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| * 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.olingo.odata2.core.commons; |
| |
| import java.io.UnsupportedEncodingException; |
| |
| /** |
| * Encodes a Java String (in its internal UTF-16 encoding) into its |
| * percent-encoded UTF-8 representation according to |
| * <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986</a> |
| * (with consideration of its predecessor RFC 2396). |
| * |
| */ |
| public class Encoder { |
| |
| /** |
| * Encodes a Java String (in its internal UTF-16 encoding) into its |
| * percent-encoded UTF-8 representation according to |
| * <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986</a>, |
| * suitable for parts of an OData path segment. |
| * @param value the Java String |
| * @return the encoded String |
| */ |
| public static String encode(final String value) { |
| return encoder.encodeInternal(value); |
| } |
| |
| // OData has special handling for "'", so we allow that to remain unencoded. |
| // Other sub-delims not used neither by JAX-RS nor by OData could be added |
| // if the encoding is considered to be too aggressive. |
| // RFC 3986 would also allow the gen-delims ":" and "@" to appear literally |
| // in path-segment parts. |
| private static final String ODATA_UNENCODED = "'"; |
| |
| // Character classes from RFC 3986 |
| private final static String UNRESERVED = "-._~"; // + ALPHA + DIGIT |
| // RFC 3986 says: "For consistency, URI producers and normalizers should |
| // use uppercase hexadecimal digits for all percent-encodings." |
| private final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07", "%08", "%09", "%0A", |
| "%0B", "%0C", "%0D", "%0E", "%0F", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17", "%18", "%19", "%1A", |
| "%1B", "%1C", "%1D", "%1E", "%1F", "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2A", |
| "%2B", "%2C", "%2D", "%2E", "%2F", "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3A", |
| "%3B", "%3C", "%3D", "%3E", "%3F", "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47", "%48", "%49", "%4A", |
| "%4B", "%4C", "%4D", "%4E", "%4F", "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57", "%58", "%59", "%5A", |
| "%5B", "%5C", "%5D", "%5E", "%5F", "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68", "%69", "%6A", |
| "%6B", "%6C", "%6D", "%6E", "%6F", "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7A", |
| "%7B", "%7C", "%7D", "%7E", "%7F", "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87", "%88", |
| "%89", "%8A", "%8B", "%8C", "%8D", "%8E", "%8F", "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97", "%98", |
| "%99", "%9A", "%9B", "%9C", "%9D", "%9E", "%9F", "%A0", "%A1", "%A2", "%A3", "%A4", "%A5", "%A6", "%A7", "%A8", |
| "%A9", "%AA", "%AB", "%AC", "%AD", "%AE", "%AF", "%B0", "%B1", "%B2", "%B3", "%B4", "%B5", "%B6", "%B7", "%B8", |
| "%B9", "%BA", "%BB", "%BC", "%BD", "%BE", "%BF", "%C0", "%C1", "%C2", "%C3", "%C4", "%C5", "%C6", "%C7", "%C8", |
| "%C9", "%CA", "%CB", "%CC", "%CD", "%CE", "%CF", "%D0", "%D1", "%D2", "%D3", "%D4", "%D5", "%D6", "%D7", "%D8", |
| "%D9", "%DA", "%DB", "%DC", "%DD", "%DE", "%DF", "%E0", "%E1", "%E2", "%E3", "%E4", "%E5", "%E6", "%E7", "%E8", |
| "%E9", "%EA", "%EB", "%EC", "%ED", "%EE", "%EF", "%F0", "%F1", "%F2", "%F3", "%F4", "%F5", "%F6", "%F7", "%F8", |
| "%F9", "%FA", "%FB", "%FC", "%FD", "%FE", "%FF" }; |
| |
| private static final Encoder encoder = new Encoder(ODATA_UNENCODED); |
| |
| /** characters to remain unencoded in addition to {@link #UNRESERVED} */ |
| private final String unencoded; |
| |
| private Encoder(final String unencoded) { |
| this.unencoded = unencoded == null ? "" : unencoded; |
| } |
| |
| /** |
| * <p>Returns the percent-encoded UTF-8 representation of a String.</p> |
| * <p>In order to avoid producing percent-encoded CESU-8 (as described in |
| * the Unicode Consortium's <a href="http://www.unicode.org/reports/tr26/"> |
| * Technical Report #26</a>), this is done in two steps: |
| * <ol> |
| * <li>Re-encode the characters from their Java-internal UTF-16 representations |
| * into their UTF-8 representations.</li> |
| * <li>Percent-encode each of the bytes in the UTF-8 representation. |
| * This is possible on byte level because all characters that do not have |
| * a <code>%xx</code> representation are represented in one byte in UTF-8.</li> |
| * </ol></p> |
| * @param input input String |
| * @return encoded representation |
| */ |
| private String encodeInternal(final String input) { |
| StringBuilder resultStr = new StringBuilder(); |
| |
| try { |
| for (byte utf8Byte : input.getBytes("UTF-8")) { |
| final char character = (char) utf8Byte; |
| if (isUnreserved(character)) { |
| resultStr.append(character); |
| } else if (isUnencoded(character)) { |
| resultStr.append(character); |
| } else if (utf8Byte >= 0) { |
| resultStr.append(hex[utf8Byte]); |
| } else { |
| // case UTF-8 continuation byte |
| resultStr.append(hex[256 + utf8Byte]); // index adjusted for the usage of signed bytes |
| } |
| } |
| } catch (final UnsupportedEncodingException e) { // should never happen; UTF-8 is always there |
| return null; |
| } |
| return resultStr.toString(); |
| } |
| |
| private static boolean isUnreserved(final char character) { |
| return 'A' <= character && character <= 'Z' // case A..Z |
| || 'a' <= character && character <= 'z' // case a..z |
| || '0' <= character && character <= '9' // case 0..9 |
| || UNRESERVED.indexOf(character) >= 0; |
| } |
| |
| private boolean isUnencoded(final char character) { |
| return unencoded.indexOf(character) >= 0; |
| } |
| } |