001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027
028package org.apache.http.impl.io;
029
030import java.io.IOException;
031
032import org.apache.http.Header;
033import org.apache.http.HeaderIterator;
034import org.apache.http.HttpException;
035import org.apache.http.HttpMessage;
036import org.apache.http.io.HttpMessageWriter;
037import org.apache.http.io.SessionOutputBuffer;
038import org.apache.http.message.BasicLineFormatter;
039import org.apache.http.message.LineFormatter;
040import org.apache.http.params.HttpParams;
041import org.apache.http.util.Args;
042import org.apache.http.util.CharArrayBuffer;
043
044/**
045 * Abstract base class for HTTP message writers that serialize output to
046 * an instance of {@link SessionOutputBuffer}.
047 *
048 * @since 4.0
049 */
050@SuppressWarnings("deprecation")
051public abstract class AbstractMessageWriter<T extends HttpMessage> implements HttpMessageWriter<T> {
052
053    protected final SessionOutputBuffer sessionBuffer;
054    protected final CharArrayBuffer lineBuf;
055    protected final LineFormatter lineFormatter;
056
057    /**
058     * Creates an instance of AbstractMessageWriter.
059     *
060     * @param buffer the session output buffer.
061     * @param formatter the line formatter.
062     * @param params HTTP parameters.
063     *
064     * @deprecated (4.3) use
065     *   {@link AbstractMessageWriter#AbstractMessageWriter(SessionOutputBuffer, LineFormatter)}
066     */
067    @Deprecated
068    public AbstractMessageWriter(final SessionOutputBuffer buffer,
069                                 final LineFormatter formatter,
070                                 final HttpParams params) {
071        super();
072        Args.notNull(buffer, "Session input buffer");
073        this.sessionBuffer = buffer;
074        this.lineBuf = new CharArrayBuffer(128);
075        this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
076    }
077
078    /**
079     * Creates an instance of AbstractMessageWriter.
080     *
081     * @param buffer the session output buffer.
082     * @param formatter the line formatter If {@code null} {@link BasicLineFormatter#INSTANCE}
083     *   will be used.
084     *
085     * @since 4.3
086     */
087    public AbstractMessageWriter(
088            final SessionOutputBuffer buffer,
089            final LineFormatter formatter) {
090        super();
091        this.sessionBuffer = Args.notNull(buffer, "Session input buffer");
092        this.lineFormatter = (formatter != null) ? formatter : BasicLineFormatter.INSTANCE;
093        this.lineBuf = new CharArrayBuffer(128);
094    }
095
096    /**
097     * Subclasses must override this method to write out the first header line
098     * based on the {@link HttpMessage} passed as a parameter.
099     *
100     * @param message the message whose first line is to be written out.
101     * @throws IOException in case of an I/O error.
102     */
103    protected abstract void writeHeadLine(T message) throws IOException;
104
105    @Override
106    public void write(final T message) throws IOException, HttpException {
107        Args.notNull(message, "HTTP message");
108        writeHeadLine(message);
109        for (final HeaderIterator it = message.headerIterator(); it.hasNext(); ) {
110            final Header header = it.nextHeader();
111            this.sessionBuffer.writeLine
112                (lineFormatter.formatHeader(this.lineBuf, header));
113        }
114        this.lineBuf.clear();
115        this.sessionBuffer.writeLine(this.lineBuf);
116    }
117
118}