简单的优先级队列

 

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class PriorityQueue< T >{

    /** Main lock guarding all access */
    final ReentrantLock lock = new ReentrantLock( );

    /** Condition for waiting takes */
    private final Condition notEmpty = lock.newCondition( );

    /** Condition for waiting puts */
    @SuppressWarnings ( "unused" )
    private final Condition notFull = lock.newCondition( );

    private final AtomicInteger count = new AtomicInteger( );

    private List< Queue< T > > lbqList;

    private int capacity;

    private Priority< T > priority;

    private boolean queue;

    public PriorityQueue( int capacity , Priority< T > priority , boolean queue ) {
        this.capacity = capacity;
        this.priority = priority;
        this.queue = queue;
        init( );
    }

    private void init( ) {
        lbqList = new ArrayList<>( this.capacity );
        for ( int i = 0 ; i < capacity ; i++ ) {
            if ( queue ) {
                lbqList.add( new LinkedList<>( ) );
            } else {
                lbqList.add( new LinkedBlockingQueue<>( ) );
            }
        }
    }

    public int add( T t ) throws Exception {
        int pr = priority.getPriority( t );
        Queue< T > queue = lbqList.get( pr );
        if ( count.get( ) > 0 ) {
            count.getAndIncrement( );
            queue.add( t );
            if ( count.get( ) <= 1 ) {
                final ReentrantLock lock = this.lock;
                try {
                    lock.lockInterruptibly( );
                    notEmpty.signal( );
                } catch ( Exception e ) {
                    return -1;
                } finally {
                    lock.unlock( );
                }
            }
        } else {

            final ReentrantLock lock = this.lock;
            try {
                lock.lockInterruptibly( );
                queue.add( t );
                count.getAndIncrement( );
                notEmpty.signal( );
                return pr;
            } catch ( Exception e ) {
                throw e;
            } finally {
                lock.unlock( );
            }
        }
       
        return pr;
    }

    public T get( ) throws InterruptedException {
        T t;
        if ( count.get( ) > 0 ) {
            t = getData();
            if(t != null){
                return t;
            }
        }
        final ReentrantLock lock = this.lock;
        lock.lock( );
        try {
            while ( ( t = getData( ) ) == null )
                notEmpty.await( );
            return t;
        } finally {
            lock.unlock( );
        }
    }

   
   
   
    public static interface Priority< T > {
        int getPriority( T t );
    }

    public T getData(){
        int i = 0;
        T t;
        for( ; ;){
            t = lbqList.get( i++ ).poll( );
            if( t != null){
                count.getAndDecrement( );
                return t;
            }
            if( i >= capacity ){
                return null;
            }
        }
    }


    public int size( ) {
        return count.get( );
    }

    public boolean isEmpty( ) {
        return count.get( ) == 0;
    }


   
}

 

 

test代码

	@Test
	public void testQ( ) throws InterruptedException {
		Priority< Notification > priority = new Priority< Notification >( ) {

			@Override
			public int getPriority( Notification t ) {
				return t.getPriority( );
			}
		};
		PriorityQueue< Notification > rq = new PriorityQueue<>( 6 , priority , false );
		ThreadPoolExecutor te = new ThreadPoolExecutor( 8 , 8 , 100 , TimeUnit.MICROSECONDS ,
				new LinkedBlockingQueue< Runnable >( ) );
		ThreadPoolExecutor ted = new ThreadPoolExecutor(4 , 4 , 100 , TimeUnit.MICROSECONDS ,
				new LinkedBlockingQueue< Runnable >( ) );
		int sum = 100;
		int read = sum , write = sum;
		boolean boo = true;
		AtomicLong at = new AtomicLong( );
		for ( ; ; ) {
			int i = rr.nextInt( 10 );
			if ( boo && read > 0) {
				for (int j = 0 ; i >= j ; j++ ) {

					te.execute( new Runnable( ) {

						@Override
						public void run( ) {
							try {
								Notification nf = new Notification( );
								nf.setId( at.getAndIncrement( ) );
								//nf.setPriority( r.nextInt( 6 ) );
								nf.setPriority( nf.getId( )%30==0?5:1 );
								rq.add( nf );
								System.out.println( String.format( " read tid : %d  data : %s" ,Thread.currentThread( ).getId( ) , nf ) );
							} catch ( Exception e ) {
								e.printStackTrace( );
							}

						}
					} );
				}
				read = read - i;
				boo = !boo;
			} else if( !boo && write > 0){
				for ( int j = 0 ; i >= j ; j++ ) {
					ted.execute( new Runnable( ) {

						@Override
						public void run( ) {
							try {
								Notification nf = rq.get( );
								System.out.println( String.format( " write tid : %d  data : %s" ,Thread.currentThread( ).getId( ) , nf ) );
							} catch ( InterruptedException e ) {
								// TODO 自动生成的 catch 块
								e.printStackTrace( );
							}

						}
					} );
				}
				boo = !boo;
				write = write - i;
			}
			if ( read <= 0 && write <= 0 ) {
				break;
			}
			if( read <= 0){
				boo = false;
			}
			if( write <= 0 ){
				boo = true;
			}
		}
		System.out.println( "---------------------------------------------------------------------" );
		Thread.sleep( 1000000000 );
	}