nbubna 2004/07/21 14:57:59
Modified: src/java/org/apache/velocity/tools/generic MathTool.java
Log:
add methods for summing and averaging numbers in a list (adapted from the
AggregateTool contributed by Leon Messerschmidt)
Revision Changes Path
1.10 +241 -1
jakarta-velocity-tools/src/java/org/apache/velocity/tools/generic/MathTool.java
Index: MathTool.java
===================================================================
RCS file:
/home/cvs/jakarta-velocity-tools/src/java/org/apache/velocity/tools/generic/MathTool.java,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -r1.9 -r1.10
--- MathTool.java 16 Apr 2004 20:12:42 -0000 1.9
+++ MathTool.java 21 Jul 2004 21:57:59 -0000 1.10
@@ -16,6 +16,11 @@
package org.apache.velocity.tools.generic;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import org.apache.commons.beanutils.PropertyUtils;
+
/**
* <p>Tool for performing math in Velocity.</p>
*
@@ -41,6 +46,7 @@
* </pre></p>
*
* @author <a href="mailto:[EMAIL PROTECTED]">Nathan Bubna</a>
+ * @author Leon Messerschmidt
* @version $Revision$ $Date$
*/
public class MathTool
@@ -560,6 +566,240 @@
{
return new Double(value);
}
+ }
+
+
+
+ // ------------------------- Aggregation methods ------------------
+
+ /**
+ * Get the sum of the values from a list
+ *
+ * @param collection A collection containing Java beans
+ * @param field A Java Bean field for the objects in <i>collection</i> that
+ * will return a number.
+ * @return The sum of the values in <i>collection</i>.
+ */
+ public Number getTotal(Collection collection, String field)
+ {
+ if (collection == null || field == null)
+ {
+ return null;
+ }
+ try
+ {
+ double result = 0;
+ // hold the first number and use it to match return type
+ Number first = null;
+ for (Iterator i = collection.iterator(); i.hasNext();)
+ {
+ Object property = PropertyUtils.getProperty(i.next(), field);
+ Number value = toNumber(property);
+ if (first == null)
+ {
+ first = value;
+ }
+ result += value.doubleValue();
+ }
+ return matchType(first, result);
+ }
+ catch (Exception e)
+ {
+ //FIXME? Log this?
+ return null;
+ }
+ }
+
+ /**
+ * Get the average of the values from a list
+ *
+ * @param collection A collection containing Java beans
+ * @param field A Java Bean field for the objects in <i>collection</i> that
+ * will return a number.
+ * @return The average of the values in <i>collection</i>.
+ */
+ public Number getAverage(Collection collection, String field)
+ {
+ Number result = getTotal(collection, field);
+ if (result == null)
+ {
+ return null;
+ }
+ double avg = result.doubleValue() / collection.size();
+ return matchType(result, avg);
+ }
+
+ /**
+ * Get the sum of the values from a list
+ *
+ * @param collection A collection containing Java beans
+ * @param field A Java Bean field for the objects in <i>array</i> that
+ * will return a number.
+ * @return The sum of the values in <i>array</i>.
+ */
+ public Number getTotal(Object[] array, String field)
+ {
+ return getTotal(Arrays.asList(array), field);
+ }
+
+ /**
+ * Get the sum of the values from a list
+ *
+ * @param array A collection containing Java beans
+ * @param field A Java Bean field for the objects in <i>array</i> that
+ * will return a number.
+ * @return The sum of the values in <i>array</i>.
+ */
+ public Number getAverage(Object[] array, String field)
+ {
+ return getAverage(Arrays.asList(array), field);
+ }
+
+ /**
+ * Get the sum of the values
+ *
+ * @param collection A collection containing numeric values
+ * @return The sum of the values in <i>collection</i>.
+ */
+ public Number getTotal(Collection collection)
+ {
+ if (collection == null)
+ {
+ return null;
+ }
+
+ double result = 0;
+ // grab the first number and use it to match return type
+ Number first = null;
+ for (Iterator i = collection.iterator(); i.hasNext();)
+ {
+ Number value = toNumber(i.next());
+ if (value == null)
+ {
+ //FIXME? or should we ignore this and keep adding?
+ return null;
+ }
+ if (first == null)
+ {
+ first = value;
+ }
+ result += value.doubleValue();
+ }
+ return matchType(first, result);
+ }
+
+ /**
+ * Get the average of the values
+ *
+ * @param collection A collection containing number values
+ * @return The average of the values in <i>collection</i>.
+ */
+ public Number getAverage(Collection collection)
+ {
+ Number result = getTotal(collection);
+ if (result == null)
+ {
+ return null;
+ }
+ double avg = result.doubleValue() / collection.size();
+ return matchType(result, avg);
+ }
+
+ /**
+ * Get the sum of the values
+ *
+ * @param array An array containing number values
+ * @return The sum of the values in <i>array</i>.
+ */
+ public Number getTotal(Object[] array)
+ {
+ return getTotal(Arrays.asList(array));
+ }
+
+ /**
+ * Get the average of the values
+ *
+ * @param array An array containing number values
+ * @return The sum of the values in <i>array</i>.
+ */
+ public Number getAverage(Object[] array)
+ {
+ return getAverage(Arrays.asList(array));
+ }
+
+ /**
+ * Get the sum of the values
+ *
+ * @param values The list of double values to add up.
+ * @return The sum of the arrays
+ */
+ public Number getTotal(double[] values)
+ {
+ if (values == null)
+ {
+ return null;
+ }
+
+ double result = 0;
+ for (int i = 0; i < values.length; i++)
+ {
+ result += values[i];
+ }
+ return new Double(result);
+ }
+
+ /**
+ * Get the average of the values in an array of double values
+ *
+ * @param values The list of double values
+ * @return The average of the array of values
+ */
+ public Number getAverage(double[] values)
+ {
+ Number total = getTotal(values);
+ if (total == null)
+ {
+ return null;
+ }
+ return new Double(total.doubleValue() / values.length);
+ }
+
+ /**
+ * Get the sum of the values
+ *
+ * @param values The list of long values to add up.
+ * @return The sum of the arrays
+ */
+ public Number getTotal(long[] values)
+ {
+ if (values == null)
+ {
+ return null;
+ }
+
+ long result = 0;
+ for (int i = 0; i < values.length; i++)
+ {
+ result += values[i];
+ }
+ return new Long(result);
+ }
+
+ /**
+ * Get the average of the values in an array of long values
+ *
+ * @param values The list of long values
+ * @return The average of the array of values
+ */
+ public Number getAverage(long[] values)
+ {
+ Number total = getTotal(values);
+ if (total == null)
+ {
+ return null;
+ }
+ double avg = total.doubleValue() / values.length;
+ return matchType(total, avg);
}
}
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