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package org.apidesign.delegatingwriter;

import java.io.BufferedWriter;

import java.io.IOException;

import java.io.Writer;

/**

 * This is a regular {@link BufferedWriter}, just it optimizes for

 * huge {@link CharSequence} objects set to its {@link #append} method.

 * Instead of converting them to string, which might required too much

 * temporary memory, it delegates it directly.

 * <p>

 * This class is <q>simulating</q> would would happen if JDK's BufferedWriter 

 * in revision 1.5

 * was designed to delegate its newly added <code>append</code> methods

 * instead of calling its already existing <code>write</code> ones.

 * 

 * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 */

public class ExBufferedWriter extends BufferedWriter {

    private final Writer out;

    public ExBufferedWriter(Writer out, int sz, boolean optimized) {

        super(out, sz);

        this.out = optimized ? out : null;

    }

    @Override

    public Writer append(CharSequence csq) throws IOException {

        if (out != null) {

            // efficient, yet dangerous delegation skipping methods known to 

            // subclasses that used version 1.4

            out.append(csq);

            return this;

        } else {

            // non-efficient variant of delegating via converting to String first 

            // and using one of methods that existed in 1.4

            if (csq == null) {

                write("null");

            } else {

                write(csq.toString());

            }

            return this;

        }

    }

}