Package org.jppf.node.policy

Class NodesMatching

java.lang.Object

org.jppf.node.policy.ExecutionPolicy

org.jppf.node.policy.NodesMatching

All Implemented Interfaces:

Serializable

public class NodesMatching
extends ExecutionPolicy

An execution policy rule that checks whether a specified number of nodes match a node execution policy. The number of nodes is expressed as a condtion of type actualNbNodes comp expectedNbNodes, where comp is a comparison operator among ==, !=, <, >, <=, >=.

Instances of this class can only apply to, and be used in, a server.

As an example, the condition "if there are more than 4 nodes idle and with at least 2 processors" can be expressed as follows:

 ExecutionPolicy nodePolicy = new Equal("jppf.node.idle", true).and(new AtLeast("availableProcessors", 2));
 ExecutionPolicy globalPolicy = new NodesMatching(Operator.GREATER, 4, nodePolicy);
 

Alternatively, it can also be written as an XML document:

 <NodesMatching operator="GREATER" expected="4">
   <AND>
     <Equal valueType="boolean">
       <Property>jppf.node.idle</Property>
       <Value>true</Value>
     </Equal>
     <AtLeast>
       <Property>availableProcessors</Property>
       <Value>2</Value>
     </AtLeast>
   </AND>
 </NodesMatching>
 

Since:

5.2

Author:

Laurent Cohen

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.jppf.node.policy.ExecutionPolicy

ExecutionPolicy.AndRule, ExecutionPolicy.NotRule, ExecutionPolicy.OrRule, ExecutionPolicy.XorRule

Field Summary

Fields

Modifier and Type	Field	Description
static final String	XML_TAG	Name of the corresponding XML element.

Fields inherited from class org.jppf.node.policy.ExecutionPolicy

children

Constructor Summary

Constructors

Constructor	Description
NodesMatching(Operator operator, long expectedNodes, ExecutionPolicy nodePolicy)	Initialize this execution policy.
NodesMatching(Operator operator, String expectedNodes, ExecutionPolicy nodePolicy)	Initialize this execution policy.

Method Summary

Modifier and Type	Method	Description
boolean	accepts(PropertiesCollection<String> info)	Determines whether this policy accepts the specified node.
String	toString(int n)	Get an xml string representation of this policy with the specified starting indentation level.

Methods inherited from class org.jppf.node.policy.ExecutionPolicy

and, and, andNot, andNot, checkRules, evaluate, getChildren, getContext, getProperty, indent, negate, not, Not, or, or, orNot, orNot, setContext, setContext, tagEnd, tagStart, toString, toXML, xmlElement, xmlElement, xor, xor

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

XML_TAG

public static final String XML_TAG

Name of the corresponding XML element.

Constructor Details

NodesMatching

public NodesMatching(Operator operator,
 long expectedNodes,
 ExecutionPolicy nodePolicy)

Initialize this execution policy.

Parameters:

operator - the comparison operator to use for the number of nodes.

expectedNodes - the expected number of nodes to use in the comparison.

nodePolicy - the execution policy to match the nodes against. If null, then all the nodes will match.

NodesMatching

public NodesMatching(Operator operator,
 String expectedNodes,
 ExecutionPolicy nodePolicy)

Initialize this execution policy.

Parameters:

operator - the comparison operator to use for the number of nodes.

expectedNodes - an expression that evaluates to the number of expected nodes.

nodePolicy - the execution policy to match the nodes against. If null, then all the nodes will match.

Method Details

accepts

public boolean accepts(PropertiesCollection<String> info)

Description copied from class: ExecutionPolicy

Determines whether this policy accepts the specified node. This method must be overriden in subclasses.

Specified by:

accepts in class ExecutionPolicy

Parameters:

info - system information for the node on which the tasks will run if accepted.

Returns:

true if the node is accepted, false otherwise.

toString

public String toString(int n)

Description copied from class: ExecutionPolicy

Get an xml string representation of this policy with the specified starting indentation level.

Specified by:

toString in class ExecutionPolicy

Parameters:

n - the size of the indent to startwith.

Returns:

an indented string depending on the value of toStringIndent.