Java tutorial
/* * #%L * Protempa Framework * %% * Copyright (C) 2012 - 2013 Emory University * %% * 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. * #L% */ /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package org.protempa.proposition; import java.io.IOException; import java.io.InvalidObjectException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import org.apache.commons.lang3.builder.ToStringBuilder; /** * A global unique identifier for {@link Proposition}s. It * implements {@link Serializable} so that unique identifiers * can be serialized along with {@link Proposition}s. * * @author Andrew Post */ public final class UniqueId implements Serializable { private static final long serialVersionUID = 396847781133676191L; private SourceId sourceId; private LocalUniqueId localUniqueId; private transient volatile int hashCode; /** * Copy constructor. * * @param other another {@link UniqueIdentifier}. */ public UniqueId(UniqueId other) { if (other == null) { throw new IllegalArgumentException("other cannot be null"); } this.sourceId = other.sourceId; this.localUniqueId = other.localUniqueId; } /** * Instantiates a new unique identifier. * * @param dataSourceBackendId the data source backend it from which the * {@link Proposition} came. Cannot be <code>null</code>. * @param localUniqueId the {@link LocalUniqueIdentifier}, a data source * backend-specific unique id for a {@link Proposition}. */ public UniqueId(SourceId newSourceId, LocalUniqueId localUniqueId) { if (newSourceId == null) { throw new IllegalArgumentException("dataSourceBackendId cannot be null"); } if (localUniqueId == null) { throw new IllegalArgumentException("localUniqueId cannot be null"); } this.sourceId = newSourceId; this.localUniqueId = localUniqueId.clone(); } public SourceId getSourceId() { return this.sourceId; } public LocalUniqueId getLocalUniqueId() { return this.localUniqueId; } public String getStringRepresentation() { return this.sourceId.getId() + "^" + this.localUniqueId.getId(); } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final UniqueId other = (UniqueId) obj; if (!this.sourceId.equals(other.sourceId)) { return false; } if (!this.localUniqueId.equals(other.localUniqueId)) { return false; } return true; } @Override public int hashCode() { if (this.hashCode == 0) { int result = 17; /* * We weight localUniqueId higher because it is the primary source * of variability (there only will be a few different source ids * being used at a time). */ result = 37 * result + this.localUniqueId.hashCode(); result = 104743 * result + this.sourceId.hashCode(); this.hashCode = result; } return this.hashCode; } @Override public String toString() { return ToStringBuilder.reflectionToString(this); } private void writeObject(ObjectOutputStream s) throws IOException { boolean derived = (this.sourceId instanceof DerivedSourceId); s.writeBoolean(derived); if (!derived) { s.writeObject(this.sourceId.getId()); } s.writeObject(this.localUniqueId); } private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { if (s.readBoolean()) { this.sourceId = DerivedSourceId.getInstance(); } else { String id = (String) s.readObject(); if (id == null) { throw new InvalidObjectException("Can't restore. Null id"); } this.sourceId = DataSourceBackendId.getInstance(id); } this.localUniqueId = (LocalUniqueId) s.readObject(); } }