1 files changed, 105 insertions, 0 deletions
diff --git a/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/cache/HysteresisConditionPolicy.java b/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/cache/HysteresisConditionPolicy.java
new file mode 100644
index 0000000000..2b0dd4f99e
--- /dev/null
+++ b/plugins/org.eclipse.net4j.util/src/org/eclipse/net4j/util/cache/HysteresisConditionPolicy.java
@@ -0,0 +1,105 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2008 Eike Stepper, Germany.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.net4j.util.cache;
+
+import org.eclipse.net4j.util.cache.ICacheMonitor.Condition;
+
+/**
+ * @author Eike Stepper
+ */
+public class HysteresisConditionPolicy extends ThresholdConditionPolicy
+{
+  private long thresholdYellowRed;
+
+  private long thresholdGreenYellow;
+
+  public HysteresisConditionPolicy(long thresholdYellowRed, long thresholdRedYellow, long thresholdGreenYellow,
+      long thresholdYellowGreen)
+  {
+    super(thresholdRedYellow, thresholdYellowGreen);
+    if (thresholdYellowRed > thresholdRedYellow)
+    {
+      throw new IllegalArgumentException("thresholdYellowRed > thresholdRedYellow");
+    }
+
+    if (thresholdRedYellow > thresholdGreenYellow)
+    {
+      throw new IllegalArgumentException("thresholdRedYellow > thresholdGreenYellow");
+    }
+
+    if (thresholdGreenYellow > thresholdYellowGreen)
+    {
+      throw new IllegalArgumentException("thresholdGreenYellow > thresholdYellowGreen");
+    }
+
+    this.thresholdGreenYellow = thresholdGreenYellow;
+    this.thresholdYellowRed = thresholdYellowRed;
+  }
+
+  public long getThresholdYellowRed()
+  {
+    return thresholdYellowRed;
+  }
+
+  public long getThresholdGreenYellow()
+  {
+    return thresholdGreenYellow;
+  }
+
+  @Override
+  protected Condition getNewCondition(Condition oldCondition, long freeMemory)
+  {
+    switch (oldCondition)
+    {
+    case GREEN:
+      if (freeMemory < thresholdYellowRed)
+      {
+        return Condition.RED;
+      }
+
+      if (freeMemory < thresholdGreenYellow)
+      {
+        return Condition.YELLOW;
+      }
+
+      return Condition.GREEN;
+
+    case YELLOW:
+      if (freeMemory < thresholdYellowRed)
+      {
+        return Condition.RED;
+      }
+
+      if (freeMemory > getThresholdYellowGreen())
+      {
+        return Condition.GREEN;
+      }
+
+      return Condition.YELLOW;
+
+    case RED:
+      if (freeMemory > getThresholdYellowGreen())
+      {
+        return Condition.GREEN;
+      }
+
+      if (freeMemory > getThresholdRedYellow())
+      {
+        return Condition.YELLOW;
+      }
+
+      return Condition.RED;
+
+    default:
+      throw new IllegalArgumentException("oldCondition == " + oldCondition);
+    }
+  }
+}