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569 lines
16 KiB
Java
569 lines
16 KiB
Java
/* java.lang.Integer
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Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.lang;
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/**
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* Instances of class <code>Integer</code> represent primitive
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* <code>int</code> values.
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*
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* Additionally, this class provides various helper functions and variables
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* related to ints.
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*
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* @author Paul Fisher
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* @author John Keiser
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* @author Warren Levy
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* @since JDK 1.0
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*/
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public final class Integer extends Number implements Comparable
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{
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// compatible with JDK 1.0.2+
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private static final long serialVersionUID = 1360826667806852920L;
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/**
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* The minimum value an <code>int</code> can represent is -2147483648.
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*/
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public static final int MIN_VALUE = 0x80000000;
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/**
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* The maximum value an <code>int</code> can represent is 2147483647.
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*/
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public static final int MAX_VALUE = 0x7fffffff;
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/**
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* The primitive type <code>int</code> is represented by this
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* <code>Class</code> object.
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*/
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public static final Class TYPE = VMClassLoader.getPrimitiveClass ("int");
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/**
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* The immutable value of this Integer.
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*/
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private final int value;
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/**
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* Create an <code>Integer</code> object representing the value of the
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* <code>int</code> argument.
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*
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* @param value the value to use
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*/
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public Integer(int value)
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{
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this.value = value;
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}
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/**
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* Create an <code>Integer</code> object representing the value of the
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* argument after conversion to an <code>int</code>.
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*
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* @param s the string to convert.
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*/
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public Integer(String s) throws NumberFormatException
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{
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value = parseInt(s, 10);
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}
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/**
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* Return a hashcode representing this Object.
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*
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* <code>Integer</code>'s hash code is calculated by simply returning its
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* value.
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*
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* @return this Object's hash code.
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*/
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public int hashCode()
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{
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return value;
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}
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/**
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* If the <code>Object</code> is not <code>null</code>, is an
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* <code>instanceof</code> <code>Integer</code>, and represents
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* the same primitive <code>int</code> value return
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* <code>true</code>. Otherwise <code>false</code> is returned.
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*/
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public boolean equals(Object obj)
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{
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return obj instanceof Integer && value == ((Integer)obj).value;
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}
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/**
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* Get the specified system property as an <code>Integer</code>.
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*
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* The <code>decode()</code> method will be used to interpret the value of
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* the property.
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* @param nm the name of the system property
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* @return the system property as an <code>Integer</code>, or
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* <code>null</code> if the property is not found or cannot be
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* decoded as an <code>Integer</code>.
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* @see java.lang.System#getProperty(java.lang.String)
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* @see #decode(int)
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*/
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public static Integer getInteger(String nm)
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{
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return getInteger(nm, null);
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}
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/**
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* Get the specified system property as an <code>Integer</code>, or use a
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* default <code>int</code> value if the property is not found or is not
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* decodable.
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*
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* The <code>decode()</code> method will be used to interpret the value of
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* the property.
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*
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* @param nm the name of the system property
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* @param val the default value to use if the property is not found or not
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* a number.
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* @return the system property as an <code>Integer</code>, or the default
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* value if the property is not found or cannot be decoded as an
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* <code>Integer</code>.
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* @see java.lang.System#getProperty(java.lang.String)
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* @see #decode(int)
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* @see #getInteger(java.lang.String,java.lang.Integer)
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*/
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public static Integer getInteger(String nm, int val)
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{
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Integer result = getInteger(nm, null);
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return (result == null) ? new Integer(val) : result;
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}
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/**
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* Get the specified system property as an <code>Integer</code>, or use a
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* default <code>Integer</code> value if the property is not found or is
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* not decodable.
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*
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* The <code>decode()</code> method will be used to interpret the value of
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* the property.
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*
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* @param nm the name of the system property
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* @param val the default value to use if the property is not found or not
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* a number.
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* @return the system property as an <code>Integer</code>, or the default
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* value if the property is not found or cannot be decoded as an
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* <code>Integer</code>.
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* @see java.lang.System#getProperty(java.lang.String)
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* @see #decode(int)
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* @see #getInteger(java.lang.String,int)
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*/
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public static Integer getInteger(String nm, Integer def)
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{
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String val = System.getProperty(nm);
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if (val == null) return def;
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try
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{
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return decode(nm);
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}
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catch (NumberFormatException e)
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{
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return def;
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}
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}
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private static String toUnsignedString(int num, int exp)
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{
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// Use an array large enough for a binary number.
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int radix = 1 << exp;
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int mask = radix - 1;
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char[] buffer = new char[32];
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int i = 32;
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do
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{
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buffer[--i] = Character.forDigit(num & mask, radix);
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num = num >>> exp;
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}
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while (num != 0);
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return String.valueOf(buffer, i, 32-i);
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}
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/**
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* Converts the <code>int</code> to a <code>String</code> assuming it is
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* unsigned in base 16.
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* @param i the <code>int</code> to convert to <code>String</code>
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* @return the <code>String</code> representation of the argument.
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*/
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public static String toHexString(int i)
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{
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return toUnsignedString(i, 4);
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}
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/**
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* Converts the <code>int</code> to a <code>String</code> assuming it is
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* unsigned in base 8.
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* @param i the <code>int</code> to convert to <code>String</code>
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* @return the <code>String</code> representation of the argument.
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*/
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public static String toOctalString(int i)
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{
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return toUnsignedString(i, 3);
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}
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/**
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* Converts the <code>int</code> to a <code>String</code> assuming it is
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* unsigned in base 2.
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* @param i the <code>int</code> to convert to <code>String</code>
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* @return the <code>String</code> representation of the argument.
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*/
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public static String toBinaryString(int i)
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{
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return toUnsignedString(i, 1);
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}
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/**
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* Converts the <code>int</code> to a <code>String</code> and assumes
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* a radix of 10.
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* @param i the <code>int</code> to convert to <code>String</code>
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* @return the <code>String</code> representation of the argument.
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*/
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public static String toString(int i)
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{
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// This is tricky: in libgcj, String.valueOf(int) is a fast native
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// implementation. In Classpath it just calls back to
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// Integer.toString(int,int).
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return String.valueOf (i);
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}
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/**
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* Converts the <code>Integer</code> value to a <code>String</code> and
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* assumes a radix of 10.
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* @return the <code>String</code> representation of this <code>Integer</code>.
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*/
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public String toString()
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{
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return toString (value);
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}
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/**
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* Converts the <code>int</code> to a <code>String</code> using
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* the specified radix (base).
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* @param i the <code>int</code> to convert to <code>String</code>.
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* @param radix the radix (base) to use in the conversion.
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* @return the <code>String</code> representation of the argument.
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*/
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public static String toString(int num, int radix)
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{
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if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
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radix = 10;
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// For negative numbers, print out the absolute value w/ a leading '-'.
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// Use an array large enough for a binary number.
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char[] buffer = new char[33];
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int i = 33;
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boolean isNeg;
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if (num < 0)
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{
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isNeg = true;
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num = -(num);
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// When the value is MIN_VALUE, it overflows when made positive
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if (num < 0)
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{
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buffer[--i] = Character.forDigit(-(num + radix) % radix, radix);
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num = -(num / radix);
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}
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}
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else
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isNeg = false;
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do
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{
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buffer[--i] = Character.forDigit(num % radix, radix);
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num /= radix;
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}
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while (num > 0);
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if (isNeg)
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buffer[--i] = '-';
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return String.valueOf(buffer, i, 33-i);
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}
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/**
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* Creates a new <code>Integer</code> object using the <code>String</code>,
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* assuming a radix of 10.
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* @param s the <code>String</code> to convert.
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* @return the new <code>Integer</code>.
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* @see #Integer(java.lang.String)
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* @see #parseInt(java.lang.String)
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* @exception NumberFormatException thrown if the <code>String</code>
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* cannot be parsed as an <code>int</code>.
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*/
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public static Integer valueOf(String s) throws NumberFormatException
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{
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return new Integer(parseInt(s));
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}
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/**
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* Creates a new <code>Integer</code> object using the <code>String</code>
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* and specified radix (base).
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* @param s the <code>String</code> to convert.
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* @param radix the radix (base) to convert with.
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* @return the new <code>Integer</code>.
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* @see #parseInt(java.lang.String,int)
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* @exception NumberFormatException thrown if the <code>String</code>
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* cannot be parsed as an <code>int</code>.
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*/
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public static Integer valueOf(String s, int radix)
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throws NumberFormatException
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{
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return new Integer(parseInt(s, radix));
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}
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/**
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* Converts the specified <code>String</code> into an <code>int</code>.
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* This function assumes a radix of 10.
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*
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* @param s the <code>String</code> to convert
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* @return the <code>int</code> value of the <code>String</code>
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* argument.
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* @exception NumberFormatException thrown if the <code>String</code>
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* cannot be parsed as an <code>int</code>.
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*/
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public static int parseInt(String s) throws NumberFormatException
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{
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return parseInt(s, 10);
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}
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/**
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* Converts the specified <code>String</code> into an <code>int</code>
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* using the specified radix (base).
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*
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* @param s the <code>String</code> to convert
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* @param radix the radix (base) to use in the conversion
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* @return the <code>String</code> argument converted to </code>int</code>.
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* @exception NumberFormatException thrown if the <code>String</code>
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* cannot be parsed as a <code>int</code>.
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*/
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public static int parseInt(String str, int radix)
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throws NumberFormatException
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{
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final int len;
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if ((len = str.length()) == 0 ||
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radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
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throw new NumberFormatException();
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boolean isNeg = false;
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int index = 0;
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if (str.charAt(index) == '-')
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if (len > 1)
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{
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isNeg = true;
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index++;
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}
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else
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throw new NumberFormatException();
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return parseInt(str, index, len, isNeg, radix);
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}
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private static int parseInt(String str, int index, int len, boolean isNeg,
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int radix)
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throws NumberFormatException
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{
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int val = 0;
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int digval;
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int max = MAX_VALUE / radix;
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// We can't directly write `max = (MAX_VALUE + 1) / radix'.
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// So instead we fake it.
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if (isNeg && MAX_VALUE % radix == radix - 1)
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++max;
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for ( ; index < len; index++)
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{
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if (val < 0 || val > max)
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throw new NumberFormatException();
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if ((digval = Character.digit(str.charAt(index), radix)) < 0)
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throw new NumberFormatException();
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// Throw an exception for overflow if result is negative.
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// However, we special-case the most negative value.
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val = val * radix + digval;
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if (val < 0 && (! isNeg || val != MIN_VALUE))
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throw new NumberFormatException();
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}
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return isNeg ? -(val) : val;
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}
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/**
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* Convert the specified <code>String</code> into an <code>Integer</code>.
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* The <code>String</code> may represent decimal, hexadecimal, or
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* octal numbers.
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*
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* The <code>String</code> argument is interpreted based on the leading
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* characters. Depending on what the String begins with, the base will be
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* interpreted differently:
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*
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* <table border=1>
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* <tr><th>Leading<br>Characters</th><th>Base</th></tr>
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* <tr><td>#</td><td>16</td></tr>
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* <tr><td>0x</td><td>16</td></tr>
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* <tr><td>0X</td><td>16</td></tr>
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* <tr><td>0</td><td>8</td></tr>
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* <tr><td>Anything<br>Else</td><td>10</td></tr>
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* </table>
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*
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* @param str the <code>String</code> to interpret.
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* @return the value of the String as an <code>Integer</code>.
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* @exception NumberFormatException thrown if the <code>String</code>
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* cannot be parsed as an <code>int</code>.
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*/
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public static Integer decode(String str) throws NumberFormatException
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{
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boolean isNeg = false;
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int index = 0;
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int radix = 10;
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final int len;
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if (str == null || (len = str.length()) == 0)
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throw new NumberFormatException("string null or empty");
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// Negative numbers are always radix 10.
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if (str.charAt(index) == '-')
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{
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radix = 10;
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index++;
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isNeg = true;
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}
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else if (str.charAt(index) == '#')
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{
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radix = 16;
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index++;
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}
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else if (str.charAt(index) == '0')
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{
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// Check if str is just "0"
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if (len == 1)
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return new Integer(0);
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index++;
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if (str.charAt(index) == 'x' || str.charAt(index) == 'X')
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{
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radix = 16;
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index++;
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}
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else
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radix = 8;
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}
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if (index >= len)
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throw new NumberFormatException("empty value");
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return new Integer(parseInt(str, index, len, isNeg, radix));
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}
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|
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/** Return the value of this <code>Integer</code> as a <code>byte</code>.
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** @return the value of this <code>Integer</code> as a <code>byte</code>.
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**/
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public byte byteValue()
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{
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return (byte) value;
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}
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/** Return the value of this <code>Integer</code> as a <code>short</code>.
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** @return the value of this <code>Integer</code> as a <code>short</code>.
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**/
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public short shortValue()
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{
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return (short) value;
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}
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|
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/** Return the value of this <code>Integer</code> as an <code>int</code>.
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** @return the value of this <code>Integer</code> as an <code>int</code>.
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**/
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public int intValue()
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{
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return value;
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}
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/** Return the value of this <code>Integer</code> as a <code>long</code>.
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** @return the value of this <code>Integer</code> as a <code>long</code>.
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**/
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public long longValue()
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{
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return value;
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}
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|
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/** Return the value of this <code>Integer</code> as a <code>float</code>.
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|
** @return the value of this <code>Integer</code> as a <code>float</code>.
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**/
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public float floatValue()
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{
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return value;
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}
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|
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/** Return the value of this <code>Integer</code> as a <code>double</code>.
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|
** @return the value of this <code>Integer</code> as a <code>double</code>.
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**/
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|
public double doubleValue()
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|
{
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return value;
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}
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|
|
/**
|
|
* Compare two Integers numerically by comparing their
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* <code>int</code> values.
|
|
* @return a positive value if this <code>Integer</code> is greater
|
|
* in value than the argument <code>Integer</code>; a negative value
|
|
* if this <code>Integer</code> is smaller in value than the argument
|
|
* <code>Integer</code>; and <code>0</code>, zero, if this
|
|
* <code>Integer</code> is equal in value to the argument
|
|
* <code>Integer</code>.
|
|
*
|
|
* @since 1.2
|
|
*/
|
|
public int compareTo(Integer i)
|
|
{
|
|
if (this.value == i.value)
|
|
return 0;
|
|
|
|
// Returns just -1 or 1 on inequality; doing math might overflow.
|
|
if (this.value > i.value)
|
|
return 1;
|
|
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* Behaves like <code>compareTo(java.lang.Integer)</code> unless the Object
|
|
* is not a <code>Integer</code>. Then it throws a
|
|
* <code>ClassCastException</code>.
|
|
* @exception ClassCastException if the argument is not a
|
|
* <code>Integer</code>.
|
|
*
|
|
* @since 1.2
|
|
*/
|
|
public int compareTo(Object o)
|
|
{
|
|
return compareTo((Integer)o);
|
|
}
|
|
}
|