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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.schema.internal;
import com.yahoo.language.Language;
import com.yahoo.language.process.Embedder;
import com.yahoo.tensor.Tensor;
import com.yahoo.tensor.TensorType;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A class which knows how to convert an Object value to a tensor of a given type.
*
* @author bratseth
*/
public class TensorConverter {
private static final Pattern embedderArgumentRegexp = Pattern.compile("^([A-Za-z0-9_\\-.]+),\\s*([\"'].*[\"'])");
private final Map<String, Embedder> embedders;
public TensorConverter(Map<String, Embedder> embedders) {
this.embedders = embedders;
}
public Tensor convertTo(TensorType type, String key, Object value, Language language) {
var context = new Embedder.Context(key).setLanguage(language);
Tensor tensor = toTensor(type, value, context);
if (tensor == null) return null;
if (! tensor.type().isAssignableTo(type))
throw new IllegalArgumentException("Require a tensor of type " + type);
return tensor;
}
private Tensor toTensor(TensorType type, Object value, Embedder.Context context) {
if (value instanceof Tensor) return (Tensor)value;
if (value instanceof String && isEmbed((String)value)) return embed((String)value, type, context);
if (value instanceof String) return Tensor.from(type, (String)value);
return null;
}
static boolean isEmbed(String value) {
return value.startsWith("embed(");
}
private Tensor embed(String s, TensorType type, Embedder.Context embedderContext) {
if ( ! s.endsWith(")"))
throw new IllegalArgumentException("Expected any string enclosed in embed(), but the argument does not end by ')'");
String argument = s.substring("embed(".length(), s.length() - 1);
Embedder embedder;
String embedderId;
// Check if arguments specifies an embedder with the format embed(embedder, "text to encode")
Matcher matcher = embedderArgumentRegexp.matcher(argument);
if (matcher.matches()) {
embedderId = matcher.group(1);
argument = matcher.group(2);
if ( ! embedders.containsKey(embedderId)) {
throw new IllegalArgumentException("Can't find embedder '" + embedderId + "'. " +
"Valid embedders are " + validEmbedders(embedders));
}
embedder = embedders.get(embedderId);
} else if (embedders.size() == 0) {
throw new IllegalStateException("No embedders provided"); // should never happen
} else if (embedders.size() > 1) {
throw new IllegalArgumentException("Multiple embedders are provided but no embedder id is given. " +
"Valid embedders are " + validEmbedders(embedders));
} else {
var entry = embedders.entrySet().stream().findFirst().get();
embedderId = entry.getKey();
embedder = entry.getValue();
}
return embedder.embed(removeQuotes(argument), embedderContext.copy().setEmbedderId(embedderId), type);
}
private static String removeQuotes(String s) {
if (s.startsWith("'") && s.endsWith("'")) {
return s.substring(1, s.length() - 1);
}
if (s.startsWith("\"") && s.endsWith("\"")) {
return s.substring(1, s.length() - 1);
}
return s;
}
private static String validEmbedders(Map<String, Embedder> embedders) {
List<String> embedderIds = new ArrayList<>();
embedders.forEach((key, value) -> embedderIds.add(key));
embedderIds.sort(null);
return String.join(",", embedderIds);
}
}
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