Java Service.getAttribute方法代码示例

import java.security.Provider.Service; //导入方法依赖的package包/类
/**
 * Returns a <code>TransformService</code> that supports the specified
 * algorithm URI (ex: {@link Transform#XPATH2}) and mechanism type
 * (ex: DOM) as supplied by the specified provider. Note that the specified
 * <code>Provider</code> object does not have to be registered in the
 * provider list.
 *
 * @param algorithm the URI of the algorithm
 * @param mechanismType the type of the XML processing mechanism and
 *   representation
 * @param provider the <code>Provider</code> object
 * @return a new <code>TransformService</code>
 * @throws NullPointerException if <code>provider</code>,
 *   <code>algorithm</code>, or <code>mechanismType</code> is
 *   <code>null</code>
 * @throws NoSuchAlgorithmException if a <code>TransformService</code>
 *   implementation for the specified algorithm and mechanism type is not
 *   available from the specified <code>Provider</code> object
 * @see Provider
 */
public static TransformService getInstance
    (String algorithm, String mechanismType, Provider provider)
    throws NoSuchAlgorithmException {
    if (mechanismType == null || algorithm == null || provider == null) {
        throw new NullPointerException();
    }

    boolean dom = false;
    if (mechanismType.equals("DOM")) {
        dom = true;
    }
    Service s = provider.getService("TransformService", algorithm);
    if (s != null) {
        String value = s.getAttribute("MechanismType");
        if ((value == null && dom) ||
            (value != null && value.equals(mechanismType))) {
            Object obj = s.newInstance(null);
            if (obj instanceof TransformService) {
                TransformService ts = (TransformService) obj;
                ts.algorithm = algorithm;
                ts.mechanism = mechanismType;
                ts.provider = provider;
                return ts;
            }
        }
    }
    throw new NoSuchAlgorithmException
        (algorithm + " algorithm and " + mechanismType
             + " mechanism not available from " + provider.getName());
}
 

import java.security.Provider.Service; //导入方法依赖的package包/类
/**
 * Returns a <code>TransformService</code> that supports the specified
 * algorithm URI (ex: {@link Transform#XPATH2}) and mechanism type
 * (ex: DOM).
 *
 * <p>This method uses the standard JCA provider lookup mechanism to
 * locate and instantiate a <code>TransformService</code> implementation
 * of the desired algorithm and <code>MechanismType</code> service
 * attribute. It traverses the list of registered security
 * <code>Provider</code>s, starting with the most preferred
 * <code>Provider</code>. A new <code>TransformService</code> object
 * from the first <code>Provider</code> that supports the specified
 * algorithm and mechanism type is returned.
 *
 * <p> Note that the list of registered providers may be retrieved via
 * the {@link Security#getProviders() Security.getProviders()} method.
 *
 * @param algorithm the URI of the algorithm
 * @param mechanismType the type of the XML processing mechanism and
 *   representation
 * @return a new <code>TransformService</code>
 * @throws NullPointerException if <code>algorithm</code> or
 *   <code>mechanismType</code> is  <code>null</code>
 * @throws NoSuchAlgorithmException if no <code>Provider</code> supports a
 *   <code>TransformService</code> implementation for the specified
 *   algorithm and mechanism type
 * @see Provider
 */
public static TransformService getInstance
    (String algorithm, String mechanismType)
    throws NoSuchAlgorithmException {
    if (mechanismType == null || algorithm == null) {
        throw new NullPointerException();
    }
    boolean dom = false;
    if (mechanismType.equals("DOM")) {
        dom = true;
    }
    List<Service> services = GetInstance.getServices("TransformService", algorithm);
    for (Iterator<Service> t = services.iterator(); t.hasNext(); ) {
        Service s = t.next();
        String value = s.getAttribute("MechanismType");
        if ((value == null && dom) ||
            (value != null && value.equals(mechanismType))) {
            Instance instance = GetInstance.getInstance(s, null);
            TransformService ts = (TransformService) instance.impl;
            ts.algorithm = algorithm;
            ts.mechanism = mechanismType;
            ts.provider = instance.provider;
            return ts;
        }
    }
    throw new NoSuchAlgorithmException
        (algorithm + " algorithm and " + mechanismType
             + " mechanism not available");
}
 

import java.security.Provider.Service; //导入方法依赖的package包/类
private static int supports(Service s, String attrName, String value) {
    if (value == null) {
        return S_YES;
    }
    String regexp = s.getAttribute(attrName);
    if (regexp == null) {
        return S_MAYBE;
    }
    return matches(regexp, value) ? S_YES : S_NO;
}