Java tutorial
/* * Copyright (c) 2005-2010, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * 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.apache.synapse.commons.throttle.core; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.io.Serializable; import java.util.UUID; import java.util.concurrent.atomic.AtomicLong; /** * Contains all runtime data for a particular remote caller. * provides the default rate based access controller algorithm implementation. * This is not thread-safe */ public abstract class CallerContext implements Serializable, Cloneable { private static final long serialVersionUID = 1652165180220263492L; private static Log log = LogFactory.getLog(CallerContext.class.getName()); /* next access time - the end of prohibition */ private long nextAccessTime = 0; /* first access time - when caller came across the on first time */ private long firstAccessTime = 0; /* The nextTimeWindow - beginning of next unit time period- end of current unit time period */ private long nextTimeWindow = 0; /* The globalCount to keep track number of request */ private AtomicLong globalCount = new AtomicLong(0); private long unitTime; /** * Count to keep track of local (specific to this node) number of requests */ private AtomicLong localCount = new AtomicLong(0); /** * Used for debugging purposes. * */ private UUID uuid = UUID.randomUUID(); /* The Id of caller */ private String id; public CallerContext clone() throws CloneNotSupportedException { super.clone(); CallerContext clone = new CallerContext(this.id) { @Override public int getType() { return CallerContext.this.getType(); } }; clone.nextAccessTime = this.nextAccessTime; clone.firstAccessTime = this.firstAccessTime; clone.nextTimeWindow = this.nextTimeWindow; clone.globalCount = new AtomicLong(this.globalCount.longValue()); clone.localCount = new AtomicLong(this.localCount.longValue()); localCount.set(0); return clone; } public CallerContext(String ID) { if (ID == null || "".equals(ID)) { throw new InstantiationError("Couldn't create a CallContext for an empty " + "remote caller ID"); } this.id = ID.trim(); } public UUID getUuid() { return uuid; } /** * @return Returns Id of caller */ public String getId() { return this.id; } /** * Init the access for a particular caller , caller will registered with context * * @param configuration -The Configuration for this caller * @param throttleContext -The Throttle Context * @param currentTime -The system current time in milliseconds */ private void initAccess(CallerConfiguration configuration, ThrottleContext throttleContext, long currentTime) { this.unitTime = configuration.getUnitTime(); this.firstAccessTime = currentTime; this.nextTimeWindow = this.firstAccessTime + this.unitTime; //Also we need to pick counter value associated with time window. throttleContext.addCallerContext(this, this.id); throttleContext.replicateTimeWindow(this.id); } /** * To verify access if the unit time has already not over * * @param configuration - The Configuration for this caller * @param throttleContext -The Throttle Context * @param currentTime -The system current time * @return boolean -The boolean value which say access will allow or not */ private boolean canAccessIfUnitTimeNotOver(CallerConfiguration configuration, ThrottleContext throttleContext, long currentTime) { boolean canAccess = false; int maxRequest = configuration.getMaximumRequestPerUnitTime(); if (maxRequest != 0) { if ((this.globalCount.get() + this.localCount.get()) < maxRequest) { //If the globalCount is less than max request if (log.isDebugEnabled()) { log.debug( "CallerContext Checking access if unit time is not over and less than max count>> Access " + "allowed=" + maxRequest + " available=" + (maxRequest - (this.globalCount.get() + this.localCount.get())) + " key=" + this.getId() + " currentGlobalCount=" + globalCount + " currentTime=" + currentTime + " " + "nextTimeWindow=" + this.nextTimeWindow + " currentLocalCount=" + localCount + " Tier=" + configuration.getID() + " nextAccessTime=" + this.nextAccessTime); } canAccess = true; // can continue access this.localCount.incrementAndGet(); // Send the current state to others (clustered env) throttleContext.flushCallerContext(this, id); // can complete access } else { //else , if caller has not already prohibit if (this.nextAccessTime == 0) { //and if there is no prohibit time period in configuration long prohibitTime = configuration.getProhibitTimePeriod(); if (prohibitTime == 0) { //prohibit access until unit time period is over this.nextAccessTime = this.firstAccessTime + configuration.getUnitTime(); } else { //if there is a prohibit time period in configuration ,then //set it as prohibit period this.nextAccessTime = currentTime + prohibitTime; } if (log.isDebugEnabled()) { String type = ThrottleConstants.IP_BASE == configuration.getType() ? "IP address" : "domain"; log.debug( "Maximum Number of requests are reached for caller with " + type + " - " + this.id); } // Send the current state to others (clustered env) throttleContext.flushCallerContext(this, id); } else { // else , if the caller has already prohibit and prohibit // time period has already over if (this.nextAccessTime <= currentTime) { if (log.isDebugEnabled()) { log.debug( "CallerContext Checking access if unit time is not over before time window exceed >> " + "Access allowed=" + maxRequest + " available=" + (maxRequest - (this.globalCount.get() + this.localCount.get())) + " key=" + this.getId() + " currentGlobalCount=" + globalCount + " currentTime=" + currentTime + " " + "nextTimeWindow=" + this.nextTimeWindow + " currentLocalCount=" + localCount + " " + "Tier=" + configuration.getID() + " nextAccessTime=" + this.nextAccessTime); } // remove previous caller context if (this.nextTimeWindow != 0) { throttleContext.removeCallerContext(id); } // reset the states so that, this is the first access this.nextAccessTime = 0; canAccess = true; this.globalCount.set(0);// can access the system and this is same as first access this.localCount.set(1); this.firstAccessTime = currentTime; this.nextTimeWindow = currentTime + configuration.getUnitTime(); throttleContext.addAndFlushCallerContext(this, this.id); throttleContext.replicateTimeWindow(this.id); if (log.isDebugEnabled()) { log.debug("Caller=" + this.getId() + " has reset counters and added for replication when unit " + "time is not over"); } } else { if (log.isDebugEnabled()) { String type = ThrottleConstants.IP_BASE == configuration.getType() ? "IP address" : "domain"; log.debug("Prohibit period is not yet over for caller with " + type + " - " + this.id); } } } } } return canAccess; } /** * To verify access if unit time has already over * * @param configuration -The Configuration for this caller * @param throttleContext -The Throttle that caller having pass * @param currentTime -The system current time * @return boolean -The boolean value which say access will allow or not */ private boolean canAccessIfUnitTimeOver(CallerConfiguration configuration, ThrottleContext throttleContext, long currentTime) { boolean canAccess = false; // if number of access for a unit time is less than MAX and // if the unit time period (session time) has just over int maxRequest = configuration.getMaximumRequestPerUnitTime(); if (maxRequest != 0) { if ((this.globalCount.get() + this.localCount.get()) < maxRequest) { if (this.nextTimeWindow != 0) { // Removes and sends the current state to others (clustered env) throttleContext.removeAndFlushCaller(this.id); } if (log.isDebugEnabled()) { log.debug("CallerContext Checking access if unit time over next time window>> Access allowed=" + maxRequest + " available=" + (maxRequest - (this.globalCount.get() + this.localCount.get())) + " key=" + this.getId() + " currentGlobalCount=" + globalCount + " currentTime=" + currentTime + " nextTimeWindow=" + this.nextTimeWindow + " currentLocalCount=" + localCount + " Tier=" + configuration.getID() + " nextAccessTime=" + this.nextAccessTime); } canAccess = true; // this is bonus access //next time callers can access as a new one } else { // if number of access for a unit time has just been greater than MAX now same as a new session // OR if caller in prohibit session and prohibit period has just over if ((this.nextAccessTime == 0) || (this.nextAccessTime <= currentTime)) { if (log.isDebugEnabled()) { log.debug("CallerContext Checking access if unit time over>> Access allowed=" + maxRequest + " available=" + (maxRequest - (this.globalCount.get() + this.localCount.get())) + " key=" + this.getId() + " currentGlobalCount=" + globalCount + " currentTime=" + currentTime + " nextTimeWindow=" + this.nextTimeWindow + " currentLocalCount=" + localCount + " Tier=" + configuration.getID() + " nextAccessTime=" + this.nextAccessTime); } //remove previous callercontext instance if (this.nextTimeWindow != 0) { throttleContext.removeCallerContext(id); } // reset the states so that, this is the first access this.nextAccessTime = 0; canAccess = true; this.globalCount.set(0);// can access the system and this is same as first access this.localCount.set(1); this.firstAccessTime = currentTime; this.nextTimeWindow = currentTime + configuration.getUnitTime(); // registers caller and send the current state to others (clustered env) throttleContext.addAndFlushCallerContext(this, id); throttleContext.replicateTimeWindow(this.id); if (log.isDebugEnabled()) { log.debug("Caller=" + this.getId() + " has reset counters and added for replication when unit " + "time is over"); } } else { // if caller in prohibit session and prohibit period has not over if (log.isDebugEnabled()) { String type = ThrottleConstants.IP_BASE == configuration.getType() ? "IP address" : "domain"; log.debug("Even unit time has over , CallerContext in prohibit state :" + type + " - " + this.id); } } } } return canAccess; } /** * Clean up the callers - remove all callers that have expired their time window * * @param configuration -The Configuration for this caller * @param throttleContext -The Throttle that caller having pass * @param currentTime -The system current time */ public void cleanUpCallers(CallerConfiguration configuration, ThrottleContext throttleContext, long currentTime) { if (log.isDebugEnabled()) { log.debug("Cleaning up the inactive caller's states ... "); } if (configuration == null) { if (log.isDebugEnabled()) { log.debug("Couldn't find the configuration ."); } return; } // if number of access for a unit time is less than MAX and // if the unit time period (session time) has over int maxRequest = configuration.getMaximumRequestPerUnitTime(); if (!(maxRequest == 0)) { if ((this.globalCount.get() + this.localCount.get()) <= (maxRequest - 1)) { if (this.nextTimeWindow != 0 && this.nextTimeWindow < (currentTime - this.unitTime)) { if (log.isDebugEnabled()) { log.debug("Removing caller with id " + this.id); } //Removes the previous callercontext and Sends the current state to // others (clustered env) throttleContext.removeAndDestroyShareParamsOfCaller(id); } } else { // if number of access for a unit time has just been greater than MAX // now same as a new session // OR // if caller in prohibit session and prohibit period has just over and only if ((this.nextAccessTime == 0) || this.nextAccessTime < (currentTime - this.unitTime)) { if (this.nextTimeWindow != 0 && this.nextTimeWindow < (currentTime - this.unitTime)) { if (log.isDebugEnabled()) { log.debug("Removing caller with id " + this.id); } //Removes the previous callercontext and Sends // the current state to others (clustered env) throttleContext.removeAndDestroyShareParamsOfCaller(id); } } } } } /** * Check whether that caller can access or not ,based on current state and pre-defined policy * * @param throttleContext -The Context for this caller - runtime state * @param configuration -The Configuration for this caller - data from policy * @param currentTime -The current system time * @return boolean -The boolean value which say access will allow or not * @throws ThrottleException throws for invalid throttle configuration */ public boolean canAccess(ThrottleContext throttleContext, CallerConfiguration configuration, long currentTime) throws ThrottleException { boolean canAccess; if (configuration == null) { if (log.isDebugEnabled()) { log.debug("Couldn't find the configuration ."); } return true; } if (configuration.getMaximumRequestPerUnitTime() < 0 || configuration.getUnitTime() <= 0 || configuration.getProhibitTimePeriod() < 0) { throw new ThrottleException("Invalid Throttle Configuration"); } // if caller access first time in his new session if (this.firstAccessTime == 0) { initAccess(configuration, throttleContext, currentTime); } // if unit time period (session time) is not over if (this.nextTimeWindow > currentTime) { canAccess = canAccessIfUnitTimeNotOver(configuration, throttleContext, currentTime); } else { canAccess = canAccessIfUnitTimeOver(configuration, throttleContext, currentTime); } return canAccess; } /** * Returns the next time window * * @return long value of next time window */ public long getNextTimeWindow() { return this.nextTimeWindow; } public void incrementGlobalCounter(int incrementBy) { globalCount.addAndGet(incrementBy); } public long getGlobalCounter() { return globalCount.get(); } public void setGlobalCounter(long counter) { globalCount.set(counter); } public long getLocalCounter() { return localCount.get(); } public void resetLocalCounter() { localCount.set(0); } public void resetGlobalCounter() { globalCount.set(0); } /** * Gets type of throttle that this caller belong ex : ip/domain * * @return Returns the type of the throttle */ public abstract int getType(); public long getFirstAccessTime() { return firstAccessTime; } public void setFirstAccessTime(long firstAccessTime) { this.firstAccessTime = firstAccessTime; } public void setNextTimeWindow(long nextTimeWindow) { this.nextTimeWindow = nextTimeWindow; } public long getUnitTime() { return unitTime; } public void setUnitTime(long unitTime) { this.unitTime = unitTime; } }