X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=srcjar_unused%2Forg%2Fapache%2Flog4j%2Fhelpers%2FCyclicBuffer.java;fp=srcjar_unused%2Forg%2Fapache%2Flog4j%2Fhelpers%2FCyclicBuffer.java;h=5c830131065ccef272ac202d51de155264adf7d0;hb=ec8f3cedf60fb1feed6d34de6b49f6bfa78b9dd8;hp=0000000000000000000000000000000000000000;hpb=056dad85a910551cc95e44d451a61f6b8c4dd35d;p=jalview.git diff --git a/srcjar_unused/org/apache/log4j/helpers/CyclicBuffer.java b/srcjar_unused/org/apache/log4j/helpers/CyclicBuffer.java new file mode 100644 index 0000000..5c83013 --- /dev/null +++ b/srcjar_unused/org/apache/log4j/helpers/CyclicBuffer.java @@ -0,0 +1,166 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.log4j.helpers; + +import org.apache.log4j.spi.LoggingEvent; + +/** + + CyclicBuffer is used by other appenders to hold {@link LoggingEvent + LoggingEvents} for immediate or differed display. + +
This buffer gives read access to any element in the buffer not
+ just the first or last element.
+
+ @author Ceki Gülcü
+ @since 0.9.0
+
+ */
+public class CyclicBuffer {
+
+ LoggingEvent[] ea;
+ int first;
+ int last;
+ int numElems;
+ int maxSize;
+
+ /**
+ Instantiate a new CyclicBuffer of at most maxSize
events.
+
+ The maxSize
argument must a positive integer.
+
+ @param maxSize The maximum number of elements in the buffer.
+ */
+ public CyclicBuffer(int maxSize) throws IllegalArgumentException {
+ if(maxSize < 1) {
+ throw new IllegalArgumentException("The maxSize argument ("+maxSize+
+ ") is not a positive integer.");
+ }
+ this.maxSize = maxSize;
+ ea = new LoggingEvent[maxSize];
+ first = 0;
+ last = 0;
+ numElems = 0;
+ }
+
+ /**
+ Add an event
as the last event in the buffer.
+
+ */
+ public
+ void add(LoggingEvent event) {
+ ea[last] = event;
+ if(++last == maxSize) {
+ last = 0;
+ }
+
+ if(numElems < maxSize) {
+ numElems++;
+ } else if(++first == maxSize) {
+ first = 0;
+ }
+ }
+
+
+ /**
+ Get the ith oldest event currently in the buffer. If
+ i is outside the range 0 to the number of elements
+ currently in the buffer, then null
is returned.
+
+
+ */
+ public
+ LoggingEvent get(int i) {
+ if(i < 0 || i >= numElems) {
+ return null;
+ }
+
+ return ea[(first + i) % maxSize];
+ }
+
+ public
+ int getMaxSize() {
+ return maxSize;
+ }
+
+ /**
+ Get the oldest (first) element in the buffer. The oldest element
+ is removed from the buffer.
+ */
+ public
+ LoggingEvent get() {
+ LoggingEvent r = null;
+ if(numElems > 0) {
+ numElems--;
+ r = ea[first];
+ ea[first] = null;
+ if(++first == maxSize) {
+ first = 0;
+ }
+ }
+ return r;
+ }
+
+ /**
+ Get the number of elements in the buffer. This number is
+ guaranteed to be in the range 0 to maxSize
+ (inclusive).
+ */
+ public
+ int length() {
+ return numElems;
+ }
+
+ /**
+ Resize the cyclic buffer to newSize
.
+
+ @throws IllegalArgumentException if newSize
is negative.
+ */
+ public
+ void resize(int newSize) {
+ if(newSize < 0) {
+ throw new IllegalArgumentException("Negative array size ["+newSize+
+ "] not allowed.");
+ }
+ if(newSize == numElems)
+ {
+ return; // nothing to do
+ }
+
+ LoggingEvent[] temp = new LoggingEvent[newSize];
+
+ int loopLen = newSize < numElems ? newSize : numElems;
+
+ for(int i = 0; i < loopLen; i++) {
+ temp[i] = ea[first];
+ ea[first] = null;
+ if(++first == numElems) {
+ first = 0;
+ }
+ }
+ ea = temp;
+ first = 0;
+ numElems = loopLen;
+ maxSize = newSize;
+ if (loopLen == newSize) {
+ last = 0;
+ } else {
+ last = loopLen;
+ }
+ }
+}