| // Copyright 2011 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package com.google.enterprise.adaptor; |
| |
| /** |
| * Refers to a unique document in repository. It is a thin wrapper of {@link |
| * String} that adds meaning to the String and prevents the string from being |
| * confused with others that do not refer to documents. |
| * |
| * <p>You provide a {@code DocId} to methods like {@link DocIdPusher#pushDocIds} |
| * to inform the GSA about the document's existance, so that it can crawl and |
| * index it. When the GSA requests that document's contents, {@link |
| * Request#getDocId} will have the same unique id as {@code DocId} you provided. |
| * However, just because a {@code DocId} is provided, does not mean the value it |
| * represents exists or ever existed. The GSA can query for documents that have |
| * been deleted and users can query for documents that never existed. |
| */ |
| public class DocId implements Comparable<DocId> { |
| private final String uniqId; // Not null. |
| |
| /** |
| * Construct an identifier based on {@code id}. |
| * |
| * @param id non-{@code null} document identifier |
| */ |
| public DocId(String id) { |
| if (id == null) { |
| throw new NullPointerException(); |
| } |
| this.uniqId = id; |
| } |
| |
| /** |
| * Returns the string identifier provided to the constructor. |
| */ |
| public String getUniqueId() { |
| return uniqId; |
| } |
| |
| /** Generates a string useful for debugging that contains the unique id. */ |
| @Override |
| public String toString() { |
| return "DocId(" + uniqId + ")"; |
| } |
| |
| /** |
| * Determines equality based on the unique id string. |
| */ |
| @Override |
| public boolean equals(Object o) { |
| if (null == o || !getClass().equals(o.getClass())) { |
| return false; |
| } |
| DocId d = (DocId) o; |
| return this.uniqId.equals(d.uniqId); |
| } |
| |
| /** |
| * Generates a hash code based on the unique id string. |
| */ |
| @Override |
| public int hashCode() { |
| return this.uniqId.hashCode(); |
| } |
| |
| /** |
| * Provides comparison for ids based on the unique id string. |
| */ |
| @Override |
| public int compareTo(DocId docId) { |
| return uniqId.compareTo(docId.uniqId); |
| } |
| } |