org.apache.commons.codec.StringEncoderComparator Maven / Gradle / Ivy
/*
* 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.commons.codec;
import java.util.Comparator;
/**
* Compares Strings using a {@link StringEncoder}. This comparator is used to sort Strings by an encoding scheme such as
* Soundex, Metaphone, etc. This class can come in handy if one need to sort Strings by an encoded form of a name such
* as Soundex.
*
* This class is immutable and thread-safe.
*/
@SuppressWarnings("rawtypes")
// TODO ought to implement Comparator but that's not possible whilst maintaining binary compatibility.
public class StringEncoderComparator implements Comparator {
/**
* Internal encoder instance.
*/
private final StringEncoder stringEncoder;
/**
* Constructs a new instance.
*
* @deprecated Creating an instance without a {@link StringEncoder} leads to a {@link NullPointerException}. Will be
* removed in 2.0.
*/
@Deprecated
public StringEncoderComparator() {
this.stringEncoder = null; // Trying to use this will cause things to break
}
/**
* Constructs a new instance with the given algorithm.
*
* @param stringEncoder
* the StringEncoder used for comparisons.
*/
public StringEncoderComparator(final StringEncoder stringEncoder) {
this.stringEncoder = stringEncoder;
}
/**
* Compares two strings based not on the strings themselves, but on an encoding of the two strings using the
* StringEncoder this Comparator was created with.
*
* If an {@link EncoderException} is encountered, return {@code 0}.
*
* @param o1
* the object to compare
* @param o2
* the object to compare to
* @return the Comparable.compareTo() return code or 0 if an encoding error was caught.
* @see Comparable
*/
@Override
public int compare(final Object o1, final Object o2) {
int compareCode = 0;
try {
@SuppressWarnings("unchecked") // May fail with CCE if encode returns something that is not Comparable
// However this was always the case.
final Comparable> s1 = (Comparable>) this.stringEncoder.encode(o1);
final Comparable s2 = (Comparable) this.stringEncoder.encode(o2);
compareCode = s1.compareTo(s2);
} catch (final EncoderException ee) {
compareCode = 0;
}
return compareCode;
}
}