ConfigurableNavigationHandler.java

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package javax.faces.application;

import java.util.Map;
import java.util.Set;

import javax.faces.context.FacesContext;
import javax.faces.flow.Flow;

/**
 * <p class="changed_added_2_0">
 * <strong class="changed_modified_2_2">ConfigurableNavigationHandler</strong> extends the contract
 * of {@link NavigationHandler} to allow runtime inspection of the {@link NavigationCase}s that make
 * up the rule-base for navigation. An implementation compliant with the version of the
 * specification in which this class was introduced (or a later version) must make it so that its
 * <code>NavigationHandler</code> is an extension of this class.
 * </p>
 *
 * @since 2.0
 */
public abstract class ConfigurableNavigationHandler extends NavigationHandler {

    /**
     * <p class="changed_added_2_0">
     * Return the {@link NavigationCase} representing the navigation that would be taken had
     * {@link NavigationHandler#handleNavigation} been called with the same arguments or
     * <code>null</code> if there is no such case.
     * </p>
     *
     * @param context The {@link FacesContext} for the current request
     * @param fromAction The action binding expression that was evaluated to retrieve the specified
     *            outcome, or <code>null</code> if the outcome was acquired by some other means
     * @param outcome The logical outcome returned by a previous invoked application action (which
     *            may be <code>null</code>)
     * @return the navigation case, or <code>null</code>.
     * @throws NullPointerException if <code>context</code> is <code>null</code>
     * @since 2.0
     */
    public abstract NavigationCase getNavigationCase(FacesContext context, String fromAction, String outcome);

    /**
     * <p class="changed_added_2_2">
     * Return the {@link NavigationCase} representing the navigation that would be taken had
     * {@link NavigationHandler#handleNavigation} been called with the same arguments or
     * <code>null</code> if there is no such case. Implementations that comply the version of the
     * specification in which this method was introduced must override this method. For
     * compatibility with decorated implementations that comply with an earlier version of the
     * specification, an implementation is provided that simply calls through to
     * {@link #getNavigationCase(javax.faces.context.FacesContext, java.lang.String, java.lang.String)},
     * ignoring the {@code toFlowDocumentId} parameter.
     * </p>
     * 
     * @param context The {@link FacesContext} for the current request
     * @param fromAction The action binding expression that was evaluated to retrieve the specified
     *            outcome, or <code>null</code> if the outcome was acquired by some other means
     * @param outcome The logical outcome returned by a previous invoked application action (which
     *            may be <code>null</code>)
     * @param toFlowDocumentId The value of the <code>toFlowDocumentId</code> property for the
     *            navigation case (which may be <code>null</code>)
     * @return the navigation case, or <code>null</code>.
     * @throws NullPointerException if <code>context</code> is <code>null</code>
     * @since 2.2
     */
    public NavigationCase getNavigationCase(FacesContext context, String fromAction, String outcome, String toFlowDocumentId) {
        return getNavigationCase(context, fromAction, outcome);
    }

    /**
     * <p class="changed_added_2_0">
     * Return a <code>Map<String,
     * Set<NavigationCase>></code> where the keys are <code><from-view-id></code>
     * values and the values are <code>Set<NavigationCase></code> where each element in the
     * Set is a <code>NavigationCase</code> that applies to that <code><from-view-id></code>.
     * The implementation must support live modifications to this <code>Map</code>.
     * </p>
     *
     * @return a map with navigation cases.
     * @since 2.0
     */
    public abstract Map<String, Set<NavigationCase>> getNavigationCases();

    /**
     * <p class="changed_added_2_0">
     * A convenience method to signal the JavaServer Faces implementation to perform navigation with
     * the provided outcome. When the NavigationHandler is invoked, the current viewId is treated as
     * the "from viewId" and the "from action" is null.
     * </p>
     * 
     * @param outcome the provided outcome.
     * @throws IllegalStateException if this method is called after this instance has been released
     */
    public void performNavigation(String outcome) {
        this.handleNavigation(FacesContext.getCurrentInstance(), null, outcome);
    }

    /**
     * <p class="changed_added_2_2">
     * Called by the flow system to cause the flow to be inspected for navigation rules. For
     * backward compatibility with earlier implementations, an empty method is provided.
     * </p>
     * 
     * @param context the Faces context.
     * @param flow the flow.
     * @since 2.2
     */
    public void inspectFlow(FacesContext context, Flow flow) {
    }
}