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java/javax/el/StandardELContext.java

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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.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @since EL 3.0
+ */
+public class StandardELContext extends ELContext {
+
+    private final ELContext wrappedContext;
+    private final VariableMapper variableMapper;
+    private final FunctionMapper functionMapper;
+    private final CompositeELResolver standardResolver;
+    private final CompositeELResolver customResolvers;
+    private final Map<String,Object> localBeans = new HashMap<>();
+
+
+    public StandardELContext(ExpressionFactory factory) {
+        wrappedContext = null;
+        variableMapper = new StandardVariableMapper();
+        functionMapper =
+                new StandardFunctionMapper(factory.getInitFunctionMap());
+        standardResolver = new CompositeELResolver();
+        customResolvers = new CompositeELResolver();
+
+        ELResolver streamResolver = factory.getStreamELResolver();
+
+        // Add resolvers in order
+        standardResolver.add(new BeanNameELResolver(
+                new StandardBeanNameResolver(localBeans)));
+        standardResolver.add(customResolvers);
+        if (streamResolver != null) {
+            standardResolver.add(streamResolver);
+        }
+        standardResolver.add(new StaticFieldELResolver());
+        standardResolver.add(new MapELResolver());
+        standardResolver.add(new ResourceBundleELResolver());
+        standardResolver.add(new ListELResolver());
+        standardResolver.add(new ArrayELResolver());
+        standardResolver.add(new BeanELResolver());
+    }
+
+    public StandardELContext(ELContext context) {
+        wrappedContext = context;
+        variableMapper = context.getVariableMapper();
+        functionMapper = context.getFunctionMapper();
+        standardResolver = new CompositeELResolver();
+        customResolvers = new CompositeELResolver();
+
+        // Add resolvers in order
+        standardResolver.add(new BeanNameELResolver(
+                new StandardBeanNameResolver(localBeans)));
+        standardResolver.add(customResolvers);
+        // Use resolvers from context from this point on
+        standardResolver.add(context.getELResolver());
+    }
+
+    // Can't use Class<?> because API needs to match specification
+    @Override
+    public void putContext(@SuppressWarnings("rawtypes") Class key,
+            Object contextObject) {
+        if (wrappedContext == null) {
+            super.putContext(key, contextObject);
+        } else {
+            wrappedContext.putContext(key, contextObject);
+        }
+    }
+
+    @Override
+    public Object getContext(@SuppressWarnings("rawtypes") Class key) {
+        if (wrappedContext == null) {
+            return super.getContext(key);
+        } else {
+            return wrappedContext.getContext(key);
+        }
+    }
+
+    @Override
+    public ELResolver getELResolver() {
+        return standardResolver;
+    }
+
+    public void addELResolver(ELResolver resolver) {
+        customResolvers.add(resolver);
+    }
+
+    @Override
+    public FunctionMapper getFunctionMapper() {
+        return functionMapper;
+    }
+
+    @Override
+    public VariableMapper getVariableMapper() {
+        return variableMapper;
+    }
+
+
+    Map<String,Object> getLocalBeans() {
+        return localBeans;
+    }
+
+
+    private static class StandardVariableMapper extends VariableMapper {
+
+        private Map<String, ValueExpression> vars;
+
+        @Override
+        public ValueExpression resolveVariable(String variable) {
+            if (vars == null) {
+                return null;
+            }
+            return vars.get(variable);
+        }
+
+        @Override
+        public ValueExpression setVariable(String variable,
+                ValueExpression expression) {
+            if (vars == null)
+                vars = new HashMap<>();
+            if (expression == null) {
+                return vars.remove(variable);
+            } else {
+                return vars.put(variable, expression);
+            }
+        }
+    }
+
+
+    private static class StandardBeanNameResolver extends BeanNameResolver {
+
+        private final Map<String,Object> beans;
+
+        public StandardBeanNameResolver(Map<String,Object> beans) {
+            this.beans = beans;
+        }
+
+        @Override
+        public boolean isNameResolved(String beanName) {
+            return beans.containsKey(beanName);
+        }
+
+        @Override
+        public Object getBean(String beanName) {
+            return beans.get(beanName);
+        }
+
+        @Override
+        public void setBeanValue(String beanName, Object value)
+                throws PropertyNotWritableException {
+            beans.put(beanName, value);
+        }
+
+        @Override
+        public boolean isReadOnly(String beanName) {
+            return false;
+        }
+
+        @Override
+        public boolean canCreateBean(String beanName) {
+            return true;
+        }
+    }
+
+
+    private static class StandardFunctionMapper extends FunctionMapper {
+
+        private final Map<String,Method> methods = new HashMap<>();
+
+        public StandardFunctionMapper(Map<String,Method> initFunctionMap) {
+            if (initFunctionMap != null) {
+                methods.putAll(initFunctionMap);
+            }
+        }
+
+        @Override
+        public Method resolveFunction(String prefix, String localName) {
+            String key = prefix + ':' + localName;
+            return methods.get(key);
+        }
+
+        @Override
+        public void mapFunction(String prefix, String localName,
+                Method method) {
+            String key = prefix + ':' + localName;
+            if (method == null) {
+                methods.remove(key);
+            } else {
+                methods.put(key, method);
+            }
+        }
+    }
+}