Java tutorial
/* * (This file extracted from Apache HttpClient 4.2.1, used to * provide support on Android platform - where only 4.0 is present. * Modifications are only to package/import locations to reflect location * of this code.) * * ==================================================================== * 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 com.gistlabs.mechanize.util.apache; import java.nio.charset.Charset; import java.nio.charset.UnsupportedCharsetException; import java.util.Locale; import org.apache.http.Header; import org.apache.http.HeaderElement; import org.apache.http.HttpEntity; import org.apache.http.NameValuePair; import org.apache.http.ParseException; import org.apache.http.annotation.Immutable; import org.apache.http.message.BasicHeaderValueParser; /** * Content type information consisting of a MIME type and an optional charset. * <p/> * This class makes no attempts to verify validity of the MIME type. * The input parameters of the {@link #create(String, String)} method, however, may not * contain characters <">, <;>, <,> reserved by the HTTP specification. * * @since 4.2 */ @Immutable public final class ContentType { // constants public static final ContentType APPLICATION_ATOM_XML = create("application/atom+xml", Consts.ISO_8859_1); public static final ContentType APPLICATION_FORM_URLENCODED = create("application/x-www-form-urlencoded", Consts.ISO_8859_1); public static final ContentType APPLICATION_JSON = create("application/json", Consts.UTF_8); public static final ContentType APPLICATION_OCTET_STREAM = create("application/octet-stream", (Charset) null); public static final ContentType APPLICATION_SVG_XML = create("application/svg+xml", Consts.ISO_8859_1); public static final ContentType APPLICATION_XHTML_XML = create("application/xhtml+xml", Consts.ISO_8859_1); public static final ContentType APPLICATION_XML = create("application/xml", Consts.ISO_8859_1); public static final ContentType MULTIPART_FORM_DATA = create("multipart/form-data", Consts.ISO_8859_1); public static final ContentType TEXT_HTML = create("text/html", Consts.ISO_8859_1); public static final ContentType TEXT_PLAIN = create("text/plain", Consts.ISO_8859_1); public static final ContentType TEXT_XML = create("text/xml", Consts.ISO_8859_1); public static final ContentType WILDCARD = create("*/*", (Charset) null); // defaults public static final ContentType DEFAULT_TEXT = TEXT_PLAIN; public static final ContentType DEFAULT_BINARY = APPLICATION_OCTET_STREAM; private final String mimeType; private final Charset charset; /** * Given a MIME type and a character set, constructs a ContentType. * @param mimeType The MIME type to use for the ContentType header. * @param charset The optional character set to use with the ContentType header. * @throws UnsupportedCharsetException * If no support for the named charset is available in this Java virtual machine */ ContentType(final String mimeType, final Charset charset) { this.mimeType = mimeType; this.charset = charset; } public String getMimeType() { return this.mimeType; } public Charset getCharset() { return this.charset; } /** * Converts a ContentType to a string which can be used as a ContentType header. * If a charset is provided by the ContentType, it will be included in the string. */ @Override public String toString() { StringBuilder buf = new StringBuilder(); buf.append(this.mimeType); if (this.charset != null) { buf.append("; charset="); buf.append(this.charset.name()); } return buf.toString(); } private static boolean valid(final String s) { for (int i = 0; i < s.length(); i++) { char ch = s.charAt(i); if (ch == '"' || ch == ',' || ch == ';') { return false; } } return true; } /** * Creates a new instance of {@link ContentType}. * * @param mimeType MIME type. It may not be <code>null</code> or empty. It may not contain * characters <">, <;>, <,> reserved by the HTTP specification. * @param charset charset. * @return content type */ public static ContentType create(final String mimeType, final Charset charset) { if (mimeType == null) { throw new IllegalArgumentException("MIME type may not be null"); } String type = mimeType.trim().toLowerCase(Locale.US); if (type.length() == 0) { throw new IllegalArgumentException("MIME type may not be empty"); } if (!valid(type)) { throw new IllegalArgumentException("MIME type may not contain reserved characters"); } return new ContentType(type, charset); } /** * Creates a new instance of {@link ContentType} without a charset. * * @param mimeType MIME type. It may not be <code>null</code> or empty. It may not contain * characters <">, <;>, <,> reserved by the HTTP specification. * @return content type */ public static ContentType create(final String mimeType) { return new ContentType(mimeType, (Charset) null); } /** * Creates a new instance of {@link ContentType}. * * @param mimeType MIME type. It may not be <code>null</code> or empty. It may not contain * characters <">, <;>, <,> reserved by the HTTP specification. * @param charset charset. It may not contain characters <">, <;>, <,> reserved by the HTTP * specification. This parameter is optional. * @return content type */ public static ContentType create(final String mimeType, final String charset) throws UnsupportedCharsetException { return create(mimeType, charset != null ? Charset.forName(charset) : null); } private static ContentType create(final HeaderElement helem) { String mimeType = helem.getName(); String charset = null; NameValuePair param = helem.getParameterByName("charset"); if (param != null) { charset = param.getValue(); } return create(mimeType, charset); } /** * Parses textual representation of <code>Content-Type</code> value. * * @param s text * @return content type * @throws ParseException if the given text does not represent a valid * <code>Content-Type</code> value. */ public static ContentType parse(final String s) throws ParseException, UnsupportedCharsetException { if (s == null) { throw new IllegalArgumentException("Content type may not be null"); } HeaderElement[] elements = BasicHeaderValueParser.parseElements(s, null); if (elements.length > 0) { return create(elements[0]); } else { throw new ParseException("Invalid content type: " + s); } } /** * Extracts <code>Content-Type</code> value from {@link HttpEntity} exactly as * specified by the <code>Content-Type</code> header of the entity. Returns <code>null</code> * if not specified. * * @param entity HTTP entity * @return content type * @throws ParseException if the given text does not represent a valid * <code>Content-Type</code> value. */ public static ContentType get(final HttpEntity entity) throws ParseException, UnsupportedCharsetException { if (entity == null) { return null; } Header header = entity.getContentType(); if (header != null) { HeaderElement[] elements = header.getElements(); if (elements.length > 0) { return create(elements[0]); } } return null; } /** * Extracts <code>Content-Type</code> value from {@link HttpEntity} or returns default value * if not explicitly specified. * * @param entity HTTP entity * @return content type * @throws ParseException if the given text does not represent a valid * <code>Content-Type</code> value. */ public static ContentType getOrDefault(final HttpEntity entity) throws ParseException { ContentType contentType = get(entity); return contentType != null ? contentType : DEFAULT_TEXT; } }