org.eclipse.mylyn.internal.java.ui.editor.FocusedJavaProposalProcessor.java Source code

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/*******************************************************************************
 * Copyright (c) 2004, 2009 Tasktop Technologies and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Tasktop Technologies - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylyn.internal.java.ui.editor;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.internal.ui.text.java.AbstractJavaCompletionProposal;
import org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposal;
import org.eclipse.jdt.ui.text.java.IJavaCompletionProposalComputer;
import org.eclipse.mylyn.commons.core.StatusHandler;
import org.eclipse.mylyn.commons.ui.CommonImages;
import org.eclipse.mylyn.context.core.ContextCore;
import org.eclipse.mylyn.context.core.IInteractionElement;
import org.eclipse.mylyn.internal.java.ui.JavaUiBridgePlugin;

/**
 * TODO: parametrize relevance levels (requires JDT changes, bug 119063)
 * 
 * @author Mik Kersten
 */
public class FocusedJavaProposalProcessor {

    /**
     * Range above which elements are part of the context.
     */
    private static final int THRESHOLD_INTEREST = 10000;

    /**
     * Range for implicitly interesting element, such as method parameters.
     */
    private static final int THRESHOLD_IMPLICIT_INTEREST = THRESHOLD_INTEREST * 2;

    /**
     * Threshold for determining which JDT proposals should be implicitly interesting.
     */
    private static final int RELEVANCE_IMPLICIT_INTEREST_JAVA = 600;

    /**
     * Threshold for implicit interest of IJavaElement proposals.
     */
    private static final int RELEVANCE_IMPLICIT_INTEREST_MISC = 300;

    private static final String IDENTIFIER_THIS = "this"; //$NON-NLS-1$

    public static final String LABEL_SEPARATOR = " -------------------------------------------- "; //$NON-NLS-1$

    public static final FocusedProposalSeparator PROPOSAL_SEPARATOR = new FocusedProposalSeparator();

    private final List<IJavaCompletionProposalComputer> monitoredProposalComputers = new ArrayList<IJavaCompletionProposalComputer>();

    private final List<IJavaCompletionProposalComputer> alreadyComputedProposals = new ArrayList<IJavaCompletionProposalComputer>();

    private final List<IJavaCompletionProposalComputer> alreadyContainSeparator = new ArrayList<IJavaCompletionProposalComputer>();

    private final List<IJavaCompletionProposalComputer> containsSingleInterestingProposal = new ArrayList<IJavaCompletionProposalComputer>();

    private static FocusedJavaProposalProcessor INSTANCE = new FocusedJavaProposalProcessor();

    private FocusedJavaProposalProcessor() {
    }

    public static FocusedJavaProposalProcessor getDefault() {
        return INSTANCE;
    }

    public void addMonitoredComputer(IJavaCompletionProposalComputer proposalComputer) {
        monitoredProposalComputers.add(proposalComputer);
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public List projectInterestModel(IJavaCompletionProposalComputer proposalComputer, List proposals) {
        try {
            if (!ContextCore.getContextManager().isContextActive()) {
                return proposals;
            } else {
                boolean hasInterestingProposals = false;
                for (Object object : proposals) {
                    if (object instanceof AbstractJavaCompletionProposal) {
                        boolean foundInteresting = boostRelevanceWithInterest(
                                (AbstractJavaCompletionProposal) object);
                        if (!hasInterestingProposals && foundInteresting) {
                            hasInterestingProposals = true;
                        }
                    }
                }

                // NOTE: this annoying state needs to be maintainted to ensure
                // the
                // separator is added only once, and not added for single
                // proposals
                if (containsSingleInterestingProposal.size() > 0 && proposals.size() > 0) {
                    proposals.add(FocusedJavaProposalProcessor.PROPOSAL_SEPARATOR);
                } else if (hasInterestingProposals && alreadyContainSeparator.isEmpty()) {
                    if (proposals.size() == 1) {
                        containsSingleInterestingProposal.add(proposalComputer);
                    } else {
                        proposals.add(FocusedJavaProposalProcessor.PROPOSAL_SEPARATOR);
                        alreadyContainSeparator.add(proposalComputer);
                    }
                }

                alreadyComputedProposals.add(proposalComputer);
                if (alreadyComputedProposals.size() == monitoredProposalComputers.size()) {
                    alreadyComputedProposals.clear();
                    alreadyContainSeparator.clear();
                    containsSingleInterestingProposal.clear();
                }

                return proposals;
            }
        } catch (Throwable t) {
            StatusHandler.log(new Status(IStatus.ERROR, JavaUiBridgePlugin.ID_PLUGIN,
                    "Failed to project interest onto propsals", t)); //$NON-NLS-1$
            return proposals;
        }
    }

    private boolean boostRelevanceWithInterest(AbstractJavaCompletionProposal proposal) {
        boolean hasInteresting = false;
        IJavaElement javaElement = proposal.getJavaElement();
        if (javaElement != null) {
            IInteractionElement interactionElement = ContextCore.getContextManager()
                    .getElement(javaElement.getHandleIdentifier());
            float interest = interactionElement.getInterest().getValue();
            if (interest > ContextCore.getCommonContextScaling().getInteresting()) {
                // TODO: losing precision here, only going to one decimal place
                proposal.setRelevance(THRESHOLD_INTEREST + (int) (interest * 10));
                hasInteresting = true;
            } else if (proposal.getRelevance() > RELEVANCE_IMPLICIT_INTEREST_JAVA) {
                proposal.setRelevance(THRESHOLD_IMPLICIT_INTEREST + proposal.getRelevance());
            }
        } else if (isImplicitlyInteresting(proposal)) {
            proposal.setRelevance(THRESHOLD_IMPLICIT_INTEREST + proposal.getRelevance());
            hasInteresting = true;
        }
        return hasInteresting;
    }

    public boolean isImplicitlyInteresting(AbstractJavaCompletionProposal proposal) {
        return proposal.getRelevance() > RELEVANCE_IMPLICIT_INTEREST_MISC
                && !IDENTIFIER_THIS.equals(proposal.getDisplayString());
    }

    static class FocusedProposalSeparator extends JavaCompletionProposal {
        public FocusedProposalSeparator() {
            super("", 0, 0, CommonImages.getImage(CommonImages.SEPARATOR_LIST), LABEL_SEPARATOR, //$NON-NLS-1$
                    FocusedJavaProposalProcessor.THRESHOLD_INTEREST);
        }
    }
}