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Diffstat (limited to 'p1/Repository.java')
| -rw-r--r-- | p1/Repository.java | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/p1/Repository.java b/p1/Repository.java new file mode 100644 index 0000000..dff76e7 --- /dev/null +++ b/p1/Repository.java @@ -0,0 +1,241 @@ +import java.util.*; +import java.text.SimpleDateFormat; + +public class Repository { + + private String name; + private Commit head; + private int size; + + public Repository(String name) { + if (name == null || name.isEmpty()) { + throw new IllegalArgumentException("Repository needs a name!"); + } + + this.name = name; + } + + public String getRepoHead() { + if (head == null) { + return null; + } + return head.id; + } + + public int getRepoSize() { + Commit temp = head; + int size = 0; + while (temp != null) { + size++; + temp = temp.past; + } + this.size = size; + return size; + } + + public String toString() { + if (head == null) { + return name + " - No commits"; + } + return name + " - Current head: " + head.toString(); + } + + public boolean contains(String targetId) { + Commit temp = head; + + while (temp != null) { + if (temp.id.equals(targetId)) { + return true; + } + temp = temp.past; + } + + return false; + } + + public String getHistory(int n) { + if (n <= 0) { + throw new IllegalArgumentException("do you want the history or not?"); + } + + Commit temp = head; + String history = ""; + if (n > size) { + while (temp != null) { + history += temp.toString() + "\n"; + temp = temp.past; + } + } + + for (int i = 0; i < n && temp != null; i++) { + history += temp.toString() + "\n"; + temp = temp.past; + } + + return history; + } + + public String commit(String message) { + if (head == null) { + head = new Commit(message); + return head.id; + } + Commit old = head; + head = new Commit(message, old); + size++; + return head.id; + } + + public boolean drop(String targetId) { + // list is empty + if (head == null) { + return false; + } + + size--; + Commit temp = head; + + // front + if (temp.id.equals(targetId)) { + head = temp.past; + return true; + } + + // middle + while (temp.past != null && temp.past.past != null) { + if (temp.past.id == targetId) { + temp.past = temp.past.past; + return true; + } + temp = temp.past; + } + + // end + if (temp.past != null && temp.past.id.equals(targetId)) { + temp.past = null; + return true; + } + + // if we get here, targetId was not found, return size to initial state + size++; + return false; + } + + public void synchronize(Repository other) { + if (head == null && other.head == null) { + head = null; + } else if (head == null) { + head = other.head; + other.head = null; + } else if (other.head == null) { + other.head = null; + } else { + List<Commit> commitList = new ArrayList<>(); + Comparator commitComparator = new Comparator<Commit>() { + public int compare(Commit one, Commit two) { + return Long.compare(one.timeStamp, two.timeStamp); + } + }; + Commit temp = head; + while (temp != null) { + commitList.add(temp); + temp = temp.past; + } + temp = other.head; + while (temp != null) { + commitList.add(temp); + temp = temp.past; + } + commitList.sort(commitComparator); + Commit prev = null; + for (Commit commit : commitList) { + commit.past = prev; + prev = commit; + } + head = commitList.get(commitList.size() - 1); + other.head = null; + } + } + /** + * DO NOT MODIFY + * A class that represents a single commit in the repository. + * Commits are characterized by an identifier, a commit message, + * and the time that the commit was made. A commit also stores + * a reference to the immediately previous commit if it exists. + * + * Staff Note: You may notice that the comments in this + * class openly mention the fields of the class. This is fine + * because the fields of the Commit class are public. In general, + * be careful about revealing implementation details! + */ + public class Commit { + + private static int currentCommitID; + + /** + * The time, in milliseconds, at which this commit was created. + */ + public final long timeStamp; + + /** + * A unique identifier for this commit. + */ + public final String id; + + /** + * A message describing the changes made in this commit. + */ + public final String message; + + /** + * A reference to the previous commit, if it exists. Otherwise, null. + */ + public Commit past; + + /** + * Constructs a commit object. The unique identifier and timestamp + * are automatically generated. + * @param message A message describing the changes made in this commit. + * @param past A reference to the commit made immediately before this + * commit. + */ + public Commit(String message, Commit past) { + this.id = "" + currentCommitID++; + this.message = message; + this.timeStamp = System.currentTimeMillis(); + this.past = past; + } + + /** + * Constructs a commit object with no previous commit. The unique + * identifier and timestamp are automatically generated. + * @param message A message describing the changes made in this commit. + */ + public Commit(String message) { + this(message, null); + } + + /** + * Returns a string representation of this commit. The string + * representation consists of this commit's unique identifier, + * timestamp, and message, in the following form: + * "[identifier] at [timestamp]: [message]" + * @return The string representation of this collection. + */ + @Override + public String toString() { + SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd 'at' HH:mm:ss z"); + Date date = new Date(timeStamp); + + return id + " at " + formatter.format(date) + ": " + message; + } + + /** + * Resets the IDs of the commit nodes such that they reset to 0. + * Primarily for testing purposes. + */ + public static void resetIds() { + Commit.currentCommitID = 0; + } + } +} |