Coverage Report - org.apache.commons.lang3.tuple.Pair
 
Classes in this File Line Coverage Branch Coverage Complexity
Pair
100%
14/14
91%
11/12
1,7
 
 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  
 package org.apache.commons.lang3.tuple;
 18  
 
 19  
 import java.io.Serializable;
 20  
 import java.util.Map;
 21  
 
 22  
 import org.apache.commons.lang3.ObjectUtils;
 23  
 import org.apache.commons.lang3.builder.CompareToBuilder;
 24  
 
 25  
 /**
 26  
  * <p>A pair consisting of two elements.</p>
 27  
  * 
 28  
  * <p>This class is an abstract implementation defining the basic API.
 29  
  * It refers to the elements as 'left' and 'right'. It also implements the
 30  
  * {@code Map.Entry} interface where the key is 'left' and the value is 'right'.</p>
 31  
  * 
 32  
  * <p>Subclass implementations may be mutable or immutable.
 33  
  * However, there is no restriction on the type of the stored objects that may be stored.
 34  
  * If mutable objects are stored in the pair, then the pair itself effectively becomes mutable.</p>
 35  
  *
 36  
  * @param <L> the left element type
 37  
  * @param <R> the right element type
 38  
  *
 39  
  * @since Lang 3.0
 40  
  * @version $Id: Pair.java 1557584 2014-01-12 18:26:49Z britter $
 41  
  */
 42  1715
 public abstract class Pair<L, R> implements Map.Entry<L, R>, Comparable<Pair<L, R>>, Serializable {
 43  
 
 44  
     /** Serialization version */
 45  
     private static final long serialVersionUID = 4954918890077093841L;
 46  
 
 47  
     /**
 48  
      * <p>Obtains an immutable pair of from two objects inferring the generic types.</p>
 49  
      * 
 50  
      * <p>This factory allows the pair to be created using inference to
 51  
      * obtain the generic types.</p>
 52  
      * 
 53  
      * @param <L> the left element type
 54  
      * @param <R> the right element type
 55  
      * @param left  the left element, may be null
 56  
      * @param right  the right element, may be null
 57  
      * @return a pair formed from the two parameters, not null
 58  
      */
 59  
     public static <L, R> Pair<L, R> of(final L left, final R right) {
 60  1422
         return new ImmutablePair<L, R>(left, right);
 61  
     }
 62  
 
 63  
     //-----------------------------------------------------------------------
 64  
     /**
 65  
      * <p>Gets the left element from this pair.</p>
 66  
      * 
 67  
      * <p>When treated as a key-value pair, this is the key.</p>
 68  
      * 
 69  
      * @return the left element, may be null
 70  
      */
 71  
     public abstract L getLeft();
 72  
 
 73  
     /**
 74  
      * <p>Gets the right element from this pair.</p>
 75  
      * 
 76  
      * <p>When treated as a key-value pair, this is the value.</p>
 77  
      * 
 78  
      * @return the right element, may be null
 79  
      */
 80  
     public abstract R getRight();
 81  
 
 82  
     /**
 83  
      * <p>Gets the key from this pair.</p>
 84  
      * 
 85  
      * <p>This method implements the {@code Map.Entry} interface returning the
 86  
      * left element as the key.</p>
 87  
      * 
 88  
      * @return the left element as the key, may be null
 89  
      */
 90  
     @Override
 91  
     public final L getKey() {
 92  2807
         return getLeft();
 93  
     }
 94  
 
 95  
     /**
 96  
      * <p>Gets the value from this pair.</p>
 97  
      * 
 98  
      * <p>This method implements the {@code Map.Entry} interface returning the
 99  
      * right element as the value.</p>
 100  
      * 
 101  
      * @return the right element as the value, may be null
 102  
      */
 103  
     @Override
 104  
     public R getValue() {
 105  2339
         return getRight();
 106  
     }
 107  
 
 108  
     //-----------------------------------------------------------------------
 109  
     /**
 110  
      * <p>Compares the pair based on the left element followed by the right element.
 111  
      * The types must be {@code Comparable}.</p>
 112  
      * 
 113  
      * @param other  the other pair, not null
 114  
      * @return negative if this is less, zero if equal, positive if greater
 115  
      */
 116  
     @Override
 117  
     public int compareTo(final Pair<L, R> other) {
 118  8
       return new CompareToBuilder().append(getLeft(), other.getLeft())
 119  
               .append(getRight(), other.getRight()).toComparison();
 120  
     }
 121  
 
 122  
     /**
 123  
      * <p>Compares this pair to another based on the two elements.</p>
 124  
      * 
 125  
      * @param obj  the object to compare to, null returns false
 126  
      * @return true if the elements of the pair are equal
 127  
      */
 128  
     @SuppressWarnings( "deprecation" ) // ObjectUtils.equals(Object, Object) has been deprecated in 3.2
 129  
     @Override
 130  
     public boolean equals(final Object obj) {
 131  374
         if (obj == this) {
 132  4
             return true;
 133  
         }
 134  370
         if (obj instanceof Map.Entry<?, ?>) {
 135  368
             final Map.Entry<?, ?> other = (Map.Entry<?, ?>) obj;
 136  368
             return ObjectUtils.equals(getKey(), other.getKey())
 137  
                     && ObjectUtils.equals(getValue(), other.getValue());
 138  
         }
 139  2
         return false;
 140  
     }
 141  
 
 142  
     /**
 143  
      * <p>Returns a suitable hash code.
 144  
      * The hash code follows the definition in {@code Map.Entry}.</p>
 145  
      * 
 146  
      * @return the hash code
 147  
      */
 148  
     @Override
 149  
     public int hashCode() {
 150  
         // see Map.Entry API specification
 151  733
         return (getKey() == null ? 0 : getKey().hashCode()) ^
 152  
                 (getValue() == null ? 0 : getValue().hashCode());
 153  
     }
 154  
 
 155  
     /**
 156  
      * <p>Returns a String representation of this pair using the format {@code ($left,$right)}.</p>
 157  
      * 
 158  
      * @return a string describing this object, not null
 159  
      */
 160  
     @Override
 161  
     public String toString() {
 162  11
         return new StringBuilder().append('(').append(getLeft()).append(',').append(getRight()).append(')').toString();
 163  
     }
 164  
 
 165  
     /**
 166  
      * <p>Formats the receiver using the given format.</p>
 167  
      * 
 168  
      * <p>This uses {@link java.util.Formattable} to perform the formatting. Two variables may
 169  
      * be used to embed the left and right elements. Use {@code %1$s} for the left
 170  
      * element (key) and {@code %2$s} for the right element (value).
 171  
      * The default format used by {@code toString()} is {@code (%1$s,%2$s)}.</p>
 172  
      * 
 173  
      * @param format  the format string, optionally containing {@code %1$s} and {@code %2$s}, not null
 174  
      * @return the formatted string, not null
 175  
      */
 176  
     public String toString(final String format) {
 177  1
         return String.format(format, getLeft(), getRight());
 178  
     }
 179  
 
 180  
 }