FreeMarker代码分析第八篇

2021SC@SDUSC

• servlet包
• • AllHttpScopesHashModel.java
  • • 代码分析
  • HttpRequestHashModel
  • • 代码分析
  • HttpRequestParametersHashModel.java
  • • 代码分析
  • HttpSessionHashModel.java
  • • 代码分析

package freemarker.ext.servlet;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import freemarker.template.ObjectWrapper;
import freemarker.template.SimpleHash;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.utility.NullArgumentException;


public class AllHttpScopesHashModel extends SimpleHash {
    private final ServletContext context;
    private final HttpServletRequest request;
    private final Map unlistedModels = new HashMap();
     
    
    public AllHttpScopesHashModel(ObjectWrapper objectWrapper,
            ServletContext context, HttpServletRequest request) {
        super(objectWrapper);
        NullArgumentException.check("wrapper", objectWrapper);
        this.context = context;
        this.request = request;
    }
    
    
    public void putUnlistedModel(String key, TemplateModel model) {
        unlistedModels.put(key, model);
    }

    @Override
    public TemplateModel get(String key) throws TemplateModelException {
        // Lookup in page scope
        TemplateModel model = super.get(key);
        if (model != null) {
            return model;
        }

        // Look in unlisted models
        model = (TemplateModel) unlistedModels.get(key);
        if (model != null) {
            return model;
        }
        
        // Lookup in request scope
        Object obj = request.getAttribute(key);
        if (obj != null) {
            return wrap(obj);
        }

        // Lookup in session scope
        HttpSession session = request.getSession(false);
        if (session != null) {
            obj = session.getAttribute(key);
            if (obj != null) {
                return wrap(obj);
            }
        }

        // Lookup in application scope
        obj = context.getAttribute(key);
        if (obj != null) {
            return wrap(obj);
        }

        // return wrapper's null object (probably null).        
        return wrap(null);
    }
}

package freemarker.ext.servlet;

import java.util.ArrayList;
import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import freemarker.template.ObjectWrapper;
import freemarker.template.ObjectWrapperAndUnwrapper;
import freemarker.template.SimpleCollection;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;


public final class HttpRequestHashModel implements TemplateHashModelEx {
    private final HttpServletRequest request;
    private final HttpServletResponse response;
    private final ObjectWrapper wrapper;

    
    public HttpRequestHashModel(
        HttpServletRequest request, ObjectWrapper wrapper) {
        this(request, null, wrapper);
    }

    public HttpRequestHashModel(
        HttpServletRequest request, HttpServletResponse response, 
        ObjectWrapper wrapper) {
        this.request = request;
        this.response = response;
        this.wrapper = wrapper;
    }
    
    @Override
    public TemplateModel get(String key) throws TemplateModelException {
        return wrapper.wrap(request.getAttribute(key));
    }

    @Override
    public boolean isEmpty() {
        return !request.getAttributeNames().hasMoreElements();
    }
    
    @Override
    public int size() {
        int result = 0;
        for (Enumeration enumeration = request.getAttributeNames(); enumeration.hasMoreElements(); ) {
            enumeration.nextElement();
            ++result;
        }
        return result;
    }
    
    @Override
    public TemplateCollectionModel keys() {
        ArrayList keys = new ArrayList();
        for (Enumeration enumeration = request.getAttributeNames(); enumeration.hasMoreElements(); ) {
            keys.add(enumeration.nextElement());
        }
        return new SimpleCollection(keys.iterator());
    }
    
    @Override
    public TemplateCollectionModel values() {
        ArrayList values = new ArrayList();
        for (Enumeration enumeration = request.getAttributeNames(); enumeration.hasMoreElements(); ) {
            values.add(request.getAttribute((String) enumeration.nextElement()));
        }
        return new SimpleCollection(values.iterator(), wrapper);
    }

    public HttpServletRequest getRequest() {
        return request;
    }
    
    public HttpServletResponse getResponse() {
        return response;
    }
    
    public ObjectWrapper getObjectWrapper() {
        return wrapper;
    }
}

package freemarker.ext.servlet;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import freemarker.template.SimpleCollection;
import freemarker.template.SimpleScalar;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;



public class HttpRequestParametersHashModel
    implements
    TemplateHashModelEx {
    private final HttpServletRequest request;
    private List keys;
        
    public HttpRequestParametersHashModel(HttpServletRequest request) {
        this.request = request;
    }

    @Override
    public TemplateModel get(String key) {
        String value = request.getParameter(key);
        return value == null ? null : new SimpleScalar(value);
    }

    @Override
    public boolean isEmpty() {
        return !request.getParameterNames().hasMoreElements();
    }
    
    @Override
    public int size() {
        return getKeys().size();
    }
    
    @Override
    public TemplateCollectionModel keys() {
        return new SimpleCollection(getKeys().iterator());
    }
    
    @Override
    public TemplateCollectionModel values() {
        final Iterator iter = getKeys().iterator();
        return new SimpleCollection(
            new Iterator() {
                @Override
                public boolean hasNext() {
                    return iter.hasNext();
                }
                @Override
                public Object next() {
                    return request.getParameter((String) iter.next()); 
                }
                @Override
                public void remove() {
                    throw new UnsupportedOperationException();
                }
            });
    }

    protected String transcode(String string) {
        return string;
    }

    private synchronized List getKeys() {
        if (keys == null) {
            keys = new ArrayList();
            for (Enumeration enumeration = request.getParameterNames(); enumeration.hasMoreElements(); ) {
                keys.add(enumeration.nextElement());
            }
        }
        return keys;
    }
}

package freemarker.ext.servlet;

import java.io.Serializable;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import freemarker.template.ObjectWrapper;
import freemarker.template.TemplateHashModel;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;



public final class HttpSessionHashModel implements TemplateHashModel, Serializable {
    private static final long serialVersionUID = 1L;
    private transient HttpSession session;
    private transient final ObjectWrapper wrapper;

    // These are required for lazy initializing session
    private transient final FreemarkerServlet servlet;
    private transient final HttpServletRequest request;
    private transient final HttpServletResponse response;
    
    
    public HttpSessionHashModel(HttpSession session, ObjectWrapper wrapper) {
        this.session = session;
        this.wrapper = wrapper;

        this.servlet = null;
        this.request = null;
        this.response = null;
    }

    
    public HttpSessionHashModel(FreemarkerServlet servlet, HttpServletRequest request, HttpServletResponse response, ObjectWrapper wrapper) {
        this.wrapper = wrapper;
        
        this.servlet = servlet;
        this.request = request;
        this.response = response;
    }

    @Override
    public TemplateModel get(String key) throws TemplateModelException {
        checkSessionExistence();
        return wrapper.wrap(session != null ? session.getAttribute(key) : null);
    }

    private void checkSessionExistence() throws TemplateModelException {
        if (session == null && request != null) {
            session = request.getSession(false);
            if (session != null && servlet != null) {
                try {
                    servlet.initializeSessionAndInstallModel(request, response, 
                            this, session);
                } catch (RuntimeException e) {
                    throw e;
                } catch (Exception e) {
                    throw new TemplateModelException(e);
                }
            }
        }
    }

    boolean isOrphaned(HttpSession currentSession) {
        return (session != null && session != currentSession) || 
            (session == null && request == null);
    }
    
    @Override
    public boolean isEmpty()
    throws TemplateModelException {
        checkSessionExistence();
        return session == null || !session.getAttributeNames().hasMoreElements();
    }
}