| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.kernel.bo.service.internal; |
| 17 | |
| 18 | import java.util.HashMap; |
| 19 | import java.util.Iterator; |
| 20 | import java.util.Map; |
| 21 | |
| 22 | import org.qedeq.base.trace.Trace; |
| 23 | import org.qedeq.base.utility.StringUtility; |
| 24 | import org.qedeq.kernel.bo.common.QedeqBo; |
| 25 | import org.qedeq.kernel.bo.common.QedeqBoSet; |
| 26 | import org.qedeq.kernel.bo.common.ServiceJob; |
| 27 | import org.qedeq.kernel.bo.job.InternalModuleServiceCallImpl; |
| 28 | import org.qedeq.kernel.bo.module.InternalModuleServiceCall; |
| 29 | import org.qedeq.kernel.bo.module.InternalServiceJob; |
| 30 | import org.qedeq.kernel.bo.module.ModuleArbiter; |
| 31 | import org.qedeq.kernel.se.common.Service; |
| 32 | import org.qedeq.kernel.se.visitor.InterruptException; |
| 33 | |
| 34 | /** |
| 35 | * Get locks for modules. |
| 36 | * TODO 20130508 m31: Currently we make no difference between read and write locks. We also lock |
| 37 | * a module during the whole plugin processing for that module. This could be limited to status |
| 38 | * changes only. |
| 39 | * |
| 40 | * @author Michael Meyling |
| 41 | */ |
| 42 | public class ModuleArbiterImpl implements ModuleArbiter { |
| 43 | |
| 44 | /** This class. */ |
| 45 | private static final Class CLASS = ModuleArbiterImpl.class; |
| 46 | |
| 47 | /** Map blocked QEDEQ modules to service processes. */ |
| 48 | private final Map blocked; |
| 49 | |
| 50 | /** |
| 51 | * Constructor. |
| 52 | */ |
| 53 | public ModuleArbiterImpl() { |
| 54 | blocked = new HashMap(); |
| 55 | } |
| 56 | |
| 57 | public boolean lockRequiredModule(final InternalModuleServiceCall call) throws InterruptException { |
| 58 | call.pause(); |
| 59 | call.getInternalServiceProcess().setBlocked(true); |
| 60 | try { |
| 61 | final boolean result = lockRequiredModule(call.getInternalServiceProcess(), call.getQedeq(), |
| 62 | call.getService()); |
| 63 | ((InternalModuleServiceCallImpl) call).setNewlyBlockedModule(result); |
| 64 | return result; |
| 65 | } finally { |
| 66 | call.getInternalServiceProcess().setBlocked(false); |
| 67 | call.resume(); |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | private boolean lockRequiredModule(final InternalServiceJob process, |
| 72 | final QedeqBo qedeq, final Service service) throws InterruptException { |
| 73 | if (isAlreadyLocked(process, qedeq)) { |
| 74 | return false; |
| 75 | } |
| 76 | process.setBlocked(true); |
| 77 | // we try to get a lock, if not we wait |
| 78 | try { |
| 79 | while (!lock(process, qedeq, service)) { |
| 80 | final Object monitor = new Object(); |
| 81 | synchronized (monitor) { |
| 82 | try { |
| 83 | monitor.wait(1000); |
| 84 | } catch (InterruptedException e) { |
| 85 | process.setInterruptedState(); |
| 86 | throw new InterruptException(qedeq.getModuleAddress().createModuleContext()); |
| 87 | } |
| 88 | } |
| 89 | if (Thread.interrupted()) { |
| 90 | process.setInterruptedState(); |
| 91 | throw new InterruptException(qedeq.getModuleAddress().createModuleContext()); |
| 92 | } |
| 93 | } |
| 94 | } finally { |
| 95 | process.setBlocked(false); |
| 96 | } |
| 97 | return true; |
| 98 | } |
| 99 | |
| 100 | public boolean unlockRequiredModule(final InternalModuleServiceCall call) { |
| 101 | // TODO 20130521 m31: do it without cast |
| 102 | if (call != null && ((InternalModuleServiceCallImpl) call).getNewlyBlockedModule()) { |
| 103 | return unlockRequiredModule(call.getInternalServiceProcess(), call.getQedeq()); |
| 104 | } |
| 105 | return false; |
| 106 | } |
| 107 | |
| 108 | public boolean unlockRequiredModule(final ServiceJob process, final QedeqBo qedeq) { |
| 109 | return unlock(process, qedeq); |
| 110 | |
| 111 | } |
| 112 | |
| 113 | private synchronized boolean lock(final ServiceJob process, final QedeqBo qedeq, final Service service) { |
| 114 | final String method = "lock"; |
| 115 | if (Trace.isTraceOn()) { |
| 116 | Trace.info(CLASS, this, method, getName(process) + " is trying to lock " + qedeq.getName()); |
| 117 | } |
| 118 | final ServiceJob origin = getProcess(qedeq); |
| 119 | if (origin != null) { |
| 120 | if (Trace.isTraceOn()) { |
| 121 | Trace.info(CLASS, this, method, getName(process) + " failed to lock " + qedeq.getName() |
| 122 | + "\tbecause it is locked by " + getName(origin)); |
| 123 | } |
| 124 | return false; |
| 125 | } |
| 126 | addLock(process, qedeq); |
| 127 | ((DefaultKernelQedeqBo) qedeq).setCurrentlyRunningService(service); |
| 128 | return true; |
| 129 | } |
| 130 | |
| 131 | private synchronized boolean unlock(final ServiceJob process, final QedeqBo qedeq) { |
| 132 | final String method = "unlock"; |
| 133 | if (Trace.isTraceOn()) { |
| 134 | Trace.info(CLASS, this, method, getName(process) + " is trying to unlock " + qedeq.getName()); |
| 135 | } |
| 136 | ((DefaultKernelQedeqBo) qedeq).setCurrentlyRunningService(null); |
| 137 | final ServiceJob origin = getProcess(qedeq); |
| 138 | if (origin != null) { |
| 139 | if (origin.equals(process)) { |
| 140 | removeLock(process, qedeq); |
| 141 | return true; |
| 142 | } else { |
| 143 | RuntimeException e = new IllegalArgumentException(getName(process) + " illegal unlock try for " |
| 144 | + qedeq.getName() + " which is currently locked by service process " + getName(origin)); |
| 145 | Trace.fatal(CLASS, this, method, "Programming error. Unallowed unlock try.", e); |
| 146 | // TODO 20130324 m31: later on we might handle this differently but for now: |
| 147 | throw e; |
| 148 | } |
| 149 | } else { |
| 150 | if (Trace.isTraceOn()) { |
| 151 | Trace.info(CLASS, this, method, getName(process) + " unlock unnecessary " + qedeq.getName()); |
| 152 | } |
| 153 | return false; |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | private String getName(final ServiceJob process) { |
| 158 | return StringUtility.format(process.getId(), 3) + " " |
| 159 | + (process.getModuleServiceCall() != null ? StringUtility.getLastDotString( |
| 160 | process.getModuleServiceCall().getService().getServiceId()) : ""); |
| 161 | } |
| 162 | |
| 163 | private synchronized ServiceJob getProcess(final QedeqBo qedeq) { |
| 164 | return (ServiceJob) blocked.get(qedeq); |
| 165 | } |
| 166 | |
| 167 | private synchronized boolean isAlreadyLocked(final ServiceJob process, |
| 168 | final QedeqBo qedeq) { |
| 169 | return process.equals(blocked.get(qedeq)); |
| 170 | } |
| 171 | |
| 172 | private synchronized void addLock(final ServiceJob process, final QedeqBo qedeq) { |
| 173 | if (Trace.isTraceOn()) { |
| 174 | Trace.info(CLASS, this, "addLock", getName(process) + " locked successfuly " + qedeq.getName()); |
| 175 | } |
| 176 | blocked.put(qedeq, process); |
| 177 | } |
| 178 | |
| 179 | private synchronized void removeLock(final ServiceJob process, final QedeqBo qedeq) { |
| 180 | if (Trace.isTraceOn()) { |
| 181 | Trace.info(CLASS, this, "removeLock", getName(process) + " unlocked " + qedeq.getName()); |
| 182 | } |
| 183 | blocked.remove(qedeq); |
| 184 | } |
| 185 | |
| 186 | public synchronized QedeqBoSet getBlockedModules(final ServiceJob process) { |
| 187 | QedeqBoSet result = new QedeqBoSet(); |
| 188 | final Iterator i = blocked.entrySet().iterator(); |
| 189 | while (i.hasNext()) { |
| 190 | final Map.Entry entry = (Map.Entry) i.next(); |
| 191 | QedeqBo qedeq = (QedeqBo) entry.getKey(); |
| 192 | if (process.equals(entry.getValue())) { |
| 193 | result.add(qedeq); |
| 194 | } |
| 195 | } |
| 196 | return result; |
| 197 | } |
| 198 | |
| 199 | } |