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Java example source code file (ServletSpiVisitor.java)

This example Java source code file (ServletSpiVisitor.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

assertionfailederror, defaultbindingtargetvisitor, http, integer, list, log, map, object, override, params, request, response, servlet, servletmoduletargetvisitor, servletspivisitor, set, string, uripatterntype, util

The ServletSpiVisitor.java Java example source code

/**
 * Copyright (C) 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.inject.servlet;

import com.google.common.base.MoreObjects;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.Stage;
import com.google.inject.spi.DefaultBindingTargetVisitor;

import junit.framework.AssertionFailedError;

import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Logger;

import javax.servlet.Filter;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * A visitor for testing the servlet SPI extension.
 *
 * @author sameb@google.com (Sam Berlin)
 */
class ServletSpiVisitor
    extends DefaultBindingTargetVisitor<Object, Integer>
    implements ServletModuleTargetVisitor<Object, Integer> {

  int otherCount = 0;
  int currentCount = 0;
  List<Params> actual = Lists.newArrayList();

  /* The set of classes that are allowed to be "other" bindings. */
  Set<Class> allowedClasses;

  ServletSpiVisitor(boolean forInjector) {
    ImmutableSet.Builder<Class> builder = ImmutableSet.builder();
    // always ignore these things...
    builder.add(ServletRequest.class,
        ServletResponse.class, ManagedFilterPipeline.class, ManagedServletPipeline.class,
        FilterPipeline.class, ServletContext.class, HttpServletRequest.class, Filter.class,
        HttpServletResponse.class, HttpSession.class, Map.class, HttpServlet.class,
        InternalServletModule.BackwardsCompatibleServletContextProvider.class,
        GuiceFilter.class);
    if(forInjector) {
      // only ignore these if this is for the live injector, any other time it'd be an error!
      builder.add(Injector.class, Stage.class, Logger.class);
    }
    this.allowedClasses = builder.build();
  }

  public Integer visit(InstanceFilterBinding binding) {
    actual.add(new Params(binding, binding.getFilterInstance()));
    return currentCount++;
  }

  public Integer visit(InstanceServletBinding binding) {
    actual.add(new Params(binding, binding.getServletInstance()));
    return currentCount++;
  }

  public Integer visit(LinkedFilterBinding binding) {
    actual.add(new Params(binding, binding.getLinkedKey()));
    return currentCount++;
  }

  public Integer visit(LinkedServletBinding binding) {
    actual.add(new Params(binding, binding.getLinkedKey()));
    return currentCount++;
  }

  @Override
  protected Integer visitOther(Binding<? extends Object> binding) {
    if(!allowedClasses.contains(binding.getKey().getTypeLiteral().getRawType())) {
      throw new AssertionFailedError("invalid other binding: " + binding);
    }
    otherCount++;
    return currentCount++;
  }

  static class Params {
    private final String pattern;
    private final Object keyOrInstance;
    private final Map<String, String> params;
    private final UriPatternType patternType;

    Params(ServletModuleBinding binding, Object keyOrInstance) {
      this.pattern = binding.getPattern();
      this.keyOrInstance = keyOrInstance;
      this.params = binding.getInitParams();
      this.patternType = binding.getUriPatternType();
    }

    Params(String pattern, Object keyOrInstance, Map params, UriPatternType patternType) {
      this.pattern = pattern;
      this.keyOrInstance = keyOrInstance;
      this.params = params;
      this.patternType = patternType;
    }

    @Override
    public boolean equals(Object obj) {
      if(obj instanceof Params) {
        Params o = (Params)obj;
        return Objects.equal(pattern, o.pattern)
            && Objects.equal(keyOrInstance, o.keyOrInstance)
            && Objects.equal(params, o.params)
            && Objects.equal(patternType, o.patternType);
      } else {
        return false;
      }
    }

    @Override
    public int hashCode() {
      return Objects.hashCode(pattern, keyOrInstance, params, patternType);
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper(Params.class)
        .add("pattern", pattern)
        .add("keyOrInstance", keyOrInstance)
        .add("initParams", params)
        .add("patternType", patternType)
        .toString();
    }
  }
}

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