Author: erans
Date: Fri Sep 9 23:01:59 2011
New Revision: 1167387
URL: http://svn.apache.org/viewvc?rev=1167387&view=rev
Log:
New constructor that enables one to customize the behaviour at counter
exhaustion (namely, select which exception to throw).
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/Incrementor.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/IncrementorTest.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/Incrementor.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/Incrementor.java?rev=1167387&r1=1167386&r2=1167387&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/Incrementor.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/Incrementor.java
Fri Sep 9 23:01:59 2011
@@ -19,8 +19,12 @@ package org.apache.commons.math.util;
import org.apache.commons.math.exception.MaxCountExceededException;
/**
- * Utility that increments a counter until a maximum is reached, at which
- * point it will throw an exception.
+ * Utility that increments a counter until a maximum is reached, at
+ * which point, the instance will by default throw a
+ * {@link MaxCountExceededException}.
+ * However, the user is able to override this behaviour by defining a
+ * custom {@link MaxCountExceededCallback callback}, in order to e.g.
+ * select which exception must be thrown.
*
* @version $Id$
* @since 3.0
@@ -33,7 +37,11 @@ public class Incrementor {
/**
* Current count.
*/
- private int count;
+ private int count = 0;
+ /**
+ * Function called at counter exhaustion.
+ */
+ private final MaxCountExceededCallback maxCountCallback;
/**
* Default constructor.
@@ -50,12 +58,30 @@ public class Incrementor {
* @param max Maximal count.
*/
public Incrementor(int max) {
+ this(max,
+ new MaxCountExceededCallback() {
+ /** {@inheritDoc} */
+ public void trigger(int max) {
+ throw new MaxCountExceededException(max);
+ }
+ });
+ }
+
+ /**
+ * Defines a maximal count and a callback method to be triggered at
+ * counter exhaustion.
+ *
+ * @param max Maximal count.
+ * @param cb Function to be called when the maximal count has been reached.
+ */
+ public Incrementor(int max,
+ MaxCountExceededCallback cb) {
maximalCount = max;
- count = 0;
+ maxCountCallback = cb;
}
/**
- * Set the upper limit for the counter.
+ * Sets the upper limit for the counter.
* This does not automatically reset the current count to zero (see
* {@link #resetCount()}).
*
@@ -66,7 +92,7 @@ public class Incrementor {
}
/**
- * Get the upper limit of the counter.
+ * Gets the upper limit of the counter.
*
* @return the counter upper limit.
*/
@@ -75,7 +101,7 @@ public class Incrementor {
}
/**
- * Get the current count.
+ * Gets the current count.
*
* @return the current count.
*/
@@ -84,7 +110,7 @@ public class Incrementor {
}
/**
- * Check whether a single increment is allowed.
+ * Checks whether a single increment is allowed.
*
* @return {@code false} if the next call to {@link #incrementCount(int)
* incrementCount} will trigger a {@code MaxCountExceededException},
@@ -95,7 +121,7 @@ public class Incrementor {
}
/**
- * Perform multiple increments.
+ * Performs multiple increments.
* See the other {@link #incrementCount() incrementCount} method).
*
* @param value Number of increments.
@@ -108,20 +134,41 @@ public class Incrementor {
}
/**
- * Add one to the current iteration count.
- *
- * @throws MaxCountExceededException at counter exhaustion.
+ * Adds one to the current iteration count.
+ * At counter exhaustion, this method will call the
+ * {@link MaxCountExceededCallback#trigger(int) trigger} method of the
+ * callback object passed to the
+ * {@link #Incrementor(int,MaxCountExceededCallback) constructor}.
+ * If not explictly set, a default callback is used that will throw
+ * a {@code MaxCountExceededException}.
+ *
+ * @throws MaxCountExceededException at counter exhaustion, unless a
+ * custom {@link MaxCountExceededCallback callback} has been set at
+ * construction.
*/
public void incrementCount() {
if (++count > maximalCount) {
- throw new MaxCountExceededException(maximalCount);
+ maxCountCallback.trigger(maximalCount);
}
}
/**
- * Reset the counter to 0.
+ * Resets the counter to 0.
*/
public void resetCount() {
count = 0;
}
+
+ /**
+ * Defines a method to be called at counter exhaustion.
+ * The {@link #trigger(int) trigger} method should usually throw an
exception.
+ */
+ public interface MaxCountExceededCallback {
+ /**
+ * Function called when the maximal count has been reached.
+ *
+ * @param maximalCount Maximal count.
+ */
+ void trigger(int maximalCount);
+ }
}
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/IncrementorTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/IncrementorTest.java?rev=1167387&r1=1167386&r2=1167387&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/IncrementorTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/IncrementorTest.java
Fri Sep 9 23:01:59 2011
@@ -14,6 +14,7 @@
package org.apache.commons.math.util;
import org.apache.commons.math.exception.MaxCountExceededException;
+import org.apache.commons.math.exception.TooManyEvaluationsException;
import org.junit.Assert;
import org.junit.Test;
@@ -96,6 +97,20 @@ public class IncrementorTest {
i.incrementCount();
}
+ @Test(expected=TooManyEvaluationsException.class)
+ public void testAlternateException() {
+ final Incrementor.MaxCountExceededCallback cb
+ = new Incrementor.MaxCountExceededCallback() {
+ /** {@inheritDoc} */
+ public void trigger(int max) {
+ throw new TooManyEvaluationsException(max);
+ }
+ };
+
+ final Incrementor i = new Incrementor(0, cb);
+ i.incrementCount();
+ }
+
@Test
public void testReset() {
final Incrementor i = new Incrementor();
