set of values that have been added.
+ *
* @return values Iterator
*/
public Iterator valuesIterator() {
- return freqTable.uniqueSet().iterator();
+ return freqTable.keySet().iterator();
}
//-------------------------------------------------------------------------
/**
- * Returns the sum of all frequencies
+ * Returns the sum of all frequencies.
+ *
* @return the total frequency count.
*/
public long getSumFreq() {
- return freqTable.size();
+ long result = 0;
+ Iterator iterator = freqTable.values().iterator();
+ while (iterator.hasNext()) {
+ result += ((Long) iterator.next()).longValue();
+ }
+ return result;
}
/**
- * Returns the number of values = v
+ * Returns the number of values = v.
+ *
* @param v the value to lookup.
* @return the frequency of v.
*/
public long getCount(Object v) {
long result = 0;
try {
- result = freqTable.getCount(v);
+ Long count = (Long) freqTable.get(v);
+ if (count != null) {
+ result = count.longValue();
+ }
} catch (ClassCastException ex) {
// ignore and return 0 -- ClassCastException will be thrown if value is not comparable
}
@@ -158,48 +183,33 @@ public class Frequency implements Serializable {
}
/**
- * Returns the number of values = v
+ * Returns the number of values = v.
+ *
* @param v the value to lookup.
* @return the frequency of v.
*/
public long getCount(int v) {
- long result = 0;
- try {
- result = freqTable.getCount(new Long(v));
- } catch (ClassCastException ex) {
- // ignore and return 0 -- ClassCastException will be thrown if value is not comparable
- }
- return result;
+ return getCount(new Long(v));
}
/**
- * Returns the number of values = v
+ * Returns the number of values = v.
+ *
* @param v the value to lookup.
* @return the frequency of v.
*/
public long getCount(long v) {
- long result = 0;
- try {
- result = freqTable.getCount(new Long(v));
- } catch (ClassCastException ex) {
- // ignore and return 0 -- ClassCastException will be thrown if value is not comparable
- }
- return result;
+ return getCount(new Long(v));
}
/**
- * Returns the number of values = v
+ * Returns the number of values = v.
+ *
* @param v the value to lookup.
* @return the frequency of v.
*/
public long getCount(char v) {
- long result = 0;
- try {
- result = freqTable.getCount(new Character(v));
- } catch (ClassCastException ex) {
- // ignore and return 0 -- ClassCastException will be thrown if value is not comparable
- }
- return result;
+ return getCount(new Character(v));
}
//-------------------------------------------------------------
@@ -207,7 +217,8 @@ public class Frequency implements Serializable {
/**
* Returns the percentage of values that are equal to v
* (as a proportion between 0 and 1).
- * @param v the value to lookup.
+ *
+ * @param v the value to lookup
* @return the proportion of values equal to v
*/
public double getPct(Object v) {
@@ -217,7 +228,8 @@ public class Frequency implements Serializable {
/**
* Returns the percentage of values that are equal to v
* (as a proportion between 0 and 1).
- * @param v the value to lookup.
+ *
+ * @param v the value to lookup
* @return the proportion of values equal to v
*/
public double getPct(int v) {
@@ -227,7 +239,8 @@ public class Frequency implements Serializable {
/**
* Returns the percentage of values that are equal to v
* (as a proportion between 0 and 1).
- * @param v the value to lookup.
+ *
+ * @param v the value to lookup
* @return the proportion of values equal to v
*/
public double getPct(long v) {
@@ -237,7 +250,8 @@ public class Frequency implements Serializable {
/**
* Returns the percentage of values that are equal to v
* (as a proportion between 0 and 1).
- * @param v the value to lookup.
+ *
+ * @param v the value to lookup
* @return the proportion of values equal to v
*/
public double getPct(char v) {
@@ -257,20 +271,27 @@ public class Frequency implements Serializable {
public long getCumFreq(Object v) {
Comparator c = freqTable.comparator();
if (c == null) {
- c = ComparatorUtils.NATURAL_COMPARATOR;
+ c = new NaturalComparator();
}
long result = 0;
+
try {
- result = freqTable.getCount(v);
+ Long value = (Long) freqTable.get(v);
+ if (value != null) {
+ result = value.longValue();
+ }
} catch (ClassCastException ex) {
return result; // v is not comparable
}
- if (c.compare(v, freqTable.first()) < 0) {
+
+ if (c.compare(v, freqTable.firstKey()) < 0) {
return 0; // v is comparable, but less than first value
}
- if (c.compare(v, freqTable.last()) >= 0) {
+
+ if (c.compare(v, freqTable.lastKey()) >= 0) {
return getSumFreq(); // v is comparable, but greater than the last value
}
+
Iterator values = valuesIterator();
while (values.hasNext()) {
Object nextValue = values.next();
@@ -288,7 +309,7 @@ public class Frequency implements Serializable {
*
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values equal to v */ public long getCumFreq(int v) { @@ -300,7 +321,7 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values equal to v */ public long getCumFreq(long v) { @@ -312,7 +333,7 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values equal to v */ public long getCumFreq(char v) { @@ -327,7 +348,7 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values less than or equal to v */ public double getCumPct(Object v) { @@ -340,7 +361,7 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values less than or equal to v */ public double getCumPct(int v) { @@ -353,7 +374,7 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values less than or equal to v */ public double getCumPct(long v) { @@ -366,10 +387,33 @@ public class Frequency implements Serializable { *
* Returns 0 if v is not comparable to the values set. * - * @param v the value to lookup. + * @param v the value to lookup * @return the proportion of values less than or equal to v */ public double getCumPct(char v) { return getCumPct(new Character(v)); } + + /** + * A Comparator that compares comparable objects using the + * natural order. Copied from Commons Collections ComparableComparator. + */ + private class NaturalComparator implements Comparator { + /** + * Compare the two {@link Comparable Comparable} arguments. + * This method is equivalent to: + *
(({@link Comparable Comparable})o1).{@link Comparable#compareTo compareTo}(o2)
+ *
+ * @param o1 the first object
+ * @param o2 the second object
+ * @return result of comparison
+ * @throws NullPointerException when o1 is null,
+ * or when ((Comparable)o1).compareTo(o2) does
+ * @throws ClassCastException when o1 is not a {@link Comparable Comparable},
+ * or when ((Comparable)o1).compareTo(o2) does
+ */
+ public int compare(Object o1, Object o2) {
+ return ((Comparable)o1).compareTo(o2);
+ }
+ }
}