java.lang.Thread
dk.opi.io.opc.opcclient.OpcClientApi
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java.lang.Object
This class is the interface to the Java native methods necessary for tapping into the OPC (D)COM interface, ie. use this interface when you want to read/write item values from/to a device which has an OPC server. The example below shows how to use this interface in order to monitor values from an simulated ICONICS OPC server.
import dk.opi.io.*;
import dk.opi.io.opc.opcclient.*;
public class SimpleExample implements IOListener {
protected IOItem boolItem;
protected IOItem intItem;
protected IOItem stringItem;
IOServer is = null;
public static void main(String[] args) {
SimpleExample opct = new SimpleExample();
}
public SimpleExample() {
try {
// Connect to OPC server and create items
connect();
// Create test group and add items to it. This object is assigned as
// listener when values change
IOGroup g1 = createGroup1(this);
// Fire an onValueChange() event for all added items in order to
// get the initial item values
g1.fireAllItems(this);
// Try to change value of one of the registers and note that the
// onValueChanged() method is called whenever the value change
boolean bVals[] = {false, true, false};
int iVals[] = {10, 20, 30};
String sVals[] = {"string1", "string2", "string3"};
for (int i = 0; i < 3; i++) {
try {
System.out.println("Writing loop=" + i);
boolItem.writeValue(new Boolean(bVals[i]));
intItem.writeValue(iVals[i]);
stringItem.writeValue(sVals[i]);
}
catch (RbxIOException e) {
e.printStackTrace();
}
try {Thread.sleep(2000);} catch(Exception e){};
}
}
catch (RbxIOException e) {
e.printStackTrace();
}
// release connection to OPC server again. It's important to call this
// method. If it's not called the OPC server will not shut down
// automatically
if (is != null)
is.releaseConnection();
System.exit(0);
}
// This method implements the specific details of connecting to the OPC
// server
public void connect() throws RbxIOException {
// Initialize the OPC client interface to a Iconics simulated OPC server
this.is = new OpcClientApi("ICONICS.Simulator");
}
// This method implements the specific details of adding groups and
// items to the already open OPC server
public IOGroup createGroup1(IOListener iol) throws RbxIOException {
// Get the reference to the OPC Server
OpcClientApi oa1 = (OpcClientApi)this.is;
// Add a group to this server
OpcGroup og1 = oa1.addGroup("testgrp", true, 500, 0f);
// Sign up specified listener for value change events. The
// onValueChanged() method of the listener will be callled. It's
// important to sign up as listener before items are added, otherwise
// notifications may be lost
og1.addIOListener(iol);
// Add three items - the item name is specific for the type of device
// you are going to read from. The specified item name (ie.
// "Device1.boolItem") must match the item name as it is known to the
// OPC server.
boolItem = og1.addItem("Device1.boolItem", null, true,
IOItem.DATATYPE_BOOL, "myBoolItem");
intItem = og1.addItem("Device1.intItem", null, true,
IOItem.DATATYPE_INT, "myIntItem");
stringItem = og1.addItem("Device1.stringItem", null, true,
IOItem.DATATYPE_STRING, "myStringItem");
return(og1);
}
// Called when a data value has changed
public void onValueChanged(IOItem i) {
System.out.println("onValueChanged action=" + i.getActionCommand() + " " +
i + "=" + i.getOldValue());
}
}
The following is sample ouput generated by the above example:
C:\>java OPCTest2 onValueChanged action=myBoolItem Device1.boolItem=false onValueChanged action=myIntItem Device1.intItem=0 onValueChanged action=myStringItem Device1.stringItem= Writing loop=0 onValueChanged action=myStringItem Device1.stringItem=string1 onValueChanged action=myIntItem Device1.intItem=10 Writing loop=1 onValueChanged action=myStringItem Device1.stringItem=string2 onValueChanged action=myIntItem Device1.intItem=20 onValueChanged action=myBoolItem Device1.boolItem=true Writing loop=2 onValueChanged action=myStringItem Device1.stringItem=string3 onValueChanged action=myIntItem Device1.intItem=30 onValueChanged action=myBoolItem Device1.boolItem=false
| Field Summary | |
static int |
DEBUG_LEVEL_ALL
the highest debug level |
static int |
DEBUG_LEVEL_DEBUG
debug level - a lot of debug info is printed |
static int |
DEBUG_LEVEL_INFO
informational debug level - top level info is printed |
static int |
DEBUG_LEVEL_NORMAL
the normal debug level - only errors are printed |
| Fields inherited from class java.lang.Thread |
MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY |
| Constructor Summary | |
OpcClientApi(String name)
Create OpcClientApi object |
|
OpcClientApi(String name,
int msecTimeout)
Create OpcClientApi object |
|
OpcClientApi(String hName,
String name)
Create OpcClientApi object |
|
OpcClientApi(String hName,
String name,
int msecTimeout)
Create OpcClientApi object |
|
| Method Summary | |
OpcGroup |
addGroup(String name,
boolean active,
int updateRate,
float percentDeadBand)
Add a group to this server |
OpcGroup |
addGroup(String name,
boolean active,
int updateRate,
float percentDeadBand,
String descr)
Add a group to this server |
Vector |
getGroups()
Return Vector of all IOGroups currently added to this server. |
int |
getHandle()
|
String |
getServerHostName()
Returns the name of the machine hosting the OPC server this client connects to |
static IOServerInfo[] |
getServerInfo()
Static method returning an array of IOServerInfo objects holding information about OPC servers available from the local machine. |
IOItemBrowseTreeNode |
getServerItemsInfo()
This method returns a tree of available groups and items on the OPC server. |
String |
getServerName()
Returns the server name for the OPC server this client connects to, ie. |
Object |
readValue(OpcItem i)
Read a value for specified item. |
Object |
readValue(OpcItem i,
int dataSource)
Read an value for specified item. |
void |
releaseConnection()
Close client connections and release all handles and connections to the OPC server. |
void |
releaseConnection(int msecTimeout)
Close client connections and release all handles and connections to the OPC server. |
void |
removeGroup(IOGroup iog)
Remove a group from this server |
void |
run()
Thread started when object connects to the OPC server. |
void |
setDebugLevel(int level)
Set the debug level. |
boolean |
setGroupActive(OpcGroup g,
boolean value)
Make group inactive or active. |
void |
writeDoubleValue(OpcItem i,
double value)
Write a double value for specified item. |
void |
writeFloatValue(OpcItem i,
float value)
Write a float value for specified item. |
void |
writeIntValue(OpcItem i,
int value)
Write an integer value for specified item. |
boolean |
writeMultipleItems(Vector itemWriteList)
Used for bulk write of one or more OpcItem objects. |
void |
writeStringValue(OpcItem i,
String value)
Write a String value for specified item. |
| Methods inherited from class java.lang.Thread |
activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Field Detail |
public static final int DEBUG_LEVEL_NORMAL
public static final int DEBUG_LEVEL_INFO
public static final int DEBUG_LEVEL_DEBUG
public static final int DEBUG_LEVEL_ALL
| Constructor Detail |
public OpcClientApi(String name)
throws RbxIOException
name - name of the server to contact, ie. ICONICS.Simulator. The server should
be located on the local machine. Alternatively the NT dcomcnf.exe utility
may be used in order to specify a different location. In any way the
OPC server should have been installed on the local machine, in order to
create reference to the CLSID in the local registry.
RbxIOException - thrown if the server connection could not be established
public OpcClientApi(String name,
int msecTimeout)
throws RbxIOException
name - name of the server to contact, ie. ICONICS.Simulator. The server should
be located on the local machine. Alternatively the NT dcomcnf.exe utility
may be used in order to specify a different location. In any way the
OPC server should have been installed on the local machine, in order to
create reference to the CLSID in the local registry.msecTimeout - number of milliseconds to wait before timing out on the connect
attempt. Due to DCOM implementation details two orphan connection threads
will pend for a while after a timeout, but the threads will eventually
disappear. Use a value of 0 to specify no timeout.
RbxIOException - thrown if the server connection could not be established
public OpcClientApi(String hName,
String name)
throws RbxIOException
hName - name of the machine hosting the OPC server that this client should
connect to. The name may be specified as an IP-address, a DNS name
(ie. server.com). Specify null if the server is located on the local
machine.If the server is located on a remote machine, it is still necessary to install it locally first, in order to create the CLSID in the local registry. Alternatively the CLSID may be created manually, consult documentation of your OPC server for more info on this issue.
name - name of the server to contact, ie. ICONICS.Simulator
RbxIOException - thrown if the server connection could not be established
public OpcClientApi(String hName,
String name,
int msecTimeout)
throws RbxIOException
hName - name of the machine hosting the OPC server that this client should
connect to. The name may be specified as an IP-address, a DNS name
(ie. server.com). Specify null if the server is located on the local
machine.If the server is located on a remote machine, it is still necessary to install it locally first, in order to create the CLSID in the local registry. Alternatively the CLSID may be created manually, consult documentation of your OPC server for more info on this issue.
name - name of the server to contact, ie. ICONICS.SimulatormsecTimeout - number of milliseconds to wait before timing out on the connect
attempt. Due to DCOM implementation details two orphan connection threads
will pend for a while after a timeout, but the threads will eventually
disappear. Use a value of 0 to specify no timeout.
RbxIOException - thrown if the server connection could not be established| Method Detail |
public String getServerName()
public OpcGroup addGroup(String name,
boolean active,
int updateRate,
float percentDeadBand)
throws RbxIOException
name - name of the group. Must be unique within this serveractive - if items in this group are going to be monitoredupdateRate - requested update rate for items in this group in milli secondspercentDeadBand - if items in this group are monitored using AdviseSink function then
values are only changed when they have been changed more than specified
by this value.
RbxIOException - thrown if the group could not be addded
public OpcGroup addGroup(String name,
boolean active,
int updateRate,
float percentDeadBand,
String descr)
throws RbxIOException
name - name of the group. Must be unique within this serveractive - if items in this group are going to be monitoredupdateRate - requested update rate for items in this group in milli secondspercentDeadBand - if items in this group are monitored using AdviseSink function then
values are only changed when they have been changed more than specified
by this value.descr - description of the item. Can be queried by a call to getDescription()
RbxIOException - thrown if the group could not be adddedpublic Vector getGroups()
getGroups in interface IOServer
public void removeGroup(IOGroup iog)
throws RbxIOException
removeGroup in interface IOServeriog - The group to remove
RbxIOException - thrown if it was not possible to remove the specified group, for
instance if the specified group is not a member of this server.public int getHandle()
public void releaseConnection()
Known bug: Releasing and immidiately after reconnecting to the same OPC server instance may cause an error, if the OPC server is closed on the call to releaseConnection(). This is caused by a flaw in the DCOM object activation frame work. A workaround is to always sleep app. 500 ms. before reconnecting to the same OPC server, in order to allow the OPC server to completely shut down before creating a new connection.
releaseConnection in interface IOServer
public void releaseConnection(int msecTimeout)
throws RbxIOException
Known bug: Releasing and immidiately after reconnecting to the same OPC server instance may cause an error, if the OPC server is closed on the call to releaseConnection(). This is caused by a flaw in the DCOM object activation frame work. A workaround is to always sleep app. 500 ms. before reconnecting to the same OPC server, in order to allow the OPC server to completely shut down before creating a new connection.
releaseConnection in interface IOServermsecTimeout - number of milliseconds to wait before timing out in case connection
could not be released within specified timeout period. A timeout may
occur in the event that the delegating releaseConnection call to
the OPC server hangs, eg. the OPC server is currently unavailable on the
network.Even in the event of a timeout all claimed resources will be released, thus the caller should not attempt any further calls to releaseConnection(), even after a timeout
RbxIOException - thrown in case of timeout, however connection will still be released.
public Object readValue(OpcItem i)
throws RbxIOException
i - Item to read value from
RbxIOException - thrown if the read operation failed
public Object readValue(OpcItem i,
int dataSource)
throws RbxIOException
i - Item to read value from
RbxIOException - thrown if the read operation failed
public boolean writeMultipleItems(Vector itemWriteList)
throws RbxIOException
OpcItem objects. Use this
method to improve write performance when writing to many items at the same
time. All the items are sent to the OPC server as a single package, thus
minimizing network bandwidth.
The method runs to completion. The values are written to the DEVICE. That is, the method will not return until it verifies that the device has actually accepted (or rejected) the data.
Writes are not affected by the ACTIVE state of the item.
Example of usage:
import java.util.Vector;
import dk.opi.io.*;
import dk.opi.io.opc.opcclient.*;
IOServer2 is;
IOItem intItem;
IOItem boolItem;
IOItem stringItem;
Vector witems = new Vector();
witems.addElement(new IOItemWriteValue(intItem, new Integer(22)));
witems.addElement(new IOItemWriteValue(boolItem, Boolean.TRUE));
witems.addElement(new IOItemWriteValue(stringItem, "test string"));
if (is.writeMultipleItems(witems)) {
// one or more items not written - check the error
for (int j = 0; j < witems.size(); j++) {
IOItemWriteValue wVal = (IOItemWriteValue )witems.elementAt(j);
String errText = wVal.getErrorText();
if (errText != null) {
System.out.println("errorText item no." + j +
" errorText=" + errText);
} // end of if ()
} // end of for (int = 0; < ; ++)
} // end of if ()
writeMultipleItems in interface IOServer2itemWriteList - a Vector holding
IOItemWriteValue objects. If an element in
itemWriteList is not of this type, an exception will be thrown
IOItemWriteValue.getErrorText()
method for the error description. In case false is returned all items
were sucessfully written, so the user need not query the
itemWriteList Vector.
RbxIOException - if an write failure occured or if the size of
the items and values Vectors are not the same.
public void writeIntValue(OpcItem i,
int value)
throws RbxIOException
i - Item to write value tovalue - the value to write
RbxIOException - thrown if the write operation failed
public void writeFloatValue(OpcItem i,
float value)
throws RbxIOException
i - Item to write value tovalue - the value to write
RbxIOException - thrown if the write operation failed
public void writeDoubleValue(OpcItem i,
double value)
throws RbxIOException
i - Item to write value tovalue - the value to write
RbxIOException - thrown if the write operation failed
public void writeStringValue(OpcItem i,
String value)
throws RbxIOException
i - Item to write value tovalue - the value to write
RbxIOException - thrown if the write operation failed
public boolean setGroupActive(OpcGroup g,
boolean value)
Important: not intended for public use, instead use the
OpcGroup.setActive(boolean) method
g - Group to set active/inactivevalue - true if group should be set to active, false otherwise.
public static IOServerInfo[] getServerInfo()
throws RbxIOException
IOServerInfo[] srvList = OpcClientApi.getServerInfo(); OpcClientApi server = new OpcClientApi(srvList[1].getName());
IOServerInfo objects. An array
with length 0 means no servers are availble
RbxIOException - if an error occur
public IOItemBrowseTreeNode getServerItemsInfo()
throws RbxIOException
The returned tree may be shown in a JTree by using the wrapper class
JTreeIOTreeNode, please refer to this class for an
example of the usage of IOItemBrowseTreeNode in combination
with a JTree.
IOItemBrowseTreeNode value
RbxIOException - if an error occurpublic void setDebugLevel(int level)
level - any of the values DEBUG_LEVEL_NORMAL, DEBUG_LEVEL_INFO,
DEBUG_LEVEL_DEBUG or DEBUG_LEVEL_ALL
IllegalArgumentException - if level is unknownpublic void run()
run in interface Runnablepublic String getServerHostName()
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