如何将GWT Place URL从默认的":"更改为"/"？

Question

默认情况下,GWT Place URL包含Place的简单类名(如"HelloPlace"),后跟冒号(:)和PlaceTokenizer返回的标记.

我的问题是如何将":"改为"/"？

Answer 1

我刚刚创建了自己的PlaceHistoryMapper,它直接实现了接口,而不是使用AbstractPlaceHistoryMapper:

public class AppPlaceHistoryMapper implements PlaceHistoryMapper
{
    String delimiter = "/";

    @Override
    public Place getPlace(String token)
    {

        String[] tokens = token.split(delimiter, 2); 

            if (tokens[0].equals("HelloPlace"))
                 ...
    }

    @Override
    public String getToken(Place place)
    {
        if (place instanceof HelloPlace)
        {
            return "HelloPlace" + delimiter + whatever;
        }
        else ...
    }
}

这肯定是额外的代码编写,但你可以在一个地方控制你的url结构,并使用斜杠而不是冒号!

Answer 2

以下是如何在使用标准GWT位置时自定义分隔符.(PlaceHistoryMapper)

没有别的东西需要改变; 它适用于使用Places和Tokenizers的标准方法.

插入gwt.xml

 <generate-with
  class="com.google.gwt.place.rebind.CustomPlaceHistoryMapperGenerator">
  <when-type-assignable class="com.google.gwt.place.shared.PlaceHistoryMapper" />
 </generate-with>

添加CustomAbstractPlaceHistoryMapper

package com.siderakis.client.mvp;

import com.google.gwt.place.impl.AbstractPlaceHistoryMapper;
import com.google.gwt.place.shared.Place;
import com.google.gwt.place.shared.PlaceTokenizer;

public abstract class CustomAbstractPlaceHistoryMapper extends AbstractPlaceHistoryMapper {
 public final static String DELIMITER = "/";

 public static class CustomPrefixAndToken extends PrefixAndToken {
  public CustomPrefixAndToken(String prefix, String token) {
   super(prefix, token);
   assert prefix != null && !prefix.contains(DELIMITER);
  }

  @Override
  public String toString() {
   return (prefix.length() == 0) ? token : prefix + DELIMITER + token;
  }

 }

 @Override
 public Place getPlace(String token) {
  int colonAt = token.indexOf(DELIMITER);
  String initial;
  String rest;
  if (colonAt >= 0) {
   initial = token.substring(0, colonAt);
   rest = token.substring(colonAt + 1);
  } else {
   initial = "";
   rest = token;
  }
  PlaceTokenizer tokenizer = getTokenizer(initial);
  if (tokenizer != null) {
   return tokenizer.getPlace(rest);
  }
  return null;
 }

}

添加CustomPlaceHistoryMapperGenerator

/*
 * Copyright 2010 Google Inc.
 * 
 * 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 com.google.gwt.place.rebind;

import java.io.PrintWriter;

import com.siderakis.client.mvp.CustomAbstractPlaceHistoryMapper;
import com.siderakis.client.mvp.CustomAbstractPlaceHistoryMapper.CustomPrefixAndToken;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.ext.Generator;
import com.google.gwt.core.ext.GeneratorContext;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.core.ext.typeinfo.JMethod;
import com.google.gwt.place.shared.Place;
import com.google.gwt.place.shared.PlaceTokenizer;
import com.google.gwt.user.rebind.ClassSourceFileComposerFactory;
import com.google.gwt.user.rebind.SourceWriter;

/**
 * Generates implementations of
 * {@link com.google.gwt.place.shared.PlaceHistoryMapper PlaceHistoryMapper}.
 */
public class CustomPlaceHistoryMapperGenerator extends Generator {
  private PlaceHistoryGeneratorContext context;

  @Override
  public String generate(TreeLogger logger, GeneratorContext generatorContext,
      String interfaceName) throws UnableToCompleteException {

    context = PlaceHistoryGeneratorContext.create(logger,
        generatorContext.getTypeOracle(), interfaceName);

    if (context == null) {
      return null;
    }

    PrintWriter out = generatorContext.tryCreate(logger, context.packageName,
        context.implName);

    if (out != null) {
      generateOnce(generatorContext, context, out);
    }

    return context.packageName + "." + context.implName;
  }

  private void generateOnce(GeneratorContext generatorContext, PlaceHistoryGeneratorContext context,
      PrintWriter out) throws UnableToCompleteException {

    TreeLogger logger = context.logger.branch(TreeLogger.DEBUG, String.format(
        "Generating implementation of %s", context.interfaceType.getName()));
    ClassSourceFileComposerFactory f = new ClassSourceFileComposerFactory(
        context.packageName, context.implName);

    String superClassName = String.format("%s<%s>",
        CustomAbstractPlaceHistoryMapper.class.getSimpleName(),
        context.factoryType == null ? "Void" : context.factoryType.getName());
    f.setSuperclass(superClassName);
    f.addImplementedInterface(context.interfaceType.getName());

    f.addImport(CustomAbstractPlaceHistoryMapper.class.getName());
    f.addImport(context.interfaceType.getQualifiedSourceName());

    f.addImport(CustomAbstractPlaceHistoryMapper.class.getCanonicalName());
    if (context.factoryType != null) {
      f.addImport(context.factoryType.getQualifiedSourceName());
    }

    f.addImport(Place.class.getCanonicalName());
    f.addImport(PlaceTokenizer.class.getCanonicalName());
    f.addImport(CustomPrefixAndToken.class.getCanonicalName());

    f.addImport(GWT.class.getCanonicalName());

    SourceWriter sw = f.createSourceWriter(generatorContext, out);
    sw.println();

    writeGetPrefixAndToken(context, sw);
    sw.println();

    writeGetTokenizer(context, sw);
    sw.println();

    sw.outdent();
    sw.println("}");
    generatorContext.commit(logger, out);
  }

  private void writeGetPrefixAndToken(PlaceHistoryGeneratorContext context,
      SourceWriter sw) throws UnableToCompleteException {
    sw.println("protected CustomPrefixAndToken getPrefixAndToken(Place newPlace) {");
    sw.indent();
    for (JClassType placeType : context.getPlaceTypes()) {
      String placeTypeName = placeType.getQualifiedSourceName();
      String prefix = context.getPrefix(placeType);

      sw.println("if (newPlace instanceof " + placeTypeName + ") {");
      sw.indent();
      sw.println(placeTypeName + " place = (" + placeTypeName + ") newPlace;");

      JMethod getter = context.getTokenizerGetter(prefix);
      if (getter != null) {
        sw.println(String.format("return new CustomPrefixAndToken(\"%s\", "
            + "factory.%s().getToken(place));", escape(prefix),
            getter.getName()));
      } else {
        sw.println(String.format(
            "PlaceTokenizer<%s> t = GWT.create(%s.class);", placeTypeName,
            context.getTokenizerType(prefix).getQualifiedSourceName()));
        sw.println(String.format("return new CustomPrefixAndToken(\"%s\", "
            + "t.getToken((%s) place));", escape(prefix), placeTypeName));
      }

      sw.outdent();
      sw.println("}");
    }

    sw.println("return null;");
    sw.outdent();
    sw.println("}");
  }

  private void writeGetTokenizer(PlaceHistoryGeneratorContext context,
      SourceWriter sw) throws UnableToCompleteException {
    sw.println("protected PlaceTokenizer getTokenizer(String prefix) {");
    sw.indent();

    for (String prefix : context.getPrefixes()) {
      JMethod getter = context.getTokenizerGetter(prefix);

      sw.println("if (\"" + escape(prefix) + "\".equals(prefix)) {");
      sw.indent();

      if (getter != null) {
        sw.println("return factory." + getter.getName() + "();");
      } else {
        sw.println(String.format("return GWT.create(%s.class);",
            context.getTokenizerType(prefix).getQualifiedSourceName()));
      }

      sw.outdent();
      sw.println("}");
    }

    sw.println("return null;");
    sw.outdent();
    sw.println("}");
    sw.outdent();
  }

}