/*

 * 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.

 *

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package com.sun.tools.doclets.internal.toolkit;

import com.sun.tools.doclets.internal.toolkit.util.*;

/**

 * A class to create content for javadoc output pages.

 *

 * @author Bhavesh Patel

 */

public abstract class Content {

    /**

     * Returns a string representation of the content.

     *

     * @return string representation of the content

     */

    public String toString() {

        StringBuilder contentBuilder = new StringBuilder();

        write(contentBuilder);

        return contentBuilder.toString();

    }

    /**

     * Adds content to the existing content.

     *

     * @param content content that needs to be added

     */

    public abstract void addContent(Content content);

    /**

     * Adds a string content to the existing content.

     *

     * @param stringContent the string content to be added

     */

    public abstract void addContent(String stringContent);

    /**

     * Writes content to a StringBuilder.

     *

     */

    public abstract void write(StringBuilder contentBuilder);

    /**

     * Returns true if the content is empty.

     *

     * @return true if no content to be displayed else return false

     */

    public abstract boolean isEmpty();

    /**

     * Returns true if the content is valid.

     *

     * @return true if the content is valid else return false

     */

    public boolean isValid() {

        return !isEmpty();

    }

    /**

     * Checks for null values.

     *

     * @param t reference type to check for null values

     * @return the reference type if not null or else throws a null pointer exception

     */

    protected static <T> T nullCheck(T t) {

        t.getClass();

        return t;

    }

    /**

     * Returns true if the content ends with a newline character. Empty content

     * is considered as ending with new line.

     *

     * @param contentBuilder content to test for newline character at the end

     * @return true if the content ends with newline.

     */

    protected boolean endsWithNewLine(StringBuilder contentBuilder) {

        int contentLength = contentBuilder.length();

        if (contentLength == 0) {

            return true;

        }

        int nlLength = DocletConstants.NL.length();

        if (contentLength < nlLength) {

            return false;

        }

        int contentIndex = contentLength - 1;

        int nlIndex = nlLength - 1;

        while (nlIndex >= 0) {

            if (contentBuilder.charAt(contentIndex) != DocletConstants.NL.charAt(nlIndex)) {

                return false;

            }

            contentIndex--;

            nlIndex--;

        }

        return true;

    }

}