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Java GUI Resource and Application Framework with Form Extensions
/*
* Copyright 2006-2010 The JGUIraffe Team.
*
* Licensed 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 net.sf.jguiraffe.di.impl;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import net.sf.jguiraffe.di.BeanProvider;
import net.sf.jguiraffe.di.BeanStore;
import net.sf.jguiraffe.di.ConversionHelper;
import net.sf.jguiraffe.di.MutableBeanStore;
import org.apache.commons.lang.ObjectUtils;
/**
*
* A simple yet fully functional default implementation of the
* BeanStore interface.
*
*
* This implementation is based on a HashMap.
* BeanProvider objects can be added to this map using the
* addBeanProvider() method. They can then be queried through the
* getBeanProvider method.
*
*
* Note: This implementation is not thread-safe. The underlying map is not
* synchronized. This does not cause any problems when used read-only by the
* dependency injection framework. But if bean providers should be concurrently
* added or other properties are to be manipulated, manual synchronization is
* required. The intended use case is that an instance is created and populated
* with {@link BeanProvider} objects in an initialization phase. Then it should
* only be accessed in a read-only fashion by the dependency injection
* framework.
*
*
* @author Oliver Heger
* @version $Id: DefaultBeanStore.java 192 2010-08-22 16:15:22Z oheger $
*/
public class DefaultBeanStore implements MutableBeanStore
{
/** Constant for the prefix used for anonymous bean providers. */
private static final String PREFIX_ANONYMOUS = "_jguiraffe.anonymousBean_";
/** A map with the contained bean providers. */
private final Map providers;
/** Stores the parent store. */
private BeanStore parent;
/** The conversion helper associated with this bean store. */
private ConversionHelper conversionHelper;
/** Stores the name of this bean store. */
private String name;
/**
* Creates a new instance of DefaultBeanStore.
*/
public DefaultBeanStore()
{
providers = new HashMap();
}
/**
* Creates a new instance of DefaultBeanStore and sets the name
* and the reference to the parent.
*
* @param name the name of this bean store
* @param parent the reference to the parent bean store
*/
public DefaultBeanStore(String name, BeanStore parent)
{
this();
setName(name);
setParent(parent);
}
/**
* Returns the {@code ConversionHelper} associated with this object.
*
* @return the {@code ConversionHelper}
*/
public ConversionHelper getConversionHelper()
{
return conversionHelper;
}
/**
* Sets the {@code ConversionHelper} object to be associated with this
* instance. The object passed to this method is returned by
* {@link #getConversionHelper()}.
*
* @param conversionHelper the {@code ConversionHelper} object
*/
public void setConversionHelper(ConversionHelper conversionHelper)
{
this.conversionHelper = conversionHelper;
}
/**
* A convenience method for retrieving a {@code ConversionHelper} object
* from a hierarchy of bean stores. This method queries the specified
* {@code BeanStore} for its {@code ConversionHelper}. If it has one, the
* helper object is returned. Otherwise, the parent {@code BeanStore} is
* queried. This continues until a {@code ConversionHelper} object is found
* or the top of the hierarchy is reached. If no {@code ConversionHelper}
* can be found and the {@code createIfNecessary} flag is true, a new
* default helper object is created. Otherwise, the method returns
* null if no helper can be found.
*
* @param store the {@code BeanStore} where to start the search
* @param createIfNecessary a flag whether a default helper instance should
* be created if none can be found
* @return the found {@code ConversionHelper} or null
*/
public static ConversionHelper fetchConversionHelper(BeanStore store,
boolean createIfNecessary)
{
BeanStore currentStore = store;
while (currentStore != null)
{
ConversionHelper ch = currentStore.getConversionHelper();
if (ch != null)
{
return ch;
}
currentStore = currentStore.getParent();
}
return createIfNecessary ? new ConversionHelper() : null;
}
/**
* Adds the specified BeanProvider to this bean store under the
* given name.
*
* @param name the name of the bean provider (must not be null)
* @param provider the BeanProvider to be registered
* @throws IllegalArgumentException if the name or the provider is
* null
*/
public void addBeanProvider(String name, BeanProvider provider)
{
if (name == null)
{
throw new IllegalArgumentException(
"Name of bean provider must not be null!");
}
if (provider == null)
{
throw new IllegalArgumentException(
"Bean providern must not be null!");
}
providers.put(name, provider);
}
/**
* Adds an anonymous BeanProvider. This method will generate a
* special name (which is mainly used internally) for the bean provider to
* add and store it under this name. The name is returned.
*
* @param index the index of the bean provider
* @param provider the BeanProvider to be added (must not be
* null)
* @return the name used for this BeanProvider
* @throws IllegalArgumentException if the provider is null
*/
public String addAnonymousBeanProvider(int index, BeanProvider provider)
{
String name = PREFIX_ANONYMOUS + index;
addBeanProvider(name, provider);
return name;
}
/**
* Removes the BeanProvider with the specified name from this
* bean store. If this provider cannot be found, this operation has no
* effect.
*
* @param name the name of the provider to remove
* @return a reference to the removed provider or null if it could
* not be found
*/
public BeanProvider removeBeanProvider(String name)
{
return providers.remove(name);
}
/**
* Removes all BeanProviders from this bean store.
*/
public void clear()
{
providers.clear();
}
/**
* Returns the BeanProvider with the specified name. If no such
* element exists, null is returned.
*
* @param name the name of the desired provider
* @return the BeanProvider with this name
*/
public BeanProvider getBeanProvider(String name)
{
return providers.get(name);
}
/**
* Returns the name of this bean store.
*
* @return the name of this bean store
*/
public String getName()
{
return name;
}
/**
* Sets the name of this bean store.
*
* @param n the new name
*/
public void setName(String n)
{
name = n;
}
/**
* Returns the parent of this bean store or null if this is a top
* level store.
*
* @return the parent of this bean store
*/
public BeanStore getParent()
{
return parent;
}
/**
* Sets the parent for this bean store.
*
* @param p the parent
*/
public void setParent(BeanStore p)
{
parent = p;
}
/**
* Returns a set with the names of all contained bean providers. This
* implementation ensures that the names of anonymous bean providers do not
* appear in the set returned.
*
* @return the names of the registered bean providers
*/
public Set providerNames()
{
Set names = new HashSet(providers.keySet());
// remove names of anonymous providers
for (Iterator it = names.iterator(); it.hasNext();)
{
if (it.next().startsWith(PREFIX_ANONYMOUS))
{
it.remove();
}
}
return Collections.unmodifiableSet(names);
}
/**
* Returns a string representation of this object. This implementation
* returns a string listing all bean providers that belong to this store.
*
* @return a string for this object
*/
@Override
public String toString()
{
StringBuilder buf =
new StringBuilder(ObjectUtils.identityToString(this));
buf.append("[ name = ").append(getName());
buf.append(" providers = { ");
boolean first = true;
for (Map.Entry e : providers.entrySet())
{
if (first)
{
first = false;
}
else
{
buf.append(", ");
}
buf.append(e.getKey()).append(" = ").append(e.getValue());
}
buf.append(" } ]");
return buf.toString();
}
}
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