Java tutorial
/*************************************************************************** * Copyright (C) 2012 by H-Store Project * * Brown University * * Massachusetts Institute of Technology * * Yale University * * * * http://hstore.cs.brown.edu/ * * * * Permission is hereby granted, free of charge, to any person obtaining * * a copy of this software and associated documentation files (the * * "Software"), to deal in the Software without restriction, including * * without limitation the rights to use, copy, modify, merge, publish, * * distribute, sublicense, and/or sell copies of the Software, and to * * permit persons to whom the Software is furnished to do so, subject to * * the following conditions: * * * * The above copyright notice and this permission notice shall be * * included in all copies or substantial portions of the Software. * * * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR * * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * * OTHER DEALINGS IN THE SOFTWARE. * ***************************************************************************/ package com.oltpbenchmark.benchmarks.auctionmark.util; import java.util.Arrays; import java.util.Iterator; import java.util.Map; import org.apache.commons.collections15.map.ListOrderedMap; import org.apache.commons.lang.NotImplementedException; import com.oltpbenchmark.util.Histogram; import com.oltpbenchmark.util.StringUtil; public class UserIdGenerator implements Iterator<UserId> { private final int numClients; private final Integer clientId; private final int usersPerItemCounts[]; private final int minItemCount; private final int maxItemCount; private final long totalUsers; private UserId next = null; private int currentItemCount = -1; private int currentOffset; private int currentPosition = 0; /** * Construct a new generator based on the given histogram. * If clientId is not null, then this generator will only return UserIds that are mapped * to that clientId based on the UserId's offset * @param users_per_item_count * @param numClients * @param clientId */ public UserIdGenerator(Histogram<Long> users_per_item_count, int numClients, Integer clientId) { assert (users_per_item_count != null); if (numClients <= 0) throw new IllegalArgumentException("numClients must be more than 0 : " + numClients); if (clientId != null && clientId < 0) throw new IllegalArgumentException("clientId must be more than or equal to 0 : " + clientId); this.numClients = numClients; this.clientId = clientId; Long temp = users_per_item_count.getMaxValue(); if (temp == null) temp = users_per_item_count.getMaxValue(); assert (temp != null) : "Invalid Users Per Item Histogram:\n" + users_per_item_count; this.maxItemCount = temp.intValue(); this.usersPerItemCounts = new int[this.maxItemCount + 2]; for (int i = 0; i < this.usersPerItemCounts.length; i++) { this.usersPerItemCounts[i] = users_per_item_count.get((long) i, 0); } // FOR temp = users_per_item_count.getMinValue(); this.minItemCount = (temp != null ? temp.intValue() : 0); this.totalUsers = users_per_item_count.getSampleCount(); this.setCurrentItemCount(this.minItemCount); } public UserIdGenerator(Histogram<Long> users_per_item_count, int numClients) { this(users_per_item_count, numClients, null); } public long getTotalUsers() { return (this.totalUsers); } public void setCurrentItemCount(int size) { // It's lame, but we need to make sure that we prime total_ctr // so that we always get the same UserIds back per client this.currentPosition = 0; for (int i = 0; i < size; i++) { this.currentPosition += this.usersPerItemCounts[i]; } // FOR this.currentItemCount = size; this.currentOffset = this.usersPerItemCounts[this.currentItemCount]; } public int getCurrentPosition() { return (this.currentPosition); } public UserId seekToPosition(int position) { assert (position <= this.getTotalUsers()) : String.format("%d < %d", position, this.getTotalUsers()); UserId user_id = null; this.currentPosition = 0; this.currentItemCount = 0; while (true) { int num_users = this.usersPerItemCounts[this.currentItemCount]; if (this.currentPosition + num_users > position) { this.next = null; this.currentOffset = num_users - (position - this.currentPosition); this.currentPosition = position; user_id = this.next(); break; } else { this.currentPosition += num_users; } this.currentItemCount++; } // WHILE return (user_id); } /** * Returns true if the given UserId should be processed by the given * client id * @param user_id * @return */ public boolean checkClient(UserId user_id) { if (this.clientId == null) return (true); int tmp_count = 0; int tmp_position = 0; while (tmp_count <= this.maxItemCount) { assert (tmp_count < this.usersPerItemCounts.length) : String .format("Unexpected itemCount '%d' [maxItemCount=%d]", tmp_count, this.maxItemCount); int num_users = this.usersPerItemCounts[tmp_count]; if (tmp_count == user_id.getItemCount()) { tmp_position += (num_users - user_id.getOffset()) + 1; break; } tmp_position += num_users; tmp_count++; } return (tmp_position % this.numClients == this.clientId.intValue()); } private UserId findNextUserId() { // Find the next id for this size level Long found = null; while (this.currentItemCount <= this.maxItemCount) { while (this.currentOffset > 0) { long nextCtr = this.currentOffset--; this.currentPosition++; // If we weren't given a clientId, then we'll generate UserIds // for all users in a given size level if (this.clientId == null) { found = nextCtr; break; } // Otherwise we have to spin through and find one for our client else if (this.currentPosition % this.numClients == this.clientId.intValue()) { found = nextCtr; break; } } // WHILE if (found != null) break; this.currentItemCount++; this.currentOffset = this.usersPerItemCounts[this.currentItemCount]; } // WHILE if (found == null) return (null); return (new UserId((int) this.currentItemCount, found.intValue())); } @Override public boolean hasNext() { if (this.next == null) { this.next = this.findNextUserId(); } return (this.next != null); } @Override public UserId next() { if (this.next == null) { this.next = this.findNextUserId(); } UserId ret = this.next; this.next = null; return (ret); } @Override public void remove() { throw new NotImplementedException("Cannot call remove!!"); } @Override public String toString() { Map<String, Object> m = new ListOrderedMap<String, Object>(); m.put("numClients", this.numClients); m.put("clientId", this.clientId); m.put("minItemCount", this.minItemCount); m.put("maxItemCount", this.maxItemCount); m.put("totalUsers", this.totalUsers); m.put("currentItemCount", this.currentItemCount); m.put("currentOffset", this.currentOffset); m.put("currentPosition", this.currentPosition); m.put("next", this.next); m.put("users_per_item_count", String.format("[Length:%d] => %s", this.usersPerItemCounts.length, Arrays.toString(this.usersPerItemCounts))); return StringUtil.formatMaps(m); } }