Java tutorial
/* * Copyright 2009-2015 Hewlett-Packard Development Company, L.P. * Licensed under the MIT License (the "License"); you may not use this file except in compliance with the License. */ package com.hp.autonomy.aci.content.identifier.id; import org.apache.commons.lang.Validate; import java.util.Collections; import java.util.Iterator; /** * A representation of a document id. A document id is a number that uniquely identifies a document within a particular * instance of IDOL's Content server, as found in the <autn:id> tag of a query response. Note that the use of * document ids is usually discouraged because they are ambiguous in a distributed system - document references are * preferred. */ public class Id extends AbstractIds implements Comparable<Id> { private final int id; /** * Creates a new {@code Id} instance for the specified numeric document id. * * @param id The document id */ public Id(final int id) { Validate.isTrue(id > 0, "ID must be at least 1"); this.id = id; } @Override public Iterator<Id> iterator() { // Should probably rewrite this to use a custom iterator return Collections.singletonList(this).iterator(); } /** * Accessor for the numeric value of the document id. * * @return The document id */ public int getId() { return id; } /** * For a single id the size is always 1. * * @return {@code 1} */ @Override public int size() { return 1; } /** * A single id can never be empty. * * @return {@code false} */ @Override public boolean isEmpty() { return false; } @Override public String toString() { return String.valueOf(id); } /** * Provides a natural ordering for the Id class such that Ids can be sorted into increasing numerical order. * * @param id An id object for comparision * @return {@code -1}, {@code 0} or {@code 1} */ @Override public int compareTo(final Id id) { return Integer.valueOf(this.id).compareTo(id.id); } }