package org.jdom;

import java.io.Serializable;

/**
 * <p><code>DocType</code> represents an XML
 *   DOCTYPE declaration.
 * </p>
 *
 * @author Brett McLaughlin
 * @author Jason Hunter
 * @version 1.0
 */
public class DocType implements Serializable, Cloneable {

	private static final String CVS_ID = 
		"@(#) $RCSfile: DocType.java,v $ $Revision: 1.14 $ $Date: 2001/04/27 18:21:19 $ $Name:  $";

	/** The element being constrained */
	protected String elementName;

	/** The public ID of the DOCTYPE */
	protected String publicID;

	/** The system ID of the DOCTYPE */
	protected String systemID;

	/** The document having this DOCTYPE */
	protected Document document;

	/** The internal subset of the DOCTYPE */
	protected String internalSubset;

	/**
	 * <p>
	 * Default, no-args constructor for implementations
	 *   to use if needed.
	 * </p>
	 */
	protected DocType() {}
	/**
	 * <p>
	 * This will create the <code>DocType</code> with
	 *   the specified element name
	 * </p>
	 *
	 * @param elementName <code>String</code> name of
	 *        element being constrained.
	 */
	public DocType(String elementName) {
		this(elementName, "", "");
	}
	/**
	 * <p>
	 * This will create the <code>DocType</code> with
	 *   the specified element name and reference to an
	 *   external DTD.
	 * </p>
	 *
	 * @param elementName <code>String</code> name of
	 *        element being constrained.
	 * @param systemID <code>String</code> system ID of
	 *        referenced DTD
	 */
	public DocType(String elementName, String systemID) {
		this(elementName, "", systemID);
	}
	/*
	 * XXX:
	 *   We need to take care of entities and notations here.
	 */

	/**
	 * <p>
	 * This will create the <code>DocType</code> with
	 *   the specified element name and a reference to an
	 *   external DTD.
	 * </p>
	 *
	 * @param elementName <code>String</code> name of
	 *        element being constrained.
	 * @param publicID <code>String</code> public ID of
	 *        referenced DTD
	 * @param systemID <code>String</code> system ID of
	 *        referenced DTD
	 */
	public DocType(String elementName, String publicID, String systemID) {
		this.elementName = elementName;
		this.publicID = publicID;
		this.systemID = systemID;
	}
	/**
	 * <p>
	 *  This will return a clone of this <code>DocType</code>.
	 * </p>
	 *
	 * @return <code>Object</code> - clone of this <code>DocType</code>.
	 */
	public Object clone() {
		DocType docType = null;

		try {
			docType = (DocType) super.clone();
		} catch (CloneNotSupportedException ce) {
			// Can't happen
		}

		docType.document = null;

		// elementName, publicID, and systemID are all immutable 
		// (Strings) and references are copied by Object.clone()
		return docType;
	}
	/**
	 * <p>
	 *  This tests for equality of this <code>DocType</code> to the supplied
	 *    <code>Object</code>.
	 * </p>
	 *
	 * @param ob <code>Object</code> to compare to.
	 * @return <code>boolean</code> - whether the <code>DocType</code> is
	 *         equal to the supplied <code>Object</code>.
	 */
	public final boolean equals(Object ob) {
		if (ob instanceof DocType) {
			DocType dt = (DocType) ob;
			return (stringEquals(dt.elementName, elementName) &&
					stringEquals(dt.publicID, publicID) &&
					stringEquals(dt.systemID, systemID));
		}
		return false;
	}
	/**
	 * <p>
	 * This retrieves the owning <code>{@link Document}</code> for
	 *   this DocType, or null if not a currently a member of a
	 *   <code>{@link Document}</code>.
	 * </p>
	 *
	 * @return <code>Document</code> owning this DocType, or null.
	 */
	public Document getDocument() {
		return this.document;
	}
	/**
	 * <p>
	 * This will retrieve the element name being
	 *   constrained.
	 * </p>
	 *
	 * @return <code>String</code> - element name for DOCTYPE
	 */
	public String getElementName() {
		return elementName;
	}
	/**
	 * get the data for the internal subset
	 * 
	 * @return java.lang.String
	 */
	public java.lang.String getInternalSubset() {
		return internalSubset;
	}
	/**
	 * <p>
	 * This will retrieve the public ID of an externally
	 *   referenced DTD, or an empty <code>String</code> if
	 *   none is referenced.
	 * </p>
	 *
	 * @return <code>String</code> - public ID of referenced DTD.
	 */
	public String getPublicID() {
		return publicID;
	}
	/**
	 * <p>
	 *  This will return the <code>DocType</code> in XML format,
	 *    usable in an XML document.
	 * </p>
	 *
	 * @return <code>String</code> - the serialized form of the
	 *         <code>DocType</code>.
	 *
	 * @deprecated Deprecated in Beta7, use XMLOutputter.outputString(DocType)
	 * instead
	 */
	public final String getSerializedForm() {
		boolean hasPublic = false;

		StringBuffer serForm = new StringBuffer()
			.append("<!DOCTYPE ")
			.append(elementName);

		if ((publicID != null) && (!publicID.equals(""))) {
			serForm.append(" PUBLIC \"")
				.append(publicID)
				.append("\"");
			hasPublic = true;
		}

		if ((systemID != null) && (!systemID.equals(""))) {
			if (!hasPublic) {
				serForm.append(" SYSTEM");
			}
			serForm.append(" \"")
				.append(systemID)
				.append("\"");
		}
		serForm.append(">");

		return serForm.toString();
	}
	/**
	 * <p>
	 * This will retrieve the system ID of an externally
	 *   referenced DTD, or an empty <code>String</code> if
	 *   none is referenced.
	 * </p>
	 *
	 * @return <code>String</code> - system ID of referenced DTD.
	 */
	public String getSystemID() {
		return systemID;
	}
	/**
	 * <p>
	 *  This returns the hash code for this <code>DocType</code>.
	 * </p>
	 *
	 * @return <code>int</code> - hash code.
	 */
	public final int hashCode() {
		return super.hashCode();
	}
	/**
	 * <p>
	 * This sets the <code>{@link Document}</code> holding this doctype.
	 * </p>
	 *
	 * @param document <code>Document</code> holding this doctype
	 * @return <code>Document</code> this <code>DocType</code> modified
	 */
	protected DocType setDocument(Document document) {
		this.document = document;
		return this;
	}
	/**
	 * set the data for the internal subset
	 * 
	 * @param newData java.lang.String
	 */
	public void setInternalSubset(java.lang.String newData) {
		internalSubset = newData;
	}
	/**
	 * <p>
	 * This will set the public ID of an externally
	 *   referenced DTD.
	 * </p>
	 *
	 * @return publicID <code>String</code> public ID of
	 *                  referenced DTD.
	 */
	public DocType setPublicID(String publicID) {
		this.publicID = publicID;

		return this;
	}
	/**
	 * <p>
	 * This will set the system ID of an externally
	 *   referenced DTD.
	 * </p>
	 *
	 * @return systemID <code>String</code> system ID of
	 *                  referenced DTD.
	 */
	public DocType setSystemID(String systemID) {
		this.systemID = systemID;

		return this;
	}
	// Utility function to help with equals()
	private boolean stringEquals(String s1, String s2) {
		if (s1 == null && s2 == null) {
			return true;
		}
		else if (s1 == null && s2 != null) {
			return false;
		}
		else {
			// If we get here we know s1 can't be null 
			return s1.equals(s2);
		}
	}
	/**
	 * <p>
	 *  This returns a <code>String</code> representation of the
	 *    <code>DocType</code>, suitable for debugging. 
	 * </p>
	 *
	 * @return <code>String</code> - information about the
	 *         <code>DocType</code>
	 */
	public String toString() {
		return new StringBuffer()
			.append("[DocType: ")
			.append(new org.jdom.output.XMLOutputter().outputString(this))
			.append("]")
			.toString();
	}
}