| /* |
| * 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.text.similarity; |
| |
| import org.apache.commons.lang3.Validate; |
| |
| /** |
| * <p> |
| * This stores a {@link EditDistance} implementation and a {@link CharSequence} "left" string. |
| * The {@link #apply(CharSequence right)} method accepts the "right" string and invokes the |
| * comparison function for the pair of strings. |
| * </p> |
| * |
| * <p> |
| * The following is an example which finds the most similar string: |
| * </p> |
| * <pre> |
| * EditDistance<Integer> editDistance = new LevenshteinDistance(); |
| * String target = "Apache"; |
| * EditDistanceFrom<Integer> editDistanceFrom = |
| * new EditDistanceFrom<Integer>(editDistance, target); |
| * String mostSimilar = null; |
| * Integer shortestDistance = null; |
| * |
| * for (String test : new String[] { "Appaloosa", "a patchy", "apple" }) { |
| * Integer distance = editDistanceFrom.apply(test); |
| * if (shortestDistance == null || distance < shortestDistance) { |
| * shortestDistance = distance; |
| * mostSimilar = test; |
| * } |
| * } |
| * |
| * System.out.println("The string most similar to \"" + target + "\" " |
| * + "is \"" + mostSimilar + "\" because " |
| * + "its distance is only " + shortestDistance + "."); |
| * </pre> |
| * |
| * @param <R> This is the type of similarity score used by the EditDistance function. |
| * @since 1.0 |
| */ |
| public class EditDistanceFrom<R> { |
| |
| /** |
| * Edit distance. |
| */ |
| private final EditDistance<R> editDistance; |
| /** |
| * Left parameter used in distance function. |
| */ |
| private final CharSequence left; |
| |
| /** |
| * <p>This accepts the edit distance implementation and the "left" string.</p> |
| * |
| * @param editDistance This may not be null. |
| * @param left This may be null here, |
| * but the EditDistance#compare(CharSequence left, CharSequence right) |
| * implementation may not accept nulls. |
| */ |
| public EditDistanceFrom(final EditDistance<R> editDistance, final CharSequence left) { |
| Validate.isTrue(editDistance != null, "The edit distance may not be null."); |
| |
| this.editDistance = editDistance; |
| this.left = left; |
| } |
| |
| /** |
| * <p> |
| * This compares "left" field against the "right" parameter |
| * using the "edit distance" implementation. |
| * </p> |
| * |
| * @param right the second CharSequence |
| * @return the similarity score between two CharSequences |
| */ |
| public R apply(final CharSequence right) { |
| return editDistance.apply(left, right); |
| } |
| |
| /** |
| * Gets the left parameter. |
| * |
| * @return the left parameter |
| */ |
| public CharSequence getLeft() { |
| return left; |
| } |
| |
| /** |
| * Gets the edit distance. |
| * |
| * @return the edit distance |
| */ |
| public EditDistance<R> getEditDistance() { |
| return editDistance; |
| } |
| |
| } |