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 * 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).
 *
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 * 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 jdk.javadoc.internal.doclets.toolkit;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Objects;


A class to create content for javadoc output pages.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.

/**
 * A class to create content for javadoc output pages.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public abstract class Content {

    
Returns a string representation of the content.

Returns:string representation of the content
/**
     * Returns a string representation of the content.
     *
     * @return string representation of the content
     */
    @Override
    public String toString() {
        StringWriter out = new StringWriter();
        try {
            write(out, true);
        } catch (IOException e) {
            // cannot happen from StringWriter
            throw new AssertionError(e);
        }
        return out.toString();
    }

    
Adds content to the existing content.
This is an optional operation.

Params:
  • content – content to be added
Throws:
Implementation Requirements:This implementation throws UnsupportedOperationException.
Returns:this object
/**
     * Adds content to the existing content.
     * This is an optional operation.
     *
     * @implSpec This implementation throws {@linkplain UnsupportedOperationException}.
     *
     * @param content content to be added
     * @return this object
     * @throws UnsupportedOperationException if this operation is not supported by
     *                                       a particular implementation
     * @throws IllegalArgumentException      if the content is not suitable to be added
     */
    public Content add(Content content) {
        throw new UnsupportedOperationException();
    }

    
Adds a string content to the existing content.
This is an optional operation.

Params:
  • stringContent – the string content to be added
Throws:
Implementation Requirements: This implementation throws UnsupportedOperationException.
Returns:this object
/**
     * Adds a string content to the existing content.
     * This is an optional operation.
     *
     * @implSpec
     * This implementation throws {@linkplain UnsupportedOperationException}.
     *
     * @param stringContent the string content to be added
     * @return this object
     * @throws UnsupportedOperationException if this operation is not supported by
     *                                       a particular implementation
     * @throws IllegalArgumentException      if the content is not suitable to be added
     */
    public Content add(CharSequence stringContent) {
        throw new UnsupportedOperationException();
    }

    
Writes content to a writer.

Params:
  • writer – the writer
  • atNewline – whether the writer has just written a newline
Throws:
  • IOException – if an error occurs while writing the output
Returns: whether the writer has just written a newline
/**
     * Writes content to a writer.
     *
     * @param writer the writer
     * @param atNewline whether the writer has just written a newline
     * @return  whether the writer has just written a newline
     * @throws IOException if an error occurs while writing the output
     */
    public abstract boolean write(Writer writer, boolean atNewline) throws IOException ;

    
Returns true if the content is empty.

Returns:true if no content to be displayed else return false
/**
     * 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.

Returns:true if the content is valid else return false
/**
     * Returns true if the content is valid.
     *
     * @return true if the content is valid else return false
     */
    public boolean isValid() {
        return !isEmpty();
    }

    
Return the number of characters of plain text content in this object
(optional operation.)

Returns:the number of characters of plain text content in this
/**
     * Return the number of characters of plain text content in this object
     * (optional operation.)
     * @return the number of characters of plain text content in this
     */
    public int charCount() {
        return 0;
    }
}