/*
* 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 java.text;
import java.io.Serializable;
/**
* The base class for all formats.
* <p>
* This is an abstract base class which specifies the protocol for classes which
* convert other objects or values, such as numeric values and dates, and their
* string representations. In some cases these representations may be localized
* or contain localized characters or strings. For example, a numeric formatter
* such as {@code DecimalFormat} may convert a numeric value such as 12345 to
* the string "$12,345". It may also parse the string back into a numeric value.
* A date and time formatter like {@code SimpleDateFormat} may represent a
* specific date, encoded numerically, as a string such as "Wednesday, February
* 26, 1997 AD".
* <p>
* Many of the concrete subclasses of {@code Format} employ the notion of a
* pattern. A pattern is a string representation of the rules which govern the
* conversion between values and strings. For example, a {@code DecimalFormat}
* object may be associated with the pattern "$#,##0.00;($#,##0.00)", which is a
* common US English format for currency values, yielding strings such as
* "$1,234.45" for 1234.45, and "($987.65)" for -987.6543. The specific syntax
* of a pattern is defined by each subclass. Even though many subclasses use
* patterns, the notion of a pattern is not inherent to {@code Format} classes
* in general, and is not part of the explicit base class protocol.
* <p>
* Two complex formatting classes are worth mentioning: {@code MessageFormat}
* and {@code ChoiceFormat}. {@code ChoiceFormat} is a subclass of
* {@code NumberFormat} which allows the user to format different number ranges
* as strings. For instance, 0 may be represented as "no files", 1 as "one
* file", and any number greater than 1 as "many files". {@code MessageFormat}
* is a formatter which utilizes other {@code Format} objects to format a string
* containing multiple values. For instance, a {@code MessageFormat} object
* might produce the string "There are no files on the disk MyDisk on February
* 27, 1997." given the arguments 0, "MyDisk", and the date value of 2/27/97.
* See the {@link ChoiceFormat} and {@link MessageFormat} descriptions for
* further information.
*/
public abstract class Format implements Serializable, Cloneable {
private static final long serialVersionUID = -299282585814624189L;
/**
* Used by subclasses. This was public in Java 5.
*/
protected Format() {
}
/**
* Returns a copy of this {@code Format} instance.
*
* @return a shallow copy of this format.
*
* @see java.lang.Cloneable
*/
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
/**
* Formats the specified object using the rules of this format.
*
* @param object
* the object to format.
* @return the formatted string.
* @throws IllegalArgumentException
* if the object cannot be formatted by this format.
*/
public final String format(Object object) {
return format(object, new StringBuffer(), new FieldPosition(0))
.toString();
}
/**
* Appends the specified object to the specified string buffer using the
* rules of this format.
* <p>
* {@code field} is an input/output parameter. If its {@code field}
* member contains an enum value specifying a field on input, then its
* {@code beginIndex} and {@code endIndex} members will be updated with the
* text offset of the first occurrence of this field in the formatted text.
*
* @param object
* the object to format.
* @param buffer
* the string buffer where the formatted string is appended to.
* @param field
* on input: an optional alignment field; on output: the offsets
* of the alignment field in the formatted text.
* @return the string buffer.
* @throws IllegalArgumentException
* if the object cannot be formatted by this format.
*/
public abstract StringBuffer format(Object object, StringBuffer buffer,
FieldPosition field);
/**
* Formats the specified object using the rules of this format and returns
* an {@code AttributedCharacterIterator} with the formatted string and no
* attributes.
* <p>
* Subclasses should return an {@code AttributedCharacterIterator} with the
* appropriate attributes.
*
* @param object
* the object to format.
* @return an {@code AttributedCharacterIterator} with the formatted object
* and attributes.
* @throws IllegalArgumentException
* if the object cannot be formatted by this format.
*/
public AttributedCharacterIterator formatToCharacterIterator(Object object) {
return new AttributedString(format(object)).getIterator();
}
/**
* Parses the specified string using the rules of this format.
*
* @param string
* the string to parse.
* @return the object resulting from the parse.
* @throws ParseException
* if an error occurs during parsing.
*/
public Object parseObject(String string) throws ParseException {
ParsePosition position = new ParsePosition(0);
Object result = parseObject(string, position);
if (position.getIndex() == 0) {
throw new ParseException("Parse failure", position.getErrorIndex());
}
return result;
}
/**
* Parses the specified string starting at the index specified by
* {@code position}. If the string is successfully parsed then the index of
* the {@code ParsePosition} is updated to the index following the parsed
* text. On error, the index is unchanged and the error index of
* {@code ParsePosition} is set to the index where the error occurred.
*
* @param string
* the string to parse.
* @param position
* input/output parameter, specifies the start index in
* {@code string} from where to start parsing. If parsing is
* successful, it is updated with the index following the parsed
* text; on error, the index is unchanged and the error index is
* set to the index where the error occurred.
* @return the object resulting from the parse or {@code null} if there is
* an error.
*/
public abstract Object parseObject(String string, ParsePosition position);
static boolean upTo(String string, ParsePosition position,
StringBuffer buffer, char stop) {
int index = position.getIndex(), length = string.length();
boolean lastQuote = false, quote = false;
while (index < length) {
char ch = string.charAt(index++);
if (ch == '\'') {
if (lastQuote) {
buffer.append('\'');
}
quote = !quote;
lastQuote = true;
} else if (ch == stop && !quote) {
position.setIndex(index);
return true;
} else {
lastQuote = false;
buffer.append(ch);
}
}
position.setIndex(index);
return false;
}
static boolean upToWithQuotes(String string, ParsePosition position,
StringBuffer buffer, char stop, char start) {
int index = position.getIndex(), length = string.length(), count = 1;
boolean quote = false;
while (index < length) {
char ch = string.charAt(index++);
if (ch == '\'') {
quote = !quote;
}
if (!quote) {
if (ch == stop) {
count--;
}
if (count == 0) {
position.setIndex(index);
return true;
}
if (ch == start) {
count++;
}
}
buffer.append(ch);
}
throw new IllegalArgumentException("Unmatched braces in the pattern");
}
/**
* Inner class used to represent {@code Format} attributes in the
* {@code AttributedCharacterIterator} that the
* {@code formatToCharacterIterator()} method returns in {@code Format}
* subclasses.
*/
public static class Field extends AttributedCharacterIterator.Attribute {
private static final long serialVersionUID = 276966692217360283L;
/**
* Constructs a new instance of {@code Field} with the given field name.
*
* @param fieldName
* the field name.
*/
protected Field(String fieldName) {
super(fieldName);
}
}
}