https://openjdk.java.net/ 
/*
 * Copyright (c) 1998, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.swing.text.html.parser;

import java.util.BitSet;
import java.util.Vector;
import java.io.*;



A stack of tags. Used while parsing an HTML document.
It, together with the ContentModelStates, defines the
complete state of the parser while reading a document.
When a start tag is encountered an element is pushed onto
the stack, when an end tag is enountered an element is popped
of the stack.

Author:     Arthur van Hoff
See Also:
/**
 * A stack of tags. Used while parsing an HTML document.
 * It, together with the ContentModelStates, defines the
 * complete state of the parser while reading a document.
 * When a start tag is encountered an element is pushed onto
 * the stack, when an end tag is enountered an element is popped
 * of the stack.
 *
 * @see Parser
 * @see DTD
 * @see ContentModelState
 * @author      Arthur van Hoff
 */
final
class TagStack implements DTDConstants {
    TagElement tag;
    Element elem;
    ContentModelState state;
    TagStack next;
    BitSet inclusions;
    BitSet exclusions;
    boolean net;
    boolean pre;

    
Construct a stack element.

/**
     * Construct a stack element.
     */
    TagStack(TagElement tag, TagStack next) {
        this.tag = tag;
        this.elem = tag.getElement();
        this.next = next;

        Element elem = tag.getElement();
        if (elem.getContent() != null) {
            this.state = new ContentModelState(elem.getContent());
        }

        if (next != null) {
            inclusions = next.inclusions;
            exclusions = next.exclusions;
            pre = next.pre;
        }
        if (tag.isPreformatted()) {
            pre = true;
        }

        if (elem.inclusions != null) {
            if (inclusions != null) {
                inclusions = (BitSet)inclusions.clone();
                inclusions.or(elem.inclusions);
            } else {
                inclusions = elem.inclusions;
            }
        }
        if (elem.exclusions != null) {
            if (exclusions != null) {
                exclusions = (BitSet)exclusions.clone();
                exclusions.or(elem.exclusions);
            } else {
                exclusions = elem.exclusions;
            }
        }
    }

    
Return the element that must come next in the
input stream.

/**
     * Return the element that must come next in the
     * input stream.
     */
    public Element first() {
        return (state != null) ? state.first() : null;
    }

    
Return the ContentModel that must be satisfied by
what comes next in the input stream.

/**
     * Return the ContentModel that must be satisfied by
     * what comes next in the input stream.
     */
    public ContentModel contentModel() {
        if (state == null) {
            return null;
        } else {
            return state.getModel();
        }
    }

    
Return true if the element that is contained at
the index specified by the parameter is part of
the exclusions specified in the DTD for the element
currently on the TagStack.

/**
     * Return true if the element that is contained at
     * the index specified by the parameter is part of
     * the exclusions specified in the DTD for the element
     * currently on the TagStack.
     */
    boolean excluded(int elemIndex) {
        return (exclusions != null) && exclusions.get(elem.getIndex());
    }

    
Update the Vector elemVec with all the elements that
are part of the inclusions listed in DTD for the element
currently on the TagStack.

/**
     * Update the Vector elemVec with all the elements that
     * are part of the inclusions listed in DTD for the element
     * currently on the TagStack.
     */
    boolean included(Vector elemVec, DTD dtd) {

        for (int i = 0 ; i < inclusions.size(); i++) {
            if (inclusions.get(i)) {
                elemVec.addElement(dtd.getElement(i));
                System.out.println("Element add thru' inclusions: " + dtd.getElement(i).getName());
            }
        }
        return (!elemVec.isEmpty());
    }


    
Advance the state by reducing the given element.
Returns false if the element is not legal and the
state is not advanced.

/**
     * Advance the state by reducing the given element.
     * Returns false if the element is not legal and the
     * state is not advanced.
     */
    boolean advance(Element elem) {
        if ((exclusions != null) && exclusions.get(elem.getIndex())) {
            return false;
        }
        if (state != null) {
            ContentModelState newState = state.advance(elem);
            if (newState != null) {
                state = newState;
                return true;
            }
        } else if (this.elem.getType() == ANY) {
            return true;
        }
        return (inclusions != null) && inclusions.get(elem.getIndex());
    }

    
Return true if the current state can be terminated.

/**
     * Return true if the current state can be terminated.
     */
    boolean terminate() {
        return (state == null) || state.terminate();
    }

    
Convert to a string.

/**
     * Convert to a string.
     */
    public String toString() {
        return (next == null) ?
            "<" + tag.getElement().getName() + ">" :
            next + " <" + tag.getElement().getName() + ">";
    }
}

class NPrintWriter extends PrintWriter {

    private int numLines = 5;
    private int numPrinted = 0;

    public NPrintWriter (int numberOfLines) {
        super(System.out);
        numLines = numberOfLines;
    }

    public void println(char[] array) {
        if (numPrinted >= numLines) {
            return;
        }

        char[] partialArray = null;

        for (int i = 0; i < array.length; i++) {
            if (array[i] == '\n') {
                numPrinted++;
            }

            if (numPrinted == numLines) {
                System.arraycopy(array, 0, partialArray, 0, i);
            }
        }

        if (partialArray != null) {
            super.print(partialArray);
        }

        if (numPrinted == numLines) {
            return;
        }

        super.println(array);
        numPrinted++;
    }
}