DBusDictEntry.java

/*
 * SPDX-FileCopyrightText: 2025 Lucimber UG
 * SPDX-License-Identifier: Apache-2.0
 */
package com.lucimber.dbus.type;

import java.util.AbstractMap;
import java.util.Map;
import java.util.Objects;

/**
 * A map entry (key-value pair).
 *
 * @param <KeyT> The key's data type.
 * @param <ValueT> The value's data type.
 */
public final class DBusDictEntry<KeyT extends DBusBasicType, ValueT extends DBusType>
        implements Map.Entry<KeyT, ValueT>, DBusContainerType {

    private final KeyT key;
    private final DBusSignature signature;
    private ValueT value;

    /**
     * Constructs a new instance.
     *
     * @param signature a {@link DBusSignature}; must describe an dict-entry
     * @param key a {@link DBusBasicType}
     */
    public DBusDictEntry(final DBusSignature signature, final KeyT key) {
        this(signature, key, null);
    }

    /**
     * Constructs a new instance.
     *
     * @param signature a {@link DBusSignature}; must describe an dict-entry
     * @param key a {@link DBusBasicType}
     * @param value a {@link DBusType}
     */
    public DBusDictEntry(final DBusSignature signature, final KeyT key, final ValueT value) {
        this.signature = Objects.requireNonNull(signature);
        if (!signature.isDictionaryEntry()) {
            throw new IllegalArgumentException("Signature must describe a dictionary entry.");
        }
        this.key = Objects.requireNonNull(key);
        this.value = value;
    }

    /**
     * Constructs a new instance from another.
     *
     * @param other a {@link DBusDictEntry}
     */
    public DBusDictEntry(final DBusDictEntry<KeyT, ValueT> other) {
        signature = other.signature;
        key = other.key;
        value = other.value;
    }

    @Override
    public Type getType() {
        return Type.DICT_ENTRY;
    }

    @Override
    public DBusSignature getSignature() {
        return signature;
    }

    @Override
    public Map.Entry<KeyT, ValueT> getDelegate() {
        return new AbstractMap.SimpleEntry<>(key, value);
    }

    @Override
    public KeyT getKey() {
        return key;
    }

    @Override
    public ValueT getValue() {
        return value;
    }

    @Override
    public ValueT setValue(final ValueT value) {
        final ValueT oldValue = this.value;
        this.value = value;
        return oldValue;
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        final DBusDictEntry<?, ?> that = (DBusDictEntry<?, ?>) o;
        return key.equals(that.key) && Objects.equals(value, that.value);
    }

    @Override
    public int hashCode() {
        return Objects.hash(key, value);
    }

    @Override
    public String toString() {
        return key + "=" + value;
    }
}