| Clover coverage report - gsbase - 2.0.1 |
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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| BlockingCircularQueue.java | 0% | 0% | 0% | 0% |
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| 1 | /* | |
| 2 | * Copyright (c) 1998, 2005 Gargoyle Software Inc. All rights reserved. | |
| 3 | * | |
| 4 | * Redistribution and use in source and binary forms, with or without | |
| 5 | * modification, are permitted provided that the following conditions are met: | |
| 6 | * | |
| 7 | * 1. Redistributions of source code must retain the above copyright notice, | |
| 8 | * this list of conditions and the following disclaimer. | |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright notice, | |
| 10 | * this list of conditions and the following disclaimer in the documentation | |
| 11 | * and/or other materials provided with the distribution. | |
| 12 | * 3. The end-user documentation included with the redistribution, if any, must | |
| 13 | * include the following acknowledgment: | |
| 14 | * | |
| 15 | * "This product includes software developed by Gargoyle Software Inc. | |
| 16 | * (http://www.GargoyleSoftware.com/)." | |
| 17 | * | |
| 18 | * Alternately, this acknowledgment may appear in the software itself, if | |
| 19 | * and wherever such third-party acknowledgments normally appear. | |
| 20 | * 4. The name "Gargoyle Software" must not be used to endorse or promote | |
| 21 | * products derived from this software without prior written permission. | |
| 22 | * For written permission, please contact info@GargoyleSoftware.com. | |
| 23 | * 5. Products derived from this software may not be called "GSBase", nor may | |
| 24 | * "GSBase" appear in their name, without prior written permission of | |
| 25 | * Gargoyle Software Inc. | |
| 26 | * | |
| 27 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, | |
| 28 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND | |
| 29 | * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GARGOYLE | |
| 30 | * SOFTWARE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 31 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 32 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, | |
| 33 | * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
| 34 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
| 35 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, | |
| 36 | * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 37 | */ | |
| 38 | package com.gargoylesoftware.base.trace; | |
| 39 | ||
| 40 | import com.gargoylesoftware.base.util.DetailedIllegalArgumentException; | |
| 41 | import com.gargoylesoftware.base.util.DetailedNullPointerException; | |
| 42 | import java.io.Serializable; | |
| 43 | ||
| 44 | /** | |
| 45 | * <p style="color: orange">Internal use only.</p>. | |
| 46 | * <p>A circular queue with blocking semantics.</p> | |
| 47 | * | |
| 48 | * @version $Revision: 1.8 $ | |
| 49 | * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a> | |
| 50 | */ | |
| 51 | public class BlockingCircularQueue | |
| 52 | implements | |
| 53 | Serializable { | |
| 54 | ||
| 55 | // Required for serialization - do not remove or modify | |
| 56 | private static final long serialVersionUID = 2206052328240171051L; | |
| 57 | ||
| 58 | // Locks for blocking on add/next | |
| 59 | private final Object getLock_ = new Object(); | |
| 60 | private final Object addLock_ = new Object(); | |
| 61 | ||
| 62 | // The actual storage | |
| 63 | private final Object queue_[]; | |
| 64 | ||
| 65 | private final int capacity_; | |
| 66 | private int size_; | |
| 67 | ||
| 68 | // Objects get added to the front and removed from the back | |
| 69 | private int front_; | |
| 70 | private int back_; | |
| 71 | ||
| 72 | ||
| 73 | /** | |
| 74 | * Create the queue with a capacity of 20 | |
| 75 | */ | |
| 76 | 0 | public BlockingCircularQueue() { |
| 77 | 0 | this( 20 ); |
| 78 | } | |
| 79 | ||
| 80 | ||
| 81 | ||
| 82 | /** | |
| 83 | * Create the queue with the specified capacity | |
| 84 | * | |
| 85 | *@param capacity The size of the queue | |
| 86 | */ | |
| 87 | 0 | public BlockingCircularQueue( final int capacity ) { |
| 88 | 0 | queue_ = new Object[capacity]; |
| 89 | 0 | capacity_ = capacity; |
| 90 | 0 | if( capacity < 2 ) { |
| 91 | 0 | throw new DetailedIllegalArgumentException( "capacity", capacity, "Must be larger than two" ); |
| 92 | } | |
| 93 | } | |
| 94 | ||
| 95 | ||
| 96 | /** | |
| 97 | * Remove all items from the queue | |
| 98 | */ | |
| 99 | 0 | public synchronized void clear() { |
| 100 | 0 | front_ = 0; |
| 101 | 0 | back_ = 0; |
| 102 | 0 | size_ = 0; |
| 103 | ||
| 104 | // Remove any current object references so that they can be | |
| 105 | // garbage collected. | |
| 106 | 0 | int i; |
| 107 | 0 | for( i = 0; i < capacity_; i++ ) { |
| 108 | 0 | queue_[i] = null; |
| 109 | } | |
| 110 | } | |
| 111 | ||
| 112 | ||
| 113 | /** | |
| 114 | * Add an object to the queue. If the collection is currently full then | |
| 115 | * block until an object is removed. | |
| 116 | * | |
| 117 | * @param object The object to add. | |
| 118 | * @return true if the object was successfully added. | |
| 119 | */ | |
| 120 | 0 | public boolean add( final Object object ) { |
| 121 | 0 | assertNotNull( "object", object ); |
| 122 | 0 | while( true ) { |
| 123 | 0 | synchronized( this ) { |
| 124 | 0 | if( size_ != capacity_ ) { |
| 125 | 0 | if( size_ == 0 ) { |
| 126 | 0 | front_ = 0; |
| 127 | 0 | back_ = 0; |
| 128 | } | |
| 129 | else { | |
| 130 | 0 | front_ = incrementPosition( front_ ); |
| 131 | } | |
| 132 | 0 | queue_[front_] = object; |
| 133 | 0 | synchronized( getLock_ ) { |
| 134 | 0 | getLock_.notify(); |
| 135 | } | |
| 136 | 0 | size_++; |
| 137 | 0 | return true; |
| 138 | } | |
| 139 | } | |
| 140 | 0 | synchronized( addLock_ ) { |
| 141 | 0 | try { |
| 142 | 0 | addLock_.wait(); |
| 143 | } | |
| 144 | catch( final InterruptedException e ) { | |
| 145 | //TODO: We should be doing something here | |
| 146 | } | |
| 147 | } | |
| 148 | } | |
| 149 | } | |
| 150 | ||
| 151 | ||
| 152 | /** | |
| 153 | * Return the next item in the queue. The returned item is removed from the | |
| 154 | * collection. If no objects are present then block until an object has | |
| 155 | * been added. | |
| 156 | * | |
| 157 | * @return The next item. | |
| 158 | */ | |
| 159 | 0 | public Object next() { |
| 160 | 0 | while( true ) { |
| 161 | // If there's something in the queue then return it now. | |
| 162 | 0 | synchronized( this ) { |
| 163 | 0 | if( isEmpty() == false ) { |
| 164 | 0 | final Object object = queue_[back_]; |
| 165 | 0 | queue_[back_] = null;// help the garbage collector |
| 166 | 0 | back_ = incrementPosition( back_ ); |
| 167 | 0 | synchronized( addLock_ ) { |
| 168 | 0 | addLock_.notify(); |
| 169 | } | |
| 170 | 0 | size_--; |
| 171 | 0 | return object; |
| 172 | } | |
| 173 | } | |
| 174 | // There wasn't anything in the queue. Block until something gets added. | |
| 175 | 0 | synchronized( getLock_ ) { |
| 176 | 0 | try { |
| 177 | 0 | getLock_.wait(); |
| 178 | } | |
| 179 | catch( InterruptedException e ) { | |
| 180 | //TODO: Do something here | |
| 181 | } | |
| 182 | } | |
| 183 | } | |
| 184 | } | |
| 185 | ||
| 186 | ||
| 187 | /** | |
| 188 | * Utility method to increment the position and roll back to zero once we | |
| 189 | * hit the end. Return the new position after the adjustment. | |
| 190 | * @param position The position to increment | |
| 191 | * @return the new position | |
| 192 | */ | |
| 193 | 0 | private int incrementPosition( final int position ) { |
| 194 | 0 | if( ( position < 0 ) || ( position >= capacity_ ) ) { |
| 195 | 0 | throw new DetailedIllegalArgumentException( |
| 196 | "position", new Integer( position ), "Must be within 1 and " + capacity_ ); | |
| 197 | } | |
| 198 | 0 | int newPosition = position + 1; |
| 199 | 0 | if( newPosition == capacity_ ) { |
| 200 | 0 | newPosition = 0; |
| 201 | } | |
| 202 | 0 | return newPosition; |
| 203 | } | |
| 204 | ||
| 205 | ||
| 206 | /** | |
| 207 | * Return the number of objects currently in the collection. | |
| 208 | * @return The object count. | |
| 209 | */ | |
| 210 | 0 | public int size() { |
| 211 | 0 | return size_; |
| 212 | } | |
| 213 | ||
| 214 | ||
| 215 | /** | |
| 216 | * Return true if the collection is empty. | |
| 217 | * @return true if the collection is empty. | |
| 218 | */ | |
| 219 | 0 | public boolean isEmpty() { |
| 220 | 0 | return size_ == 0; |
| 221 | } | |
| 222 | ||
| 223 | ||
| 224 | /** | |
| 225 | * Return a string representation of this object. | |
| 226 | * @return a string representation of this object. | |
| 227 | */ | |
| 228 | 0 | public String toString() { |
| 229 | 0 | final StringBuffer buffer = new StringBuffer(); |
| 230 | 0 | buffer.append( getClass().getName() ); |
| 231 | 0 | buffer.append( ": capacity_=" ); |
| 232 | 0 | buffer.append( capacity_ ); |
| 233 | 0 | buffer.append( " size_=" ); |
| 234 | 0 | buffer.append( size_ ); |
| 235 | 0 | buffer.append( " front_=" ); |
| 236 | 0 | buffer.append( front_ ); |
| 237 | 0 | buffer.append( " back_=" ); |
| 238 | 0 | buffer.append( back_ ); |
| 239 | 0 | return buffer.toString(); |
| 240 | } | |
| 241 | ||
| 242 | ||
| 243 | /** | |
| 244 | * Verify that the specified value is not null. If it is then throw an | |
| 245 | * exception | |
| 246 | * | |
| 247 | *@param fieldName The name of the field to check | |
| 248 | *@param fieldValue The value of the field to check | |
| 249 | *@exception DetailedNullPointerException If fieldValue is null | |
| 250 | */ | |
| 251 | 0 | protected final void assertNotNull( final String fieldName, final Object fieldValue ) |
| 252 | throws DetailedNullPointerException { | |
| 253 | 0 | if( fieldValue == null ) { |
| 254 | 0 | throw new DetailedNullPointerException( fieldName ); |
| 255 | } | |
| 256 | } | |
| 257 | } | |
| 258 |
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