/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0/module-main/src/main/java/org/apache/http/message/BasicLineFormatter.java $
* $Revision: 744527 $
* $Date: 2009-02-14 18:06:25 +0100 (Sat, 14 Feb 2009) $
*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.message;
import org.apache.http.ProtocolVersion;
import org.apache.http.RequestLine;
import org.apache.http.StatusLine;
import org.apache.http.Header;
import org.apache.http.FormattedHeader;
import org.apache.http.util.CharArrayBuffer;
/**
* Interface for formatting elements of the HEAD section of an HTTP message.
* This is the complement to {@link LineParser}.
* There are individual methods for formatting a request line, a
* status line, or a header line. The formatting does <i>not</i> include the
* trailing line break sequence CR-LF.
* The formatted lines are returned in memory, the formatter does not depend
* on any specific IO mechanism.
* Instances of this interface are expected to be stateless and thread-safe.
*
*
*
* <!-- empty lines above to avoid 'svn diff' context problems -->
* @version $Revision: 744527 $
*
* @since 4.0
*/
public class BasicLineFormatter implements LineFormatter {
/**
* A default instance of this class, for use as default or fallback.
* Note that {@link BasicLineFormatter} is not a singleton, there can
* be many instances of the class itself and of derived classes.
* The instance here provides non-customized, default behavior.
*/
public final static BasicLineFormatter DEFAULT = new BasicLineFormatter();
// public default constructor
/**
* Obtains a buffer for formatting.
*
* @param buffer a buffer already available, or <code>null</code>
*
* @return the cleared argument buffer if there is one, or
* a new empty buffer that can be used for formatting
*/
protected CharArrayBuffer initBuffer(CharArrayBuffer buffer) {
if (buffer != null) {
buffer.clear();
} else {
buffer = new CharArrayBuffer(64);
}
return buffer;
}
/**
* Formats a protocol version.
*
* @param version the protocol version to format
* @param formatter the formatter to use, or
* <code>null</code> for the
* {@link #DEFAULT default}
*
* @return the formatted protocol version
*/
public final static
String formatProtocolVersion(final ProtocolVersion version,
LineFormatter formatter) {
if (formatter == null)
formatter = BasicLineFormatter.DEFAULT;
return formatter.appendProtocolVersion(null, version).toString();
}
// non-javadoc, see interface LineFormatter
public CharArrayBuffer appendProtocolVersion(final CharArrayBuffer buffer,
final ProtocolVersion version) {
if (version == null) {
throw new IllegalArgumentException
("Protocol version may not be null");
}
// can't use initBuffer, that would clear the argument!
CharArrayBuffer result = buffer;
final int len = estimateProtocolVersionLen(version);
if (result == null) {
result = new CharArrayBuffer(len);
} else {
result.ensureCapacity(len);
}
result.append(version.getProtocol());
result.append('/');
result.append(Integer.toString(version.getMajor()));
result.append('.');
result.append(Integer.toString(version.getMinor()));
return result;
}
/**
* Guesses the length of a formatted protocol version.
* Needed to guess the length of a formatted request or status line.
*
* @param version the protocol version to format, or <code>null</code>
*
* @return the estimated length of the formatted protocol version,
* in characters
*/
protected int estimateProtocolVersionLen(final ProtocolVersion version) {
return version.getProtocol().length() + 4; // room for "HTTP/1.1"
}
/**
* Formats a request line.
*
* @param reqline the request line to format
* @param formatter the formatter to use, or
* <code>null</code> for the
* {@link #DEFAULT default}
*
* @return the formatted request line
*/
public final static String formatRequestLine(final RequestLine reqline,
LineFormatter formatter) {
if (formatter == null)
formatter = BasicLineFormatter.DEFAULT;
return formatter.formatRequestLine(null, reqline).toString();
}
// non-javadoc, see interface LineFormatter
public CharArrayBuffer formatRequestLine(CharArrayBuffer buffer,
RequestLine reqline) {
if (reqline == null) {
throw new IllegalArgumentException
("Request line may not be null");
}
CharArrayBuffer result = initBuffer(buffer);
doFormatRequestLine(result, reqline);
return result;
}
/**
* Actually formats a request line.
* Called from {@link #formatRequestLine}.
*
* @param buffer the empty buffer into which to format,
* never <code>null</code>
* @param reqline the request line to format, never <code>null</code>
*/
protected void doFormatRequestLine(final CharArrayBuffer buffer,
final RequestLine reqline) {
final String method = reqline.getMethod();
final String uri = reqline.getUri();
// room for "GET /index.html HTTP/1.1"
int len = method.length() + 1 + uri.length() + 1 +
estimateProtocolVersionLen(reqline.getProtocolVersion());
buffer.ensureCapacity(len);
buffer.append(method);
buffer.append(' ');
buffer.append(uri);
buffer.append(' ');
appendProtocolVersion(buffer, reqline.getProtocolVersion());
}
/**
* Formats a status line.
*
* @param statline the status line to format
* @param formatter the formatter to use, or
* <code>null</code> for the
* {@link #DEFAULT default}
*
* @return the formatted status line
*/
public final static String formatStatusLine(final StatusLine statline,
LineFormatter formatter) {
if (formatter == null)
formatter = BasicLineFormatter.DEFAULT;
return formatter.formatStatusLine(null, statline).toString();
}
// non-javadoc, see interface LineFormatter
public CharArrayBuffer formatStatusLine(final CharArrayBuffer buffer,
final StatusLine statline) {
if (statline == null) {
throw new IllegalArgumentException
("Status line may not be null");
}
CharArrayBuffer result = initBuffer(buffer);
doFormatStatusLine(result, statline);
return result;
}
/**
* Actually formats a status line.
* Called from {@link #formatStatusLine}.
*
* @param buffer the empty buffer into which to format,
* never <code>null</code>
* @param statline the status line to format, never <code>null</code>
*/
protected void doFormatStatusLine(final CharArrayBuffer buffer,
final StatusLine statline) {
int len = estimateProtocolVersionLen(statline.getProtocolVersion())
+ 1 + 3 + 1; // room for "HTTP/1.1 200 "
final String reason = statline.getReasonPhrase();
if (reason != null) {
len += reason.length();
}
buffer.ensureCapacity(len);
appendProtocolVersion(buffer, statline.getProtocolVersion());
buffer.append(' ');
buffer.append(Integer.toString(statline.getStatusCode()));
buffer.append(' '); // keep whitespace even if reason phrase is empty
if (reason != null) {
buffer.append(reason);
}
}
/**
* Formats a header.
*
* @param header the header to format
* @param formatter the formatter to use, or
* <code>null</code> for the
* {@link #DEFAULT default}
*
* @return the formatted header
*/
public final static String formatHeader(final Header header,
LineFormatter formatter) {
if (formatter == null)
formatter = BasicLineFormatter.DEFAULT;
return formatter.formatHeader(null, header).toString();
}
// non-javadoc, see interface LineFormatter
public CharArrayBuffer formatHeader(CharArrayBuffer buffer,
Header header) {
if (header == null) {
throw new IllegalArgumentException
("Header may not be null");
}
CharArrayBuffer result = null;
if (header instanceof FormattedHeader) {
// If the header is backed by a buffer, re-use the buffer
result = ((FormattedHeader)header).getBuffer();
} else {
result = initBuffer(buffer);
doFormatHeader(result, header);
}
return result;
} // formatHeader
/**
* Actually formats a header.
* Called from {@link #formatHeader}.
*
* @param buffer the empty buffer into which to format,
* never <code>null</code>
* @param header the header to format, never <code>null</code>
*/
protected void doFormatHeader(final CharArrayBuffer buffer,
final Header header) {
final String name = header.getName();
final String value = header.getValue();
int len = name.length() + 2;
if (value != null) {
len += value.length();
}
buffer.ensureCapacity(len);
buffer.append(name);
buffer.append(": ");
if (value != null) {
buffer.append(value);
}
}
} // class BasicLineFormatter