com.twelvemonkeys.imageio.metadata.AbstractDirectory Maven / Gradle / Ivy

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/*
 * Copyright (c) 2009, Harald Kuhr
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name "TwelveMonkeys" nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.twelvemonkeys.imageio.metadata;

import java.util.*;

import static com.twelvemonkeys.lang.Validate.noNullElements;

/**
 * AbstractDirectory
 *
 * @author Harald Kuhr
 * @author last modified by $Author: haraldk$
 * @version $Id: AbstractDirectory.java,v 1.0 Nov 11, 2009 5:31:04 PM haraldk Exp$
 */
public abstract class AbstractDirectory implements Directory {
    private final List entries = new ArrayList();
    private final List unmodifiable = Collections.unmodifiableList(entries);

    protected AbstractDirectory(final Collection entries) {
        if (entries != null) {
            this.entries.addAll(noNullElements(entries));
        }
    }

    public Entry getEntryById(final Object identifier) {
        for (Entry entry : this) {
            if (entry.getIdentifier().equals(identifier)) {
                return entry;
            }
        }

        return null;
    }

    public Entry getEntryByFieldName(final String fieldName) {
        for (Entry entry : this) {
            if (entry.getFieldName() != null && entry.getFieldName().equals(fieldName)) {
                return entry;
            }
        }

        return null;
    }

    public Iterator iterator() {
        return isReadOnly() ? unmodifiable.iterator() : entries.iterator();
    }

    /**
     * Throws {@code UnsupportedOperationException} if this directory is read-only.
     * 
     * @throws UnsupportedOperationException if this directory is read-only.
     * @see #isReadOnly()
     */
    protected final void assertMutable() {
        if (isReadOnly()) {
            throw new UnsupportedOperationException("Directory is read-only");
        }
    }

    public boolean add(final Entry entry) {
        assertMutable();

        // TODO: Replace if entry is already present?
        // Some directories may need special ordering, or may/may not support multiple entries for certain ids...
        return entries.add(entry);
    }

    @SuppressWarnings({"SuspiciousMethodCalls"})
    public boolean remove(final Object entry) {
        assertMutable();

        return entries.remove(entry);
    }

    public int size() {
        return entries.size();
    }

    /**
     * This implementation returns {@code true}.
     * Subclasses should override this method, if the directory is mutable.
     *
     * @return {@code true}
     */
    public boolean isReadOnly() {
        return true;
    }

    /// Standard object support

    @Override
    public int hashCode() {
        return entries.hashCode();
    }

    @Override
    public boolean equals(final Object pOther) {
        if (this == pOther) {
            return true;
        }

        if (pOther == null || getClass() != pOther.getClass()) {
            return false;
        }

        // Safe cast, as it must be a subclass for the classes to be equal
        AbstractDirectory other = (AbstractDirectory) pOther;

        return entries.equals(other.entries);
    }

    @Override
    public String toString() {
        return String.format("%s%s", getClass().getSimpleName(), entries.toString());
    }
}