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JPPF, the open source grid computing solution
/*
* JPPF.
* Copyright (C) 2005-2015 JPPF Team.
* http://www.jppf.org
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jppf.node.policy;
import java.io.Serializable;
import org.jppf.node.protocol.*;
import org.jppf.utils.*;
import org.jppf.utils.stats.JPPFStatistics;
/**
* Interface for all execution policy implementations.
* This API defines a DSL for predicate-oriented expressions.
* @author Laurent Cohen
*/
public abstract class ExecutionPolicy implements Serializable {
/**
* Explicit serialVersionUID.
*/
private static final long serialVersionUID = 1L;
/**
* Level of indentation used in the toString() method.
*/
static int toStringIndent = 0;
/**
* Stores the XML representation of this object.
* Used to avoid doing it more than once.
*/
transient String computedToString = null;
/**
* The children of this rule.
* @exclude
*/
protected final ExecutionPolicy[] children;
/**
* The root of an execution policy graph, set by the queue manager on the client or server side.
*/
transient ExecutionPolicy root = null;
/**
* The context for this policy.
*/
transient PolicyContext context = null;
/**
* Initialize this policy with the specified children.
* @param children the children of this policy.
*/
protected ExecutionPolicy(final ExecutionPolicy... children) {
this.children = children;
}
/**
* Determines whether this policy accepts the specified node.
* @param info system information for the node on which the tasks will run if accepted.
* @return true if the node is accepted, false otherwise.
*/
public abstract boolean accepts(PropertiesCollection info);
/**
* Create an execution policy that is a logical "AND" combination of this policy and the one specified as operand.
* @param rule the rule to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "AND" operation.
*/
public ExecutionPolicy and(final ExecutionPolicy rule) {
return and(new ExecutionPolicy[] {rule});
}
/**
* Create an execution policy that is a logical "AND" combination of this policy and those specified as operands.
* @param rules rules to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "AND" operation.
*/
public ExecutionPolicy and(final ExecutionPolicy...rules) {
return new AndRule(makeRuleArray(this, rules));
}
/**
* Create an execution policy that is a logical "NOT" combination of this policy and the negations of the one specified as argument.
* @param rule the rule to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "AND" operation.
*/
public ExecutionPolicy andNot(final ExecutionPolicy rule) {
return andNot(new ExecutionPolicy[] {rule});
}
/**
* Create an execution policy that is a logical "AND" combination of this policy and the negations of those specified as argumens.
* @param rules rules to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "AND" operation.
*/
public ExecutionPolicy andNot(final ExecutionPolicy...rules) {
return new AndRule(makeNotRuleArray(this, rules));
}
/**
* Create an execution policy that is a logical "OR" combination of this policy and the one specified as operand.
* @param rule the rule to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "OR" operation.
*/
public ExecutionPolicy or(final ExecutionPolicy rule) {
return or(new ExecutionPolicy[] {rule});
}
/**
* Create an execution policy that is a logical "OR" combination of this policy and those specified as operands.
* @param rules rules to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "OR" operation.
*/
public ExecutionPolicy or(final ExecutionPolicy...rules) {
return new OrRule(makeRuleArray(this, rules));
}
/**
* Create an execution policy that is a logical "OR" combination of this policy and the negations of the one specified as argument.
* @param rule rules to combine this one with.
* @return an execution policy that combines the this policy with the negated operand in an "OR NOT" operation.
*/
public ExecutionPolicy orNot(final ExecutionPolicy rule) {
return orNot(new ExecutionPolicy[] {rule});
}
/**
* Create an execution policy that is a logical "OR" combination of this policy and the negations of those specified as arguments.
* @param rules rules to combine this one with.
* @return an execution policy that combines the this policy with the negated operand in an "OR NOT" operation.
*/
public ExecutionPolicy orNot(final ExecutionPolicy...rules) {
return new OrRule(makeNotRuleArray(this, rules));
}
/**
* Create an execution policy that is a logical "XOR" combination of this policy and the one specified as operand.
* @param rule the rule to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "XOR" operation.
*/
public ExecutionPolicy xor(final ExecutionPolicy rule) {
return xor(new ExecutionPolicy[] {rule});
}
/**
* Create an execution policy that is a logical "XOR" combination of the this policy and those specified as operands.
* @param rules rules to combine this one with.
* @return an execution policy that combines the this policy with the operand in an "XOR" operation.
*/
public ExecutionPolicy xor(final ExecutionPolicy...rules) {
return new XorRule(makeRuleArray(this, rules));
}
/**
* Create an execution policy that is a negation of this policy.
* @return an execution policy that negates this policy.
*/
public ExecutionPolicy not() {
return new NotRule(this);
}
/**
* Get the children of this rule.
* @return an array of {@link ExecutionPolicy} instances, or {@code null} for leaf rules.
* @exclude
*/
public ExecutionPolicy[] getChildren() {
return children;
}
/**
* Generate new array with size +1 and the specified rule as first element.
* @param rule the rule to set as first element.
* @param ruleArray the array of other rules.
* @return an array of ExecutionPolicy instances.
*/
private static ExecutionPolicy[] makeRuleArray(final ExecutionPolicy rule, final ExecutionPolicy[] ruleArray) {
ExecutionPolicy[] result = new ExecutionPolicy[ruleArray.length + 1];
int count = 0;
result[count++] = rule;
for (ExecutionPolicy r: ruleArray) result[count++] = r;
return result;
}
/**
* Generate new array with size +1 and the specified rule as first element,
* while the other rules are negated before being added to the new array.
* @param rule the rule to set as first element.
* @param ruleArray the array of other rules.
* @return an array of ExecutionPolicy instances.
*/
private static ExecutionPolicy[] makeNotRuleArray(final ExecutionPolicy rule, final ExecutionPolicy[] ruleArray) {
ExecutionPolicy[] result = new ExecutionPolicy[ruleArray.length + 1];
int count = 0;
result[count++] = rule;
for (ExecutionPolicy r: ruleArray) result[count++] = r.not();
return result;
}
/**
* Get the value of the specified property in the specified set of system information.
* @param info the system information in which to lookup the property.
* @param name the name of the property to look for.
* @return the value of the property, or null if it could not be found.
*/
public String getProperty(final PropertiesCollection info, final String name) {
for (TypedProperties props: info.getPropertiesArray()) {
String value = props.getString(name);
if (value != null) return value;
}
return null;
}
/**
* Get an indented string.
* @return an indented string depending on the value of toStringIndent.
* @exclude
*/
protected static String indent() {
StringBuilder sb = new StringBuilder();
for (int i=0; i\n").append(super.toString()).append(indent()).append("\n").toString();
}
}
return computedToString;
}
}
/**
* An execution policy that realizes a logical "OR" combination of multiple policies specified as operands.
*/
public static class OrRule extends LogicalRule {
/**
* Initialize this OR operator with the specified operands.
* @param rules the rules to combine.
*/
public OrRule(final ExecutionPolicy...rules) {
super(rules);
}
/**
* Determine if a node is acceptable for this policy.
* @param info system information for the node on which the tasks will run if accepted.
* @return true if at least one of the operands' accepts() method returns true.
*/
@Override
public boolean accepts(final PropertiesCollection info) {
if ((children == null) || (children.length <= 0)) return true;
boolean b = false;
for (ExecutionPolicy ep: children) b = b || ep.accepts(info);
return b;
}
/**
* Print this object to a string.
* @return an XML string representation of this object
*/
@Override
public String toString() {
if (computedToString == null) {
synchronized(ExecutionPolicy.class) {
computedToString = new StringBuilder().append(indent()).append("\n").append(super.toString()).append(indent()).append(" \n").toString();
}
}
return computedToString;
}
}
/**
* An execution policy that realizes a logical "XOR" combination of multiple policies specified as operands.
*/
public static class XorRule extends LogicalRule {
/**
* Initialize this OR operator with the specified operands.
* @param rules the rules to combine.
*/
public XorRule(final ExecutionPolicy...rules) {
super(rules);
}
/**
* Determine if a node is acceptable for this policy.
* @param info system information for the node on which the tasks will run if accepted.
* @return true if and only if the operands' accepts() method return different values.
*/
@Override
public boolean accepts(final PropertiesCollection info) {
if ((children == null) || (children.length <= 0)) return true;
boolean b = children[0].accepts(info);
if (children.length >= 1) for (int i=1; i\n").append(super.toString()).append(indent()).append("\n").toString();
}
}
return computedToString;
}
}
/**
* An execution policy that realizes the negation of a policy specified as operand.
*/
public static class NotRule extends ExecutionPolicy {
/**
* Initialize this binary logical operator with the specified operands.
* @param rule the operand.
*/
public NotRule(final ExecutionPolicy rule) {
super(new ExecutionPolicy[] { rule });
if (rule == null) throw new IllegalArgumentException("negated rule cannot be null");
}
/**
* Determine if a node is acceptable for this policy.
* @param info system information for the node on which the tasks will run if accepted.
* @return true if and only if the 2 operands' accepts() method return true.
*/
@Override
public boolean accepts(final PropertiesCollection info) {
return !children[0].accepts(info);
}
/**
* Print this object to a string.
* @return an XML string representation of this object.
*/
@Override
public String toString() {
if (computedToString == null) {
synchronized(ExecutionPolicy.class) {
StringBuilder sb = new StringBuilder();
sb.append(indent()).append("\n");
toStringIndent++;
sb.append(children[0].toString());
toStringIndent--;
sb.append(indent()).append(" \n");
computedToString = sb.toString();
}
}
return computedToString;
}
}
/**
* A convenience method to provide a way to negate a policy that is consistent with the execution policy DSL.
* @param policy the policy to negate.
* @return An execution policy which negates the specified policy, or null if the specified policy was null.
*/
public static ExecutionPolicy Not(final ExecutionPolicy policy) {
return policy == null ? null : new NotRule(policy);
}
/**
* Format the specified name as <name>.
* @param name the name of the tag.
* @return an XML start tag built from the name.
* @exclude
*/
protected String tagStart(final String name) {
return new StringBuilder().append('<').append(name).append('>').toString();
}
/**
* Format the specified name as </name>.
* @param name the name of the tag.
* @return an XML end tag built from the name.
* @exclude
*/
protected String tagEnd(final String name) {
return new StringBuilder().append('<').append(name).append('>').toString();
}
/**
* Format an XML element as <tag;>value</tag>.
* @param tag the name of the XML tag.
* @param value the string value of the XML element.
* @return an XML element built from the tag name and value.
* @exclude
*/
protected String xmlElement(final String tag, final String value) {
StringBuilder sb = new StringBuilder();
sb.append('<').append(tag).append('>');
sb.append(value);
sb.append("');
return sb.toString();
}
/**
* Format an XML element as <tag;>value</tag>.
* @param tag the name of the XML tag.
* @param value the value of the XML element as a double.
* @return an XML element built from the tag name and value.
* @exclude
*/
protected String xmlElement(final String tag, final double value) {
return xmlElement(tag, Double.toString(value));
}
/**
* Initialize the root for all the elements in the policy graph for which this is the root.
* @since 5.0
*/
private void initializeRoot() {
if (children != null) {
for (ExecutionPolicy child: children) child.initializeRoot(this);
}
}
/**
* Initialize the specified root for all the elements in the policy sub-graph for which this is the root.
* @param root the root to set.
* @since 5.0
*/
private void initializeRoot(final ExecutionPolicy root) {
if (this.root != null) return;
this.root = root;
if (children != null) {
for (ExecutionPolicy child: children) child.initializeRoot(root);
}
}
/**
* Set the parameters used as bound variables in the script.
* @param sla the job server-side sla.
* @param clientSla the job client-side sla.
* @param metadata the job metadata.
* @param jobDispatches the number of nodes the job is already dispatched to.
* @param stats the server statistics.
* @since 5.0
* @exclude
*/
public void setContext(final JobSLA sla, final JobClientSLA clientSla, final JobMetadata metadata, final int jobDispatches, final JPPFStatistics stats) {
initializeRoot();
context = new PolicyContext(sla, clientSla, metadata, jobDispatches, stats);
}
/**
* Get the context for this policy.
* @return a {@link PolicyContext} object.
* @since 5.0
*/
public PolicyContext getContext() {
return root == null ? context : root.context;
}
}
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