org.snmp4j.agent.mo.MOTableRelation Maven / Gradle / Ivy
/*_############################################################################
_##
_## SNMP4J-Agent 3 - MOTableRelation.java
_##
_## Copyright (C) 2005-2018 Frank Fock (SNMP4J.org)
_##
_## Licensed 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.snmp4j.agent.mo;
import org.snmp4j.smi.OID;
/**
* The MOTableRelation class models table relations like sparse
* table relationship and augmentation. This class implements the augmentation
* relationship. In order to implement a sparse table relationship, sub-classing
* MOTableRelation is needed and the methods
* {@link #hasDependentRow} and {@link #getDependentIndexes} must be overwritten
* then.
*
* @param
* The row type of the base table.
* @param
* The row type of the dependent table.
*
* @author Frank Fock
* @version 3.0.0
*/
public class MOTableRelation {
@SuppressWarnings("rawtypes")
private MOTable> baseTable;
@SuppressWarnings("rawtypes")
private MOTable> dependentTable;
private MOTableRowListener relationShipListener;
/**
* Creates a table relation from a base table and the dependent table.
* To actually set up the relationship between those tables
* {@link #createRelationShip()} needs to be called.
*
* @param baseTable
* the base table.
* @param dependentTable
* the dependent (augmenting) table.
*/
@SuppressWarnings("rawtypes")
public MOTableRelation(MOTable> baseTable,
MOTable> dependentTable) {
this.baseTable = baseTable;
this.dependentTable = dependentTable;
}
/**
* Actually sets up the relationship between base and dependent table by
* adding this instance as row listener to the base table.
*/
public void createRelationShip() {
this.baseTable.addMOTableRowListener(createRelationShipListener());
}
/**
* Removes the relationship between base and dependent table by
* removing this instance as row listener from the base table.
*
* @since 3.0.0
*/
public void removeRelationShip() {
if (relationShipListener != null) {
this.baseTable.removeMOTableRowListener(relationShipListener);
}
}
protected MOTableRowListener createRelationShipListener() {
this.relationShipListener = new RelationShipListener();
return this.relationShipListener;
}
/**
* Indicates whether the specified baseTableRow has any dependent rows.
* By default this method returns true because the default
* implementation represents an augmentation relationship.
* Overwrite this method in a sub-class to implement a sparse table
* relationship.
*
* @param baseTableRow
* a row of the base table.
*
* @return true if the row has dependent rows.
*/
public boolean hasDependentRow(BaseRow baseTableRow) {
// by default this is an augmentation
// overwrite in a subclass to implement sparse relationship
return true;
}
/**
* Returns the dependent indexes for the specified base row. By default, this
* method returns the base rows index in a one element array, because
* the default implementation represents an augmentation relationship.
* Overwrite this method in a sub-class to implement a sparse table
* relationship.
*
* @param baseRow
* a row of the base table.
*
* @return an array of row index values of the dependent rows.
*/
public OID[] getDependentIndexes(BaseRow baseRow) {
// by default this is an augmentation
// overwrite in a subclass to implement sparse relationship
return new OID[]{baseRow.getIndex()};
}
@SuppressWarnings("rawtypes")
public MOTable> getBaseTable() {
return baseTable;
}
@SuppressWarnings("rawtypes")
public MOTable> getDependentTable() {
return dependentTable;
}
public MOTableRowListener getRelationShipListener() {
return relationShipListener;
}
/**
* Adds all dependent rows for the specified base table row to the dependent
* table. This method is automatically called if {@link #createRelationShip()}
* has been called.
*
* @param baseTableRow
* a row of the base table.
*/
protected void addDependentRows(BaseRow baseTableRow) {
OID[] indexes = getDependentIndexes(baseTableRow);
for (OID index : indexes) {
DependentRow depRow =
dependentTable.createRow(index, dependentTable.getDefaultValues());
depRow.setBaseRow(baseTableRow);
dependentTable.addRow(depRow);
}
}
/**
* Update the {@link MOTableRow#getBaseRow()} reference all dependent rows for the specified base table row in
* the dependent table. This method is automatically called if {@link #createRelationShip()}
* has been called.
*
* @param baseTableRow
* a row of the base table.
*/
protected void updateDependentRows(BaseRow baseTableRow) {
OID[] indexes = getDependentIndexes(baseTableRow);
for (OID index : indexes) {
DependentRow depRow = dependentTable.getModel().getRow(index);
depRow.setBaseRow(baseTableRow);
}
}
/**
* Removes all dependent rows for the specified base table row
* from the dependent table. This method is automatically called if
* {@link #createRelationShip()} has been called.
*
* @param baseTableRow
* a row of the base table.
*
* @return an array of the removed rows.
*/
@SuppressWarnings("rawtypes")
protected MOTableRow[] removeDependentRows(BaseRow baseTableRow) {
OID[] indexes = getDependentIndexes(baseTableRow);
MOTableRow[] removedRows = new MOTableRow[indexes.length];
for (int i = 0; i < indexes.length; i++) {
removedRows[i] = dependentTable.removeRow(indexes[i]);
}
return removedRows;
}
protected class RelationShipListener implements MOTableRowListener {
public void rowChanged(MOTableRowEvent event) {
switch (event.getType()) {
case MOTableRowEvent.EXISTS:
case MOTableRowEvent.ADD: {
if ((event.getRow() == null) || dependentTable.getModel().containsRow(event.getRow().getIndex())) {
if (event.getRow() != null) {
// update baseRow reference
updateDependentRows(event.getRow());
}
return;
} else if (hasDependentRow(event.getRow())) {
addDependentRows(event.getRow());
}
break;
}
case MOTableRowEvent.DELETE: {
removeDependentRows(event.getRow());
}
}
}
@SuppressWarnings("rawtypes")
public MOTable> getDependentTable() {
return dependentTable;
}
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy