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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 embedderArgumentAndQuotedTextRegexp = Pattern.compile("^([A-Za-z0-9_@\\-.]+),\\s*([\"'].*[\"'])");
private static final Pattern embedderArgumentAndReferenceRegexp = 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,
Map<String, String> contextValues) {
var context = new Embedder.Context(key).setLanguage(language).setContextValues(contextValues);
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;
if (( matcher = embedderArgumentAndQuotedTextRegexp.matcher(argument)).matches()) {
embedderId = matcher.group(1);
embedder = requireEmbedder(embedderId);
argument = matcher.group(2);
} else if (( matcher = embedderArgumentAndReferenceRegexp.matcher(argument)).matches()) {
embedderId = matcher.group(1);
embedder = requireEmbedder(embedderId);
argument = matcher.group(2);
} else if (embedders.isEmpty()) {
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(resolve(argument, embedderContext), embedderContext.copy().setEmbedderId(embedderId), type);
}
private Embedder requireEmbedder(String embedderId) {
if ( ! embedders.containsKey(embedderId))
throw new IllegalArgumentException("Can't find embedder '" + embedderId + "'. " +
"Valid embedders are " + validEmbedders(embedders));
return embedders.get(embedderId);
}
private static String resolve(String s, Embedder.Context embedderContext) {
if (s.startsWith("'") && s.endsWith("'"))
return s.substring(1, s.length() - 1);
if (s.startsWith("\"") && s.endsWith("\""))
return s.substring(1, s.length() - 1);
if (s.startsWith("@"))
return resolveReference(s, embedderContext);
return s;
}
private static String resolveReference(String s, Embedder.Context embedderContext) {
String referenceKey = s.substring(1);
String referencedValue = embedderContext.getContextValues().get(referenceKey);
if (referencedValue == null)
throw new IllegalArgumentException("Could not resolve query parameter reference '" + referenceKey +
"' used in an embed() argument");
return referencedValue;
}
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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