ealvatag.tag.NullTag.java Source code

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Here is the source code for ealvatag.tag.NullTag.java

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/*
 * Copyright (c) 2017 Eric A. Snell
 *
 * This file is part of eAlvaTag.
 *
 * eAlvaTag is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 *
 * eAlvaTag is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with eAlvaTag.  If not,
 * see <http://www.gnu.org/licenses/>.
 */

package ealvatag.tag;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import ealvatag.tag.images.Artwork;

import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.List;

/**
 * No-op {@link Tag} implementation. Especially useful for testing
 * <p>
 * Created by Eric A. Snell on 1/22/17.
 */
public final class NullTag implements Tag {
    public static final Tag INSTANCE = new NullTag();

    private NullTag() {
    }

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

    @Override
    public ImmutableSet<FieldKey> getSupportedFields() {
        return ImmutableSet.of();
    }

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

    @Override
    public boolean hasField(final FieldKey genericKey) throws IllegalArgumentException, UnsupportedFieldException {
        return false;
    }

    @Override
    public boolean hasField(final String id) {
        return false;
    }

    @Override
    public int getFieldCount(final Key genericKey) throws IllegalArgumentException, UnsupportedFieldException {
        return 0;
    }

    @Override
    public int getFieldCount() {
        return 0;
    }

    @Override
    public Tag setField(final FieldKey genericKey, final String... values)
            throws IllegalArgumentException, UnsupportedFieldException, FieldDataInvalidException {
        return this;
    }

    @Override
    public Tag addField(final FieldKey genericKey, final String... values)
            throws IllegalArgumentException, UnsupportedFieldException, FieldDataInvalidException {
        return this;
    }

    @Override
    public String getFirst(final FieldKey genericKey) throws IllegalArgumentException, UnsupportedFieldException {
        return "";
    }

    @Override
    public String getFirst(final String id) throws IllegalArgumentException, UnsupportedFieldException {
        return null;
    }

    @Override
    public Optional<String> getValue(final FieldKey genericKey) throws IllegalArgumentException {
        return Optional.absent();
    }

    @Override
    public Optional<String> getValue(final FieldKey genericKey, final int index) throws IllegalArgumentException {
        return Optional.absent();
    }

    @Override
    public String getFieldAt(final FieldKey genericKey, final int index)
            throws IllegalArgumentException, UnsupportedFieldException {
        return "";
    }

    @Override
    public List<String> getAll(final FieldKey genericKey)
            throws IllegalArgumentException, UnsupportedFieldException {
        return ImmutableList.of();
    }

    @Override
    public Tag deleteField(final FieldKey genericKey) throws IllegalArgumentException, UnsupportedFieldException {
        return this;
    }

    @Override
    public Tag deleteField(final String id) throws IllegalArgumentException, UnsupportedFieldException {
        return this;
    }

    @Override
    public Tag setArtwork(final Artwork artwork)
            throws IllegalArgumentException, UnsupportedFieldException, FieldDataInvalidException {
        return this;
    }

    @Override
    public Tag addArtwork(final Artwork artwork)
            throws IllegalArgumentException, UnsupportedFieldException, FieldDataInvalidException {
        return this;
    }

    @Override
    public Optional<Artwork> getFirstArtwork() throws UnsupportedFieldException {
        return Optional.absent();
    }

    @Override
    public List<Artwork> getArtworkList() throws UnsupportedFieldException {
        return ImmutableList.of();
    }

    @Override
    public Tag deleteArtwork() throws UnsupportedFieldException {
        return this;
    }

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

    @Override
    public int getFieldCountIncludingSubValues() {
        return 0;
    }

    @Override
    public boolean setEncoding(final Charset enc) throws FieldDataInvalidException {
        return false;
    }

    @Override
    public TagField createField(final FieldKey genericKey, final String... value)
            throws IllegalArgumentException, UnsupportedFieldException, FieldDataInvalidException {
        return NullTagField.INSTANCE;
    }

    @Override
    public TagField createArtwork(final Artwork artwork)
            throws UnsupportedFieldException, FieldDataInvalidException {
        return NullTagField.INSTANCE;
    }

    @Override
    public ImmutableList<TagField> getFields(final FieldKey genericKey)
            throws IllegalArgumentException, UnsupportedFieldException {
        return ImmutableList.of();
    }

    @Override
    public Iterator<TagField> getFields() {
        return ImmutableList.<TagField>of().iterator();
    }

    @Override
    public ImmutableList<TagField> getFields(final String id) {
        return ImmutableList.of();
    }

    @Override
    public Optional<TagField> getFirstField(final String id)
            throws IllegalArgumentException, UnsupportedFieldException {
        return Optional.absent();
    }

    @Override
    public Optional<TagField> getFirstField(final FieldKey genericKey)
            throws IllegalArgumentException, UnsupportedFieldException {
        return Optional.absent();
    }

    @Override
    public TagField createCompilationField(final boolean value) throws UnsupportedFieldException {
        return NullTagField.INSTANCE;
    }
}