Changed the root package from net.sf.briar to org.briarproject.

briar-api/src/org/briarproject/api/UniqueId.java

@@ -0,0 +1,30 @@
+package org.briarproject.api;
+
+import java.util.Arrays;
+
+public abstract class UniqueId {
+
+	/** The length of a unique identifier in bytes. */
+	public static final int LENGTH = 48;
+
+	protected final byte[] id;
+
+	private int hashCode = -1;
+
+	protected UniqueId(byte[] id) {
+		if(id.length != LENGTH) throw new IllegalArgumentException();
+		this.id = id;
+	}
+
+	public byte[] getBytes() {
+		return id;
+	}
+
+	@Override
+	public int hashCode() {
+		// Thread-safe because if two or more threads check and update the
+		// value, they'll calculate the same value
+		if(hashCode == -1) hashCode = Arrays.hashCode(id);
+		return hashCode;
+	}
+}