Java tutorial
/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.text; import java.io.InvalidObjectException; import java.io.Serializable; import java.util.HashMap; import java.util.Map; import java.util.Set; /** * An {@code AttributedCharacterIterator} allows iteration through both text and * related attribute information. * * <p> * An attribute is a key/value pair, identified by the key. No two * attributes on a given character can have the same key. * * <p>The values for an attribute are immutable, or must not be mutated * by clients or storage. They are always passed by reference, and not * cloned. * * <p>A <em>run with respect to an attribute</em> is a maximum text range for * which: * <ul> * <li>the attribute is undefined or {@code null} for the entire range, or * <li>the attribute value is defined and has the same non-{@code null} value for the * entire range. * </ul> * * <p>A <em>run with respect to a set of attributes</em> is a maximum text range for * which this condition is met for each member attribute. * * <p>When getting a run with no explicit attributes specified (i.e., * calling {@link #getRunStart()} and {@link #getRunLimit()}), any * contiguous text segments having the same attributes (the same set * of attribute/value pairs) are treated as separate runs if the * attributes have been given to those text segments separately. * * <p>The returned indexes are limited to the range of the iterator. * * <p>The returned attribute information is limited to runs that contain * the current character. * * <p> * Attribute keys are instances of {@link AttributedCharacterIterator.Attribute} and its * subclasses, such as {@link java.awt.font.TextAttribute}. * * @see AttributedCharacterIterator.Attribute * @see java.awt.font.TextAttribute * @see AttributedString * @see Annotation * @since 1.2 */ public interface AttributedCharacterIterator extends CharacterIterator { /** * Defines attribute keys that are used to identify text attributes. These * keys are used in {@code AttributedCharacterIterator} and {@code AttributedString}. * @see AttributedCharacterIterator * @see AttributedString * @since 1.2 */ public static class Attribute implements Serializable { /** * The name of this {@code Attribute}. The name is used primarily by {@code readResolve} * to look up the corresponding predefined instance when deserializing * an instance. * @serial */ private String name; // table of all instances in this class, used by readResolve private static final Map<String, Attribute> instanceMap = new HashMap<>(7); /** * Constructs an {@code Attribute} with the given name. * * @param name the name of {@code Attribute} */ protected Attribute(String name) { this.name = name; if (this.getClass() == Attribute.class) { instanceMap.put(name, this); } } /** * Compares two objects for equality. This version only returns true * for {@code x.equals(y)} if {@code x} and {@code y} refer * to the same object, and guarantees this for all subclasses. */ public final boolean equals(Object obj) { return super.equals(obj); } /** * Returns a hash code value for the object. This version is identical to * the one in {@code Object}, but is also final. */ public final int hashCode() { return super.hashCode(); } /** * Returns a string representation of the object. This version returns the * concatenation of class name, {@code "("}, a name identifying the attribute * and {@code ")"}. */ public String toString() { return getClass().getName() + "(" + name + ")"; } /** * Returns the name of the attribute. * * @return the name of {@code Attribute} */ protected String getName() { return name; } /** * Resolves instances being deserialized to the predefined constants. * * @return the resolved {@code Attribute} object * @throws InvalidObjectException if the object to resolve is not * an instance of {@code Attribute} */ protected Object readResolve() throws InvalidObjectException { if (this.getClass() != Attribute.class) { throw new InvalidObjectException("subclass didn't correctly implement readResolve"); } Attribute instance = instanceMap.get(getName()); if (instance != null) { return instance; } else { throw new InvalidObjectException("unknown attribute name"); } } /** * Attribute key for the language of some text. * <p> Values are instances of {@link java.util.Locale Locale}. * @see java.util.Locale */ public static final Attribute LANGUAGE = new Attribute("language"); /** * Attribute key for the reading of some text. In languages where the written form * and the pronunciation of a word are only loosely related (such as Japanese), * it is often necessary to store the reading (pronunciation) along with the * written form. * <p>Values are instances of {@link Annotation} holding instances of {@link String}. * * @see Annotation * @see java.lang.String */ public static final Attribute READING = new Attribute("reading"); /** * Attribute key for input method segments. Input methods often break * up text into segments, which usually correspond to words. * <p>Values are instances of {@link Annotation} holding a {@code null} reference. * @see Annotation */ public static final Attribute INPUT_METHOD_SEGMENT = new Attribute("input_method_segment"); // make sure the serial version doesn't change between compiler versions private static final long serialVersionUID = -9142742483513960612L; }; /** * Returns the index of the first character of the run * with respect to all attributes containing the current character. * * <p>Any contiguous text segments having the same attributes (the * same set of attribute/value pairs) are treated as separate runs * if the attributes have been given to those text segments separately. * * @return the index of the first character of the run */ public int getRunStart(); /** * Returns the index of the first character of the run * with respect to the given {@code attribute} containing the current character. * * @param attribute the desired attribute. * @return the index of the first character of the run */ public int getRunStart(Attribute attribute); /** * Returns the index of the first character of the run * with respect to the given {@code attributes} containing the current character. * * @param attributes a set of the desired attributes. * @return the index of the first character of the run */ public int getRunStart(Set<? extends Attribute> attributes); /** * Returns the index of the first character following the run * with respect to all attributes containing the current character. * * <p>Any contiguous text segments having the same attributes (the * same set of attribute/value pairs) are treated as separate runs * if the attributes have been given to those text segments separately. * * @return the index of the first character following the run */ public int getRunLimit(); /** * Returns the index of the first character following the run * with respect to the given {@code attribute} containing the current character. * * @param attribute the desired attribute * @return the index of the first character following the run */ public int getRunLimit(Attribute attribute); /** * Returns the index of the first character following the run * with respect to the given {@code attributes} containing the current character. * * @param attributes a set of the desired attributes * @return the index of the first character following the run */ public int getRunLimit(Set<? extends Attribute> attributes); /** * Returns a map with the attributes defined on the current * character. * * @return a map with the attributes defined on the current character */ public Map<Attribute, Object> getAttributes(); /** * Returns the value of the named {@code attribute} for the current character. * Returns {@code null} if the {@code attribute} is not defined. * * @param attribute the desired attribute * @return the value of the named {@code attribute} or {@code null} */ public Object getAttribute(Attribute attribute); /** * Returns the keys of all attributes defined on the * iterator's text range. The set is empty if no * attributes are defined. * * @return the keys of all attributes */ public Set<Attribute> getAllAttributeKeys(); };