/**
*
*/
package org.springframework.security.access.expression.method;
import java.util.Collection;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.security.access.expression.ExpressionUtils;
import org.springframework.security.access.prepost.PreInvocationAttribute;
import org.springframework.security.access.prepost.PreInvocationAuthorizationAdvice;
import org.springframework.security.core.Authentication;
/**
* Method pre-invocation handling based on expressions.
*
* @author Luke Taylor
* @since 3.0
*/
public class ExpressionBasedPreInvocationAdvice implements PreInvocationAuthorizationAdvice {
private MethodSecurityExpressionHandler expressionHandler = new DefaultMethodSecurityExpressionHandler();
public boolean before(Authentication authentication, MethodInvocation mi, PreInvocationAttribute attr) {
PreInvocationExpressionAttribute preAttr = (PreInvocationExpressionAttribute) attr;
EvaluationContext ctx = expressionHandler.createEvaluationContext(authentication, mi);
Expression preFilter = preAttr.getFilterExpression();
Expression preAuthorize = preAttr.getAuthorizeExpression();
if (preFilter != null) {
Object filterTarget = findFilterTarget(preAttr.getFilterTarget(), ctx, mi);
expressionHandler.filter(filterTarget, preFilter, ctx);
}
if (preAuthorize == null) {
return true;
}
return ExpressionUtils.evaluateAsBoolean(preAuthorize, ctx);
}
private Object findFilterTarget(String filterTargetName, EvaluationContext ctx, MethodInvocation mi) {
Object filterTarget = null;
if (filterTargetName.length() > 0) {
filterTarget = ctx.lookupVariable(filterTargetName);
if (filterTarget == null) {
throw new IllegalArgumentException("Filter target was null, or no argument with name "
+ filterTargetName + " found in method");
}
} else if (mi.getArguments().length == 1) {
Object arg = mi.getArguments()[0];
if (arg.getClass().isArray() || arg instanceof Collection<?>) {
filterTarget = arg;
}
if (filterTarget == null) {
throw new IllegalArgumentException("A PreFilter expression was set but the method argument type" +
arg.getClass() + " is not filterable");
}
}
if (filterTarget.getClass().isArray()) {
throw new IllegalArgumentException("Pre-filtering on array types is not supported. " +
"Using a Collection will solve this problem");
}
return filterTarget;
}
public void setExpressionHandler(MethodSecurityExpressionHandler expressionHandler) {
this.expressionHandler = expressionHandler;
}
}