org.marc4j.RecordStack Maven / Gradle / Ivy
/**
* Copyright (C) 2004 Bas Peters
*
* This file is part of MARC4J
*
* MARC4J is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* MARC4J is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with MARC4J; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
package org.marc4j;
import java.util.ArrayList;
import java.util.List;
import org.marc4j.marc.Record;
/**
* Provides push and pop operations for
* Record objects created by MarcXmlParser.
*
* @author Bas Peters
*/
public class RecordStack {
private final List list;
private RuntimeException re = null;
private boolean eof = false;
/**
* Default constuctor.
*/
public RecordStack() {
list = new ArrayList();
}
/**
* Pushes a Record object on the stack.
*
* @param record the record object
*/
public synchronized void push(final Record record) {
while (list.size() > 0) {
try {
wait();
} catch (final Exception e) {
}
}
list.add(record);
notifyAll();
}
/**
* Removes the Record object from the stack and returns that
* object.
*
* @return Record - the record object
*/
public synchronized Record pop() {
while (list.size() <= 0 && eof != true) {
try {
wait();
} catch (final Exception e) {
}
}
if (re != null) {
throw (re);
}
Record record = null;
if (list.size() > 0) {
record = list.remove(0);
}
notifyAll();
return record;
}
/**
* Returns true if there are more Record objects to expect,
* false otherwise.
*
* @return boolean
*/
public synchronized boolean hasNext() {
while (list.size() <= 0 && eof != true) {
try {
wait();
} catch (final Exception e) {
}
}
if (re != null) {
throw (re);
}
if (!isEmpty() || !eof) {
return true;
}
return false;
}
/**
* Passes the exception to the thread where the MarcXMLReader is running, so
* that the next() call that is blocked waiting for this thread, will
* receive the exception.
*
* @param e - a RuntimeException thrown here that needs to be passed to the calling thread
*/
public synchronized void passException(final RuntimeException e) {
re = e;
eof = true;
notifyAll();
}
/**
* Called when the end of the document is reached.
*/
public synchronized void end() {
eof = true;
notifyAll();
}
/**
* Returns true if the queue is empty, false otherwise.
*
* @return boolean
*/
private synchronized boolean isEmpty() {
return (list.size() == 0);
}
}