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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17
    18  /*
    19   * LongIdentity.java
    20   *
    21   */
    22
    23  package javax.jdo.identity;
    24
    25  import java.io.IOException;
    26  import java.io.ObjectInput;
    27  import java.io.ObjectOutput;
    28
    29  /** This class is for identity with a single long field.
    30   * @version 2.0
    31   */
    32  public class LongIdentity extends SingleFieldIdentity {
    33
    34      /** The key.
    35       */
    36      private long key;
    37
    38      private void construct(long key) {
    39          this.key = key;
    40          hashCode = hashClassName() ^ (int)key;
    41      }
    42
    43      /** Constructor with class and key.
    44       * @param pcClass the class
    45       * @param key the key
    46       */
    47      public LongIdentity (Class pcClass, long key) {
    48          super (pcClass);
    49          construct(key);
    50      }
    51
    52      /** Constructor with class and key.
    53       * @param pcClass the class
    54       * @param key the key
    55       */
    56      public LongIdentity (Class pcClass, Long key) {
    57          super(pcClass);
    58          setKeyAsObject(key);
    59          construct(key.longValue());
    60      }
    61
    62      /** Constructor with class and key.
    63       * @param pcClass the class
    64       * @param str the key
    65       */
    66      public LongIdentity (Class pcClass, String str) {
    67          super(pcClass);
    68          assertKeyNotNull(str);
    69          construct(Long.parseLong(str));
    70      }
    71
    72      /** Constructor only for Externalizable.
    73       */
    74      public LongIdentity () {
    75      }
    76
    77      /** Return the key.
    78       * @return the key
    79       */
    80      public long getKey () {
    81          return key;
    82      }
    83
    84      /** Return the String form of the key.
    85       * @return the String form of the key
    86       */
    87      public String toString () {
    88          return Long.toString(key);
    89      }
    90
    91      /** Determine if the other object represents the same object id.
    92       * @param obj the other object
    93       * @return true if both objects represent the same object id
    94       */
    95      public boolean equals (Object obj) {
    96          if (this == obj) {
    97              return true;
    98          } else if (!super.equals (obj)) {
    99              return false;
    100         } else {
    101             LongIdentity other = (LongIdentity) obj;
    102             return key == other.key;
    103         }
    104     }
    105
    106     /** Determine the ordering of identity objects.
    107      * @param o Other identity
    108      * @return The relative ordering between the objects
    109      * @since 2.2
    110      */
    111     public int compareTo(Object o) {
    112         if (o instanceof LongIdentity) {
    113         	LongIdentity other = (LongIdentity)o;
    114             int result = super.compare(other);
    115             if (result == 0) {
    116                 long diff = key - other.key;
    117                 if (diff == 0) {
    118                     return 0;
    119                 } else {
    120                     if (diff < 0) {
    121                         return -1;
    122                     } else {
    123                         return 1;
    124                     }
    125                 }
    126             } else {
    127                 return result;
    128             }
    129         }
    130         else if (o == null) {
    131             throw new ClassCastException("object is null");
    132         }
    133         throw new ClassCastException(this.getClass().getName() + " != " + o.getClass().getName());
    134     }
    135
    136     /** Create the key as an Object.
    137      * @return the key as an Object
    138      * @since 2.0
    139      */
    140     protected Object createKeyAsObject() {
    141         return new Long(key);
    142     }
    143
    144     /** Write this object. Write the superclass first.
    145      * @param out the output
    146      */
    147     public void writeExternal(ObjectOutput out) throws IOException {
    148         super.writeExternal (out);
    149         out.writeLong(key);
    150     }
    151
    152     /** Read this object. Read the superclass first.
    153      * @param in the input
    154      */
    155     public void readExternal(ObjectInput in)
    156 		throws IOException, ClassNotFoundException {
    157         super.readExternal (in);
    158         key = in.readLong();
    159     }
    160
    161 }