/*
* @(#)FunctionBase.java
*
* Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for use in
* the design, construction, operation or maintenance of any nuclear facility.
*/
package com.sun.xacml.cond;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Indenter;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.ctx.Status;
/**
* An abstract utility superclass for functions. Supplies several useful methods, making it easier
* to implement a <code>Function</code>. You can extend this class or implement
* <code>Function</code> directly, depending on your needs.
*
* @since 1.0
* @author Steve Hanna
* @author Seth Proctor
*
* Adding generic type support by Christian Mueller (geotools)
*/
public abstract class FunctionBase implements Function {
/**
* The standard namespace where all XACML 1.0 spec-defined functions live
*/
public static final String FUNCTION_NS = "urn:oasis:names:tc:xacml:1.0:function:";
/**
* The standard namespace where all XACML 2.0 spec-defined functions live
*/
public static final String FUNCTION_NS_2 = "urn:oasis:names:tc:xacml:2.0:function:";
// A List used by makeProcessingError() to save some steps.
private static List<String> processingErrList = null;
// the name of this function
private String functionName;
// the id used by this function
private int functionId;
// the return type of this function, and whether it's a bag
private String returnType;
private boolean returnsBag;
// flag that tells us which of the two constructors was used
private boolean singleType;
// parameter data if we're only using a single type
private String paramType;
private boolean paramIsBag;
private int numParams;
private int minParams;
// paramater data if we're using different types
private String[] paramTypes;
private boolean[] paramsAreBags;
/**
* Constructor that sets up the function as having some number of parameters all of the same
* given type. If <code>numParams</code> is -1, then the length is variable
*
* @param functionName
* the name of this function as used by the factory and any XACML policies
* @param functionId
* an optional identifier that can be used by your code for convenience
* @param paramType
* the type of all parameters to this function, as used by the factory and any XACML
* documents
* @param paramIsBag
* whether or not every parameter is actually a bag of values
* @param numParams
* the number of parameters required by this function, or -1 if any number are
* allowed
* @param returnType
* the type returned by this function, as used by the factory and any XACML documents
* @param returnsBag
* whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String paramType, boolean paramIsBag,
int numParams, String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = true;
this.paramType = paramType;
this.paramIsBag = paramIsBag;
this.numParams = numParams;
this.minParams = 0;
}
/**
* Constructor that sets up the function as having some number of parameters all of the same
* given type. If <code>numParams</code> is -1, then the length is variable, and then
* <code>minParams</code> may be used to specify a minimum number of parameters. If
* <code>numParams</code> is not -1, then <code>minParams</code> is ignored.
*
* @param functionName
* the name of this function as used by the factory and any XACML policies
* @param functionId
* an optional identifier that can be used by your code for convenience
* @param paramType
* the type of all parameters to this function, as used by the factory and any XACML
* documents
* @param paramIsBag
* whether or not every parameter is actually a bag of values
* @param numParams
* the number of parameters required by this function, or -1 if any number are
* allowed
* @param minParams
* the minimum number of parameters required if <code>numParams</code> is -1
* @param returnType
* the type returned by this function, as used by the factory and any XACML documents
* @param returnsBag
* whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String paramType, boolean paramIsBag,
int numParams, int minParams, String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = true;
this.paramType = paramType;
this.paramIsBag = paramIsBag;
this.numParams = numParams;
this.minParams = minParams;
}
/**
* Constructor that sets up the function as having different types for each given parameter.
*
* @param functionName
* the name of this function as used by the factory and any XACML policies
* @param functionId
* an optional identifier that can be used by your code for convenience
* @param paramTypes
* the type of each parameter, in order, required by this function, as used by the
* factory and any XACML documents
* @param paramIsBag
* whether or not each parameter is actually a bag of values
* @param returnType
* the type returned by this function, as used by the factory and any XACML documents
* @param returnsBag
* whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String[] paramTypes,
boolean[] paramIsBag, String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = false;
this.paramTypes = paramTypes;
this.paramsAreBags = paramIsBag;
}
/**
* Constructor that sets up some basic values for functions that will take care of parameter
* checking on their own. If you use this constructor for your function class, then you must
* override the two check methods to make sure that parameters are correct.
*
* @param functionName
* the name of this function as used by the factory and any XACML policies
* @param functionId
* an optional identifier that can be used by your code for convenience
* @param returnType
* the type returned by this function, as used by the factory and any XACML documents
* @param returnsBag
* whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String returnType, boolean returnsBag) {
this.functionName = functionName;
this.functionId = functionId;
this.returnType = returnType;
this.returnsBag = returnsBag;
}
/**
* Returns the full identifier of this function, as known by the factories.
*
* @return the function's identifier
*
* @throws IllegalArgumentException
* if the identifier isn't a valid URI
*/
public URI getIdentifier() {
// this is to get around the exception handling problems, but may
// change if this code changes to include exceptions from the
// constructors
try {
return new URI(functionName);
} catch (URISyntaxException use) {
throw new IllegalArgumentException("invalid URI");
}
}
/**
* Returns the name of the function to be handled by this particular object.
*
* @return the function name
*/
public String getFunctionName() {
return functionName;
}
/**
* Returns the Identifier of the function to be handled by this particular object.
*
* @return the function Id
*/
public int getFunctionId() {
return functionId;
}
/**
* Returns the same value as <code>getReturnType</code>. This is here to support the
* <code>Expression</code> interface.
*
* @return the return type
*/
public URI getType() {
return getReturnType();
}
/**
* Get the attribute type returned by this function.
*
* @return a <code>URI</code> indicating the attribute type returned by this function
*/
public URI getReturnType() {
try {
return new URI(returnType);
} catch (Exception e) {
return null;
}
}
/**
* Returns true if this function returns a bag of values.
*
* @return true if the function returns a bag, false otherwise
*/
public boolean returnsBag() {
return returnsBag;
}
/**
* Returns the return type for this particular object.
*
* @return the return type
*/
public String getReturnTypeAsString() {
return returnType;
}
/**
* Create an <code>EvaluationResult</code> that indicates a processing error with the specified
* message. This method may be useful to subclasses.
*
* @param message
* a description of the error (<code>null</code> if none)
* @return the desired <code>EvaluationResult</code>
*/
protected static EvaluationResult makeProcessingError(String message) {
// Build up the processing error Status.
if (processingErrList == null) {
String[] errStrings = { Status.STATUS_PROCESSING_ERROR };
processingErrList = Arrays.asList(errStrings);
}
Status errStatus = new Status(processingErrList, message);
EvaluationResult processingError = new EvaluationResult(errStatus);
return processingError;
}
/**
* Evaluates each of the parameters, in order, filling in the argument array with the resulting
* values. If any error occurs, this method returns the error, otherwise null is returned,
* signalling that evaluation was successful for all inputs, and the resulting argument list can
* be used.
*
* @param params
* a <code>List</code> of <code>Evaluatable</code> objects representing the
* parameters to evaluate
* @param context
* the representation of the request
* @param args
* an array as long as the params <code>List</code> that will, on return, contain the
* <code>AttributeValue</code>s generated from evaluating all parameters
*
* @return <code>null</code> if no errors were encountered, otherwise an
* <code>EvaluationResult</code> representing the error
*/
protected EvaluationResult evalArgs(List<? extends Expression> params, EvaluationCtx context,
AttributeValue[] args) {
Iterator<? extends Expression> it = params.iterator();
int index = 0;
while (it.hasNext()) {
// get and evaluate the next parameter
Evaluatable eval = (Evaluatable) (it.next());
EvaluationResult result = eval.evaluate(context);
// If there was an error, pass it back...
if (result.indeterminate())
return result;
// ...otherwise save it and keep going
args[index++] = result.getAttributeValue();
}
// if no error occurred then we got here, so we return no errors
return null;
}
/**
* Default handling of input checking. This does some simple checking based on the type of
* constructor used. If you need anything more complex, or if you used the simple constructor,
* then you must override this method.
*
* @param inputs
* a <code>List></code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException
* if the inputs won't work
*/
public void checkInputs(List<? extends Expression> inputs) throws IllegalArgumentException {
// first off, see what kind of function we are
if (singleType) {
// first, check the length of the inputs, if appropriate
if (numParams != -1) {
if (inputs.size() != numParams)
throw new IllegalArgumentException("wrong number of args" + " to "
+ functionName);
} else {
if (inputs.size() < minParams)
throw new IllegalArgumentException("not enough args" + " to " + functionName);
}
// now, make sure everything is of the same, correct type
Iterator<? extends Expression> it = inputs.iterator();
while (it.hasNext()) {
Evaluatable eval = (Evaluatable) (it.next());
if ((!eval.getType().toString().equals(paramType))
|| (eval.returnsBag() != paramIsBag))
throw new IllegalArgumentException("illegal parameter");
}
} else {
// first, check the length of the inputs
if (paramTypes.length != inputs.size())
throw new IllegalArgumentException("wrong number of args" + " to " + functionName);
// now, make sure everything is of the same, correct type
Iterator<? extends Expression> it = inputs.iterator();
int i = 0;
while (it.hasNext()) {
Evaluatable eval = (Evaluatable) (it.next());
if ((!eval.getType().toString().equals(paramTypes[i]))
|| (eval.returnsBag() != paramsAreBags[i]))
throw new IllegalArgumentException("illegal parameter");
i++;
}
}
}
/**
* Default handling of input checking. This does some simple checking based on the type of
* constructor used. If you need anything more complex, or if you used the simple constructor,
* then you must override this method.
*
* @param inputs
* a <code>List></code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException
* if the inputs won't work
*/
public void checkInputsNoBag(List<? extends Expression> inputs) throws IllegalArgumentException {
// first off, see what kind of function we are
if (singleType) {
// first check to see if we need bags
if (paramIsBag)
throw new IllegalArgumentException(functionName + "needs" + "bags on input");
// now check on the length
if (numParams != -1) {
if (inputs.size() != numParams)
throw new IllegalArgumentException("wrong number of args" + " to "
+ functionName);
} else {
if (inputs.size() < minParams)
throw new IllegalArgumentException("not enough args" + " to " + functionName);
}
// finally check param list
Iterator<? extends Expression> it = inputs.iterator();
while (it.hasNext()) {
Evaluatable eval = (Evaluatable) (it.next());
if (!eval.getType().toString().equals(paramType))
throw new IllegalArgumentException("illegal parameter");
}
} else {
// first, check the length of the inputs
if (paramTypes.length != inputs.size())
throw new IllegalArgumentException("wrong number of args" + " to " + functionName);
// now, make sure everything is of the same, correct type
Iterator<? extends Expression> it = inputs.iterator();
int i = 0;
while (it.hasNext()) {
Evaluatable eval = (Evaluatable) (it.next());
if ((!eval.getType().toString().equals(paramTypes[i])) || (paramsAreBags[i]))
throw new IllegalArgumentException("illegal parameter");
i++;
}
}
}
/**
* Encodes this <code>FunctionBase</code> into its XML representation and writes this encoding
* to the given <code>OutputStream</code> with no indentation.
*
* @param output
* a stream into which the XML-encoded data is written
*/
public void encode(OutputStream output) {
encode(output, new Indenter(0));
}
/**
* Encodes this <code>FunctionBase</code> into its XML representation and writes this encoding
* to the given <code>OutputStream</code> with indentation.
*
* @param output
* a stream into which the XML-encoded data is written
* @param indenter
* an object that creates indentation strings
*/
public void encode(OutputStream output, Indenter indenter) {
PrintStream out = new PrintStream(output);
out.println(indenter.makeString() + "<Function FunctionId=\"" + getFunctionName() + "\"/>");
}
}