001    /* ResolutionSyntax.java --
002       Copyright (C) 2003, 2004, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
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013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
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019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
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031    independent module, the terms and conditions of the license of that
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037    
038    package javax.print.attribute;
039    
040    import java.io.Serializable;
041    
042    /**
043     * <code>ResolutionSyntax</code> is the abstract base class of all attribute
044     * classes which provide a resolution as value (e.g. printer resolution).
045     * <p>
046     * A <code>ResolutionSyntax</code> instance consists of two integer values
047     * describing the resolution in feed and cross feed direction. The units of
048     * the given values is determined by two defined constants:
049     * <ul>
050     * <li>DPCM - dots per centimeter</li>
051     * <li>DPI - dots per inch</li>
052     * </ul>
053     * </p>
054     * <p>
055     * A resolutions attribute is constructed by two values for the resolution and
056     * one of the two constants defining the actual units of the given values.
057     * </p>
058     * <p>
059     * There are different methods provided to return the resolution values in
060     * either of the both units and to compare if a resolution is less than or
061     * equal to a given other resolution attribute.
062     * </p>
063     * <p>
064     * <b>Internal storage:</b><br>
065     * The resolutions are stored internally as dots per 100 inches (dphi). The
066     * values of the provided constants for dots per inch (value 100) and dots
067     * per centimeter (value 254) are used as conversion factors to the internal
068     * storage units. To get the internal dphi values a multiplication of a given
069     * resolution value with its units constant value is needed. Retrieving the
070     * resolution for specific units is done by dividing the internal stored
071     * value through the units constant value. Clients are therefore able to
072     * provide their own resolution units by supplying other conversion factors.
073     * Subclasses of <code>ResolutionSyntax</code> have access to the internal
074     * resolution values through the protected methods
075     * {@link #getCrossFeedResolutionDphi()} and {@link #getFeedResolutionDphi()}.
076     * </p>
077     *
078     * @author Michael Koch (konqueror@gmx.de)
079     */
080    public abstract class ResolutionSyntax
081      implements Cloneable, Serializable
082    {
083      private static final long serialVersionUID = 2706743076526672017L;
084    
085      /**
086       * Constant for units of dots per centimeter.
087       */
088      public static final int DPCM = 254;
089    
090      /**
091       * Constant for units of dots per inch
092       */
093      public static final int DPI = 100;
094    
095      private int crossFeedResolution;
096      private int feedResolution;
097    
098      /**
099       * Creates a <code>ResolutionSyntax</code> object with the given arguments.
100       *
101       * @param crossFeedResolution the cross feed resolution
102       * @param feedResolution the feed resolution
103       * @param units the unit to use (e.g. {@link #DPCM} or {@link #DPI})
104       *
105       * @exception IllegalArgumentException if preconditions fail
106       */
107      public ResolutionSyntax(int crossFeedResolution, int feedResolution,
108                              int units)
109      {
110        if (crossFeedResolution < 1
111            || feedResolution < 1
112            || units < 1)
113          throw new IllegalArgumentException("no argument may be less than 1");
114    
115        this.crossFeedResolution = crossFeedResolution * units;
116        this.feedResolution = feedResolution * units;
117      }
118    
119      /**
120       * Tests if the given object is equal to this object.
121       *
122       * @param obj the object to test
123       *
124       * @return <code>true</code> if both objects are equal,
125       * <code>false</code> otherwise.
126       */
127      public boolean equals(Object obj)
128      {
129        if(! (obj instanceof ResolutionSyntax))
130          return false;
131    
132        ResolutionSyntax tmp = (ResolutionSyntax) obj;
133    
134        return (crossFeedResolution == tmp.getCrossFeedResolutionDphi()
135                && feedResolution == tmp.getFeedResolutionDphi());
136      }
137    
138      /**
139       * Returns the cross feed resolution for the given units.
140       *
141       * @param units the unit to use (e.g. {@link #DPCM} or {@link #DPI})
142       * @return The resolution for the given units.
143       *
144       * @exception IllegalArgumentException if units &lt; 1
145       */
146      public int getCrossFeedResolution(int units)
147      {
148        if (units < 1)
149          throw new IllegalArgumentException("units may not be less then 1");
150    
151        return crossFeedResolution / units;
152      }
153    
154      /**
155       * Returns the raw cross feed resolution in dots per 100 inches.
156       *
157       * @return The raw resolution.
158       */
159      protected int getCrossFeedResolutionDphi()
160      {
161        return crossFeedResolution;
162      }
163    
164      /**
165       * Returns the feed resolution for the given units.
166       *
167       * @param units the unit to use (e.g. {@link #DPCM} or {@link #DPI})
168       * @return The resolution for the given units.
169       *
170       * @exception IllegalArgumentException if units &lt; 1
171       */
172      public int getFeedResolution(int units)
173      {
174        if (units < 1)
175          throw new IllegalArgumentException("units may not be less then 1");
176    
177        return feedResolution / units;
178      }
179    
180      /**
181       * Returns the raw feed resolution in dots per 100 inches.
182       *
183       * @return The raw resolution.
184       */
185      protected int getFeedResolutionDphi()
186      {
187        return feedResolution;
188      }
189    
190      /**
191       * Returns the resolution as two field array. Index 0 is the cross feed
192       * resolution, index 1 the feed resolution.
193       *
194       * @param units the units to use
195       *
196       * @return The array with the resolutions.
197       */
198      public int[] getResolution(int units)
199      {
200        int[] resolution = new int[2];
201        resolution[0] = getCrossFeedResolution(units);
202        resolution[1] = getFeedResolution(units);
203        return resolution;
204      }
205    
206      /**
207       * Returns the hashcode for this object.
208       *
209       * @return The hashcode.
210       */
211      public int hashCode()
212      {
213        return crossFeedResolution + feedResolution;
214      }
215    
216      /**
217       * Checks if the given resolution attribute is a lower or equal
218       * to this resolution object.
219       *
220       * @param other the resolution to check against
221       *
222       * @return <code>true</code> if other resolution attribute describes
223       * a lower or equal resolution, <code>false</code> otherwise.
224       */
225      public boolean lessThanOrEquals(ResolutionSyntax other)
226      {
227        if (other == null)
228          throw new NullPointerException("other may not be null");
229    
230        return (crossFeedResolution <= other.getCrossFeedResolutionDphi()
231                && feedResolution <= other.getFeedResolutionDphi());
232      }
233    
234      /**
235       * Returns the string representation for this object.
236       * <p>
237       * The returned string is in the form "CxF dphi" with C standing
238       * for the cross feed and F for the feed direction resolution.
239       * Units used are dots per 100 inches (dphi).
240       * </p>
241       * @return The string representation.
242       */
243      public String toString()
244      {
245        return toString(1, "dphi");
246      }
247    
248      /**
249       * Returns the string representation for this object.
250       * <p>
251       * The returned string is in the form "CxF U" with C standing
252       * for the cross feed and F for the feed direction resolution.
253       * U denotes the units name if one is supplied.
254       * </p>
255       *
256       * @param units the units to use
257       * @param unitsName the name of the units. If <code>null</code>
258       * it is ommitted from the string representation.
259       *
260       * @return The string representation.
261       */
262      public String toString(int units, String unitsName)
263      {
264        if (unitsName == null)
265          return getCrossFeedResolution(units) + "x" + getFeedResolution(units);
266    
267        return ("" + getCrossFeedResolution(units)
268                + "x" + getFeedResolution(units)
269                + " " + unitsName);
270      }
271    }