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yap-6.3/LGPL/JPL/java/jpl/Integer.java
vsc be83a4a309 jpl stuff
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1120 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2004-08-27 20:27:56 +00:00

270 lines
8.0 KiB
Java

//tabstop=4
//*****************************************************************************/
// Project: jpl
//
// File: $Id: Integer.java,v 1.1 2004-08-27 20:27:56 vsc Exp $
// Date: $Date: 2004-08-27 20:27:56 $
// Author: Fred Dushin <fadushin@syr.edu>
//
//
// Description:
//
//
// -------------------------------------------------------------------------
// Copyright (c) 2004 Paul Singleton
// Copyright (c) 1998 Fred Dushin
// All rights reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This library 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 Library Public License for more details.
//*****************************************************************************/
package jpl;
import java.util.Map;
import jpl.fli.IntHolder;
import jpl.fli.Prolog;
import jpl.fli.term_t;
//----------------------------------------------------------------------/
// Integer
/**
* Integer is a specialised Term with a long field, representing a Prolog integer value.
* <pre>
* Integer i = new Integer(1024);
* </pre>
* Once constructed, the value of an Integer instance cannot be altered.
* An Integer can be used (and re-used) as an argument of Compounds.
* Beware confusing jpl.Integer with java.lang.Integer.
*
* <hr><i>
* Copyright (C) 2004 Paul Singleton<p>
* Copyright (C) 1998 Fred Dushin<p>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.<p>
*
* This library 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 Library Public License for more details.<p>
* </i><hr>
* @author Fred Dushin <fadushin@syr.edu>
* @version $Revision: 1.1 $
* @see jpl.Term
* @see jpl.Compound
*/
public class Integer extends Term {
//==================================================================/
// Attributes
//==================================================================/
/**
* the Integer's immutable long value
*/
protected final long value;
//==================================================================/
// Constructors
//==================================================================/
/**
* @param value This Integer's (long) value
*/
public Integer(long value) {
this.value = value;
}
/**
* @param value This Integer's (int) value
*/
public Integer(int value) {
this.value = value;
}
//==================================================================/
// Methods (common)
//==================================================================/
/**
* Tests whether this Integer's functor has (int) 'name' and 'arity'
*
* @return whether this Integer's functor has (int) 'name' and 'arity'
*/
public final boolean hasFunctor(int val, int arity) {
return val == this.value && arity == 0;
}
/**
* Returns the arity (0) of this jpl.Integer
*
* @return the arity (0) of this jpl.Integer
*/
public final int arity() {
return 0;
}
/**
* Returns the value of this Integer as an int if possible, else throws exception
*
* @return the int value of this Integer (if representable)
*/
public final int intValue() {
if (value < java.lang.Integer.MIN_VALUE || value > java.lang.Integer.MAX_VALUE) {
throw new JPLException("cannot represent Integer value as an int");
} else {
return (int) value;
}
}
/**
* Returns the value of this Integer converted to a long
*
* @return the value of this Integer converted to a long
*/
public final long longValue() {
return (new java.lang.Long(value)).longValue(); // safe but inefficient...
}
/**
* Returns the value of this Integer converted to a float
*
* @return the value of this Integer converted to a float
*/
public final float floatValue() {
return (new java.lang.Long(value)).floatValue(); // safe but inefficient...
}
/**
* Returns the value of this Integer converted to a double
*
* @return the value of this Integer converted to a double
*/
public final double doubleValue() {
return (new java.lang.Long(value)).doubleValue(); // safe but inefficient...
}
/**
* Returns a Prolog source text representation of this Integer's value
*
* @return a Prolog source text representation of this Integer's value
*/
public String toString() {
return "" + value + ""; // hopefully invokes Integer.toString() or equivalent
}
//------------------------------------------------------------------/
// equals
/**
* Two Integer instances are equal if they are the same object, or if their values are equal
*
* @param obj The Object to compare (not necessarily an Integer)
* @return true if the Object satisfies the above condition
*/
public final boolean equals(Object obj) {
return this == obj || (obj instanceof Integer && value == ((Integer) obj).value);
}
public final int type() {
return Prolog.INTEGER;
}
public String typeName(){
return "Integer";
}
//==================================================================/
// Methods (deprecated)
//==================================================================/
/**
* Returns the int value of this jpl.Integer
*
* @return the Integer's value
* @deprecated
*/
public final int value() {
return (int) value;
}
/**
* The (nonexistent) args of this Integer
*
* @return the (nonexistent) args of this Integer
* @deprecated
*/
public Term[] args() {
return new Term[] {
};
}
/**
* Returns a debug-friendly representation of this Integer's value
*
* @return a debug-friendly representation of this Integer's value
* @deprecated
*/
public String debugString() {
return "(Integer " + toString() + ")";
}
//==================================================================/
// Converting JPL Terms to Prolog terms
//==================================================================/
/**
* To convert an Integer into a Prolog term, we put its value into the term_t.
*
* @param varnames_to_vars A Map from variable names to Prolog variables.
* @param term A (previously created) term_t which is to be
* set to a Prolog integer
*/
protected final void put(Map varnames_to_vars, term_t term) {
Prolog.put_integer(term, value);
}
//==================================================================/
// Converting Prolog terms to JPL Terms
//==================================================================/
/**
* Converts a Prolog term (known to be an integer) to a new Integer instance.
*
* @param vars_to_Vars A Map from Prolog variables to JPL Variables
* @param term The Prolog term (an integer) which is to be converted
* @return A new Integer instance
*/
protected static Term getTerm(Map vars_to_Vars, term_t term) {
IntHolder int_holder = new IntHolder();
Prolog.get_integer(term, int_holder); // assume it succeeds...
return new jpl.Integer(int_holder.value);
}
//==================================================================/
// Computing Substitutions
//==================================================================/
/**
* Nothing needs to be done if the Term is an Atom, Integer or Float
*
* @param varnames_to_Terms A Map from variable names to Terms.
* @param vars_to_Vars A Map from Prolog variables to JPL Variables.
*/
protected final void getSubst(Map varnames_to_Terms, Map vars_to_Vars) {
}
}
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