MemorySimulation_BestFit

package programing_3_;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;

class Process {
	int size;
	int startAddress;
	int endAddress;

	public Process() {
		Random random = new Random();
		// 프로세스 사이즈는 3~10
		size = random.nextInt(8) + 3;
	}

	public int getStartAddress() {
		return startAddress;
	}

	public void setStartAddress(int startAddress) {
		this.startAddress = startAddress;
	}

	public int getEndAddress() {
		return endAddress;
	}

	public void setEndAddress(int endAddress) {
		this.endAddress = endAddress;
	}
}

class Hole {
	int startAddress;
	int endAddress;
	int size;

	// Hole만들때는 startAddress, endAddress인자로 줘야함.
	public Hole(int startAddress, int endAddress) {
		this.startAddress = startAddress;
		this.endAddress = endAddress;
		this.size = endAddress - startAddress;
	}

	public int getStartAddress() {
		return startAddress;
	}

	public void setStartAddress(int startAddress) {
		this.startAddress = startAddress;
	}

	public int getEndAddress() {
		return endAddress;
	}

	public void setEndAddress(int endAddress) {
		this.endAddress = endAddress;
	}

	public int getSize() {
		return size;
	}

	public void setSize(int endAddress, int startAddress) {
		this.size = endAddress - startAddress;
	}

}

public class MemorySimulation_BestFit {
	public static void main(String[] args) {
		Queue<Process> processQueue = new LinkedList<Process>();
		ArrayList<Hole> hole = new ArrayList<Hole>();
		ArrayList<Process> process = new ArrayList<Process>();
		Hole firstHole = new Hole(0, 100);
		hole.add(firstHole);
		int num = 0;
		boolean externalFragmentation = false;
		int[] diffrence = null;
		int min;
		int min_index;
		while (!externalFragmentation) {
			// 프로세스 4개 생성
			for (int i = 0; i < 4; i++) {
				Process newProcess = new Process();
				processQueue.add(newProcess);
			}
			// 프로세스 큐에서 하나씩 꺼내면서 비교
			while (!processQueue.isEmpty()) {
				// 프로세스큐에서 하나씩 꺼냄
				Process removedProcess = processQueue.poll();
				diffrence = new int[hole.size()];
				for (int j = 0; j < hole.size(); j++) {
					// 꺼낸 프로세스 사이즈와 홀의 사이즈 비교
					diffrence[j] = hole.get(j).getSize() - removedProcess.size;
				}
				min = diffrence[0];
				min_index = 0;
				for (int k = 1; k < diffrence.length; k++) {
					if (diffrence[k] < min) {
						if (diffrence[k] < 0)
							continue;
						else
							min = diffrence[k];
						// 프로세스를 넣게 될 hole의 인덱스
						min_index = k;
					} else
						continue;
				}
				if (min > 0) {
					removedProcess.setStartAddress(hole.get(min_index).getStartAddress());
					removedProcess.setEndAddress(hole.get(min_index).getStartAddress() + removedProcess.size);
					hole.get(min_index).setStartAddress(removedProcess.getEndAddress());
					hole.get(min_index).setSize(hole.get(min_index).getEndAddress(),
							hole.get(min_index).getStartAddress());
					process.add(removedProcess);
				} else if (min == 0) {
					removedProcess.setStartAddress(hole.get(min_index).getStartAddress());
					removedProcess.setEndAddress(hole.get(min_index).getStartAddress() + removedProcess.size);
					hole.remove(min_index);
					process.add(removedProcess);
				} else {
					for (int k = 0; k < process.size(); k++) {
						System.out.printf("[%d]번째 프로세스 주소(%d, %d)\n", k, process.get(k).getStartAddress(),
								process.get(k).getEndAddress());
					}
					System.out.println("외부단편화 발생");
					externalFragmentation = true;
					break;
				}
				// 꺼낸 프로세스 사이즈가 홀의 사이즈보다 작다면
				/*
				 * if (removedProcess.size < hole.get(j).getSize()) {
				 * removedProcess.setStartAddress(hole.get(j).getStartAddress());
				 * removedProcess.setEndAddress(hole.get(j).getStartAddress() +
				 * removedProcess.size);
				 * hole.get(j).setStartAddress(removedProcess.getEndAddress());
				 * hole.get(j).setSize(hole.get(j).getEndAddress(),
				 * hole.get(j).getStartAddress()); process.add(removedProcess); break; } else if
				 * (removedProcess.size == hole.get(j).getSize()) {
				 * removedProcess.setStartAddress(hole.get(j).getStartAddress());
				 * removedProcess.setEndAddress(hole.get(j).getStartAddress() +
				 * removedProcess.size); hole.remove(j); process.add(removedProcess); break; }
				 * else { // hole의 리스트를 다 순회했다면 if (j == hole.size() - 1) { for (int k = 0; k <
				 * process.size(); k++) { System.out.printf("[%d]번째 프로세스 주소(%d, %d)\n", k,
				 * process.get(k).getStartAddress(), process.get(k).getEndAddress()); }
				 * System.out.println("외부단편화 발생"); externalFragmentation = true; break; }
				 * continue; }
				 */

			}

			for (int i = 0; i < 2; i++) {
				Random random = new Random();
				Process removeProcess = new Process();
				if (process.size() <= 0) {
					System.out.println("프로세스스가 비었습니다.");
					break;
				}
				num = random.nextInt(process.size());
				removeProcess = process.get(num);
				if (process.size() == 0) {
					System.out.println("hole이 비어있습니다.");
					break;
				}

				for (int j = 0; j < hole.size(); j++) {
					// 프로세스의 end주소와 hole의 start주소가 같다면(삭제하려는 프로세스가 hole과 연속된다면
					if (removeProcess.getEndAddress() == hole.get(j).startAddress) {
						hole.get(j).setStartAddress(removeProcess.getStartAddress());
						hole.get(j).setSize(hole.get(j).getEndAddress(), hole.get(j).getStartAddress());
						break;
					}
					// 프로세스의 end주소와 홀의 start주소와 같은게 없다면
					else if (j == hole.size() - 1) {
						Hole newHole = new Hole(removeProcess.getStartAddress(), removeProcess.getEndAddress());
						hole.add(newHole);
						break;
					} else
						continue;
				}
				process.remove(num);

			}

		}

	}
}