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java/javax/el/MapELResolver.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.beans.FeatureDescriptor;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+public class MapELResolver extends ELResolver {
+
+    private static final Class<?> UNMODIFIABLE =
+            Collections.unmodifiableMap(new HashMap<>()).getClass();
+
+    private final boolean readOnly;
+
+    public MapELResolver() {
+        this.readOnly = false;
+    }
+
+    public MapELResolver(boolean readOnly) {
+        this.readOnly = readOnly;
+    }
+
+    @Override
+    public Class<?> getType(ELContext context, Object base, Object property) {
+        Objects.requireNonNull(context);
+
+        if (base instanceof Map<?,?>) {
+            context.setPropertyResolved(base, property);
+            return Object.class;
+        }
+
+        return null;
+    }
+
+    @Override
+    public Object getValue(ELContext context, Object base, Object property) {
+        Objects.requireNonNull(context);
+
+        if (base instanceof Map<?,?>) {
+            context.setPropertyResolved(base, property);
+            return ((Map<?,?>) base).get(property);
+        }
+
+        return null;
+    }
+
+    @Override
+    public void setValue(ELContext context, Object base, Object property,
+            Object value) {
+        Objects.requireNonNull(context);
+
+        if (base instanceof Map<?, ?>) {
+            context.setPropertyResolved(base, property);
+
+            if (this.readOnly) {
+                throw new PropertyNotWritableException(Util.message(context,
+                        "resolverNotWriteable", base.getClass().getName()));
+            }
+
+            try {
+                @SuppressWarnings("unchecked") // Must be OK
+                Map<Object, Object> map = ((Map<Object, Object>) base);
+                map.put(property, value);
+            } catch (UnsupportedOperationException e) {
+                throw new PropertyNotWritableException(e);
+            }
+        }
+    }
+
+    @Override
+    public boolean isReadOnly(ELContext context, Object base, Object property) {
+        Objects.requireNonNull(context);
+
+        if (base instanceof Map<?, ?>) {
+            context.setPropertyResolved(base, property);
+            return this.readOnly || UNMODIFIABLE.equals(base.getClass());
+        }
+
+        return this.readOnly;
+    }
+
+    @Override
+    public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
+        if (base instanceof Map<?, ?>) {
+            Iterator<?> itr = ((Map<?, ?>) base).keySet().iterator();
+            List<FeatureDescriptor> feats = new ArrayList<>();
+            Object key;
+            FeatureDescriptor desc;
+            while (itr.hasNext()) {
+                key = itr.next();
+                desc = new FeatureDescriptor();
+                desc.setDisplayName(key.toString());
+                desc.setShortDescription("");
+                desc.setExpert(false);
+                desc.setHidden(false);
+                desc.setName(key.toString());
+                desc.setPreferred(true);
+                desc.setValue(RESOLVABLE_AT_DESIGN_TIME, Boolean.TRUE);
+                desc.setValue(TYPE, key.getClass());
+                feats.add(desc);
+            }
+            return feats.iterator();
+        }
+        return null;
+    }
+
+    @Override
+    public Class<?> getCommonPropertyType(ELContext context, Object base) {
+        if (base instanceof Map<?, ?>) {
+            return Object.class;
+        }
+        return null;
+    }
+
+}