94 lines
3.1 KiB
Java
94 lines
3.1 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package javax.el;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Objects;
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public class LambdaExpression {
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private final List<String> formalParameters;
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private final ValueExpression expression;
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private final Map<String,Object> nestedArguments = new HashMap<>();
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private ELContext context = null;
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public LambdaExpression(List<String> formalParameters,
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ValueExpression expression) {
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this.formalParameters = formalParameters;
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this.expression = expression;
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}
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public void setELContext(ELContext context) {
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this.context = context;
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}
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@SuppressWarnings("null") // args[i] can't be null due to earlier checks
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public Object invoke(ELContext context, Object... args)
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throws ELException {
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Objects.requireNonNull(context);
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int formalParamCount = 0;
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if (formalParameters != null) {
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formalParamCount = formalParameters.size();
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}
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int argCount = 0;
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if (args != null) {
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argCount = args.length;
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}
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if (formalParamCount > argCount) {
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throw new ELException(Util.message(context,
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"lambdaExpression.tooFewArgs",
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Integer.valueOf(argCount),
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Integer.valueOf(formalParamCount)));
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}
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// Build the argument map
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// Start with the arguments from any outer expressions so if there is
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// any overlap the local arguments have priority
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Map<String,Object> lambdaArguments = new HashMap<>();
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lambdaArguments.putAll(nestedArguments);
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for (int i = 0; i < formalParamCount; i++) {
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lambdaArguments.put(formalParameters.get(i), args[i]);
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}
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context.enterLambdaScope(lambdaArguments);
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try {
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Object result = expression.getValue(context);
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// Make arguments from this expression available to any nested
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// expression
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if (result instanceof LambdaExpression) {
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((LambdaExpression) result).nestedArguments.putAll(
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lambdaArguments);
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}
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return result;
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} finally {
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context.exitLambdaScope();
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}
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}
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public java.lang.Object invoke(Object... args) {
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return invoke (context, args);
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}
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}
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