de.intarsys.pdf.cos.COSDocumentElement Maven / Gradle / Ivy

Go to download
/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * 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 of intarsys 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 de.intarsys.pdf.cos;

import java.util.Map;
import java.util.Set;

/**
 * This is a cos level representation of the elements that may be contained in a
 * cos container. An element may be either a {@link
 * de.intarsys.pdf.cos.COSObject} or a
 * {@link de.intarsys.pdf.cos.COSIndirectObject} to a
 * {@link de.intarsys.pdf.cos.COSObject}. A
 * {@link de.intarsys.pdf.cos.COSIndirectObject} is never seen by an application
 * level programmer, this is an internal construct only.
 * 
 */
abstract public class COSDocumentElement implements ICOSExceptionHandler {
	protected COSDocumentElement() {
		//
	}

	/**
	 * Accept a visitor object. The receiver selects the correct implementation
	 * in the visitor by "double dispatching".
	 * 
	 * @param visitor
	 *            The object visiting the receiver.
	 * 
	 * @return Object An object depending on the visitor semantics.
	 * 
	 * @throws COSVisitorException
	 *             An exception depending on the visitor semantics.
	 */
	abstract public Object accept(ICOSObjectVisitor visitor)
			throws COSVisitorException;

	/**
	 * Add a backward reference to the container when the receiver is added to a
	 * container object. The implementation depends on the type of containment
	 * for the object so far (direct/indirect), so we delegate to the old
	 * container.
	 * 
	 * @param newContainer
	 *            the new container embedding the object
	 * @return The new {@link ICOSContainer} associated with this.
	 */
	abstract protected ICOSContainer addContainer(ICOSContainer newContainer);

	/**
	 * The {@link COSDocumentElement} suitable for use in an
	 * {@link ICOSContainer}. This may be a {@link COSIndirectObject} or the
	 * {@link COSObject} itself if not indirect.
	 * 
	 * This method should not be used by the application programmer. This is
	 * called in the {@link COSObject} lifecycle to ensure internal consistency.
	 */
	abstract public COSDocumentElement containable();

	/**
	 * see copyDeep()
	 * 
	 * 

	 * This method keeps track of already copied objects to deal with cyclic
	 * references.
	 * 
	 * 
	 * @see de.intarsys.pdf.cos.COSObject#copyDeep()
	 */
	abstract protected COSObject copyDeep(Map copied);

	abstract protected COSDocumentElement copyShallowNested();

	/**
	 * Return the real object. This is either the object itself or the object
	 * referenced by a reference object ({@link COSIndirectObject}).
	 * 
	 * @return The real object.
	 */
	abstract public COSObject dereference();

	protected boolean equals(Object o, Set visited) {
		return this.equals(o);
	}

	/**
	 * The document where this is contained or null. A
	 * {@link COSDocumentElement} is at most contained in a single
	 * {@link COSDocument}.
	 * 
	 * @return The document where this is contained.
	 */
	abstract public COSDocument getDoc();

	/*
	 * (non-Javadoc)
	 * 
	 * @see de.intarsys.pdf.cos.ICOSExceptionHandler#handleException(de.intarsys.pdf.cos.COSRuntimeException)
	 */
	public void handleException(COSRuntimeException ex)
			throws COSRuntimeException {
		COSDocument doc = getDoc();
		if (doc != null) {
			doc.handleException(ex);
		} else {
			throw ex;
		}
	}

	/**
	 * Answer true if this element is a reference (a
	 * {@link COSIndirectObject}.
	 * 
	 * @return Answer true if this element is a reference.
	 */
	public boolean isReference() {
		return false;
	}

	/**
	 * Answer true if this elements content is swapped to a
	 * persistent store.
	 * 
	 * @return Answer true if this elements content is swapped to
	 *         a persistent store.
	 */
	public boolean isSwapped() {
		return false;
	}

	/**
	 * Register the all indirect objects that can be reached from this with doc
	 * 
	 * @param doc
	 *            The container document
	 */
	abstract protected void registerWith(COSDocument doc);

	/**
	 * Remove a backward reference to the container when the receiver is removed
	 * from a container object. The implementation depends on the type of
	 * containment for the object so far (direct/indirect), so we delegate to
	 * the old container.
	 * 
	 * @param oldContainer
	 *            the container that no longer embeds the receiver
	 * @return The new {@link ICOSContainer} associated with this.
	 */
	abstract protected ICOSContainer removeContainer(ICOSContainer oldContainer);
}