/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2006, University of Maryland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba.npe;

import javax.annotation.CheckForNull;

import edu.umd.cs.findbugs.ba.XField;
import edu.umd.cs.findbugs.ba.XMethod;
import edu.umd.cs.findbugs.ba.XMethodParameter;

/**
 * @author pugh
 */
public abstract class PointerUsageRequiringNonNullValue {

    public abstract String getDescription();

    @Override
    public String toString() {
        return getDescription();
    }

    public boolean isDirect() {
        return false;
    }

    public boolean isReturnFromNonNullMethod() {
        return false;
    }

    public @CheckForNull
    XMethodParameter getNonNullParameter() {
        return null;
    }

    public @CheckForNull
    XField getNonNullField() {
        return null;
    }

    private static final PointerUsageRequiringNonNullValue instance = new PointerUsageRequiringNonNullValue() {
        @Override
        public boolean isDirect() {
            return true;
        }

        @Override
        public String getDescription() {
            return "SOURCE_LINE_DEREF";
        }
    };

    private static final PointerUsageRequiringNonNullValue nonNullReturnInstance = new PointerUsageRequiringNonNullValue() {
        @Override
        public boolean isReturnFromNonNullMethod() {
            return true;
        }

        @Override
        public String getDescription() {
            return "SOURCE_LINE_RETURNED";
        }
    };

    public static PointerUsageRequiringNonNullValue getPointerDereference() {
        return instance;
    }

    private static final PointerUsageRequiringNonNullValue nullCheckInstance = new PointerUsageRequiringNonNullValue() {

        @Override
        public String getDescription() {
            return "SOURCE_LINE_NULL_CHECKED";
        }
    };

    public static PointerUsageRequiringNonNullValue getPointerNullChecked() {
        return nullCheckInstance;
    }

    public static PointerUsageRequiringNonNullValue getReturnFromNonNullMethod(XMethod m) {
        return nonNullReturnInstance;
    }

    public static PointerUsageRequiringNonNullValue getPassedAsNonNullParameter(final XMethod m, final int param) {
        return new PointerUsageRequiringNonNullValue() {
            @Override
            public @CheckForNull
            XMethodParameter getNonNullParameter() {
                return new XMethodParameter(m, param);
            }

            @Override
            public String getDescription() {
                return "SOURCE_LINE_INVOKED";
            }

        };
    }

    public static PointerUsageRequiringNonNullValue getStoredIntoNonNullField(final XField f) {
        return new PointerUsageRequiringNonNullValue() {
            @Override
            public @CheckForNull
            XField getNonNullField() {
                return f;
            }

            @Override
            public String getDescription() {
                return "SOURCE_LINE_STORED";
            }

        };
    }
}
