com.googlecode.pondskum.client.LinkTraverserImpl.java Source code

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Here is the source code for com.googlecode.pondskum.client.LinkTraverserImpl.java

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/*
 * Copyright 2008 Sanjiv Sahayam
 *
 * 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.googlecode.pondskum.client;

import com.googlecode.pondskum.client.listener.ConnectionListener;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.IOException;

public final class LinkTraverserImpl implements LinkTraverser {

    private final DefaultHttpClient httpClient;

    public LinkTraverserImpl(final DefaultHttpClient httpClient) {
        this.httpClient = httpClient;
    }

    public void traverse(final String url, final StageHolder stageHolder, final ConnectionListener listener)
            throws LinkTraverserException {
        try {
            listener.updateStatus(stageHolder.getState(), "Connecting to url -> " + url);
            stageHolder.nextState();
            HttpResponse response = openConnection(httpClient, url);
            listener.handleEvent(httpClient, response);
            listener.updateStatus(stageHolder.getState(), "closing connection to url -> " + url);
            closeConnection(response);
        } catch (Exception e) {
            String error = "There was an error connecting to url -> " + url;
            listener.onError(stageHolder.getState(), error, e);
            throw new LinkTraverserException(error, e);
        }
    }

    private HttpResponse openConnection(final DefaultHttpClient httpClient, final String url) throws IOException {
        HttpGet httpget = new HttpGet(url);
        return httpClient.execute(httpget);
    }

    private void closeConnection(final HttpResponse response) throws IOException {
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            entity.consumeContent();
        }
    }
}