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Define a set of basic load-balancing policies and utilities.
There is a newer version: 2.2.6
/**
 * CMI : Cluster Method Invocation
 * Copyright (C) 2007,2008 Bull S.A.S.
 * Contact: [email protected]
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 * --------------------------------------------------------------------------
 * $Id: PolicyData.java 2122 2008-09-27 09:41:35Z loris $
 * --------------------------------------------------------------------------
 */

package org.ow2.cmi.lb.data;

import java.io.Serializable;
import java.util.Date;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import net.jcip.annotations.ThreadSafe;

/**
 * Contains data for a policy of load-balancing.
 * @author The new CMI team
 */
@ThreadSafe
public final class PolicyData implements Serializable, Cloneable {

    /**
     * Id for serializable class.
     */
    private static final long serialVersionUID = 7135811410484151772L;

    /**
     * Type of policy.
     */
    private volatile String policyType;

    /**
     * Properties for the policy of load-balancing.
     */
    private volatile ConcurrentHashMap properties =
        new ConcurrentHashMap();

    /**
     * Date of properties.
     * When no property is used, the date is 0.
     */
    private volatile long dateOfProperties;

    /**
     * Type of strategy.
     */
    private volatile String strategyType;


    /**
     * Constructs data for load-balancing with the specified policy, strategy and properties.
     * Generates a number of version for each datum.
     * @param policyType a type of LB policy
     * @param strategyType a type of LB strategy
     * @param properties properties for the given LB policy
     */
    public PolicyData(final String policyType, final String strategyType, final Map properties) {

        this.policyType = policyType;
        this.strategyType = strategyType;
        if(properties == null || properties.isEmpty()) {
            // Just an optimization to avoid of downloading an empty map
            dateOfProperties = 0;
        } else {
            // Gets the date that will be a number of version for the properties
            Date date = new Date();
            dateOfProperties = date.getTime();
            this.properties.putAll(properties);
        }
    }

    /**
     * Constructs data for load-balancing with the specified policy, strategy and properties.
     * Uses the current number of version for each datum.
     * @param policyType a type of LB policy
     * @param strategyType a type of LB strategy
     * @param properties properties for the given LB policy
     * @param dateOfProperties a date of properties
     */
    public PolicyData(
            final String policyType, final String strategyType,
            final Map properties, final long dateOfProperties) {

        this.policyType = policyType;
        this.strategyType = strategyType;
        this.dateOfProperties = dateOfProperties;
        if(dateOfProperties != 0) {
            this.properties.putAll(properties);
        }
    }

    /**
     * @return the type of policy
     */
    public String getPolicyType() {
        return policyType;
    }

    /**
     * Sets the type of policy.
     * @param lbPolicyType a type of policy
     */
    public void setPolicyType(final String lbPolicyType) {
        policyType = lbPolicyType;
    }

    /**
     * Returns the value of the property with the given name.
     * @return properties for policy
     */
    public Map getProperties() {
        return properties;
    }

    /**
     * Returns the value of the property with the given name.
     * @param propertyName a name of a property
     * @return the value of the property with the given name
     */
    public Object getProperty(final String propertyName) {
        return properties.get(propertyName);
    }

    /**
     * Set new properties to the policy (remove the previous).
     * @param properties properties
     */
    public void setProperties(final Map properties) {
        properties.clear();
        properties.putAll(properties);
        // Compute a new date to identify this version of properties
        Date date = new Date();
        dateOfProperties = date.getTime();
    }

    /**
     * Adds a property to the policy.
     * @param propertyName a name of a property
     * @param propertyValue a value of a property
     */
    public void setProperty(final String propertyName, final Object propertyValue) {
        properties.put(propertyName, propertyValue);
        // Compute a new date to identify this version of properties
        Date date = new Date();
        dateOfProperties = date.getTime();
    }

    /**
     * @return the date of properties
     */
    public long getDateOfProperties() {
        return dateOfProperties;
    }

    /**
     * @return the type of strategy for load-balancing
     */
    public String getStrategyType() {
        return strategyType;
    }

    /**
     * Sets the type of strategy.
     * @param lbStrategyType a type of policy
     */
    public void setStrategyType(final String lbStrategyType) {
        strategyType = lbStrategyType;
    }

    @Override
    public boolean equals(final Object object) {
        if(object == null || !(object instanceof PolicyData)) {
            return false;
        }
        PolicyData lbPolicyData = (PolicyData) object;
        return policyType.equals(lbPolicyData.policyType)
            && strategyType.equals(lbPolicyData.strategyType)
            && properties.equals(lbPolicyData.properties)
            && dateOfProperties == lbPolicyData.dateOfProperties;
    }

    public int hashCode() {
        return (int) (policyType.hashCode() + strategyType.hashCode() + properties.hashCode() + dateOfProperties);
    }

    @Override
    public String toString() {
        return "[policyType=" + policyType + ",strategyType=" + strategyType
            + ",properties=" + properties + ",dateOfProperties=" + dateOfProperties + "]";
    }

    @Override
    public PolicyData clone() throws CloneNotSupportedException {
        PolicyData lbPolicyData = (PolicyData) super.clone();
        lbPolicyData.properties = new ConcurrentHashMap(properties);
        return lbPolicyData;
    }

}