/**
* Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.id;
import java.io.Serializable;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.text.StrBuilder;
import org.joda.convert.FromString;
import org.joda.convert.ToString;
import com.opengamma.util.ArgumentChecker;
import com.opengamma.util.PublicAPI;
/**
* An immutable object identifier for an item within the OpenGamma instance.
* <p>
* This identifier is used as a handle within the system to refer to an item uniquely over time.
* All versions of the same object share an object identifier.
* A {@link UniqueId} refers to a single version of an object identifier.
* <p>
* Many external identifiers, represented by {@link ExternalId}, are not truly unique.
* This {@code ObjectId} and {@code UniqueId} are unique within the OpenGamma instance.
* <p>
* The object identifier is formed from two parts, the scheme and value.
* The scheme defines a single way of identifying items, while the value is an identifier
* within that scheme. A value from one scheme may refer to a completely different
* real-world item than the same value from a different scheme.
* <p>
* Real-world examples of {@code ObjectId} include instances of:
* <ul>
* <li>Database key - DbSec~123456</li>
* <li>In memory key - MemSec~123456</li>
* </ul>
* <p>
* This class is immutable and thread-safe.
*/
@PublicAPI
public final class ObjectId
implements Comparable<ObjectId>, ObjectIdentifiable, Serializable {
/**
* Identification scheme for the object identifier.
* This allows a unique identifier to be stored and passed using an {@code ExternalId}.
*/
public static final ExternalScheme EXTERNAL_SCHEME = ExternalScheme.of("OID");
/** Serialization version. */
private static final long serialVersionUID = 1L;
/**
* The scheme that categorizes the identifier value.
*/
private final String _scheme;
/**
* The identifier value within the scheme.
*/
private final String _value;
/**
* Obtains an {@code ObjectId} from a scheme and value.
*
* @param scheme the scheme of the object identifier, not empty, not null
* @param value the value of the object identifier, not empty, not null
* @return the object identifier, not null
*/
public static ObjectId of(String scheme, String value) {
return new ObjectId(scheme, value);
}
/**
* Parses an {@code ObjectId} from a formatted scheme and value.
* <p>
* This parses the identifier from the form produced by {@code toString()}
* which is {@code <SCHEME>~<VALUE>}.
*
* @param str the object identifier to parse, not null
* @return the object identifier, not null
* @throws IllegalArgumentException if the identifier cannot be parsed
*/
@FromString
public static ObjectId parse(String str) {
ArgumentChecker.notEmpty(str, "str");
if (str.contains("~") == false) {
str = StringUtils.replace(str, "::", "~"); // leniently parse old data
}
String[] split = StringUtils.splitByWholeSeparatorPreserveAllTokens(str, "~");
switch (split.length) {
case 2:
return ObjectId.of(split[0], split[1]);
}
throw new IllegalArgumentException("Invalid identifier format: " + str);
}
/**
* Creates an object identifier.
*
* @param scheme the scheme of the identifier, not empty, not null
* @param value the value of the identifier, not empty, not null
*/
private ObjectId(String scheme, String value) {
ArgumentChecker.notEmpty(scheme, "scheme");
ArgumentChecker.notEmpty(value, "value");
_scheme = scheme;
_value = value;
}
//-------------------------------------------------------------------------
/**
* Gets the scheme of the identifier.
* This is the first part of the object identifier.
* <p>
* This is not expected to be the same as {@link ExternalScheme}.
*
* @return the scheme, not empty, not null
*/
public String getScheme() {
return _scheme;
}
/**
* Gets the value of the identifier.
* This is the second part of the object identifier.
*
* @return the value, not empty, not null
*/
public String getValue() {
return _value;
}
//-------------------------------------------------------------------------
/**
* Returns a copy of this identifier with the specified scheme.
*
* @param scheme the new scheme of the identifier, not empty, not null
* @return an {@link ObjectId} based on this identifier with the specified scheme, not null
*/
public ObjectId withScheme(final String scheme) {
return ObjectId.of(scheme, _value);
}
/**
* Returns a copy of this identifier with the specified value.
*
* @param value the new value of the identifier, not empty, not null
* @return an {@link ObjectId} based on this identifier with the specified value, not null
*/
public ObjectId withValue(final String value) {
return ObjectId.of(_scheme, value);
}
//-------------------------------------------------------------------------
/**
* Creates a unique identifier with the latest version.
* <p>
* This creates a new unique identifier based on this object identifier marked
* to retrieve the latest version.
*
* @return a {@link UniqueId} based on this identifier at the latest version, not null
*/
public UniqueId atLatestVersion() {
return UniqueId.of(_scheme, _value, null);
}
/**
* Creates a unique identifier with the specified version.
* <p>
* This creates a new unique identifier based on this object identifier using
* the specified version.
*
* @param version the new version of the identifier, empty treated as null, null treated as latest version
* @return a {@link UniqueId} based on this identifier at the specified version, not null
*/
public UniqueId atVersion(final String version) {
return UniqueId.of(_scheme, _value, version);
}
//-------------------------------------------------------------------------
/**
* Gets the object identifier.
* <p>
* This method trivially returns {@code this}.
*
* @return {@code this}, not null
*/
@Override
public ObjectId getObjectId() {
return this;
}
//-------------------------------------------------------------------------
/**
* Compares the object identifiers, sorting alphabetically by scheme followed by value.
*
* @param other the other object identifier, not null
* @return negative if this is less, zero if equal, positive if greater
*/
@Override
public int compareTo(ObjectId other) {
int cmp = _scheme.compareTo(other._scheme);
if (cmp != 0) {
return cmp;
}
return _value.compareTo(other._value);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof ObjectId) {
ObjectId other = (ObjectId) obj;
return _scheme.equals(other._scheme) &&
_value.equals(other._value);
}
return false;
}
@Override
public int hashCode() {
return _scheme.hashCode() ^ _value.hashCode();
}
/**
* Returns the identifier in the form {@code <SCHEME>~<VALUE>}.
*
* @return a parsable representation of the identifier, not null
*/
@Override
@ToString
public String toString() {
return new StrBuilder().append(_scheme).append('~').append(_value).toString();
}
}