token.java

一款Java实现的HTTP代理服务器

package rabbit.html;

/** This class is used to describe a small part of a html page.
 *  A small part is the text between the tags, a tag, a comment or a script.
 *
 * @author <a href="mailto:[e-mail]">Robert Olofsson</a>
 */
public class Token {
    private String text; 
    private byte[] page;
    private Tag tag;
    private TokenType type;
    private boolean changed = false;
    private int startindex = 0;
    private int len = 0;

    /** Create a new Token of type TEXT with given text.
     * @param text the String of this Token.
     */
    public Token (String text) {
	this (text, TokenType.TEXT, -1);
	setChanged (true);
    }
    
    /** Create a new Token of type Tag with given Tag.
     * @param tag the Tag of this Token. 
     */
    public Token (Tag tag) {
	this (tag, -1);
	setChanged (true);
    }

    /** Create a new Token of type Tag with given Tag.
     * @param tag the Tag of this Token. 
     * @param changed if true this tag is considered changed, 
     *                if false this tag is unmodified.
     */
    public Token (Tag tag, boolean changed) {
	this (tag, -1);
	setChanged (changed);
    }

    /** Create a new Token with given arguments.
     * @param text the text of this Token.
     * @param type the type of this token.
     * @param startindex the start index of this token.
     */
    public Token (String text, TokenType type, int startindex) {
	this.text = text; 
	this.type = type;
	this.startindex = startindex;
    }

    /** Create a new Token with given arguments.
     * @param page the page this token is from.
     * @param type the type of this token.
     * @param startindex the start index of this token.
     * @param len the length of this token.
     */
    public Token (byte[] page, TokenType type, int startindex, int len) {
	this.page = page;
	this.type = type;
	this.startindex = startindex;
	this.len = len;
    }
    
    /** Create a new Token with given arguments and of type TAG.
     * @param tag the Tag of this Token.
     * @param startindex the start index of this token.
     */
    public Token (Tag tag, int startindex) {
	this.tag = tag;
	this.type = TokenType.TAG;
	tag.setToken (this);
	this.startindex = startindex;
    }

    /** Get the tag of this token.
     * @return the Tag or null if type is other than TAG.
     */
    public Tag getTag () {
	return tag;
    }

    /** Set the tag of this token, also set the type to TAG.
     * @param tag the Tag to hold.
     */
    public void setTag (Tag tag) {
	this.tag = tag;
	this.type = TokenType.TAG;
	tag.setToken (this);
	this.changed = true;
    }

    /** Get the text of this token.
     * @return the text or null if type is other than TEXT.
     */
    public String getText () {
	if ((type == TokenType.TEXT || type == TokenType.COMMENT) 
	    && text == null)
	    text = new String (page, startindex, len);
	return text;
    }

    /** Set the text of this Token, also sets the type to TEXT.
     * @param text the text of this token.
     */
    public void setText (String text) {
	this.text = text;
	this.type = TokenType.TEXT;
	this.changed = true;
    }
    
    /** Get the type of this token.
     * @return the type of this token.
     */
    public TokenType getType () {
	return type;
    }

    /** Has this Token changed since it was created?
     * @return true if this Token has changed, false otherwise.
     */
    public boolean getChanged () {
	return changed;
    }
    
    /** Set the change value of this Token.
     * @param changed the new change value of this Token.
     */
    public void setChanged (boolean changed) {
	this.changed = changed;
    }
    
    /** Get the start index of this Token.
     * @return the start index.
     */
    public int getStartIndex () {
	return startindex;
    }

    /** Set the start index of this Token.
     * @param startindex the new startindex.
     */
    public void setStartIndex (int startindex) {
	this.startindex = startindex;
    }

    /** Get the length of this token.
     */
    public int getLength () {
	return len;
    }

    /** Empty this token, That is set its type to EMPTY and set the
     *	text and tag to null.
     */
    public void empty () {
	type = TokenType.EMPTY;
	setChanged (false);
	text = null;
	tag = null;
    }

    /** Get the String representation of this object.
     * @return a String representation of this object.
     */
    public String toString () {
	if (text == null && page != null && type != TokenType.TAG)
	    text = new String (page, startindex, len);
	switch (type) {
	case EMPTY:
	    return "";
	case TEXT:
	    return text;
	case TAG:
	    return tag.toString ();
	case COMMENT:
	    return text; 
	case SCRIPT:
	    return text;
	default:
	    return text;
	}	
    }
}