mailbox/opensearch/src/main/java/org/apache/james/mailbox/opensearch/json/Subjects.java

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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
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package org.apache.james.mailbox.opensearch.json;

import java.util.Set;

import com.fasterxml.jackson.annotation.JsonValue;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;

public class Subjects implements SerializableMessage {

    public static Subjects from(Set<String> subjects) {
        Preconditions.checkNotNull(subjects, "'subjects' is mandatory");
        return new Subjects(subjects);
    }

    private final Set<String> subjects;

    private Subjects(Set<String> subjects) {
        this.subjects = subjects;
    }

    @JsonValue
    public Set<String> getSubjects() {
        return subjects;
    }

    @Override
    public String serialize() {
        return Joiner.on(" ").join(subjects);
    }
}