Add spring boot starter for pgvector.

langchain4j-pgvector-spring-boot-starter/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>dev.langchain4j</groupId>
+        <artifactId>langchain4j-spring</artifactId>
+        <version>0.37.0-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <artifactId>langchain4j-pgvector-spring-boot-starter</artifactId>
+    <name>LangChain4j Spring Boot starter for PgVector</name>
+    <packaging>jar</packaging>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>dev.langchain4j</groupId>
+            <artifactId>langchain4j-pgvector</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-autoconfigure-processor</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <!-- needed to generate automatic metadata about available config properties -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-configuration-processor</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>dev.langchain4j</groupId>
+            <artifactId>langchain4j-embeddings-all-minilm-l6-v2-q</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>dev.langchain4j</groupId>
+            <artifactId>langchain4j-spring-boot-tests</artifactId>
+            <version>${project.version}</version>
+            <classifier>tests</classifier>
+            <type>test-jar</type>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>postgresql</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.tinylog</groupId>
+            <artifactId>tinylog-impl</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.tinylog</groupId>
+            <artifactId>slf4j-tinylog</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>

langchain4j-pgvector-spring-boot-starter/src/main/java/dev/langchain4j/store/embedding/pgvector/spring/PgVectorDataSourceProperties.java

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+package dev.langchain4j.store.embedding.pgvector.spring;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = PgVectorDataSourceProperties.PREFIX)
+public class PgVectorDataSourceProperties {
+
+    static final String PREFIX = "langchain4j.pgvector.datasource";
+
+    /**
+     * Enable postgres datasource configuration, default value <code>false</code>.
+     */
+    private boolean enabled = false;
+
+    /**
+     * The pgvector database host.
+     */
+    private String host;
+
+    /**
+     * The pgvector database user.
+     */
+    private String user;
+
+    /**
+     * The pgvector database password.
+     */
+    private String password;
+
+    /**
+     * The pgvector database port.
+     */
+    private Integer port;
+
+    /**
+     * The pgvector database name.
+     */
+    private String database;
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
+
+    public String getHost() {
+        return host;
+    }
+
+    public void setHost(String host) {
+        this.host = host;
+    }
+
+    public String getUser() {
+        return user;
+    }
+
+    public void setUser(String user) {
+        this.user = user;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public Integer getPort() {
+        return port;
+    }
+
+    public void setPort(Integer port) {
+        this.port = port;
+    }
+
+    public String getDatabase() {
+        return database;
+    }
+
+    public void setDatabase(String database) {
+        this.database = database;
+    }
+}

langchain4j-pgvector-spring-boot-starter/src/main/java/dev/langchain4j/store/embedding/pgvector/spring/PgVectorEmbeddingStoreAutoConfiguration.java

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+package dev.langchain4j.store.embedding.pgvector.spring;
+
+import dev.langchain4j.model.embedding.EmbeddingModel;
+import dev.langchain4j.store.embedding.pgvector.PgVectorEmbeddingStore;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.lang.Nullable;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.SQLException;
+import java.util.Optional;
+
+import static dev.langchain4j.internal.ValidationUtils.*;
+import static dev.langchain4j.store.embedding.pgvector.spring.PgVectorEmbeddingStoreProperties.*;
+import static org.springframework.util.StringUtils.startsWithIgnoreCase;
+
+@AutoConfiguration
+@EnableConfigurationProperties({PgVectorEmbeddingStoreProperties.class, PgVectorDataSourceProperties.class})
+@ConditionalOnProperty(prefix = PREFIX, name = "enabled", havingValue = "true", matchIfMissing = true)
+public class PgVectorEmbeddingStoreAutoConfiguration {
+
+    private static final Logger log = LoggerFactory.getLogger(PgVectorEmbeddingStoreAutoConfiguration.class);
+
+    @Bean
+    @ConditionalOnMissingBean
+    @ConditionalOnBean(DataSource.class)
+    @ConditionalOnProperty(prefix = PgVectorDataSourceProperties.PREFIX, name = "enabled", havingValue = "false")
+    public PgVectorEmbeddingStore pgVectorEmbeddingStoreWithExistingDataSource(DataSource dataSource, PgVectorEmbeddingStoreProperties properties,
+                                                         @Nullable EmbeddingModel embeddingModel) {
+        // Check if the context's data source is a Postgres datasource
+        ensureTrue(isPostgresqlDataSource(dataSource), "The DataSource in Spring Context is not a Postgres datasource, you need to manually specify the Postgres datasource configuration via 'langchain4j.pgvector.datasource'.");
+
+        Integer dimension = Optional.ofNullable(properties.getDimension()).orElseGet(() -> embeddingModel == null ? null : embeddingModel.dimension());
+
+        return PgVectorEmbeddingStore.datasourceBuilder()
+                .datasource(dataSource)
+                .table(properties.getTable())
+                .createTable(properties.getCreateTable())
+                .dimension(dimension)
+                .useIndex(properties.getUseIndex())
+                .indexListSize(properties.getIndexListSize())
+                .build();
+    }
+
+    @Bean
+    @ConditionalOnMissingBean
+    @ConditionalOnProperty(prefix = PgVectorDataSourceProperties.PREFIX, name = "enabled", havingValue = "true")
+    public PgVectorEmbeddingStore pgVectorEmbeddingStoreWithCustomDataSource(PgVectorEmbeddingStoreProperties properties, PgVectorDataSourceProperties dataSourceProperties,
+                                                         @Nullable EmbeddingModel embeddingModel) {
+        Integer dimension = Optional.ofNullable(properties.getDimension()).orElseGet(() -> embeddingModel == null ? null : embeddingModel.dimension());
+
+        return PgVectorEmbeddingStore.builder()
+                .host(dataSourceProperties.getHost())
+                .port(dataSourceProperties.getPort())
+                .user(dataSourceProperties.getUser())
+                .password(dataSourceProperties.getPassword())
+                .database(dataSourceProperties.getDatabase())
+                .table(properties.getTable())
+                .createTable(properties.getCreateTable())
+                .dimension(dimension)
+                .useIndex(properties.getUseIndex())
+                .indexListSize(properties.getIndexListSize())
+                .build();
+    }
+
+    /**
+     * Check if the datasource is <code>postgresql</code>`.
+     * @param dataSource instance of {@link DataSource}.
+     * @return true means it is a postgresql data source, otherwise it is not.
+     */
+    private boolean isPostgresqlDataSource(DataSource dataSource) {
+        try (Connection connection = dataSource.getConnection()) {
+            DatabaseMetaData metaData = connection.getMetaData();
+            return startsWithIgnoreCase(metaData.getURL(), "jdbc:postgresql");
+        } catch (SQLException e) {
+            log.warn("Exception checking datasource driver type during PgVector auto-configuration .");
+            return false;
+        }
+    }
+}

langchain4j-pgvector-spring-boot-starter/src/main/java/dev/langchain4j/store/embedding/pgvector/spring/PgVectorEmbeddingStoreProperties.java

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+package dev.langchain4j.store.embedding.pgvector.spring;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = PgVectorEmbeddingStoreProperties.PREFIX)
+public class PgVectorEmbeddingStoreProperties {
+
+    static final String PREFIX = "langchain4j.pgvector";
+
+    /**
+     * The pgvector database table.
+     */
+    private String table;
+
+    /**
+     * The vector dimension.
+     */
+    private Integer dimension;
+
+    /**
+     * Should create table automatically, default value is <code>false</code>.
+     */
+    private Boolean createTable;
+
+    /**
+     * Should use <a href="https://github.com/pgvector/pgvector#ivfflat">IVFFlat</a> index.
+     */
+    private Boolean useIndex;
+
+    /**
+     * The IVFFlat number of lists.
+     */
+    private Integer indexListSize;
+
+    public String getTable() {
+        return table;
+    }
+
+    public void setTable(String table) {
+        this.table = table;
+    }
+
+    public Integer getDimension() {
+        return dimension;
+    }
+
+    public void setDimension(Integer dimension) {
+        this.dimension = dimension;
+    }
+
+    public Boolean getCreateTable() {
+        return createTable;
+    }
+
+    public void setCreateTable(Boolean createTable) {
+        this.createTable = createTable;
+    }
+
+    public Boolean getUseIndex() {
+        return useIndex;
+    }
+
+    public void setUseIndex(Boolean useIndex) {
+        this.useIndex = useIndex;
+    }
+
+    public Integer getIndexListSize() {
+        return indexListSize;
+    }
+
+    public void setIndexListSize(Integer indexListSize) {
+        this.indexListSize = indexListSize;
+    }
+}

langchain4j-pgvector-spring-boot-starter/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

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+dev.langchain4j.store.embedding.pgvector.spring.PgVectorEmbeddingStoreAutoConfiguration