printerstatereasons.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)PrinterStateReasons.java	1.11 06/04/07
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package javax.print.attribute.standard;

import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.HashMap;
import java.util.Set;

import javax.print.attribute.Attribute;
import javax.print.attribute.PrintServiceAttribute;

/**
 * Class PrinterStateReasons is a printing attribute class, a set of
 * enumeration values, that provides additional information about the
 * printer's current state, i.e., information that augments the value of the
 * printer's {@link PrinterState PrinterState} attribute. 
 * <P>
 * Instances of {@link PrinterStateReason PrinterStateReason} do not appear in
 *  a Print Service's attribute set directly. Rather, a PrinterStateReasons 
 * attribute appears in the Print Service's attribute set. The 
 * PrinterStateReasons attribute contains zero, one, or more than one {@link 
 * PrinterStateReason PrinterStateReason} objects which pertain to the Print 
 * Service's status, and each {@link PrinterStateReason PrinterStateReason} 
 * object is associated with a {@link Severity Severity} level of REPORT 
 *  (least severe), WARNING, or ERROR (most severe). The printer adds a {@link 
 * PrinterStateReason PrinterStateReason} object to the Print Service's 
 * PrinterStateReasons attribute when the corresponding condition becomes true 
 * of the printer, and the printer removes the {@link PrinterStateReason 
 * PrinterStateReason} object again when the corresponding condition becomes 
 * false, regardless of whether the Print Service's overall
 * {@link PrinterState PrinterState} also changed. 
 * <P>
 * Class PrinterStateReasons inherits its implementation from class {@link 
 * java.util.HashMap java.util.HashMap}. Each entry in the map consists of a 
 * {@link PrinterStateReason PrinterStateReason} object (key) mapping to a 
 * {@link Severity Severity} object (value):
 * <P>
 * Unlike most printing attributes which are immutable once constructed, class 
 * PrinterStateReasons is designed to be mutable; you can add {@link 
 * PrinterStateReason PrinterStateReason} objects to an existing 
 * PrinterStateReasons object and remove them again. However, like class 
 *  {@link java.util.HashMap java.util.HashMap}, class PrinterStateReasons is
 * bot multiple thread safe. If a PrinterStateReasons object will be used by 
 * multiple threads, be sure to synchronize its operations (e.g., using a 
 * synchronized map view obtained from class {@link java.util.Collections 
 * java.util.Collections}). 
 * <P>
 * <B>IPP Compatibility:</B> The string values returned by each individual 
 * {@link PrinterStateReason PrinterStateReason} object's and the associated
 * {@link Severity Severity} object's <CODE>toString()</CODE> methods,
 * concatenated 
 * together with a hyphen (<CODE>"-"</CODE>) in between, gives the IPP keyword 
 * value. The category name returned by <CODE>getName()</CODE> gives the IPP 
 * attribute name. 
 * <P>
 *
 * @author  Alan Kaminsky
 */
public final class PrinterStateReasons
    extends HashMap<PrinterStateReason,Severity>
    implements PrintServiceAttribute
{

    private static final long serialVersionUID = -3731791085163619457L;

    /**
     * Construct a new, empty printer state reasons attribute; the underlying 
     * hash map has the default initial capacity and load factor. 
     */
    public PrinterStateReasons() {
	super();
    }

    /**
     * super a new, empty printer state reasons attribute; the underlying 
     * hash map has the given initial capacity and the default load factor. 
     *
     * @param  initialCapacity  Initial capacity.
     *
     * @throws IllegalArgumentException if the initial capacity is less 
     *     than zero.
     */
    public PrinterStateReasons(int initialCapacity) {
	super (initialCapacity);
    }

    /**
     * Construct a new, empty printer state reasons attribute; the underlying 
     * hash map has the given initial capacity and load factor. 
     *
     * @param  initialCapacity  Initial capacity.
     * @param  loadFactor       Load factor.
     *
     * @throws IllegalArgumentException if the initial capacity is less 
     *     than zero.
     */
    public PrinterStateReasons(int initialCapacity, float loadFactor) {
	super (initialCapacity, loadFactor);
    }

    /**
     * Construct a new printer state reasons attribute that contains the same 
     * {@link PrinterStateReason PrinterStateReason}-to-{@link Severity 
     * Severity} mappings as the given map. The underlying hash map's initial 
     * capacity and load factor are as specified in the superclass constructor 
     * {@link java.util.HashMap#HashMap(java.util.Map) 
     * <CODE>HashMap(Map)</CODE>}. 
     *
     * @param  map  Map to copy.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>map</CODE> is null or if any 
     *     key or value in <CODE>map</CODE> is null. 
     * @throws  ClassCastException
     *     (unchecked exception) Thrown if any key in <CODE>map</CODE> is not 
     *   an instance of class {@link PrinterStateReason PrinterStateReason} or 
     *     if any value in <CODE>map</CODE> is not an instance of class 
     *     {@link Severity Severity}. 
     */
    public PrinterStateReasons(Map<PrinterStateReason,Severity> map) {
	this();
	for (Map.Entry<PrinterStateReason,Severity> e : map.entrySet())
	    put(e.getKey(), e.getValue());
    }

    /**
     * Adds the given printer state reason to this printer state reasons 
     * attribute, associating it with the given severity level. If this  
     * printer state reasons attribute previously contained a mapping for the  
     * given printer state reason, the old value is replaced. 
     *
     * @param  reason    Printer state reason. This must be an instance of
     *                    class {@link PrinterStateReason PrinterStateReason}.
     * @param  severity  Severity of the printer state reason. This must be
     *                      an instance of class {@link Severity Severity}.
     *
     * @return  Previous severity associated with the given printer state
     *          reason, or <tt>null</tt> if the given printer state reason was 
     *          not present. 
     * 
     * @throws  NullPointerException
     *     (unchecked exception) Thrown if <CODE>reason</CODE> is null or 
     *     <CODE>severity</CODE> is null. 
     * @throws  ClassCastException
     *     (unchecked exception) Thrown if <CODE>reason</CODE> is not an 
     *   instance of class {@link PrinterStateReason PrinterStateReason} or if 
     *     <CODE>severity</CODE> is not an instance of class {@link Severity 
     *     Severity}. 
     * @since 1.5
     */
    public Severity put(PrinterStateReason reason, Severity severity) {
	if (reason == null) {
	    throw new NullPointerException("reason is null");
	}
	if (severity == null) {
	    throw new NullPointerException("severity is null");
	}
	return super.put((PrinterStateReason) reason,
			 (Severity) severity);
    }

    /**
     * Get the printing attribute class which is to be used as the "category" 
     * for this printing attribute value.
     * <P>
     * For class PrinterStateReasons, the 
     * category is class PrinterStateReasons itself. 
     *
     * @return  Printing attribute class (category), an instance of class
     *          {@link java.lang.Class java.lang.Class}.
     */
    public final Class<? extends Attribute> getCategory() {
	return PrinterStateReasons.class;
    }

    /**
     * Get the name of the category of which this attribute value is an 
     * instance. 
     * <P>
     * For class PrinterStateReasons, the
     * category name is <CODE>"printer-state-reasons"</CODE>. 
     *
     * @return  Attribute category name.
     */
    public final String getName() {
	return "printer-state-reasons";
    }

    /**
     * Obtain an unmodifiable set view of the individual printer state reason 
     * attributes at the given severity level in this PrinterStateReasons 
     * attribute. Each element in the set view is a {@link PrinterStateReason 
     * PrinterStateReason} object. The only elements in the set view are the 
     * {@link PrinterStateReason PrinterStateReason} objects that map to the 
     * given severity value. The set view is backed by this
     * PrinterStateReasons attribute, so changes to this PrinterStateReasons
     * attribute are reflected  in the set view.
     * The set view does not support element insertion or 
     * removal. The set view's iterator does not support element removal. 
     *
     * @param  severity  Severity level.
     *
     * @return  Set view of the individual {@link PrinterStateReason
     *          PrinterStateReason} attributes at the given {@link Severity 
     *          Severity} level. 
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>severity</CODE> is null.
     */
    public Set<PrinterStateReason> printerStateReasonSet(Severity severity) {
	if (severity == null) {
	    throw new NullPointerException("severity is null");
	}
	return new PrinterStateReasonSet (severity, entrySet());
    }

    private class PrinterStateReasonSet
	extends AbstractSet<PrinterStateReason>
    {
	private Severity mySeverity;
	private Set myEntrySet;

	public PrinterStateReasonSet(Severity severity, Set entrySet) {
	    mySeverity = severity;
	    myEntrySet = entrySet;
	}

	public int size() {
	    int result = 0;
	    Iterator iter = iterator();
	    while (iter.hasNext()) {
		iter.next();
		++ result;
	    }
	    return result;
	}

	public Iterator iterator() {
	    return new PrinterStateReasonSetIterator(mySeverity,
						     myEntrySet.iterator());
	}
    }

    private class PrinterStateReasonSetIterator implements Iterator {
	private Severity mySeverity;
	private Iterator myIterator;
	private Map.Entry myEntry;

	public PrinterStateReasonSetIterator(Severity severity,
					     Iterator iterator) {
	    mySeverity = severity;
	    myIterator = iterator;
	    goToNext();
	}

	private void goToNext() {
	    myEntry = null;
	    while (myEntry == null && myIterator.hasNext()) {
		myEntry = (Map.Entry) myIterator.next();
		if ((Severity) myEntry.getValue() != mySeverity) {
		    myEntry = null;
		}
	    }
	}

	public boolean hasNext() {
	    return myEntry != null;
	}

	public Object next() {
	    if (myEntry == null) {
		throw new NoSuchElementException();
	    }
	    Object result = myEntry.getKey();
	    goToNext();
	    return result;
	}

	public void remove() {
	    throw new UnsupportedOperationException();
	}
    }
    
}