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/*
*
* Copyright (c) 2013,2019 AT&T Knowledge Ventures
* SPDX-License-Identifier: MIT
*/
package com.att.research.xacmlatt.pdp.std.functions;
import com.att.research.xacml.api.DataType;
import com.att.research.xacml.api.Identifier;
import com.att.research.xacml.api.Status;
import com.att.research.xacml.std.StdStatus;
import com.att.research.xacml.std.datatypes.DataTypeBoolean;
import com.att.research.xacmlatt.pdp.policy.ExpressionResult;
import com.att.research.xacmlatt.pdp.policy.FunctionDefinition;
/**
* /**
* FunctionDefinitionBase provides a common base for {@link com.att.research.xacmlatt.pdp.policy.FunctionDefinition}s.
* The child classes derived from this are of two types:
*
* - Functions returning a single simple value of a type defined in {@link com.att.research.xacml.std.datatypes.DataTypes}.
* - Functions returning a single bag with elements of a single type.
*
*
* This base class contains the following components:
*
* - The Identity for this function.
* - The DataType of the data returned from this function.
* - Commonly-used values.
*
* For Bags this means the DataType of the elements in the bag, or null if that is ambiguous.
*
* @author glenngriffin
*
* @param the java class for the Output data type returned by the FunctionDefinition
* @param the java class for the Input data type expected in the arguments to the FunctionDefinition.
* Some functions have non-homogeneous arguments but may still have a main 'type'.
*/
public abstract class FunctionDefinitionBase implements FunctionDefinition {
// The XACML identifier string for this particular function
private Identifier id;
// each function derived from this returns a single non-bag data value of the following type, or a Bag containing elements of this type
private DataType dataTypeReturn;
// All functions have input arguments and expect them to be of a given type.
// In some instances the argument gets multiple values of different types, but when the function has a 'type' associated with it's name
// specific ones of the input must be of this type.
// When an argument Input to the function is a Bag, the elements in that bag will be of this type.
// This corresponds most closely to the 'type' in the function name (as in 'type'-bag or 'type'-equals).
private DataType dataTypeArgs;
// true = the return value from this function is a bag; false = return value is a single-value DataType object
private boolean returnsBag;
/*
* For functions that return a Boolean result we create a single instance of the True/False return values that they can share
*/
protected static final ExpressionResult ER_TRUE = ExpressionResult.newSingle(DataTypeBoolean.AV_TRUE);
protected static final ExpressionResult ER_FALSE = ExpressionResult.newSingle(DataTypeBoolean.AV_FALSE);
/**
* Creates a new FunctionDefinitionBase with the {@link com.att.research.xacml.api.Identifier} idIn as
* the function id.
*
* @param idIn the Identifier for this FunctionDefinitionBase
* @param returnDataTypeIn DataType return DataType
* @param argumentDataTypeIn Input argument DataTypes
* @param returnsBagIn true if the return is a bag
*/
protected FunctionDefinitionBase(Identifier idIn, DataType returnDataTypeIn, DataType argumentDataTypeIn, boolean returnsBagIn) {
this.id = idIn;
this.dataTypeReturn = returnDataTypeIn;
this.dataTypeArgs = argumentDataTypeIn;
this.returnsBag = returnsBagIn;
}
/**
* Returns a shortened version of the Id for this function, primarilly for use with error messages to prevent them from becoming too long.
* This is a simple convenience method to reduce code bloat.
*
* @return String short function id
*/
public String getShortFunctionId() {
return this.getId().getUri().toString().substring(this.getId().getUri().toString().indexOf("function:"));
}
/**
* Returns a shortened version of the given DataType Id, primarily for use with error messages to prevent them from becoming too long.
* This is a simple convenience method to reduce code bloat.
*
* @param identifier expected to have '#' in it, and if no '#' should have ":data-type:"
* @return String get short data type id
*/
public String getShortDataTypeId(Identifier identifier) {
String idString = identifier.stringValue();
int index = idString.indexOf('#');
if (index < 0) {
index = idString.indexOf(":data-type:");
if (index < 0) {
return idString;
} else {
return idString.substring(index + 11);
}
} else {
return idString.substring(index+1);
}
}
/**
* Return a new Status that includes the name of this function in front of the original status' message.
* This is a convenience method to reduce code bloat.
*
* @param originalStatus The original Status
* @return Status object
*/
public Status getFunctionStatus(Status originalStatus) {
return new StdStatus(originalStatus.getStatusCode(), getShortFunctionId() + " " + originalStatus.getStatusMessage());
}
//
// Getters for the internal variables
//
@Override
public Identifier getId() {
return this.id;
}
@Override
public Identifier getDataTypeId() {
if (this.dataTypeReturn == null) {
return null;
} else {
return this.dataTypeReturn.getId();
}
}
public DataType getDataType() {
return this.dataTypeReturn;
}
/**
* Return the Identifier for the Input Argument(s) DataType.
*
* @return DataType{@literal} identifier
*/
public DataType getDataTypeArgs() {
return this.dataTypeArgs;
}
@Override
public boolean returnsBag() {
return returnsBag;
}
}