DynamicMapLikeFacade.java

/*
 * 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 org.apache.felix.converter.impl;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.Dictionary;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import org.osgi.util.converter.ConversionException;

abstract class DynamicMapLikeFacade<K, V> implements Map<K, V> {
    protected final ConvertingImpl convertingImpl;

    protected DynamicMapLikeFacade(ConvertingImpl convertingImpl) {
        this.convertingImpl = convertingImpl;
    }

    @Override
    public int size() {
        return keySet().size();
    }

    @Override
    public boolean isEmpty() {
        return size() == 0;
    }

    @Override
    public boolean containsKey(Object key) {
        return keySet().contains(key);
    }

    @Override
    public boolean containsValue(Object value) {
        for (Entry<K, V> entry : entrySet()) {
            if (value == null) {
                if (entry.getValue() == null) {
                    return true;
                }
            } else if (value.equals(entry.getValue())) {
                return true;
            }
        }
        return false;
    }

    @Override
    public V put(K key, V value) {
        // Should never be called; the delegate should swap to a copy in this case
        throw new UnsupportedOperationException();
    }

    @Override
    public V remove(Object key) {
        // Should never be called; the delegate should swap to a copy in this case
        throw new UnsupportedOperationException();
    }

    @Override
    public void putAll(Map<? extends K, ? extends V> m) {
        // Should never be called; the delegate should swap to a copy in this case
        throw new UnsupportedOperationException();
    }

    @Override
    public void clear() {
        // Should never be called; the delegate should swap to a copy in this case
        throw new UnsupportedOperationException();
    }

    @Override
    public Collection<V> values() {
        return entrySet().stream().map(Entry::getValue).collect(Collectors.toList());
    }

    @Override
    public Set<Entry<K, V>> entrySet() {
        Set<K> ks = keySet();

        Set<Entry<K, V>> res = new LinkedHashSet<>(ks.size());

        for (K k : ks) {
            V v = get(k);
            res.add(new MapDelegate.MapEntry<K,V>(k, v));
        }
        return res;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();

        sb.append('{');
        boolean first = true;
        for (Map.Entry<K, V> entry : entrySet()) {
            if (first)
                first = false;
            else
                sb.append(", ");

            sb.append(entry.getKey());
            sb.append('=');
            sb.append(entry.getValue());
        }
        sb.append('}');

        return sb.toString();
    }
}

class DynamicBeanFacade extends DynamicMapLikeFacade<String,Object> {
    private Map <String, Method> keys = null;
    private final Object backingObject;

    DynamicBeanFacade(Object backingObject, ConvertingImpl convertingImpl) {
        super(convertingImpl);
        this.backingObject = backingObject;
    }

    @Override
    public Object get(Object key) {
        Method m = getKeys().get(key);
        try {
            return m.invoke(backingObject);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public Set<String> keySet() {
        return getKeys().keySet();
    }

    private Map<String, Method> getKeys() {
        if (keys == null)
            keys = Util.getBeanKeys(convertingImpl.sourceClass);

        return keys;
    }
}

class DynamicDictionaryFacade<K,V> extends DynamicMapLikeFacade<K,V> {
    private final Dictionary<K, V> backingObject;

    DynamicDictionaryFacade(Dictionary<K, V> backingObject, ConvertingImpl convertingImpl) {
        super(convertingImpl);
        this.backingObject = backingObject;
    }

    @Override
    public V get(Object key) {
        return backingObject.get(key);
    }

    @Override
    public Set<K> keySet() {
        return new HashSet<>(Collections.list(backingObject.keys()));
    }
}

class DynamicMapFacade<K,V> extends DynamicMapLikeFacade<K,V> {
    private final Map<K, V> backingObject;

    DynamicMapFacade(Map<K,V> backingObject, ConvertingImpl convertingImpl) {
        super(convertingImpl);
        this.backingObject = backingObject;
    }

    @Override
    public V get(Object key) {
        return backingObject.get(key);
    }

    @Override
    public Set<K> keySet() {
        Map<K, V> m = backingObject;
        return m.keySet();
    }
}

class DynamicDTOFacade extends DynamicMapLikeFacade<String, Object> {
    private Map <String, Field> keys = null;
    private final Object backingObject;

    DynamicDTOFacade(Object backingObject, ConvertingImpl converting) {
        super(converting);
        this.backingObject = backingObject;
    }

    @Override
    public Object get(Object key) {
        Field f = getKeys().get(key);
        if (f == null)
            return null;

        try {
            return f.get(backingObject);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public Set<String> keySet() {
        return getKeys().keySet();
    }

    private Map<String, Field> getKeys() {
        if (keys == null)
            keys = Util.getDTOKeys(convertingImpl.sourceClass);

        return keys;
    }
}

class DynamicInterfaceFacade extends DynamicMapLikeFacade<String, Object> {
    private Map <String, Set<Method>> keys = null;
    private final Object backingObject;

    DynamicInterfaceFacade(Object backingObject, ConvertingImpl convertingImpl) {
        super(convertingImpl);
        this.backingObject = backingObject;
    }

    @Override
    public Object get(Object key) {
        Set<Method> set = getKeys().get(key);
        for (Iterator<Method> iterator = set.iterator();iterator.hasNext();) {
            Method m = iterator.next();
            if (m.getParameterCount() > 0)
                continue;
            try {
                return m.invoke(backingObject);
            } catch (Exception e) {
            	if (RuntimeException.class.isAssignableFrom(e.getCause().getClass()))
        			throw ((RuntimeException) e.getCause());
                throw new RuntimeException(e);
            }
        }
        throw new ConversionException("Missing no-arg method for key: " + key);
    }

    @Override
    public Set<String> keySet() {
        return getKeys().keySet();
    }

    private Map<String, Set<Method>> getKeys() {
        if (keys == null)
            keys = Util.getInterfaceKeys(convertingImpl.sourceClass, backingObject);

        return keys;
    }
}