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An implementation of the Java API for the CCSDS MAL
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/* ----------------------------------------------------------------------------
* Copyright (C) 2013 European Space Agency
* European Space Operations Centre
* Darmstadt
* Germany
* ----------------------------------------------------------------------------
* System : CCSDS MO MAL Java API
* ----------------------------------------------------------------------------
* Licensed under the European Space Agency Public License, Version 2.0
* You may not use this file except in compliance with the License.
*
* Except as expressly set forth in this License, the Software is provided to
* You on an "as is" basis and without warranties of any kind, including without
* limitation merchantability, fitness for a particular purpose, absence of
* defects or errors, accuracy or non-infringement of intellectual property rights.
*
* See the License for the specific language governing permissions and
* limitations under the License.
* ----------------------------------------------------------------------------
*/
package org.ccsds.moims.mo.mal;
import java.util.HashMap;
import org.ccsds.moims.mo.mal.structures.Identifier;
import org.ccsds.moims.mo.mal.structures.UInteger;
import org.ccsds.moims.mo.mal.structures.UOctet;
import org.ccsds.moims.mo.mal.structures.UShort;
/**
* A factory of MAL context objects.
*/
public abstract class MALContextFactory {
/**
* The Java property that is used to determine the correct implementation of
* the factory to use.
*/
public static final String MAL_FACTORY_PROPERTY = "org.ccsds.moims.mo.mal.factory.class";
/**
* The default implementation to use.
*/
public static final String MAL_DEFAULT_FACTORY = "esa.mo.mal.impl.MALContextFactoryImpl";
private static final HashMap MAL_MAP = new HashMap<>();
private static final HashMap VERSIONIZED_AREA_NUMBER_MAP = new HashMap<>();
private static final HashMap AREA_NAME_MAP = new HashMap<>();
private static final HashMap ERRORS = new HashMap<>();
private static final MALElementsRegistry ELEMENTS_REGISTRY = new MALElementsRegistry();
/**
* Registers a MALArea in the list of areas held by this context factory.
*
* @param area The new MALArea to register.
* @throws IllegalArgumentException If area is null.
* @throws MALException If area number already registered to a different
* MALArea instance.
*/
public static void registerArea(final MALArea area) throws MALException {
if (area == null) {
throw new IllegalArgumentException("NULL area argument");
}
final int num = area.getNumber().getValue();
final short ver = area.getVersion().getValue();
final VersionizedAreaNumber verArea = new VersionizedAreaNumber(num, ver);
final MALArea currentMapping = VERSIONIZED_AREA_NUMBER_MAP.get(verArea);
if ((currentMapping != null) && (currentMapping != area)) {
throw new MALException("MALArea already registered with a different instance");
}
Integer currentNum = AREA_NAME_MAP.get(area.getName().getValue());
if (currentNum != null && currentNum.shortValue() != num) {
throw new MALException("Trying to register the same 'Area Name' with a different 'Area Number'");
}
AREA_NAME_MAP.put(area.getName().getValue(), num);
VERSIONIZED_AREA_NUMBER_MAP.put(verArea, area);
}
/**
* Registers an Error number to an Error name. This method will be removed
* in the future as it is not used anywhere other than in the init methods.
* This slows down start-up and does not add value.
*
* @param areaNumber The Area number.
* @param areaVersion The Area version.
* @param errorNumber The number to use.
* @param errorName The matching name to the number.
* @throws java.lang.IllegalArgumentException if either is null.
* @throws MALException If already registered the number.
*/
@Deprecated
public static void registerError(UShort areaNumber, UOctet areaVersion, UInteger errorNumber,
Identifier errorName) throws java.lang.IllegalArgumentException, MALException {
if (areaNumber == null || areaVersion == null || errorNumber == null || errorName == null) {
throw new IllegalArgumentException("NULL argument");
}
synchronized (ERRORS) {
final Long key = generateKey(areaNumber, areaVersion, errorNumber);
final Identifier name = ERRORS.get(key);
if ((name != null) && !(name.equals(errorName))) {
throw new MALException("Error already registered with a different name!");
}
ERRORS.put(key, errorName);
}
}
private static long generateKey(UShort areaNumber, UOctet areaVersion, UInteger errorNumber) {
return ((long) areaNumber.getValue()) << 48
| ((long) areaVersion.getValue()) << 32
| ((long) errorNumber.getValue());
}
/**
* Look up a MALArea from an area name.
*
* @param areaName The area name to search for.
* @param version The version of the area to find.
* @return The matched MALArea or null if not found.
* @throws IllegalArgumentException If an argument is null.
*/
public static MALArea lookupArea(final Identifier areaName, final UOctet version)
throws IllegalArgumentException {
if (null == areaName) {
throw new IllegalArgumentException("NULL area argument");
}
if (null == version) {
throw new IllegalArgumentException("NULL version argument");
}
final Integer num = AREA_NAME_MAP.get(areaName.getValue());
if (num == null) {
return null;
}
return (MALArea) VERSIONIZED_AREA_NUMBER_MAP.get(
new VersionizedAreaNumber(num, version.getValue()));
}
/**
* Look up a MALArea from an area number.
*
* @param areaNumber The area number to search for.
* @param version The version of the area to find.
* @return The matched MALArea or null if not found.
* @throws IllegalArgumentException If an argument is null.
*/
public static MALArea lookupArea(final UShort areaNumber, final UOctet version)
throws IllegalArgumentException {
if (null == areaNumber) {
throw new IllegalArgumentException("NULL area argument");
}
if (null == version) {
throw new IllegalArgumentException("NULL version argument");
}
return (MALArea) VERSIONIZED_AREA_NUMBER_MAP.get(
new VersionizedAreaNumber(areaNumber.getValue(), version.getValue()));
}
/**
* Look up an error name from its number. This method will be removed in the
* future because it is not being used anywhere and having a HashMap costs
* memory and time during start-up.
*
* @param areaNumber The Area number.
* @param areaVersion The Area version.
* @param errorNumber The error name.
* @return The error number or null if not found.
*/
@Deprecated
public static Identifier lookupError(UShort areaNumber, UOctet areaVersion, UInteger errorNumber) {
Long key = generateKey(areaNumber, areaVersion, errorNumber);
return ERRORS.get(key);
}
/**
* Returns the elements registry.
*
* @return The Elements Registry.
*/
public static MALElementsRegistry getElementsRegistry() {
return ELEMENTS_REGISTRY;
}
/**
* Allows a specific implementation of this class to be registered where
* multiple class loaders can cause instantiation problems.
*
* @param factoryClass The factory class to register.
* @throws IllegalArgumentException if the parameter does not extend
* MALContextFactory or is null.
*/
public static void registerFactoryClass(final Class factoryClass) throws IllegalArgumentException {
if (null != factoryClass) {
if (!MALContextFactory.class.isAssignableFrom(factoryClass)) {
throw new IllegalArgumentException(
"Supplied factory class does not extend MALContextFactory: "
+ factoryClass.getName());
}
MAL_MAP.put(factoryClass.getName(), factoryClass);
} else {
throw new IllegalArgumentException("NULL argument");
}
}
/**
* Deregisters a previously registered factory class implementation. Does
* nothing if passed null.
*
* @param factoryClass The class to deregister
* @throws IllegalArgumentException if the parameter does not extend
* MALContextFactory.
*/
public static void deregisterFactoryClass(final java.lang.Class factoryClass) throws IllegalArgumentException {
if (null != factoryClass) {
if (!MALContextFactory.class.isAssignableFrom(factoryClass)) {
throw new IllegalArgumentException(
"Supplied factory class does not extend MALContextFactory: "
+ factoryClass.getName());
}
MAL_MAP.remove(factoryClass.getName());
} else {
throw new IllegalArgumentException("NULL argument");
}
}
/**
* Creates and returns a new instance of the factory class identified by the
* property.
*
* @return The new instance.
* @throws MALException If there is a problem instantiating the new
* instance.
*/
public static MALContextFactory newFactory() throws MALException {
try {
final String classname = System.getProperty(MAL_FACTORY_PROPERTY, MAL_DEFAULT_FACTORY);
Class malFactoryClass;
if (MAL_MAP.containsKey(classname)) {
malFactoryClass = (Class) MAL_MAP.get(classname);
} else {
malFactoryClass = Class.forName(classname);
registerFactoryClass(malFactoryClass);
}
return (MALContextFactory) malFactoryClass.newInstance();
} catch (ClassNotFoundException e) {
throw new MALException(e.getLocalizedMessage(), e);
} catch (InstantiationException e) {
throw new MALException(e.getLocalizedMessage(), e);
} catch (IllegalAccessException e) {
throw new MALException(e.getLocalizedMessage(), e);
}
}
/**
* Creates a MAL Context instance.
*
* @param props Properties required by the specific MALContext
* implementation
* @return The new MALContext instance.
* @throws MALException If there is a problem instantiating the new
* instance.
*/
public abstract MALContext createMALContext(java.util.Map props) throws MALException;
protected static class VersionizedAreaNumber {
public final int areaNumber;
public final short version;
public VersionizedAreaNumber(int areaNumber, short version) {
this.areaNumber = areaNumber;
this.version = version;
}
@Override
public int hashCode() {
int hash = this.areaNumber << 16;
return hash + this.version;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final VersionizedAreaNumber other = (VersionizedAreaNumber) obj;
if (this.areaNumber != other.areaNumber) {
return false;
}
return this.version == other.version;
}
}
}