HttpPlaceholderMethod.java

/**
 * Copyright (c) 2009-2011 VMware, Inc. All Rights Reserved.
 *
 * 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.springsource.insight.plugin.apache.http.hc3;

import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpMethodBase;
import org.apache.commons.httpclient.StatusLine;

import com.springsource.insight.util.ArrayUtil;

/**
 * Placeholder {@link HttpMethod} implementation used in the <code>around</code>
 * advice in case a <code>null</code> value was passed in order to generate a
 * valid operation / frame anyway. <B>Note:</B> the actual method call is allowed
 * to proceed using the original (<code>null</code>) argument, and (hopefully) an
 * exception will be generated by the code (but not by our aspect) and will be
 * caught in the <code>exitAbnormal</code> collector method.
 */
final class HttpPlaceholderMethod extends HttpMethodBase {
    /**
     * The default (shared) placeholder instance used if a <code>null</code>
     * {@link HttpMethod} instance is intercepted by the <code>around</code>
     * advice
     */
    static final HttpMethod PLACEHOLDER = new HttpPlaceholderMethod();

    static final StatusLine PLACEHOLDER_STATUS;

    static {
        try {
            PLACEHOLDER_STATUS = new StatusLine("HTTP/1.1 500 Placeholder method used");
        } catch (HttpException e) {    // unexpected
            throw new RuntimeException(e);
        }
    }

    private HttpPlaceholderMethod() {
        super(HttpClientDefinitions.PLACEHOLDER_URI_VALUE);
    }

    @Override
    public String getName() {
        return HttpClientDefinitions.PLACEHOLDER_METHOD_NAME;
    }

    @Override
    public int getStatusCode() {
        StatusLine st = getStatusLine();
        return st.getStatusCode();
    }

    @Override
    public String getStatusText() {
        StatusLine st = getStatusLine();
        return st.getReasonPhrase();
    }

    @Override
    public StatusLine getStatusLine() {
        return PLACEHOLDER_STATUS;
    }

    static HttpMethod resolveHttpMethod(Object... args) {
        if (ArrayUtil.length(args) <= 0) {
            return PLACEHOLDER;
        }

        for (Object argVal : args) {
            if (argVal instanceof HttpMethod) {
                return (HttpMethod) argVal;
            }
        }

        // no match was found
        return PLACEHOLDER;
    }
}