/**
* Copyright 2009 Google Inc.
*
* 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 org.waveprotocol.wave.media.model;
import org.waveprotocol.wave.model.id.InvalidIdException;
import org.waveprotocol.wave.model.util.Preconditions;
/**
* An attachment is identified by a tuple of a service provider id and an
* identifying token unique to that provider.
*
*/
public final class AttachmentId implements Comparable<AttachmentId> {
/** Separates the domain from the id in an attachment id. */
public static final String ATTACHMENT_PART_SEPARATOR = "/";
private final String domain;
private final String id;
private volatile String serialized = null;
/**
* Creates an AttachmentId from a serialized attachment id.
*
* @param attachmentIdString a serialized attachment id
* @return an AttachmentId
* @throws InvalidIdException if the id cannot be parsed.
*/
public static AttachmentId deserialise(String attachmentIdString)
throws InvalidIdException {
Preconditions.checkNotNull(attachmentIdString, "Null attachmentIdString");
String[] parts = attachmentIdString.split(ATTACHMENT_PART_SEPARATOR);
// Two part ids are the expected case (eg. domain/id).
if (parts.length == 2) {
return new AttachmentId(parts[0], parts[1]);
}
// One part ids are for legacy ids (pre-migration).
// TODO(user): Remove support for legacy ids after the migration.
if (parts.length == 1) {
return new AttachmentId("", parts[0]);
}
// Not a valid id, throw an exception.
throw new InvalidIdException(attachmentIdString,
"Unable to deserialise the attachment id: " + attachmentIdString +
". The attachment id needs to look like <domain>/<id> or <id>");
}
/**
* Constructs an attachment id from domain and id components. Neither the
* domain nor the id may be null or contain the '/' character used to
* separate components. An exception will be thrown if these requirements are
* violated.
*
* @param domain must not be null.
* @param id must not be null.
*/
public AttachmentId(String domain, String id) {
Preconditions.checkNotNull(domain, "Null domain");
Preconditions.checkNotNull(id, "Null id");
if (domain.contains(ATTACHMENT_PART_SEPARATOR)) {
Preconditions.illegalArgument(
"An AttachmentId domain component cannot contain the '/' domain separator: " + domain);
}
if (id.contains(ATTACHMENT_PART_SEPARATOR)) {
Preconditions.illegalArgument(
"An AttachmentId id component cannot contain the '/' id separator: " + id);
}
this.domain = domain.intern();
this.id = id;
}
/**
* @return the domain
*/
public String getDomain() {
return domain;
}
/**
* @return the id
*/
public String getId() {
return id;
}
/**
* Serialises this attachmentId into a unique string. For any two attachment
* ids, attachmentId1.serialise().equals(attachmentId2.serialise()) iff
* attachmentId1.equals(attachmentId2).
*/
public String serialise() {
if (serialized == null) {
// TODO(user): Remove support for domain-less legacy ids after the
// migration.
if (domain.isEmpty()) {
serialized = id;
} else {
serialized = domain + ATTACHMENT_PART_SEPARATOR + id;
}
}
return serialized;
}
/**
* Generated by eclipse.
* {@inheritDoc}
*/
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + domain.hashCode();
result = prime * result + id.hashCode();
return result;
}
/**
* Generated by eclipse.
* {@inheritDoc}
*/
@Override
public boolean equals(Object obj) {
if (this == obj) { return true; }
if (obj == null) { return false; }
if (getClass() != obj.getClass()) { return false; }
AttachmentId other = (AttachmentId) obj;
return domain == other.domain && id.equals(other.id);
}
@Override
public String toString() {
return "[AttachmentId:" + serialise() + "]";
}
@Override
public int compareTo(AttachmentId other) {
int domainCompare = domain.compareTo(other.domain);
if (domainCompare == 0) {
return id.compareTo(other.id);
} else {
return domainCompare;
}
}
}