001/* ResolutionSyntax.java -- 
002   Copyright (C) 2003, 2004, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
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014General Public License for more details.
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01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
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026As a special exception, the copyright holders of this library give you
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037
038package javax.print.attribute;
039
040import 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 */
080public 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}