Custom HashCode Builder : HashCodeBuilder « Apache Common « Java Tutorial






/* 
 * ========================================================================
 * 
 * Copyright 2005 Tim O'Brien.
 *
 * 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.
 * 
 * ========================================================================
 */
import java.math.BigDecimal;
import java.util.HashSet;
import java.util.Set;

import org.apache.commons.lang.builder.CompareToBuilder;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;

class TaxReturn {

  private String ssn;

  private int year;

  private String lastName;

  private BigDecimal taxableIncome;

  public TaxReturn() {
  }

  public TaxReturn(String pSsn, int pYear, String pLastName, BigDecimal pTaxableIncome) {
    setSsn(pSsn);
    setYear(pYear);
    setLastName(pLastName);
    setTaxableIncome(pTaxableIncome);
  }

  public String getSsn() {
    return ssn;
  }

  public void setSsn(String pSsn) {
    ssn = pSsn;
  }

  public int getYear() {
    return year;
  }

  public void setYear(int pYear) {
    year = pYear;
  }

  public String getLastName() {
    return lastName;
  }

  public void setLastName(String pLastName) {
    lastName = pLastName;
  }

  public BigDecimal getTaxableIncome() {
    return taxableIncome;
  }

  public void setTaxableIncome(BigDecimal pTaxableIncome) {
    taxableIncome = pTaxableIncome;
  }

  public String toString() {
    return new ToStringBuilder(this).append("ssn", ssn).append("year", year).append("lastName",
        lastName).toString();
  }

  public int hashCode() {
    return new HashCodeBuilder(3, 7).append(ssn).append(year).toHashCode();
  }

  public boolean equals(Object pObject) {
    boolean equals = false;
    if (pObject instanceof TaxReturn) {
      TaxReturn bean = (TaxReturn) pObject;
      equals = (new EqualsBuilder().append(ssn, bean.ssn).append(year, bean.year)).isEquals();
    }
    return equals;
  }

  public int compareTo(Object pObject) {
    return CompareToBuilder.reflectionCompare(this, pObject);
  }

}

public class MainClass {

  public static void main(String[] pArgs) throws Exception {
     TaxReturn return1 = new TaxReturn("012-68-3242", 1998, "O'Brien", new BigDecimal(43000.00));
     TaxReturn return2 = new TaxReturn("012-68-3242", 1999, "O'Brien", new BigDecimal(45000.00));
     TaxReturn return3 = new TaxReturn("012-68-3242", 1999, "O'Brien", new BigDecimal(53222.00));

     System.out.println("HashCodeBuilder: " + return2.hashCode());
     Set set = new HashSet();
     set.add(return1);
     set.add(return2);
     set.add(return3);
     System.out.println(set);
  }
}
HashCodeBuilder: 219210998
[TaxReturn@7ffe01[ssn=012-68-3242,year=1998,lastName=O'Brien], TaxReturn@471e30[ssn=012-68-3242,year=1999,lastName=O'Brien]]
  Download:  CommonLangCustomHashCodeBuilder.zip( 202 k)








37.16.HashCodeBuilder
37.16.1.HashCode For String
37.16.2.HashCodeBuilder.reflectionHashCode
37.16.3.HashCode Builder
37.16.4.Custom HashCode Builder