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  
  */
 41  1751
 public abstract class Pair<L, R> implements Map.Entry<L, R>, Comparable<Pair<L, R>>, Serializable {
 42  
 
 43  
     /** Serialization version */
 44  
     private static final long serialVersionUID = 4954918890077093841L;
 45  
 
 46  
     /**
 47  
      * <p>Obtains an immutable pair of from two objects inferring the generic types.</p>
 48  
      * 
 49  
      * <p>This factory allows the pair to be created using inference to
 50  
      * obtain the generic types.</p>
 51  
      * 
 52  
      * @param <L> the left element type
 53  
      * @param <R> the right element type
 54  
      * @param left  the left element, may be null
 55  
      * @param right  the right element, may be null
 56  
      * @return a pair formed from the two parameters, not null
 57  
      */
 58  
     public static <L, R> Pair<L, R> of(final L left, final R right) {
 59  1454
         return new ImmutablePair<L, R>(left, right);
 60  
     }
 61  
 
 62  
     //-----------------------------------------------------------------------
 63  
     /**
 64  
      * <p>Gets the left element from this pair.</p>
 65  
      * 
 66  
      * <p>When treated as a key-value pair, this is the key.</p>
 67  
      * 
 68  
      * @return the left element, may be null
 69  
      */
 70  
     public abstract L getLeft();
 71  
 
 72  
     /**
 73  
      * <p>Gets the right element from this pair.</p>
 74  
      * 
 75  
      * <p>When treated as a key-value pair, this is the value.</p>
 76  
      * 
 77  
      * @return the right element, may be null
 78  
      */
 79  
     public abstract R getRight();
 80  
 
 81  
     /**
 82  
      * <p>Gets the key from this pair.</p>
 83  
      * 
 84  
      * <p>This method implements the {@code Map.Entry} interface returning the
 85  
      * left element as the key.</p>
 86  
      * 
 87  
      * @return the left element as the key, may be null
 88  
      */
 89  
     @Override
 90  
     public final L getKey() {
 91  2855
         return getLeft();
 92  
     }
 93  
 
 94  
     /**
 95  
      * <p>Gets the value from this pair.</p>
 96  
      * 
 97  
      * <p>This method implements the {@code Map.Entry} interface returning the
 98  
      * right element as the value.</p>
 99  
      * 
 100  
      * @return the right element as the value, may be null
 101  
      */
 102  
     @Override
 103  
     public R getValue() {
 104  2387
         return getRight();
 105  
     }
 106  
 
 107  
     //-----------------------------------------------------------------------
 108  
     /**
 109  
      * <p>Compares the pair based on the left element followed by the right element.
 110  
      * The types must be {@code Comparable}.</p>
 111  
      * 
 112  
      * @param other  the other pair, not null
 113  
      * @return negative if this is less, zero if equal, positive if greater
 114  
      */
 115  
     @Override
 116  
     public int compareTo(final Pair<L, R> other) {
 117  8
       return new CompareToBuilder().append(getLeft(), other.getLeft())
 118  
               .append(getRight(), other.getRight()).toComparison();
 119  
     }
 120  
 
 121  
     /**
 122  
      * <p>Compares this pair to another based on the two elements.</p>
 123  
      * 
 124  
      * @param obj  the object to compare to, null returns false
 125  
      * @return true if the elements of the pair are equal
 126  
      */
 127  
     @SuppressWarnings( "deprecation" ) // ObjectUtils.equals(Object, Object) has been deprecated in 3.2
 128  
     @Override
 129  
     public boolean equals(final Object obj) {
 130  382
         if (obj == this) {
 131  4
             return true;
 132  
         }
 133  378
         if (obj instanceof Map.Entry<?, ?>) {
 134  376
             final Map.Entry<?, ?> other = (Map.Entry<?, ?>) obj;
 135  376
             return ObjectUtils.equals(getKey(), other.getKey())
 136  
                     && ObjectUtils.equals(getValue(), other.getValue());
 137  
         }
 138  2
         return false;
 139  
     }
 140  
 
 141  
     /**
 142  
      * <p>Returns a suitable hash code.
 143  
      * The hash code follows the definition in {@code Map.Entry}.</p>
 144  
      * 
 145  
      * @return the hash code
 146  
      */
 147  
     @Override
 148  
     public int hashCode() {
 149  
         // see Map.Entry API specification
 150  749
         return (getKey() == null ? 0 : getKey().hashCode()) ^
 151  
                 (getValue() == null ? 0 : getValue().hashCode());
 152  
     }
 153  
 
 154  
     /**
 155  
      * <p>Returns a String representation of this pair using the format {@code ($left,$right)}.</p>
 156  
      * 
 157  
      * @return a string describing this object, not null
 158  
      */
 159  
     @Override
 160  
     public String toString() {
 161  11
         return new StringBuilder().append('(').append(getLeft()).append(',').append(getRight()).append(')').toString();
 162  
     }
 163  
 
 164  
     /**
 165  
      * <p>Formats the receiver using the given format.</p>
 166  
      * 
 167  
      * <p>This uses {@link java.util.Formattable} to perform the formatting. Two variables may
 168  
      * be used to embed the left and right elements. Use {@code %1$s} for the left
 169  
      * element (key) and {@code %2$s} for the right element (value).
 170  
      * The default format used by {@code toString()} is {@code (%1$s,%2$s)}.</p>
 171  
      * 
 172  
      * @param format  the format string, optionally containing {@code %1$s} and {@code %2$s}, not null
 173  
      * @return the formatted string, not null
 174  
      */
 175  
     public String toString(final String format) {
 176  1
         return String.format(format, getLeft(), getRight());
 177  
     }
 178  
 
 179  
 }