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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 javax.el;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
public class LambdaExpression {
private final List<String> formalParameters;
private final ValueExpression expression;
private final Map<String,Object> nestedArguments = new HashMap<>();
private ELContext context = null;
public LambdaExpression(List<String> formalParameters,
ValueExpression expression) {
this.formalParameters = formalParameters;
this.expression = expression;
}
public void setELContext(ELContext context) {
this.context = context;
}
@SuppressWarnings("null") // args[i] can't be null due to earlier checks
public Object invoke(ELContext context, Object... args)
throws ELException {
Objects.requireNonNull(context);
int formalParamCount = 0;
if (formalParameters != null) {
formalParamCount = formalParameters.size();
}
int argCount = 0;
if (args != null) {
argCount = args.length;
}
if (formalParamCount > argCount) {
throw new ELException(Util.message(context,
"lambdaExpression.tooFewArgs",
Integer.valueOf(argCount),
Integer.valueOf(formalParamCount)));
}
// Build the argument map
// Start with the arguments from any outer expressions so if there is
// any overlap the local arguments have priority
Map<String,Object> lambdaArguments = new HashMap<>();
lambdaArguments.putAll(nestedArguments);
for (int i = 0; i < formalParamCount; i++) {
lambdaArguments.put(formalParameters.get(i), args[i]);
}
context.enterLambdaScope(lambdaArguments);
try {
Object result = expression.getValue(context);
// Make arguments from this expression available to any nested
// expression
if (result instanceof LambdaExpression) {
((LambdaExpression) result).nestedArguments.putAll(
lambdaArguments);
}
return result;
} finally {
context.exitLambdaScope();
}
}
public java.lang.Object invoke(Object... args) {
return invoke (context, args);
}
}
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