/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library 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.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.dqp.message;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import org.teiid.core.util.EquivalenceUtil;
import org.teiid.core.util.HashCodeUtil;
/**
* <p>This class represents an identifier for a request. However, there are some
* differences in what constitutes "uniqueness" for a given RequestID that
* is based on context (where the id is used). The RequestID has 2 parts:
* connectionID, and executionIDFor the purposes of the RequestID, the combined
* representation is "connectionID.executionID" - this implies a scoping
* for the name parts. The connectionID specifies a particular connection that
* is making requests. Each connection generates a unique executionID for each
* request execution, so the executionID is only unique in the context of a
* connectionID. </p>
*
* <p>When this class is used between client and server, the connectionID is implied
* and thus only the executionID part will be used. The server will qualify the
* executionID with a connectionID when it reaches the server. </p>
*
* <p>RequestIDs are immutable so no setters exist. This allows hashcodes to be
* pre-computed for faster comparison in equals.</p>
*/
public class RequestID implements Externalizable {
static final long serialVersionUID = -2888539138291776071L;
public static final String NO_CONNECTION_STR = "C"; //$NON-NLS-1$
private static final String SEPARATOR = "."; //$NON-NLS-1$
// Basic state
private String connectionID;
private long executionID;
// Derived state
private String combinedID;
/**
* Necessary for implementing Externalizable
*/
public RequestID() {
}
/**
* Create a RequestID using all of the ID parts.
* @param connectionID Identifies a connection, may be null
* @param executionID Identifies an execution, cannot be null
*/
public RequestID(String connectionID, long executionID) {
this.connectionID = connectionID;
this.executionID = executionID;
}
public RequestID(long connectionID, long executionID) {
this.connectionID = String.valueOf(connectionID);
this.executionID = executionID;
}
/**
* Create a RequestID for an execution where the connection is
* not specified.
* @param executionID Identifies an execution, cannot be null
*/
public RequestID(long executionID) {
this(null, executionID);
}
/**
* Return connectionID, may be null if connection has not been specified.
* @return Connection ID, may be null
*/
public String getConnectionID() {
return this.connectionID;
}
/**
* Return executionID, which identifies a per-connection execution.
* @return Execution ID
*/
public long getExecutionID() {
return this.executionID;
}
/**
* Create a unique combined ID string from the RequestID parts.
*/
private void createCombinedID() {
StringBuffer combinedStr = new StringBuffer();
if(this.connectionID != null) {
combinedStr.append(this.connectionID);
} else {
combinedStr.append(NO_CONNECTION_STR);
}
combinedStr.append(SEPARATOR);
combinedStr.append(this.executionID);
this.combinedID = combinedStr.toString();
}
public int hashCode() {
return HashCodeUtil.hashCode(connectionID==null?0:connectionID.hashCode(), executionID);
}
public boolean equals(Object obj) {
if(obj == this) {
return true;
} else if(obj == null || !(obj instanceof RequestID)) {
return false;
}
RequestID other = (RequestID)obj;
return this.executionID == other.executionID
&& EquivalenceUtil.areEqual(this.connectionID, other.connectionID);
}
/**
* Return a combined string for the ID.
*/
public String toString() {
if (combinedID == null) {
createCombinedID();
}
return this.combinedID;
}
/**
* @see java.io.Externalizable#readExternal(java.io.ObjectInput)
*/
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
connectionID = (String)in.readObject();
executionID = in.readLong();
}
/**
* @see java.io.Externalizable#writeExternal(java.io.ObjectOutput)
*/
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(connectionID);
out.writeLong(executionID);
}
}