MessagesImpl.java

/*
 * SPDX-FileCopyrightText: 2025 kaumei.io
 * SPDX-License-Identifier: Apache-2.0
 */
package io.kaumei.jdbc.anno.msg;

import org.jspecify.annotations.Nullable;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.TreeSet;
import java.util.function.Supplier;

import static java.util.Objects.requireNonNull;

final class MessagesImpl implements Msg.Messages {

    private final Msg.Message[] messages;

    MessagesImpl(TreeSet<Msg.Message> messages) {
        if (messages.isEmpty()) {
            throw new IllegalArgumentException("messages must not be empty");
        }
        this.messages = messages.toArray(new Msg.Message[0]);
    }

    @Override
    public String toString() {
        return '[' + join(", ") + ']';
    }

    // interface Iterable<Msg.Message> ----------------------------------------

    @Override
    public Iterator<Msg.Message> iterator() {
        return new LocalIterator();
    }

    // interface Msg.Messages -------------------------------------------------

    @Override
    public boolean hasMessages() {
        return true;
    }

    @Override
    public boolean hasNoMessages() {
        return false;
    }

    @Override
    public String join(String sep) {
        var sb = new StringBuilder();
        sb.append(messages[0].text());
        for (int i = 1; i < messages.length; i++) {
            sb.append(sep);
            sb.append(messages[i].text());
        }
        return sb.toString();
    }

    @Override
    public void join(StringBuilder sb, String sep) {
        sb.append(messages[0].text());
        for (int i = 1; i < messages.length; i++) {
            sb.append(sep);
            sb.append(messages[i].text());
        }
    }

    @Override
    public void requireEmpty() {
        throw new IllegalStateException("List not empty: " + join(", "));
    }

    @Override
    public Msg.Messages requireNoneEmpty() {
        return this;
    }

    @Override
    public <T> Msg.Result<T> build(T value) {
        requireNonNull(value, "value");
        return new MessageResultImpl<>(this);
    }

    @Override
    public <T> Msg.Result<T> build(Supplier<T> func) {
        requireNonNull(func, "func");
        return new MessageResultImpl<>(this);
    }

    @Override
    public <T> Msg.NullableResult<T> buildOpt(@Nullable T value) {
        return new MessageResultNullableImpl<>(this);
    }

    // ------------------------------------------------------------------------

    private final class LocalIterator implements Iterator<Msg.Message> {
        int index = 0;

        @Override
        public boolean hasNext() {
            return index < messages.length;
        }

        @Override
        public Msg.Message next() {
            if (this.index >= messages.length) {
                throw new NoSuchElementException(this.index + " >= " + messages.length);
            }
            return messages[this.index++];
        }
    }

}