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Tomcat example source code file (AstIdentifier.java)

This example Tomcat source code file (AstIdentifier.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

astidentifier, class, elexception, elexception, identity, methodexpression, methodexpression, methodnotfoundexception, object, object, simplenode, valueexpression, valueexpression, variablemapper

The Tomcat AstIdentifier.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
/* Generated By:JJTree: Do not edit this line. AstIdentifier.java */

package org.apache.el.parser;

import javax.el.ELException;
import javax.el.MethodExpression;
import javax.el.MethodInfo;
import javax.el.MethodNotFoundException;
import javax.el.ValueExpression;
import javax.el.VariableMapper;

import org.apache.el.lang.EvaluationContext;


/**
 * @author Jacob Hookom [jacob@hookom.net]
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: markt $
 */
public final class AstIdentifier extends SimpleNode {
    public AstIdentifier(int id) {
        super(id);
    }

    public Class getType(EvaluationContext ctx) throws ELException {
        VariableMapper varMapper = ctx.getVariableMapper();
        if (varMapper != null) {
            ValueExpression expr = varMapper.resolveVariable(this.image);
            if (expr != null) {
                return expr.getType(ctx.getELContext());
            }
        }
        ctx.setPropertyResolved(false);
        return ctx.getELResolver().getType(ctx, null, this.image);
    }

    public Object getValue(EvaluationContext ctx) throws ELException {
        VariableMapper varMapper = ctx.getVariableMapper();
        if (varMapper != null) {
            ValueExpression expr = varMapper.resolveVariable(this.image);
            if (expr != null) {
                return expr.getValue(ctx.getELContext());
            }
        }
        ctx.setPropertyResolved(false);
        return ctx.getELResolver().getValue(ctx, null, this.image);
    }

    public boolean isReadOnly(EvaluationContext ctx) throws ELException {
        VariableMapper varMapper = ctx.getVariableMapper();
        if (varMapper != null) {
            ValueExpression expr = varMapper.resolveVariable(this.image);
            if (expr != null) {
                return expr.isReadOnly(ctx.getELContext());
            }
        }
        ctx.setPropertyResolved(false);
        return ctx.getELResolver().isReadOnly(ctx, null, this.image);
    }

    public void setValue(EvaluationContext ctx, Object value)
            throws ELException {
        VariableMapper varMapper = ctx.getVariableMapper();
        if (varMapper != null) {
            ValueExpression expr = varMapper.resolveVariable(this.image);
            if (expr != null) {
                expr.setValue(ctx.getELContext(), value);
                return;
            }
        }
        ctx.setPropertyResolved(false);
        ctx.getELResolver().setValue(ctx, null, this.image, value);
    }

    private final Object invokeTarget(EvaluationContext ctx, Object target,
            Object[] paramValues) throws ELException {
        if (target instanceof MethodExpression) {
            MethodExpression me = (MethodExpression) target;
            return me.invoke(ctx.getELContext(), paramValues);
        } else if (target == null) {
            throw new MethodNotFoundException("Identity '" + this.image
                    + "' was null and was unable to invoke");
        } else {
            throw new ELException(
                    "Identity '"
                            + this.image
                            + "' does not reference a MethodExpression instance, returned type: "
                            + target.getClass().getName());
        }
    }

    public Object invoke(EvaluationContext ctx, Class[] paramTypes,
            Object[] paramValues) throws ELException {
        return this.getMethodExpression(ctx).invoke(ctx.getELContext(), paramValues);
    }
    

    public MethodInfo getMethodInfo(EvaluationContext ctx, Class[] paramTypes)
            throws ELException {
        return this.getMethodExpression(ctx).getMethodInfo(ctx.getELContext());
    }

    private final MethodExpression getMethodExpression(EvaluationContext ctx)
            throws ELException {
        Object obj = null;

        // case A: ValueExpression exists, getValue which must
        // be a MethodExpression
        VariableMapper varMapper = ctx.getVariableMapper();
        ValueExpression ve = null;
        if (varMapper != null) {
            ve = varMapper.resolveVariable(this.image);
            if (ve != null) {
                obj = ve.getValue(ctx);
            }
        }

        // case B: evaluate the identity against the ELResolver, again, must be
        // a MethodExpression to be able to invoke
        if (ve == null) {
            ctx.setPropertyResolved(false);
            obj = ctx.getELResolver().getValue(ctx, null, this.image);
        }

        // finally provide helpful hints
        if (obj instanceof MethodExpression) {
            return (MethodExpression) obj;
        } else if (obj == null) {
            throw new MethodNotFoundException("Identity '" + this.image
                    + "' was null and was unable to invoke");
        } else {
            throw new ELException(
                    "Identity '"
                            + this.image
                            + "' does not reference a MethodExpression instance, returned type: "
                            + obj.getClass().getName());
        }
    }
}

Other Tomcat examples (source code examples)

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