| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.openjpa.util; |
| |
| import java.io.Serializable; |
| |
| import org.apache.openjpa.lib.util.collections.AbstractReferenceMap.ReferenceStrength; |
| import org.apache.openjpa.lib.util.concurrent.ConcurrentReferenceHashMap; |
| |
| /** |
| * Identity class extended by built-in OpenJPA identity objects. |
| * |
| * @author Steve Kim |
| */ |
| public abstract class OpenJPAId |
| implements Comparable, Serializable { |
| |
| private static final long serialVersionUID = 1L; |
| |
| public static final char TYPE_VALUE_SEP = '-'; |
| |
| // cache the types' generated hash codes |
| private static ConcurrentReferenceHashMap _typeCache = |
| new ConcurrentReferenceHashMap(ReferenceStrength.WEAK, ReferenceStrength.HARD); |
| |
| protected Class type; |
| protected boolean subs = true; |
| |
| // type hash is based on the least-derived non-object class so that |
| // user-given ids with non-exact types match ids with exact types |
| private int _typeHash = 0; |
| |
| protected OpenJPAId() { |
| } |
| |
| protected OpenJPAId(Class type) { |
| this.type = type; |
| } |
| |
| protected OpenJPAId(Class type, boolean subs) { |
| this.type = type; |
| this.subs = subs; |
| } |
| |
| /** |
| * Return the persistent class which this id instance represents. |
| */ |
| public Class getType() { |
| return type; |
| } |
| |
| /** |
| * Whether this oid might be for a subclass of the given type. |
| * Defaults to true. |
| */ |
| public boolean hasSubclasses() { |
| return subs; |
| } |
| |
| /** |
| * Set the exact type of the described instance once it is known. |
| */ |
| public void setManagedInstanceType(Class type) { |
| setManagedInstanceType(type, false); |
| } |
| |
| /** |
| * Set the exact type of the described instance once it is known. |
| */ |
| public void setManagedInstanceType(Class type, boolean subs) { |
| this.type = type; |
| this.subs = subs; |
| } |
| |
| /** |
| * Return the identity value as an object. |
| */ |
| public abstract Object getIdObject(); |
| |
| /** |
| * Return the id's hash code. |
| */ |
| protected abstract int idHash(); |
| |
| /** |
| * Compare the id to the id of the given instance. |
| */ |
| protected abstract boolean idEquals(OpenJPAId other); |
| |
| /** |
| * Generate the hash code for this Id. Cache the type's generated hash code |
| * so that it doesn't have to be generated each time. |
| */ |
| @Override |
| public int hashCode() { |
| if (_typeHash == 0) { |
| Integer typeHashInt = (Integer) _typeCache.get(type); |
| if (typeHashInt == null) { |
| Class base = type; |
| Class superclass = base.getSuperclass(); |
| while (superclass != null && superclass != Object.class) { |
| base = base.getSuperclass(); |
| superclass = base.getSuperclass(); |
| } |
| _typeHash = base.getName().hashCode(); |
| _typeCache.put(type, _typeHash); |
| } else { |
| _typeHash = typeHashInt; |
| } |
| } |
| return _typeHash ^ idHash(); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o == this) |
| return true; |
| if (o == null || getClass() != o.getClass()) |
| return false; |
| |
| OpenJPAId id = (OpenJPAId) o; |
| return idEquals(id) && (id.type.isAssignableFrom(type) |
| || (subs && type.isAssignableFrom(id.type))); |
| } |
| |
| @Override |
| public String toString() { |
| return type.getName() + TYPE_VALUE_SEP + getIdObject(); |
| } |
| |
| @Override |
| public int compareTo(Object other) { |
| if (other == this) |
| return 0; |
| if (other == null) |
| return 1; |
| return ((Comparable) getIdObject()).compareTo(((OpenJPAId) other).getIdObject ()); |
| } |
| } |