org.apache.hudi.common.util.collection.Triple Maven / Gradle / Ivy
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* 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.hudi.common.util.collection;
import java.io.Serializable;
/**
* (NOTE: Adapted from Apache commons-lang3)
*
* A triple consisting of three elements.
*
*
*
* This class is an abstract implementation defining the basic API. It refers to the elements as 'left', 'middle' and
* 'right'.
*
*
*
* Subclass implementations may be mutable or immutable. However, there is no restriction on the type of the stored
* objects that may be stored. If mutable objects are stored in the triple, then the triple itself effectively becomes
* mutable.
*
*
* @param the left element type
* @param the middle element type
* @param the right element type
*/
public abstract class Triple implements Comparable>, Serializable {
/**
* Serialization version.
*/
private static final long serialVersionUID = 1L;
/**
*
* Obtains an immutable triple of from three objects inferring the generic types.
*
*
*
* This factory allows the triple to be created using inference to obtain the generic types.
*
*
* @param the left element type
* @param the middle element type
* @param the right element type
* @param left the left element, may be null
* @param middle the middle element, may be null
* @param right the right element, may be null
* @return a triple formed from the three parameters, not null
*/
public static Triple of(final L left, final M middle, final R right) {
return new ImmutableTriple(left, middle, right);
}
// -----------------------------------------------------------------------
/**
*
* Gets the left element from this triple.
*
*
* @return the left element, may be null
*/
public abstract L getLeft();
/**
*
* Gets the middle element from this triple.
*
*
* @return the middle element, may be null
*/
public abstract M getMiddle();
/**
*
* Gets the right element from this triple.
*
*
* @return the right element, may be null
*/
public abstract R getRight();
// -----------------------------------------------------------------------
/**
*
* Compares the triple based on the left element, followed by the middle element, finally the right element. The types
* must be {@code Comparable}.
*
*
* @param other the other triple, not null
* @return negative if this is less, zero if equal, positive if greater
*/
@Override
public int compareTo(final Triple other) {
checkComparable(this);
checkComparable(other);
Comparable thisLeft = (Comparable) getLeft();
Comparable otherLeft = (Comparable) other.getLeft();
if (thisLeft.compareTo(otherLeft) == 0) {
return Pair.of(getMiddle(), getRight()).compareTo(Pair.of(other.getMiddle(), other.getRight()));
} else {
return thisLeft.compareTo(otherLeft);
}
}
/**
*
* Compares this triple to another based on the three elements.
*
*
* @param obj the object to compare to, null returns false
* @return true if the elements of the triple are equal
*/
@SuppressWarnings("deprecation") // ObjectUtils.equals(Object, Object) has been deprecated in 3.2
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof Triple) {
final Triple other = (Triple) obj;
return getLeft().equals(other.getLeft()) && getMiddle().equals(other.getMiddle())
&& getRight().equals(other.getRight());
}
return false;
}
/**
*
* Returns a suitable hash code.
*
*
* @return the hash code
*/
@Override
public int hashCode() {
return (getLeft() == null ? 0 : getLeft().hashCode()) ^ (getMiddle() == null ? 0 : getMiddle().hashCode())
^ (getRight() == null ? 0 : getRight().hashCode());
}
/**
*
* Returns a String representation of this triple using the format {@code ($left,$middle,$right)}.
*
*
* @return a string describing this object, not null
*/
@Override
public String toString() {
return new StringBuilder().append('(').append(getLeft()).append(',').append(getMiddle()).append(',')
.append(getRight()).append(')').toString();
}
/**
*
* Formats the receiver using the given format.
*
*
*
* This uses {@link java.util.Formattable} to perform the formatting. Three variables may be used to embed the left
* and right elements. Use {@code %1$s} for the left element, {@code %2$s} for the middle and {@code %3$s} for the
* right element. The default format used by {@code toString()} is {@code (%1$s,%2$s,%3$s)}.
*
*
* @param format the format string, optionally containing {@code %1$s}, {@code %2$s} and {@code %3$s}, not null
* @return the formatted string, not null
*/
public String toString(final String format) {
return String.format(format, getLeft(), getMiddle(), getRight());
}
private void checkComparable(Triple triplet) {
if (!(triplet.getLeft() instanceof Comparable) || !(triplet.getMiddle() instanceof Comparable)
|| !(triplet.getRight() instanceof Comparable)) {
throw new IllegalArgumentException("Elements of Triple must implement Comparable :" + triplet);
}
}
}