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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.search.suggest.completion;
import org.apache.lucene.search.suggest.document.FuzzyCompletionQuery;
import org.apache.lucene.util.automaton.Operations;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.common.unit.Fuzziness;
import org.elasticsearch.common.xcontent.ObjectParser;
import org.elasticsearch.common.xcontent.ToXContentFragment;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import java.io.IOException;
import java.util.Objects;
/**
* Fuzzy options for completion suggester
*/
public class FuzzyOptions implements ToXContentFragment, Writeable {
static final ParseField FUZZY_OPTIONS = new ParseField("fuzzy");
private static final ParseField TRANSPOSITION_FIELD = new ParseField("transpositions");
private static final ParseField MIN_LENGTH_FIELD = new ParseField("min_length");
private static final ParseField PREFIX_LENGTH_FIELD = new ParseField("prefix_length");
private static final ParseField UNICODE_AWARE_FIELD = new ParseField("unicode_aware");
private static final ParseField MAX_DETERMINIZED_STATES_FIELD = new ParseField("max_determinized_states");
/**
* fuzzy : {
* "edit_distance" : STRING | INT
* "transpositions" : BOOLEAN
* "min_length" : INT
* "prefix_length" : INT
* "unicode_aware" : BOOLEAN
* "max_determinized_states" : INT
* }
*/
private static final ObjectParser PARSER = new ObjectParser<>(FUZZY_OPTIONS.getPreferredName(),
Builder::new);
static {
PARSER.declareInt(Builder::setFuzzyMinLength, MIN_LENGTH_FIELD);
PARSER.declareInt(Builder::setMaxDeterminizedStates, MAX_DETERMINIZED_STATES_FIELD);
PARSER.declareBoolean(Builder::setUnicodeAware, UNICODE_AWARE_FIELD);
PARSER.declareInt(Builder::setFuzzyPrefixLength, PREFIX_LENGTH_FIELD);
PARSER.declareBoolean(Builder::setTranspositions, TRANSPOSITION_FIELD);
PARSER.declareField(Builder::setFuzziness, Fuzziness::parse, Fuzziness.FIELD, ObjectParser.ValueType.VALUE);
}
static FuzzyOptions parse(XContentParser parser) throws IOException {
return PARSER.parse(parser, null).build();
}
public static Builder builder() {
return new Builder();
}
private int editDistance;
private boolean transpositions;
private int fuzzyMinLength;
private int fuzzyPrefixLength;
private boolean unicodeAware;
private int maxDeterminizedStates;
private FuzzyOptions(int editDistance, boolean transpositions, int fuzzyMinLength, int fuzzyPrefixLength,
boolean unicodeAware, int maxDeterminizedStates) {
this.editDistance = editDistance;
this.transpositions = transpositions;
this.fuzzyMinLength = fuzzyMinLength;
this.fuzzyPrefixLength = fuzzyPrefixLength;
this.unicodeAware = unicodeAware;
this.maxDeterminizedStates = maxDeterminizedStates;
}
/**
* Read from a stream.
*/
FuzzyOptions(StreamInput in) throws IOException {
transpositions = in.readBoolean();
unicodeAware = in.readBoolean();
editDistance = in.readVInt();
fuzzyMinLength = in.readVInt();
fuzzyPrefixLength = in.readVInt();
maxDeterminizedStates = in.readVInt();
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeBoolean(transpositions);
out.writeBoolean(unicodeAware);
out.writeVInt(editDistance);
out.writeVInt(fuzzyMinLength);
out.writeVInt(fuzzyPrefixLength);
out.writeVInt(maxDeterminizedStates);
}
/**
* Returns the maximum number of edits
*/
public int getEditDistance() {
return editDistance;
}
/**
* Returns if transpositions option is set
*
* if transpositions is set, then swapping one character for another counts as one edit instead of two.
*/
public boolean isTranspositions() {
return transpositions;
}
/**
* Returns the length of input prefix after which edits are applied
*/
public int getFuzzyMinLength() {
return fuzzyMinLength;
}
/**
* Returns the minimum length of the input prefix required to apply any edits
*/
public int getFuzzyPrefixLength() {
return fuzzyPrefixLength;
}
/**
* Returns if all measurements (like edit distance, transpositions and lengths) are in unicode code
* points (actual letters) instead of bytes.
*/
public boolean isUnicodeAware() {
return unicodeAware;
}
/**
* Returns the maximum automaton states allowed for fuzzy expansion
*/
public int getMaxDeterminizedStates() {
return maxDeterminizedStates;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
FuzzyOptions that = (FuzzyOptions) o;
if (editDistance != that.editDistance) return false;
if (transpositions != that.transpositions) return false;
if (fuzzyMinLength != that.fuzzyMinLength) return false;
if (fuzzyPrefixLength != that.fuzzyPrefixLength) return false;
if (unicodeAware != that.unicodeAware) return false;
return maxDeterminizedStates == that.maxDeterminizedStates;
}
@Override
public int hashCode() {
int result = editDistance;
result = 31 * result + (transpositions ? 1 : 0);
result = 31 * result + fuzzyMinLength;
result = 31 * result + fuzzyPrefixLength;
result = 31 * result + (unicodeAware ? 1 : 0);
result = 31 * result + maxDeterminizedStates;
return result;
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(FUZZY_OPTIONS.getPreferredName());
builder.field(Fuzziness.FIELD.getPreferredName(), editDistance);
builder.field(TRANSPOSITION_FIELD.getPreferredName(), transpositions);
builder.field(MIN_LENGTH_FIELD.getPreferredName(), fuzzyMinLength);
builder.field(PREFIX_LENGTH_FIELD.getPreferredName(), fuzzyPrefixLength);
builder.field(UNICODE_AWARE_FIELD.getPreferredName(), unicodeAware);
builder.field(MAX_DETERMINIZED_STATES_FIELD.getPreferredName(), maxDeterminizedStates);
builder.endObject();
return builder;
}
/**
* Options for fuzzy queries
*/
public static class Builder {
private int editDistance = FuzzyCompletionQuery.DEFAULT_MAX_EDITS;
private boolean transpositions = FuzzyCompletionQuery.DEFAULT_TRANSPOSITIONS;
private int fuzzyMinLength = FuzzyCompletionQuery.DEFAULT_MIN_FUZZY_LENGTH;
private int fuzzyPrefixLength = FuzzyCompletionQuery.DEFAULT_NON_FUZZY_PREFIX;
private boolean unicodeAware = FuzzyCompletionQuery.DEFAULT_UNICODE_AWARE;
private int maxDeterminizedStates = Operations.DEFAULT_MAX_DETERMINIZED_STATES;
public Builder() {
}
/**
* Sets the level of fuzziness used to create suggestions using a {@link Fuzziness} instance.
* The default value is {@link Fuzziness#ONE} which allows for an "edit distance" of one.
*/
public Builder setFuzziness(int editDistance) {
if (editDistance < 0 || editDistance > 2) {
throw new IllegalArgumentException("fuzziness must be between 0 and 2");
}
this.editDistance = editDistance;
return this;
}
/**
* Sets the level of fuzziness used to create suggestions using a {@link Fuzziness} instance.
* The default value is {@link Fuzziness#ONE} which allows for an "edit distance" of one.
*/
public Builder setFuzziness(Fuzziness fuzziness) {
Objects.requireNonNull(fuzziness, "fuzziness must not be null");
return setFuzziness(fuzziness.asDistance());
}
/**
* Sets if transpositions (swapping one character for another) counts as one character
* change or two.
* Defaults to true, meaning it uses the fuzzier option of counting transpositions as
* a single change.
*/
public Builder setTranspositions(boolean transpositions) {
this.transpositions = transpositions;
return this;
}
/**
* Sets the minimum length of input string before fuzzy suggestions are returned, defaulting
* to 3.
*/
public Builder setFuzzyMinLength(int fuzzyMinLength) {
if (fuzzyMinLength < 0) {
throw new IllegalArgumentException("fuzzyMinLength must not be negative");
}
this.fuzzyMinLength = fuzzyMinLength;
return this;
}
/**
* Sets the minimum length of the input, which is not checked for fuzzy alternatives, defaults to 1
*/
public Builder setFuzzyPrefixLength(int fuzzyPrefixLength) {
if (fuzzyPrefixLength < 0) {
throw new IllegalArgumentException("fuzzyPrefixLength must not be negative");
}
this.fuzzyPrefixLength = fuzzyPrefixLength;
return this;
}
/**
* Sets the maximum automaton states allowed for the fuzzy expansion
*/
public Builder setMaxDeterminizedStates(int maxDeterminizedStates) {
if (maxDeterminizedStates < 0) {
throw new IllegalArgumentException("maxDeterminizedStates must not be negative");
}
this.maxDeterminizedStates = maxDeterminizedStates;
return this;
}
/**
* Set to true if all measurements (like edit distance, transpositions and lengths) are in unicode
* code points (actual letters) instead of bytes. Default is false.
*/
public Builder setUnicodeAware(boolean unicodeAware) {
this.unicodeAware = unicodeAware;
return this;
}
public FuzzyOptions build() {
return new FuzzyOptions(editDistance, transpositions, fuzzyMinLength, fuzzyPrefixLength,
unicodeAware, maxDeterminizedStates);
}
}
}