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package javax.print.attribute;
import java.io.Serializable;
/**
* Class ResolutionSyntax is an abstract base class providing the common
* implementation of all attributes denoting a printer resolution.
* <P>
* A resolution attribute's value consists of two items, the cross feed
* direction resolution and the feed direction resolution. A resolution
* attribute may be constructed by supplying the two values and indicating the
* units in which the values are measured. Methods are provided to return a
* resolution attribute's values, indicating the units in which the values are
* to be returned. The two most common resolution units are dots per inch (dpi)
* and dots per centimeter (dpcm), and exported constants {@link #DPI
* DPI} and {@link #DPCM DPCM} are provided for
* indicating those units.
* <P>
* Once constructed, a resolution attribute's value is immutable.
* <P>
* <B>Design</B>
* <P>
* A resolution attribute's cross feed direction resolution and feed direction
* resolution values are stored internally using units of dots per 100 inches
* (dphi). Storing the values in dphi rather than, say, metric units allows
* precise integer arithmetic conversions between dpi and dphi and between dpcm
* and dphi: 1 dpi = 100 dphi, 1 dpcm = 254 dphi. Thus, the values can be stored
* into and retrieved back from a resolution attribute in either units with no
* loss of precision. This would not be guaranteed if a floating point
* representation were used. However, roundoff error will in general occur if a
* resolution attribute's values are created in one units and retrieved in
* different units; for example, 600 dpi will be rounded to 236 dpcm, whereas
* the true value (to five figures) is 236.22 dpcm.
* <P>
* Storing the values internally in common units of dphi lets two resolution
* attributes be compared without regard to the units in which they were
* created; for example, 300 dpcm will compare equal to 762 dpi, as they both
* are stored as 76200 dphi. In particular, a lookup service can
* match resolution attributes based on equality of their serialized
* representations regardless of the units in which they were created. Again,
* using integers for internal storage allows precise equality comparisons to be
* done, which would not be guaranteed if a floating point representation were
* used.
* <P>
* The exported constant {@link #DPI DPI} is actually the
* conversion factor by which to multiply a value in dpi to get the value in
* dphi. Likewise, the exported constant {@link #DPCM DPCM} is the
* conversion factor by which to multiply a value in dpcm to get the value in
* dphi. A client can specify a resolution value in units other than dpi or dpcm
* by supplying its own conversion factor. However, since the internal units of
* dphi was chosen with supporting only the external units of dpi and dpcm in
* mind, there is no guarantee that the conversion factor for the client's units
* will be an exact integer. If the conversion factor isn't an exact integer,
* resolution values in the client's units won't be stored precisely.
* <P>
*
* @author David Mendenhall
* @author Alan Kaminsky
*/
public abstract class ResolutionSyntax implements Serializable, Cloneable {
private static final long serialVersionUID = 2706743076526672017L;
/**
* Cross feed direction resolution in units of dots per 100 inches (dphi).
* @serial
*/
private int crossFeedResolution;
/**
* Feed direction resolution in units of dots per 100 inches (dphi).
* @serial
*/
private int feedResolution;
/**
* Value to indicate units of dots per inch (dpi). It is actually the
* conversion factor by which to multiply dpi to yield dphi (100).
*/
public static final int DPI = 100;
/**
* Value to indicate units of dots per centimeter (dpcm). It is actually
* the conversion factor by which to multiply dpcm to yield dphi (254).
*/
public static final int DPCM = 254;
/**
* Construct a new resolution attribute from the given items.
*
* @param crossFeedResolution
* Cross feed direction resolution.
* @param feedResolution
* Feed direction resolution.
* @param units
* Unit conversion factor, e.g. {@link #DPI DPI} or
* {@link #DPCM DPCM}.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if {@code crossFeedResolution < 1}
* or {@code feedResolution < 1} or {@code units < 1}.
*/
public ResolutionSyntax(int crossFeedResolution, int feedResolution,
int units) {
if (crossFeedResolution < 1) {
throw new IllegalArgumentException("crossFeedResolution is < 1");
}
if (feedResolution < 1) {
throw new IllegalArgumentException("feedResolution is < 1");
}
if (units < 1) {
throw new IllegalArgumentException("units is < 1");
}
this.crossFeedResolution = crossFeedResolution * units;
this.feedResolution = feedResolution * units;
}
/**
* Convert a value from dphi to some other units. The result is rounded to
* the nearest integer.
*
* @param dphi
* Value (dphi) to convert.
* @param units
* Unit conversion factor, e.g. {@link #DPI <CODE>DPI</CODE>} or
* {@link #DPCM <CODE>DPCM</CODE>}.
*
* @return The value of <CODE>dphi</CODE> converted to the desired units.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if <CODE>units</CODE> < 1.
*/
private static int convertFromDphi(int dphi, int units) {
if (units < 1) {
throw new IllegalArgumentException(": units is < 1");
}
int round = units / 2;
return (dphi + round) / units;
}
/**
* Get this resolution attribute's resolution values in the given units.
* The values are rounded to the nearest integer.
*
* @param units
* Unit conversion factor, e.g. {@link #DPI DPI} or
* {@link #DPCM DPCM}.
*
* @return A two-element array with the cross feed direction resolution
* at index 0 and the feed direction resolution at index 1.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if {@code units < 1}.
*/
public int[] getResolution(int units) {
return new int[] { getCrossFeedResolution(units),
getFeedResolution(units)
};
}
/**
* Returns this resolution attribute's cross feed direction resolution in
* the given units. The value is rounded to the nearest integer.
*
* @param units
* Unit conversion factor, e.g. {@link #DPI DPI} or
* {@link #DPCM DPCM}.
*
* @return Cross feed direction resolution.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if {@code units < 1}.
*/
public int getCrossFeedResolution(int units) {
return convertFromDphi (crossFeedResolution, units);
}
/**
* Returns this resolution attribute's feed direction resolution in the
* given units. The value is rounded to the nearest integer.
*
* @param units
* Unit conversion factor, e.g. {@link #DPI DPI} or {@link
* #DPCM DPCM}.
*
* @return Feed direction resolution.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if {@code units < 1}.
*/
public int getFeedResolution(int units) {
return convertFromDphi (feedResolution, units);
}
/**
* Returns a string version of this resolution attribute in the given units.
* The string takes the form <CODE>"<I>C</I>x<I>F</I> <I>U</I>"</CODE>,
* where <I>C</I> is the cross feed direction resolution, <I>F</I> is the
* feed direction resolution, and <I>U</I> is the units name. The values are
* rounded to the nearest integer.
*
* @param units
* Unit conversion factor, e.g. {@link #DPI CODE>DPI} or {@link
* #DPCM DPCM}.
* @param unitsName
* Units name string, e.g. <CODE>"dpi"</CODE> or <CODE>"dpcm"</CODE>. If
* null, no units name is appended to the result.
*
* @return String version of this resolution attribute.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if {@code units < 1}.
*/
public String toString(int units, String unitsName) {
StringBuffer result = new StringBuffer();
result.append(getCrossFeedResolution (units));
result.append('x');
result.append(getFeedResolution (units));
if (unitsName != null) {
result.append (' ');
result.append (unitsName);
}
return result.toString();
}
/**
* Determine whether this resolution attribute's value is less than or
* equal to the given resolution attribute's value. This is true if all
* of the following conditions are true:
* <UL>
* <LI>
* This attribute's cross feed direction resolution is less than or equal to
* the <CODE>other</CODE> attribute's cross feed direction resolution.
* <LI>
* This attribute's feed direction resolution is less than or equal to the
* <CODE>other</CODE> attribute's feed direction resolution.
* </UL>
*
* @param other Resolution attribute to compare with.
*
* @return True if this resolution attribute is less than or equal to the
* <CODE>other</CODE> resolution attribute, false otherwise.
*
* @exception NullPointerException
* (unchecked exception) Thrown if <CODE>other</CODE> is null.
*/
public boolean lessThanOrEquals(ResolutionSyntax other) {
return (this.crossFeedResolution <= other.crossFeedResolution &&
this.feedResolution <= other.feedResolution);
}
/**
* Returns whether this resolution attribute is equivalent to the passed in
* object. To be equivalent, all of the following conditions must be true:
* <OL TYPE=1>
* <LI>
* <CODE>object</CODE> is not null.
* <LI>
* <CODE>object</CODE> is an instance of class ResolutionSyntax.
* <LI>
* This attribute's cross feed direction resolution is equal to
* <CODE>object</CODE>'s cross feed direction resolution.
* <LI>
* This attribute's feed direction resolution is equal to
* <CODE>object</CODE>'s feed direction resolution.
* </OL>
*
* @param object Object to compare to.
*
* @return True if <CODE>object</CODE> is equivalent to this resolution
* attribute, false otherwise.
*/
public boolean equals(Object object) {
return(object != null &&
object instanceof ResolutionSyntax &&
this.crossFeedResolution ==
((ResolutionSyntax) object).crossFeedResolution &&
this.feedResolution ==
((ResolutionSyntax) object).feedResolution);
}
/**
* Returns a hash code value for this resolution attribute.
*/
public int hashCode() {
return(((crossFeedResolution & 0x0000FFFF)) |
((feedResolution & 0x0000FFFF) << 16));
}
/**
* Returns a string version of this resolution attribute. The string takes
* the form <CODE>"<I>C</I>x<I>F</I> dphi"</CODE>, where <I>C</I> is the
* cross feed direction resolution and <I>F</I> is the feed direction
* resolution. The values are reported in the internal units of dphi.
*/
public String toString() {
StringBuffer result = new StringBuffer();
result.append(crossFeedResolution);
result.append('x');
result.append(feedResolution);
result.append(" dphi");
return result.toString();
}
/**
* Returns this resolution attribute's cross feed direction resolution in
* units of dphi. (For use in a subclass.)
*
* @return Cross feed direction resolution.
*/
protected int getCrossFeedResolutionDphi() {
return crossFeedResolution;
}
/**
* Returns this resolution attribute's feed direction resolution in units
* of dphi. (For use in a subclass.)
*
* @return Feed direction resolution.
*/
protected int getFeedResolutionDphi() {
return feedResolution;
}
}