/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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
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package org.springframework.web.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

Represents a set of character entity references defined by the HTML 4.0 standard.

A complete description of the HTML 4.0 character set can be found at https://www.w3.org/TR/html4/charset.html.

Author:Juergen Hoeller, Martin Kersten, Craig Andrews
Since:1.2.1
/** * Represents a set of character entity references defined by the * HTML 4.0 standard. * * <p>A complete description of the HTML 4.0 character set can be found * at https://www.w3.org/TR/html4/charset.html. * * @author Juergen Hoeller * @author Martin Kersten * @author Craig Andrews * @since 1.2.1 */
class HtmlCharacterEntityReferences { private static final String PROPERTIES_FILE = "HtmlCharacterEntityReferences.properties"; static final char REFERENCE_START = '&'; static final String DECIMAL_REFERENCE_START = "&#"; static final String HEX_REFERENCE_START = "&#x"; static final char REFERENCE_END = ';'; static final char CHAR_NULL = (char) -1; private final String[] characterToEntityReferenceMap = new String[3000]; private final Map<String, Character> entityReferenceToCharacterMap = new HashMap<>(512);
Returns a new set of character entity references reflecting the HTML 4.0 character set.
/** * Returns a new set of character entity references reflecting the HTML 4.0 character set. */
public HtmlCharacterEntityReferences() { Properties entityReferences = new Properties(); // Load reference definition file InputStream is = HtmlCharacterEntityReferences.class.getResourceAsStream(PROPERTIES_FILE); if (is == null) { throw new IllegalStateException( "Cannot find reference definition file [HtmlCharacterEntityReferences.properties] as class path resource"); } try { try { entityReferences.load(is); } finally { is.close(); } } catch (IOException ex) { throw new IllegalStateException( "Failed to parse reference definition file [HtmlCharacterEntityReferences.properties]: " + ex.getMessage()); } // Parse reference definition properties Enumeration<?> keys = entityReferences.propertyNames(); while (keys.hasMoreElements()) { String key = (String) keys.nextElement(); int referredChar = Integer.parseInt(key); Assert.isTrue((referredChar < 1000 || (referredChar >= 8000 && referredChar < 10000)), () -> "Invalid reference to special HTML entity: " + referredChar); int index = (referredChar < 1000 ? referredChar : referredChar - 7000); String reference = entityReferences.getProperty(key); this.characterToEntityReferenceMap[index] = REFERENCE_START + reference + REFERENCE_END; this.entityReferenceToCharacterMap.put(reference, (char) referredChar); } }
Return the number of supported entity references.
/** * Return the number of supported entity references. */
public int getSupportedReferenceCount() { return this.entityReferenceToCharacterMap.size(); }
Return true if the given character is mapped to a supported entity reference.
/** * Return true if the given character is mapped to a supported entity reference. */
public boolean isMappedToReference(char character) { return isMappedToReference(character, WebUtils.DEFAULT_CHARACTER_ENCODING); }
Return true if the given character is mapped to a supported entity reference.
/** * Return true if the given character is mapped to a supported entity reference. */
public boolean isMappedToReference(char character, String encoding) { return (convertToReference(character, encoding) != null); }
Return the reference mapped to the given character, or null if none found.
/** * Return the reference mapped to the given character, or {@code null} if none found. */
@Nullable public String convertToReference(char character) { return convertToReference(character, WebUtils.DEFAULT_CHARACTER_ENCODING); }
Return the reference mapped to the given character, or null if none found.
Since:4.1.2
/** * Return the reference mapped to the given character, or {@code null} if none found. * @since 4.1.2 */
@Nullable public String convertToReference(char character, String encoding) { if (encoding.startsWith("UTF-")){ switch (character){ case '<': return "&lt;"; case '>': return "&gt;"; case '"': return "&quot;"; case '&': return "&amp;"; case '\'': return "&#39;"; } } else if (character < 1000 || (character >= 8000 && character < 10000)) { int index = (character < 1000 ? character : character - 7000); String entityReference = this.characterToEntityReferenceMap[index]; if (entityReference != null) { return entityReference; } } return null; }
Return the char mapped to the given entityReference or -1.
/** * Return the char mapped to the given entityReference or -1. */
public char convertToCharacter(String entityReference) { Character referredCharacter = this.entityReferenceToCharacterMap.get(entityReference); if (referredCharacter != null) { return referredCharacter; } return CHAR_NULL; } }