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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.unit;
import com.google.common.base.Preconditions;
import org.apache.lucene.search.FuzzyQuery;
import org.apache.lucene.util.automaton.LevenshteinAutomata;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentBuilderString;
import org.elasticsearch.common.xcontent.XContentParser;
import java.io.IOException;
/**
* A unit class that encapsulates all in-exact search
* parsing and conversion from similarities to edit distances
* etc.
*/
public final class Fuzziness implements ToXContent {
public static final XContentBuilderString X_FIELD_NAME = new XContentBuilderString("fuzziness");
public static final Fuzziness ZERO = new Fuzziness(0);
public static final Fuzziness ONE = new Fuzziness(1);
public static final Fuzziness TWO = new Fuzziness(2);
public static final Fuzziness AUTO = new Fuzziness("AUTO");
public static final ParseField FIELD = new ParseField(X_FIELD_NAME.camelCase().getValue());
private final String fuzziness;
private Fuzziness(int fuzziness) {
Preconditions.checkArgument(fuzziness >= 0 && fuzziness <= 2, "Valid edit distances are [0, 1, 2] but was [" + fuzziness + "]");
this.fuzziness = Integer.toString(fuzziness);
}
private Fuzziness(String fuzziness) {
this.fuzziness = fuzziness;
}
/**
* Creates a {@link Fuzziness} instance from an edit distance. The value must be one of [0, 1, 2]
*/
public static Fuzziness fromEdits(int edits) {
return new Fuzziness(edits);
}
public static Fuzziness build(Object fuzziness) {
if (fuzziness instanceof Fuzziness) {
return (Fuzziness) fuzziness;
}
String string = fuzziness.toString();
if (AUTO.asString().equalsIgnoreCase(string)) {
return AUTO;
}
return new Fuzziness(string);
}
public static Fuzziness parse(XContentParser parser) throws IOException {
XContentParser.Token token = parser.currentToken();
switch (token) {
case VALUE_STRING:
case VALUE_NUMBER:
final String fuzziness = parser.text();
if (AUTO.asString().equalsIgnoreCase(fuzziness)) {
return AUTO;
}
try {
final int minimumSimilarity = Integer.parseInt(fuzziness);
switch (minimumSimilarity) {
case 0:
return ZERO;
case 1:
return ONE;
case 2:
return TWO;
default:
return build(fuzziness);
}
} catch (NumberFormatException ex) {
return build(fuzziness);
}
default:
throw new IllegalArgumentException("Can't parse fuzziness on token: [" + token + "]");
}
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
return toXContent(builder, params, true);
}
public XContentBuilder toXContent(XContentBuilder builder, Params params, boolean includeFieldName) throws IOException {
if (includeFieldName) {
builder.field(X_FIELD_NAME, fuzziness);
} else {
builder.value(fuzziness);
}
return builder;
}
public int asDistance() {
return asDistance(null);
}
public int asDistance(String text) {
if (this == AUTO) { //AUTO
final int len = termLen(text);
if (len <= 2) {
return 0;
} else if (len > 5) {
return 2;
} else {
return 1;
}
}
return Math.min(2, asInt());
}
public TimeValue asTimeValue() {
if (this == AUTO) {
return TimeValue.timeValueMillis(1);
} else {
return TimeValue.parseTimeValue(fuzziness.toString(), null, "fuzziness");
}
}
public long asLong() {
if (this == AUTO) {
return 1;
}
try {
return Long.parseLong(fuzziness.toString());
} catch (NumberFormatException ex) {
return (long) Double.parseDouble(fuzziness.toString());
}
}
public int asInt() {
if (this == AUTO) {
return 1;
}
try {
return Integer.parseInt(fuzziness.toString());
} catch (NumberFormatException ex) {
return (int) Float.parseFloat(fuzziness.toString());
}
}
public short asShort() {
if (this == AUTO) {
return 1;
}
try {
return Short.parseShort(fuzziness.toString());
} catch (NumberFormatException ex) {
return (short) Float.parseFloat(fuzziness.toString());
}
}
public byte asByte() {
if (this == AUTO) {
return 1;
}
try {
return Byte.parseByte(fuzziness.toString());
} catch (NumberFormatException ex) {
return (byte) Float.parseFloat(fuzziness.toString());
}
}
public double asDouble() {
if (this == AUTO) {
return 1d;
}
return Double.parseDouble(fuzziness.toString());
}
public float asFloat() {
if (this == AUTO) {
return 1f;
}
return Float.parseFloat(fuzziness.toString());
}
private int termLen(String text) {
return text == null ? 5 : text.codePointCount(0, text.length()); // 5 avg term length in english
}
public String asString() {
return fuzziness.toString();
}
}