Support_StringWriter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package tests.support;

import java.io.IOException;
import java.io.Writer;

public class Support_StringWriter extends Writer {
    private StringBuffer buf;

    /**
     * Constructs a new StringWriter which has a StringBuffer allocated with the
     * default size of 16 characters. The StringBuffer is also the
     * <code>lock</code> used to synchronize access to this Writer.
     */
    public Support_StringWriter() {
        super();
        buf = new StringBuffer(16);
        lock = buf;
    }

    /**
     * Constructs a new StringWriter which has a StringBuffer allocated with the
     * size of <code>initialSize</code> characters. The StringBuffer is also
     * the <code>lock</code> used to synchronize access to this Writer.
     */
    public Support_StringWriter(int initialSize) {
        if (initialSize >= 0) {
            buf = new StringBuffer(initialSize);
            lock = buf;
        } else {
            throw new IllegalArgumentException();
        }
    }

    /**
     * Close this Writer. This is the concrete implementation required. This
     * particular implementation does nothing.
     *
     * @exception java.io.IOException
     *                If an IO error occurs closing this StringWriter.
     */
    @Override
    public void close() throws IOException {
    }

    /**
     * Flush this Writer. This is the concrete implementation required. This
     * particular implementation does nothing.
     *
     */
    @Override
    public void flush() {
    }

    /**
     * Answer the contents of this StringWriter as a StringBuffer. Any changes
     * made to the StringBuffer by the receiver or the caller are reflected in
     * this StringWriter.
     *
     * @return this StringWriters local StringBuffer.
     */
    public StringBuffer getBuffer() {
        synchronized (lock) {
            return buf;
        }
    }

    /**
     * Answer the contents of this StringWriter as a String. Any changes made to
     * the StringBuffer by the receiver after returning will not be reflected in
     * the String returned to the caller.
     *
     * @return this StringWriters current contents as a String.
     */
    @Override
    public String toString() {
        synchronized (lock) {
            return buf.toString();
        }
    }

    /**
     * Writes <code>count</code> characters starting at <code>offset</code>
     * in <code>buf</code> to this StringWriter.
     *
     * @param buf
     *            the non-null array containing characters to write.
     * @param offset
     *            offset in buf to retrieve characters
     * @param count
     *            maximum number of characters to write
     *
     * @exception java.lang.ArrayIndexOutOfBoundsException
     *                If offset or count are outside of bounds.
     */
    @Override
    public void write(char[] buf, int offset, int count) {
        // avoid int overflow
        if (0 <= offset && offset <= buf.length && 0 <= count
                && count <= buf.length - offset) {
            synchronized (lock) {
                this.buf.append(buf, offset, count);
            }
        } else {
            throw new ArrayIndexOutOfBoundsException();
        }
    }

    /**
     * Writes the specified character <code>oneChar</code> to this
     * StringWriter. This implementation writes the low order two bytes to the
     * Stream.
     *
     * @param oneChar
     *            The character to write
     *
     */
    @Override
    public void write(int oneChar) {
        synchronized (lock) {
            buf.append((char) oneChar);
        }
    }

    /**
     * Writes the characters from the String <code>str</code> to this
     * StringWriter.
     *
     * @param str
     *            the non-null String containing the characters to write.
     *
     */
    @Override
    public void write(String str) {
        synchronized (lock) {
            buf.append(str);
        }
    }

    /**
     * Writes <code>count</code> number of characters starting at
     * <code>offset</code> from the String <code>str</code> to this
     * StringWriter.
     *
     * @param str
     *            the non-null String containing the characters to write.
     * @param offset
     *            the starting point to retrieve characters.
     * @param count
     *            the number of characters to retrieve and write.
     *
     * @exception java.lang.ArrayIndexOutOfBoundsException
     *                If offset or count are outside of bounds.
     */
    @Override
    public void write(String str, int offset, int count) {
        String sub = str.substring(offset, offset + count);
        synchronized (lock) {
            buf.append(sub);
        }
    }
}