/*
 * 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 org.apache.wicket.util.resource;

import java.time.Instant;
import org.apache.wicket.util.string.AppendingStringBuffer;

/**
 * A string resource that can be appended to.
 * 
 * @author Jonathan Locke
 */
public class StringBufferResourceStream extends AbstractStringResourceStream
{
	private static final long serialVersionUID = 1L;

	/** Stylesheet information */
	private final AppendingStringBuffer buffer = new AppendingStringBuffer(128);

	/**
	 * Constructor.
	 */
	public StringBufferResourceStream()
	{
	}

	/**
	 * Constructor.
	 * 
	 * @param contentType
	 *            The mime type of this resource, such as "image/jpeg" or "text/html"
	 */
	public StringBufferResourceStream(final String contentType)
	{
		super(contentType);
	}

	/**
	 * Adds to this string buffer resource
	 * 
	 * @param s
	 *            The string to add
	 * @return this for chaining
	 */
	public StringBufferResourceStream append(final CharSequence s)
	{
		buffer.append(s);
		setLastModified(Instant.now());
		return this;
	}

	/**
	 * Prepends to this string buffer resource
	 * 
	 * @param s
	 *            The string to prepend
	 * @return this for chaining
	 */
	public StringBufferResourceStream prepend(final CharSequence s)
	{
		buffer.insert(0, s);
		setLastModified(Instant.now());
		return this;
	}

	/**
	 * Clears the string buffer resource.
	 * 
	 * @return this for chaining
	 */
	public StringBufferResourceStream clear()
	{
		buffer.delete(0, buffer.length());
		return this;
	}

	/**
	 * @see org.apache.wicket.util.resource.AbstractStringResourceStream#getString()
	 */
	@Override
	protected String getString()
	{
		return buffer.toString();
	}
}
