实现 PrinterStateReasons API 的Java程序
Java中的PrintStateReason API用于访问打印机设备的当前状态数据，例如打印机是否已连接或现在，是否已用完墨粉等。
类 PrinterStateReasons
java.lang.Object
java.util.AbstractMap
java.util.HashMap
javax.print.attribute.standard.PrinterStateReasons 所有实现的接口：
- 可序列化
- 可克隆
- Map
- 属性
- 打印服务属性
构造函数：
1. public PrinterStateReasons() – 它是默认构造函数。
2. public PrinterStateReasons(int initialCapacity) ——它是一个参数化的构造函数。
- 参数： initialCapacity – 初始容量。
- 例外： IllegalArgumentException – 如果初始容量小于零。
3. public PrinterStateReasons(int initialCapacity,float loadFactor)
- 参数：
- initialCapacity – 初始容量。
- loadFactor – 负载因子。
- 例外： IllegalArgumentException – 如果初始容量小于零。
所有这些构造函数都构造了一个新的空打印状态原因属性和具有默认初始容量和负载因子的底层哈希映射。
4. public PrinterStateReasons(Map
- 参数： map - 要复制的地图。
- 例外：
- NullPointerException –（未经检查的异常）如果映射为空或者映射中的任何键或值为空，则抛出。
- ClassCastException –（未经检查的异常）如果映射中的任何键不是类 PrinterStateReason 的实例或映射中的任何值不是类 Severity 的实例，则抛出该异常。
它构造了一个新的 printer-state-reasons 属性，该属性包含与给定映射相同的 PrinterStateReason-to-Severity 映射。底层哈希映射的初始容量和负载因子在超类构造函数 HashMap(Map) 中指定。
下面是问题陈述的实现：
Java
// Java Program to Implement PrinterStateReasons API
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.print.attribute.Attribute;
import javax.print.attribute.standard.PrinterStateReason;
import javax.print.attribute.standard.PrinterStateReasons;
import javax.print.attribute.standard.Severity;
public class PrinterStateReasonsImpl {
private PrinterStateReasons printerStateReasons;
// Construct a new, empty printer state reasons
// attribute; the underlying hash map has the default
// initial capacity and load factor.
public PrinterStateReasonsImpl()
{
printerStateReasons = new PrinterStateReasons();
}
// super a new, empty printer state reasons attribute;
// the underlying hash map has the given initial
// capacity and the default load factor.
public PrinterStateReasonsImpl(int initialCapacity)
{
printerStateReasons
= new PrinterStateReasons(initialCapacity);
}
// Construct a new, empty printer state reasons
// attribute; the underlying hash map has the given
// initial capacity and load factor.
public PrinterStateReasonsImpl(int initialCapacity,
float loadFactor)
{
printerStateReasons = new PrinterStateReasons(
initialCapacity, loadFactor);
}
// Construct a new printer state reasons attribute that
// contains the same PrinterStateReason-to-Severity
// mappings as the given map.
public PrinterStateReasonsImpl(
Map map)
{
printerStateReasons = new PrinterStateReasons(map);
}
// Removes all of the mappings from this map.
public void clear() { printerStateReasons.clear(); }
// Returns a shallow copy of this HashMap instance: the
// keys and values themselves are not cloned.
public Object clone()
{
return printerStateReasons.clone();
}
// Returns true if this map contains
// a mapping for the specified key.
public boolean containsKey(Object key)
{
return printerStateReasons.containsKey(key);
}
// Returns true if this map maps one
// or more keys to the specified value.
public boolean containsValue(Object value)
{
return printerStateReasons.containsValue(value);
}
// Returns a Set view of the mappings
// contained in this map.
public Set >
entrySet()
{
return printerStateReasons.entrySet();
}
// Returns the value to which the specified
// key is mapped, or null if this map contains
// no mapping for the key.
public Severity get(Object key)
{
return printerStateReasons.get(key);
}
// Returns true if this map contains
// no key-value mappings.
public boolean isEmpty()
{
return printerStateReasons.isEmpty();
}
// Returns a Set view of the
// keys contained in this map.
public Set keySet()
{
return printerStateReasons.keySet();
}
// Associates the specified value with
// the specified key in this map.
public Severity put(PrinterStateReason reason,
Severity severity)
{
return printerStateReasons.put(reason, severity);
}
// Copies all of the mappings from the
// specified map to this map.
public void putAll(Map m)
{
printerStateReasons.putAll(m);
}
// Removes the mapping for the specified
// key from this map if present.
public Severity remove(Object key)
{
return printerStateReasons.remove(key);
}
// Returns the number of key-value
// mappings in this map.
public int size() { return printerStateReasons.size(); }
// Returns a Collection view of the
// values contained in this map.
public Collection values()
{
return printerStateReasons.values();
}
// Get the printing attribute class which is to be used
// as the "category" for this printing attribute value.
public Class getCategory()
{
return printerStateReasons.getCategory();
}
// Get the name of the category of which
// this attribute value is an instance.
public String getName()
{
return printerStateReasons.getName();
}
// Obtain an unmodifiable set view of the individual
// printer state reason attributes at the given severity
// level in this PrinterStateReasons attribute.
public Set
printerStateReasonSet(Severity severity)
{
return printerStateReasons.printerStateReasonSet(
severity);
}
public static void main(String[] arg)
{
PrinterStateReasonsImpl printerStateReasons
= new PrinterStateReasonsImpl();
printerStateReasons.put(
PrinterStateReason.CONNECTING_TO_DEVICE,
Severity.ERROR);
printerStateReasons.put(
PrinterStateReason.COVER_OPEN, Severity.REPORT);
printerStateReasons.put(
PrinterStateReason.INPUT_TRAY_MISSING,
Severity.WARNING);
System.out.println(
"the key set of the printerStateReasons is ");
Set keySet
= printerStateReasons.keySet();
Iterator itr
= keySet.iterator();
while (itr.hasNext()) {
System.out.print(itr.next() + "\t");
}
System.out.println();
System.out.println(
"the values of the printerStateReasons is ");
Collection collectionValues
= printerStateReasons.values();
Iterator citr
= collectionValues.iterator();
while (citr.hasNext()) {
System.out.print(citr.next() + "\t");
}
System.out.println();
System.out.println(
"the entry set of the printerStateReasons is ");
Iterator > eitr;
Set > entrySet
= printerStateReasons.entrySet();
eitr = entrySet.iterator();
while (eitr.hasNext()) {
System.out.println(eitr.next() + "\t");
}
System.out.println(
"the printerStateReasons contains Key CONNECTING_TO_DEVICE :"
+ printerStateReasons.containsKey(
PrinterStateReason.CONNECTING_TO_DEVICE));
System.out.println(
"the printerStateReasons contains Value ERROR :"
+ printerStateReasons.containsValue(
Severity.ERROR));
System.out.println(
"the size of the printerStateReasons is "
+ printerStateReasons.size());
printerStateReasons.clear();
if (printerStateReasons.isEmpty())
System.out.println(
"the printerStateReasons is empty");
else
System.out.println(
"the printerStateReasons is not empty");
}
} 输出
the key set of the printerStateReasons is
input-tray-missing connecting-to-device cover-open
the values of the printerStateReasons is
warning error report
the entry set of the printerStateReasons is
input-tray-missing=warning
connecting-to-device=error
cover-open=report
the printerStateReasons contains Key CONNECTING_TO_DEVICE :true
the printerStateReasons contains Value ERROR :true
the size of the printerStateReasons is 3
the printerStateReasons is empty