Java tutorial
/* * 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.axis2.description; import org.apache.axiom.om.OMAttribute; import org.apache.axiom.om.OMElement; import org.apache.axis2.AxisFault; import org.apache.axis2.context.externalize.ExternalizeConstants; import org.apache.axis2.context.externalize.SafeObjectInputStream; import org.apache.axis2.context.externalize.SafeObjectOutputStream; import org.apache.axis2.context.externalize.SafeSerializable; import org.apache.axis2.deployment.DeploymentConstants; import org.apache.axis2.util.JavaUtils; import org.apache.axis2.util.Utils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.xml.namespace.QName; import java.io.Externalizable; import java.io.IOException; import java.io.ObjectInput; import java.io.ObjectOutput; import java.util.concurrent.ConcurrentHashMap; import java.util.ArrayList; import java.util.ConcurrentModificationException; import java.util.HashMap; import java.util.Iterator; import java.util.Map; /** * Class ParameterIncludeImpl */ public class ParameterIncludeImpl implements ParameterInclude, Externalizable, SafeSerializable { /* * setup for logging */ private static final Log log = LogFactory.getLog(ParameterIncludeImpl.class); private static boolean DEBUG_ENABLED = log.isTraceEnabled(); private static boolean DEBUG_PROPERTY_SET = log.isDebugEnabled(); private static final String myClassName = "ParameterIncludeImpl"; /** * @serial The serialization version ID tracks the version of the class. * If a class definition changes, then the serialization/externalization * of the class is affected. If a change to the class is made which is * not compatible with the serialization/externalization of the class, * then the serialization version ID should be updated. * Refer to the "serialVer" utility to compute a serialization * version ID. */ private static final long serialVersionUID = 8153736719090126891L; /** * @serial Tracks the revision level of a class to identify changes to the * class definition that are compatible to serialization/externalization. * If a class definition changes, then the serialization/externalization * of the class is affected. * Refer to the writeExternal() and readExternal() methods. */ // supported revision levels, add a new level to manage compatible changes private static final int REVISION_2 = 2; // current revision level of this object private static final int revisionID = REVISION_2; /** * Field parmeters */ protected Map<String, Parameter> parameters; /** * Constructor ParameterIncludeImpl. */ public ParameterIncludeImpl() { // Use a capacity large enough to prevent // resizing parameters = new HashMap<String, Parameter>(64); } /** * Method addParameter * * @param param */ public void addParameter(Parameter param) { if (param != null) { synchronized (parameters) { parameters.put(param.getName(), param); try { parameters.put(param.getName(), param); } catch (ConcurrentModificationException cme) { // The ParameteterIncludeImpl is supposed to be immutable after it is populated. // But alas, sometimes the callers forget and try to add new items. If // this occurs, swap over to the slower ConcurrentHashMap and continue. if (log.isDebugEnabled()) { log.debug("ConcurrentModificationException Occured...changing to ConcurrentHashMap"); log.debug("The exception is: " + cme); } Map newMap = new ConcurrentHashMap(parameters); newMap.put(param.getName(), param); parameters = newMap; } if (DEBUG_ENABLED) { this.debugParameterAdd(param); } } if (DEBUG_ENABLED) { this.debugParameterAdd(param); } } } public void removeParameter(Parameter param) throws AxisFault { synchronized (parameters) { try { parameters.remove(param.getName()); } catch (ConcurrentModificationException cme) { // The ParameteterIncludeImpl is supposed to be immutable after it is populated. // But alas, sometimes the callers forget and try to add new items. If // this occurs, swap over to the slower ConcurrentHashMap and continue. if (log.isDebugEnabled()) { log.debug("ConcurrentModificationException Occured...changing to ConcurrentHashMap"); log.debug("The exception is: " + cme); } Map newMap = new ConcurrentHashMap(parameters); newMap.remove(param.getName()); parameters = newMap; } } } /** * Since at runtime it parameters may be modified * to get the original state this method can be used * * @param parameters <code>OMElement</code> * @throws AxisFault */ public void deserializeParameters(OMElement parameters) throws AxisFault { Iterator iterator = parameters.getChildrenWithName(new QName(DeploymentConstants.TAG_PARAMETER)); while (iterator.hasNext()) { // this is to check whether some one has locked the parmeter at the top level OMElement parameterElement = (OMElement) iterator.next(); Parameter parameter = new Parameter(); // setting parameterElement parameter.setParameterElement(parameterElement); // setting parameter Name OMAttribute paraName = parameterElement.getAttribute(new QName(DeploymentConstants.ATTRIBUTE_NAME)); parameter.setName(paraName.getAttributeValue()); // setting parameter Value (the child element of the parameter) OMElement paraValue = parameterElement.getFirstElement(); if (paraValue != null) { parameter.setValue(parameterElement); parameter.setParameterType(Parameter.OM_PARAMETER); } else { String paratextValue = parameterElement.getText(); parameter.setValue(paratextValue); parameter.setParameterType(Parameter.TEXT_PARAMETER); } // setting locking attribute OMAttribute paraLocked = parameterElement.getAttribute(new QName(DeploymentConstants.ATTRIBUTE_LOCKED)); if (paraLocked != null) { String lockedValue = paraLocked.getAttributeValue(); if ("true".equals(lockedValue)) { parameter.setLocked(true); } else { parameter.setLocked(false); } } addParameter(parameter); } } /** * Method getParameter. * * @param name * @return Returns parameter. */ public Parameter getParameter(String name) { return parameters.get(name); } public ArrayList<Parameter> getParameters() { synchronized (parameters) { return new ArrayList<Parameter>(parameters.values()); } } // to check whether the parameter is locked at any level public boolean isParameterLocked(String parameterName) { return false; } /* =============================================================== * Externalizable support * =============================================================== */ /** * Save the contents of this object. * <p/> * NOTE: Transient fields and static fields are not saved. * Also, objects that represent "static" data are * not saved, except for enough information to be * able to find matching objects when the message * context is re-constituted. * * @param out The stream to write the object contents to * @throws IOException */ public void writeExternal(ObjectOutput o) throws IOException { SafeObjectOutputStream out = SafeObjectOutputStream.install(o); // write out contents of this object //--------------------------------------------------------- // in order to handle future changes to the message // context definition, be sure to maintain the // object level identifiers //--------------------------------------------------------- // serialization version ID out.writeLong(serialVersionUID); // revision ID out.writeInt(revisionID); //--------------------------------------------------------- // collection of parameters //--------------------------------------------------------- out.writeMap(parameters); } /** * Restore the contents of the object that was previously saved. * <p/> * NOTE: The field data must read back in the same order and type * as it was written. Some data will need to be validated when * resurrected. * * @param in The stream to read the object contents from * @throws IOException * @throws ClassNotFoundException */ public void readExternal(ObjectInput inObject) throws IOException, ClassNotFoundException { SafeObjectInputStream in = SafeObjectInputStream.install(inObject); // trace point if (log.isTraceEnabled()) { log.trace( myClassName + ":readExternal(): BEGIN bytes available in stream [" + in.available() + "] "); } // serialization version ID long suid = in.readLong(); // revision ID int revID = in.readInt(); // make sure the object data is in a version we can handle if (suid != serialVersionUID) { throw new ClassNotFoundException(ExternalizeConstants.UNSUPPORTED_SUID); } // make sure the object data is in a revision level we can handle if (revID != REVISION_2) { throw new ClassNotFoundException(ExternalizeConstants.UNSUPPORTED_REVID); } //--------------------------------------------------------- // collection of parameters //--------------------------------------------------------- in.readMap(parameters); //--------------------------------------------------------- // done //--------------------------------------------------------- } /** * Debug for for property key and value. * @param key * @param value */ private void debugParameterAdd(Parameter parameter) { if (DEBUG_PROPERTY_SET) { String key = parameter.getName(); Object value = parameter.getValue(); String className = (value == null) ? "null" : value.getClass().getName(); String classloader = "null"; if (value != null) { ClassLoader cl = Utils.getObjectClassLoader(value); if (cl != null) { classloader = cl.toString(); } } String valueText = (value instanceof String) ? value.toString() : null; String identity = getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(this)); log.debug("=================="); log.debug(" Parameter add on object " + identity); log.debug(" Key =" + key); if (valueText != null) { log.debug(" Value =" + valueText); } log.debug(" Value Class = " + className); log.debug(" Value Classloader = " + classloader); log.debug("Call Stack = " + JavaUtils.callStackToString()); log.debug("=================="); } } }